Miniature Racing Yachts and How to Build Them by Thomas Darling – 1936

PUBLISHERS’ NOTE Miniature Racine. Yacuts, by Thomas Darling, is fully illustrated by drawings and plans. The sport of racing model yachts is much more widespread than is generally realized. Many cities have their clubs where serious racing is indulged in, and there are frequent international races between a number of different countries, includin g England, France, Spain, Holland, and the United States. In addition to the real experts—who build their own boats—there are many manual training courses throughout the country where an increasing number of boys are being taught how to build model yachts. The author of this book has not only had a wide experience in naval engineering and construction but has also been a teacher of manual training, with the result that he has been able to write a book which will be of equal use both to the novice and to the expert. Starting with simple types and going on to those more advanced many plans are reproduced and instructions given so that in the end the attentive reader should be able not only to build but also design his own model yacht. MINIATURE RACING YACHTS AND HOW TO BUILD THEM By THOMAS DARLING WITH OVER ONE HUNDRED AND LINES AND OFFSETS, CHARLES FIFTY DIAGRAMS, SETS OF DESIGNED PHOTOGRAPHS, AND TABLE GRAPHS SCRIBNER’S SONS CHARLES SCRIBNER’S SONS: 1936 : NEW YORK LTD + LONDON f 4 ale ee ‘Printed in the United States of America rise All rights reserved. No part of this book may be reproduced in any form without the permission of Charles Scribner’s Sons A CONTENTS CHAPTER Ls PAGE TYPES OF CRAFT AND VII. OMMEND THEM FOR USE Il. BUILDING A HULL VIII. BY THE SOLID IX. BUILDING A HULL BY THE LIFT OR BREADAND-BUTTER IV. BUILDING A METHOD HULL OF BY THE CONSTRUCTION RIB-FRAME HOW TO MAKE FIN KEELS AND CAST BALLAST SPAR MAKING X. 25 XI. AND PLANK METHOD OF CONSTRUC TION VI. HOW TO MAKE FITTINGS 57 STEERING GEARS 61 BLOCK METHOD TIT. CHAPTER PAGE FEATURES THAT REC- SAIL MAKING RIGGING HOW TO 68 DESIGN AND CALCULATE A MINIA- TURE YACHT 74 30 XII. 49 53 XIII. RATING RULES HOW TO YACHT TUNE-UP 102 AND SAIL A MINIATURE FOREWORD Naval architecture and construction is not an exact science, rather is it an art. Scientists and mathematicians have given us enough information, data and formule to assure us of certain definite results. When all is said and done, however , the outcome of the success of a design, or of a piece of construction in work of this nature, is a gamble. It is this feature of the sport, or pastime, which tends to attract and hold the interest of many devotees. As a pastime, this activity offers fascinating work on the drawing-board or miniature mould-loft floor; the actual building; and the final sailing with its attendant satisfaction at the successful performance of the finished boat. It proves to be an instructive, healthful and pleasant way of passing happy hours with fellow enthusiasts. The sport is orderly and well organized. The Model Yacht Racing Association of America, a national agency, is organized for the purpose of creating an interest in miniature yacht building, and racing; and concerns itself with arrangi ng races between a representative of the United States of America and representatives of foreign countries, including Great Britain, France, Germany, Belgium, Denmark, and Sweden. Model yacht clubs are springing up all over the country. We find them in New York, Boston, Providence, Marble- head, Washington, New Orleans, Jacksonville, Los Angeles, San Francisco, Seattle, Chicago, Detroit, and other localities. With the above facts before us it seems reasonable to suppose that a book such as this will prove useful. The author hopes that its contents will be of help to the person desiring to sail miniatures for the pure fun of seeing them in their element, to the racing-model yachtsman, and to the teacher of mechanic arts. The author desires to gratefully acknowledge his indebtedness to: Mr. Herbert L. Stone, editor of Yachting, for his encour aging attitude and permission to use material published in that magazine. The Stanley Rule and Level Plant for permission to include material designed by the author and owned by the concern. Other persons and business houses mentioned throughout the book as consenting to the inclusion of plans, drawings, illustrations, tables, and photographs. My wife, for her patience and co-operation while this work has been going forward. Tuomas Dar.ina. feet in length, are one-sixth or onefourth their length in width, and are about 2 feet deep amid ships. They are flat-bottome d and the sides are straight, spla yed. The bottom is rockered, or has a sweep, as shown in the draw ing. because of this simple form. They are easy to build The centerboard can be replaced by a ballasted fin keel and a balanced rudder can be fitted for miniature work. The two masts are stepped in the positions shown and have no stays. The two leg-o’-mutton sails are loose-footed, and are spread on the foot by a sprit, held in plac e, at the mast, by a “‘snotte r.” The rig is simplicity itself. Sharpies were originally work boats used in the oyster busi – ness about New Haven, Conn ., and on the waters of Long Island Ficure 1. Sharpie CHAPTER I TYPES OF CRAFT AND FEATURES THAT RECOMMEND THEM FOR USE haat boat builders and designers have developed dis- tinctive types of boats. It will prove profitable for us to know something about most comm on and accepted models, their rigs, and the reasons for their proving so efficient. Particularly is this true should we desire to build models or miniatures for data to be applied in the designing and building Let us attempt to study them in the order of of large boats. their appearance on activity. the scene of the American boatman’s Figure 1 shows a “sharpie.” These boats are simple in form, being long, narrow, and sharp. They run from about 30 to 40 Ficure 2. Typical Rig of a Grand Banks Fishi ng Schooner Sound. They are believed to have originated in the Chesapeake Bay region. This type of craft is very fast and makes an admir- able model for pleasure sailing, and one-design class racing. ee ry ao) Figure 3. Cape Cod Catboat be housed or lowered in very stormy weather, or sent down during the period of the winter fishing. Spars are heavier in this kind of boat than those fitted to our pleasure schooner yachts. oe ee a Ficure 4. a, Sail Plan, Racing Catboat Figure 2 represents the typical rig of a Grand Banks fishing The number and variety of sails offer opportunity for the boat schooner. This type of fisherman has been developed by the col- owner to try various combinations when his craft is in action laboration of the practical seamen using them and some of our and to shorten down easily when it is blowing hard. famous yacht designers, located ‘‘Down East.’”’ The reader will are generally inside ballasted, but an outside shoe can be fitted Fishermen observe that they have a ‘“‘double”’ mast, that is, a lower mast to the keel for the model yachtsman’s convenience. and a topmast. of this style of rig are common to our New England fishing ports, 2 The masts are so made that the topmast can Schooners i Ficure 5. Ficure 6. Staysail-rigged Schooner Yacht Jib-headed Yawl Rig and to those of Canada. They are extremely able and very fast, been built with the beam half the over all length. and present an inspiring picture when under way with all sail set. of the catboat is very simple, consisting of one sail, set on a mast, Figure 3 shows the appearance of a catboat, a type commonly stepped in the eyes of the boat, and spread by a boom and gaff. associated with Cape Cod. These boats were originally used in this region for fishing and other waterside activities. They are The sail plan Yachtsmen find them handy and comfortable for cruising, racing, and afternoon sailing. A person interested in sailing wonderful sea boats, considering their shoal draft, and have miniatures can derive much pleasure from a craft of this type more room for a given length than any other type of boat. Their as they will sail well when properly balanced and handled. The initial stability is great, but they are sometimes inside bal- simple rig will prove attractive to some owners. lasted or have a lead shoe fitted to the keel. Their several modSome have els have been developed to meet local conditions. Figure 4 shows the sail plan and appearance of a modern racing catboat. These boats have been developed primarily for 3 square-riggers and clipper ships. This form should appeal to lovers of the schooner rig, as it is efficient, fast, and the sails are easily trimmed. The modern jib-headed yawl rig is shown in Figure 6. The mainmast is stepped where that of a sloop would be and the mizzen is located aft of the stern post of the yacht. The mizzen is sheeted to a boomkin, or outrigger. This rig is simplified for small boats by one headsail, or jib, being fitted—the forestay running high on the mast. A yawl rig is next to that of the sloop for speed. = Racing rules recognize this by rating boats rigged as yawls at 93 per cent of their figured rating. In some localities the mizzen is known as a “‘jigger.” It is practically —_ Ficure 7. Jib-headed Ketch Rig speed. They are remarkably fast and able and offer wonderful sport, both for racing and afternoon sailing. Boats of this type are generally fitted with a jib-headed or leg-o’-mutton sail. Sometimes a short gaff is used at the head. The best examples of this type are found on Barnegat Bay. Figure 5 gives us the appearance of a modern staysail-rigged schooner yacht. The masts are stepped in relatively the same positions as were those in the old gaff-rigged schooners. The usual forestaysail and jib are present with a leg-o’-mutton or jib-headed mainsail. The foot of the lower mainstaysail is spread by a boom with the upper mainstaysail or topmast staysail running on a track secured to the after side of the foremast and with the head set flying. No sheet is needed, as the sail is trimmed at the lower corner or clew. This staysail feature is simply an adaptation to modern usage of staysails as used on 4 ———— pa! —e Ficure 8. Inland Lakes Racing Scow — Aa Ficure 9. oh eee Gaff-rigged Sloop or Cutter Ficure 10. useless when on the wind, being good for work when shortened down, or as a riding sail only. The modern or jib-headed ketch rig is depicted in Figure 7. The sails are differently proportioned from those seen in the yawl rig. The mizzen being larger in proportion to the size of the mainsail, it is more efficient when sailing close-hauled. It is rapidly gaining favor with yachtsmen in large boats, because of the ease with which it can be handled when reducing sail. This rig differs from that of the yawl, too, in that the mizzenmast is Knockabout Sloop Rig stepped forward of the stern post of the boat. The stepping of the mast forward of the stern post is the most distinctive feature of the ketch rig as distinguished from that of the yawl. Figure 8 shows the above-water appearance of an Inland Lakes racing scow, a type of racing machine which has been in use for many years on the lakes of Minnesota and Wisconsin. The scow is a favorite craft on Lake St. Louis, Canada. A very live class of these boats can also be seen on Barnegat Bay, where they threaten to outdo the sneak box in popularity. The typical dimensions of this type of boat are: length over all, 28 feet, with a maximum beam of 6 feet 9 inches. area is 285 square feet. The sail These boats have two bilge boards and two rudders, which can be replaced by a fin keel, on center line, and one rudder for model work. The distribution of ballast is very important in this type as they are very sensitive as to balance. Their initial stability is good. Scows offer a very fertile field for experimentation with balance. The scow is very fast, some of them attaining speeds of from 14 to 17 miles per hour. Off the wind is their best point of sailing, and they will actually plane. Scow hulls are easily shaped, and their rig is simple, consisting of jib and mainsail. In these boats is seen the embryo of the Reliance and of Shamrock IV, the famous America’s Cup boats. The gaft-rigged sloop, or cutter, is seen in Figure 9. This rig is generally termed “sloop” in America, the term ‘“‘cutter”’ being very seldom used in describing it. The sails are known as: 7, jib topsail; 2, jib; 3, forestaysail; 4, mainsail; 5, club topsail. A smaller topsail, known as a working topsail, without clubs, is set from the masthead to the end of the gaff when less sail is required. The spars are named as follows: 4, bowsprit; B, pole mast; C, boom; D, gaff; E, clubs. The separate “lower mast” and “‘topmast”’ arrangement of mast is obsolete. Cruising model sloops have the blocks and the gear (running rigging and standing rigging) as found on full-sized craft. Rac- ing models have their rigging cut down to just those stays, halyards, and sheets required to work them efficiently. Until recently this rig was the most popular with our minia- ture racing yachtsmen. It is now being displaced by the jib and mainsail rigged knockabout sloop rig. Figure to illustrates the up-to-date knockabout sloop rig. It is high and narrow, or short fore and aft, being all inboard. No bowsprit is employed. ‘This method of rigging a sloop is simple, efficient, and the fastest yet discovered. It is superior for windward work, the sail keeping its shape better, due to the elimina- tion of the gaff. Yachtsmen have found it to work well on any point of sailing, when fitted to a properly designed hull. The standing and running rigging can be reduced to a minimum, as the mast is easily stayed, and few halyards aré required to hoist the sails. Jib-headed or leg-o’-mutton sails were first used in Bermuda and on Chesapeake Bay, and the idea seems to have spread from these regions. The jib-headed sloop rig has become common to the Atlantic coast, the Pacific coast, and the Great Lakes, for both racing and cruising boats. There are many good arguments for its use for both purposes. It is the ideal rig for a miniature boat, and is the one chiefly employed on all the M. Y. R. A. boats. Now that we have seen the variety of rigs and briefly discussed their advantages and attractive features, the prospective buyer, or builder, is at liberty to choose the one best suited to his purpose, be it for racing or cruising. If it is necessary for the sailor to row when following his boat, he should not build too large a model, as the labor will prove arduous. An outboard motor attachment will prove a great factor in overcoming this objection to a large boat. Where a run-around pond is handy, a craft of any size can be easily handled. The plans necessary to the successful building of the boats shown in this book are (1) the hull plan (consisting of the sheer plan, half-breadth plan, and body plan), (2) the spar and sail plan, and (3) the fittings plan. Before attempting the actual construction study the plans carefully, note where the sheer line C, the load water line, the keel line, and the top of the lead line are to be found on the sheer plan. These lines are all very important. Be sure you under- stand the layout of the body plan, and the location of each sta- tion or section before proceeding, as these shapes determine the 36-inch Boats Racing at Crystal Lake, Leonia, N. J. CHAPTER II BUILDING A HULL BY THE SOLID BLOCK METHOD y far the greatest number of miniature sailing boats are built by the “solid block” or ‘“carved-out” method. The necessary size block may be of one piece, or it may be of three or four members, glued together. Instructions for building with both one-piece blocks and multiple blocks will be set forth in this chapter. first. We will consider the one-piece block 36-inch Fin Keel Sloops Close Hauled in a Tryout on Conservatory Lake, Central Park, New York City contour of the finished boat, when properly and accurately located on the keel line. Locate the sheer line, the load water line, and the keel line in this view of the boat. In justice to the designer, these points should be very carefully and painstakingly handled. If this is kept in mind your product should be satis- factory in appearance and performance. Look at the half-breadth plan and note where the sheer line, the load water line, and the shape of the bottom of the ballast are to be found. Compare the three plans or views of the hull, noting the rela- tion of the lines and how they are developed. Refer to these three views constantly when laying off with the table of offsets and when picking up the shapes for the templates. For the sake of simplicity, let us consider that the keel line runs from the Brit or MatTertAL—LumMBER—36-INCH SLOOP Number of Item Name of Part Hull Block Hull Spars Spars Deck Mast Boom Hull Spars Cradle Cradle Mould Mould as our first example. These are the plans of a 36-inch fin-keel that will give good sport to its owner for many a day. The material required to build this boat is listed in Figure 12. Obtain the right size block for the hull, and dress the faces and the edges straight, smooth, and square with the plane. Mark, for recognition, the first face dressed as the working face and mark the first edge dressed as the working edge. block “bow” and “stern.” Label each end of Gauge a center line from bow to stern on both faces, and on bow and stern ends. Gauge a sec- ond line to represent the load water line, working down from the top or working face. This line is 234 inches from the top face. Carry this line around the block on the two edges and the two ends, and mark it L. W. L. The steps that we are now considering are all shown in Figure 14. Before we can proceed further it will be necessary for us to refer to Figure 13, the offset table for 36-inch Racing Sloop No. 1, and to learn how to use it. Let us consider the load water line as the base line, along which all “stations” are to be located 8 2 Club I ee BU I I I 1g” wy” 38″ Bottom 2 Bl Top 2 Bi 2 Ballast Deck beam 2 I 36″ RB” 134″ wy” Width Length 814” 36” 84″ yy” 38″ 38” 46” 24″ SY 12! 1%” 34″ a” RB 134″ 1%” 8” ta” gu” 4 me 10” Note. White pine used for hull block, deck beams, deck, mast, boom, club, and ballast mould. Whitewood may be used for deck. Mahogany, oak, white pine or whitewood may be used for cradle parts. Brit or MatertAL—HarpwarRE—36-INCH SLOOP stem head 4 to the knuckle of the transom B, using Figure 11 racing knockabout sloop, which is simple to build and is a craft Thickness I Deck beam Upright Cradle Pieces Name of Part Description Quantity Screws Screws Screws Screws Screws Nuts Nuts Wire Wire Rod Brass, machine, 1/’-—2-56 Brass, machine, 14’’—2-56 Brass, wood, flathead 1%4’-—No. 2 Brass, wood, flathead 114’’—No. 10 Brass, wood, roundhead 4’’—No. 2 Brass, hexagon, No. 2-56 Brass, hexagon, No. 3-48 Brass stock No. 37 Galvanized iron, No. 22 Brass, 33,” diameter Tubing Paint Paint Varnish Lead Lead Brass, seamless, ;3;’’ O.D. For topsides For underbody Spar White Plumbers half and half Rod Rod Sheet Tubing Note. Brass, 34’’ diameter Brass No. 18 Brass, 3g’ thick Brass, seamless, %4’’ O.D. 1% yards of Lonsdale cambric required for jib and mainsail. fish line required for sheets. FIGuRE 12 12 2 I gross 2 18 12 2 18” 120″ 1%” 4″ 6” atx 1a” 6” wr ¥% pint ¥% pint \% pint \% pound 4 pounds 6 feet of cutty-hunk SHEER PLAN Ld mn . | | é Bopy PLAN. So t 6 A q ; ” XK EE 2 4 “al ‘ga acm UA es/ | wt.: aA is Ledd rior Length over all, 36 inches Length on water 36-inch Racing Sloop Yacht line, 2534 inches Beam, extreme, 8 inches Draught, 834 inches HALF BREADTH PLAN <9. ce. fun. Sail Plan, 36-inch Racing Sloop Yach Ly sl SMS BRNO #777 COMWe 4 FIGURE II ye ate ee2r AS Grarn a oat Da ail aa | s toee eee ne\ neEa Tide 2 ewe ; Flitas i agen ar pope te ee Pf Wi cASa FT od Scfd taleoe aTT —— r p o i a | and from which we will lay off all “heights.” that the forward overhang is 5z%@ inches. The table tells us Therefore we are to measure back from the bow end this distance, and we obta in the forward perpendicular, or “F. P.” jn the table. Laying off 25% inches, the load water line length, we obtain the after perpendicular, or “A. P.” in the table . Divide the L. W. L. into six equal spaces and we obtain stati ons 2, 3, 4, 5, 6. Now locate stations 14 and 714 by dividing the forward and after overhangs into two equal spaces. Check the marks to make sure that all the stations are spaced 414 inches apart between stations Nos. Make each point plainly, and mark it with a circle so ations line LWit. wiherght bd a” fee / Transom [& TaBLe [#% SE IncH fi 2 Racing Szoop 3 2lofalals [si |2lalo No. 2j2}7 No.2 1 l olala 212191312] a 2 2] ol of o] slalslol ut | gl2liols Jj2l2lalsi2i3i3al3 Siolslol2zis[7ololsl sy A31213} 0] /1313}ol Zl ofol4lo Q| 3} 3lolalels | A 3}ol2}o AISI AZ al3 olofs}.3/ 2} s}al vf, U3) 2lolslols salalo stlalololslslolal 2l2j2l2i3i3 310/01 ol2l ofl 5] 2/01 sf ol | o ol sts ]3! N2i2lol2tololalslolslolo 2 sropatatiolotolilalofololtolal a2] | Ba2tlololst-lolol «|, lalslol slolalslolal ol lol,| fala Aloo slalolel ofalslalolslolalo an F i S My oy 3 ~ ea Nexre Sretions Spoced 44" apart from /to 7 Weterlines x 1" apart Bettecks u LE" aport Overheng forward) ox" Cverhang (ft) §" Qsck thickness 4" Naw Yark Cyt a/izae Figure 13 Io No. / xs]. of+ T2[2[ofola] sola] sJalo NMo2 l\Wateriine No.3 46 breadth HHock | o Net H2 lo 4113 os 27 ¢ i Saag bLiwie | Ficure 14 OFFSET "dew, e i | 1 and 7. Z 7 L.Wwek L - _ [7sf that the right spots can be easily disti nguished. Using the tri- square and a sharp pencil, mark these stations on each face and each edge, numbering them plain ly, as shown in Figure 14. Label the center line, too. Mark station No. 8 at the stern. Find “sheer heights” in the table and lay off the points for the sheer line, using a pair of wing-div iders. The dividers are set to the proper measurements on the rule. Note that the heights and all other dimensions quarters and sixteenths. are given in Set the this dividers to table, 234 as inches, inches, the height of stationo. Place one point of the dividers on the L. W.L. and locate the stem head mark. Circle the mark. Now set the dividers for station No. 1, which will be 23%; inches, and proceeding as for station No. o, obtain and mark this station height. Proceed in the same way for stat ions Nos. 2, 3, 4, 5, 6, 7, 7%, and 8. Locate the knuckle of the transom by measuring from the A. P. 44%; inches along L. W. L. and up 1% inches. Mark the points for the sheer line on each edge before the setting of the dividers is changed for the next stat ion height. The same method of procedure is to be followed when laying off the points on the stations for the shape of the keel and the sheer half-breadth lines. When all the points have been obta ined and properly marked for recognition, the block will appear as shown in Figure 14. Procure a smooth batten or spline 7% inch x 33; inch x 40 inches Fi z= peaik la aete eal pe lh - > sie sage ww ZH 7S tern L.wt Ficure 15 Ficure 16 in size and secure it at each point with small brads. Mark the finishing mark. After removing all the waste wood the block will half-breadth shape, making sure the batten is fair before pen- appear as shown in Figure 16. cilling the line. leave enough waste wood so that, as the final modelling is going Follow the same steps in marking the sheer line and the keel line. The block will now appear as illustrated in Figure 15, and is ready to be shaped. a No. 4 auger bit. Bore a %-inch hole at this point, using When boring this hole keep the bit at right angles to the face of the hull block. forward, you will not undercut the outline marks. Notice the piece of stock secured to the hull block to enable the worker to Before shaping out, measure 34 inch aft of station No. 6 and locate the rudder port. When roughing out to the shape Saw cut to the marks by means of the bandsaw, if you have one handy, or use the crosscut and the rip handsaws to accomplish the rough shaping. If hold his stock in the vise while modelling. This piece of stock is a block 134 inches x 134 inches x 6 inches fastened with two 24-inch No. to flathead wood screws. Replace the center lines which have been cut off. It is now time to make the templates of the stations or the body sections. Obtain a sheet of transparent paper large enough the handsaws are used a drawing-knife can be employed to re- to extend beyond the lines of the body plan. move the waste wood, and will enable one to shape closer to the B, C, D, with reference to the center line of the plan, as shown Place the paper 4, II in 7, Figure 17. ‘Trace stations 1, 2, 3, and 4 in the fore body, making sure to mark carefully the sheer line, the L. W. L., and the keel line at each station. tion. Number each station for recogni- Repeat these operations for the after body, placing the ani edge of paper C, D on the center line of the body plan. Number stations 5, 6, 7, and 8, locating and marking the sheer line, the L. W. L., and the keel line on each of the station outlines. Pen- cil the lines on each side of the sheet ready to transfer. Using heavy cardboard for template material, transfer the es el o TT outlines of the stations, leaving a horn or hook at the sheer line on each station template, as shown at 4 in 7, Figure 18. Cut the shape By of the section, with a sharp knife, and fair it with very fine sandpaper. Follow this method for all of the templates, making certain that you locate and mark the L. W. L. and the center line and the keel line on each one. X 7 on [| f 16 Number each tem- View z, Figure 18, shows a completed template for station No. 4, with all the required markings. Place the hull block in the bench vise and, using the drawing- knife, remove the arris marked X in Figure 16, cutting to an approximate section at station No. 4. Extend this cut fore and aft, being careful to leave enough wood for the required shape. Lt; owe ie 219 16 5 { to plate plainly. The block will now present the appearance shown in Figure 19, the arris being removed from bow to stern. Test with each station template constantly while performing this operation. Take inside and outside 14-inch gouges and with them groove from the sheer line to the keel line, until template No. 4 fits the block accurately. Coloring the edge of the template, which is to fit the block, with a black or blue crayon will help to show ir- regularities quickly and plainly. The color will come off on the high spots, and readily show where more cutting is necessary for – eg a proper fit. FicurE 17 12 The hooks on the template will catch at the sheer line, and when the center line of the template corresponds to the center line gauged on the hull block, the section should be fin- ished and shaped truly. Use this method of shaping the sections Station Nod Oration No.9 Figure 18 FiGuRE Ig 13 woo ang Ware f Ly zy TFT wT a ’ Ly 4 eo 24%” 14 mal: deale -4 = LEIS TES Sneen PLan r) F iimeak —— —————————————— iia Fa rire ——— de ———Sor SYS vane igs ial oe lD, ein aur recog tte fw are reduced to Ei a =e» ab yy ee kts Booy PLAN a 7 Here A : 12 1, HALF BREADTH PLAN | a —p————____| oo ee oe ire aN ny, 3 x 1 FIGURE 20 at stations 3, 2, and 1 in the fore body, and stations 5, 6, 7, and 8 Using the drawing-knife, cut down as close to the section in the after body. The hull block will now show a groove at each shapes as possible, removing all the waste wood and fairing the station, as shown by the broken lines in Figure 19. hull to shape. Now use the spokeshave and the block plane and Remove the waste wood between the stations with the drawing-knife. By smooth out all the rough tool marks, until the contour of hull is doing this you will not have so much material to dig through true, just working out the section grooves. when grooving the section shapes, as the waste stock is removed deeply. following the general contour of the hull. plan. one side of the hull, then on the other. Finish this step on Do not cut too Shape the transom, obtaining the bevel from the sheer Sand out all the tool marks, using No. 114 sandpaper at the oe) sanding until the hull feels free of all and is absolutely smooth. rIGURE lumps and irregularities Measure 14% inches aft of station No. 3 and mark the location for the forward edge of the fin keel with a knife mark. Marking it in this way will insur e your finding it later, when ready to fit the fin. Remove the holding block and fast en it to the bottom of the boat in preparation for the job of holl owing or digging out the hull. These two screw holes, made when fastening the block, can later be filled with wooden plugs, glue d in, and trimmed smooth. Starting 11% inches from the stern , gauge a line 3 inch in from the side of the boat, running it up to the center line, at the bow. Do this on both sides of the hull. Mark across the stern, following the curve carefully. This layout will leave a goodly BIL. oF MaTertaL—LumBer—4o -INcu Item Hull Hull Hull Hull Hull Hull Name of Part A block B block C block Deck beams Deck Rudder Pieces I I I 2, I I Spars Mast I Spars Boom I Spars Cradle Cradle Mould box Mould box Club Bottom Shores Top Bottom Mould box _ Sides Mould box Ends SLoop Number of I I 2 I I 2 2 Thickness 3” gi ait Bw” ye” yn 4″ age 38″ Vi Width Length 814″ ~— 40″ Ble” 2614″ gy 14″ 84″ 134″ 13” 8” 50” yy” 26″ 34″ 8” 15” 12’ Bl wy” 1″ 3” sa” 3%” yg” yy” 6” xa? 12” 3″ 3%” 12” a” Note. White pine used for Blocks A, B, C, deck beam, deck, rudder, mast, boom, club and mould box. Whitewood may be used for deck. White Pine, mahogany or whitewood used for cradle parts. Figure 21 16 Name of Part Washers Continued Brass, 4″ Brass, machine, a”‘—2-56 Nuts Hexagon, brass, No. 3-48 Nuts Bolts Wire Wire Rod Rod Rod Sheet Tubing Tubing Screws Screws Screws Glue Paint Paint Varnish Lead Lead Note. 40-INCH SLOop Description Screws aot 654″ 5B” 21, Bint or Marertat- -HARDWARE: Quantity 5 3 Hexagon, brass, No. 10-32 10 Brass stock, No. 10-32 Brass stock, No. 37 ad a4” Galvanized iron, No. 22 Brass, Brass, Brass, Brass, Brass, ;3,”’ diameter 34” diameter No. 18 31,” thick seamless, 14” O.D. Brass, seamless, 33,’ O.D. Wood, flathead, brass, 14’’-—No. 2 Wood, roundhead, brass, 14’’—No. 2 Wood, flathead, brass, 134’’—No . to Waterproof For topsides For underbody Spar White Plumbers half and half 2 12! 3″ iy” 18” 3” x 8” ig” yw” I gross 18 3 % pound \% pint M% pint ¥% pint % pound § pounds 1¥% yards of Lonsdale cambric for mainsail and jib, required. amount of material at the bow, the stern and the sheer line, the places where it is needed for stre ngth and to secure the fittings. Do not remove this gauged mark with the cutting tools. The ¥4-inch outside gouge is the best tool to use when digging out. Gouge an outlining groove arou nd the sides and across the stern of the boat. Start carving out the inside waste wood, trav – eling in a fore-and-aft direction, but always going with the Continue the hollowing out until the hull has a uniform thickness of 1 inch, swelling at the sheer line to the ¥-I1nch grain. mark as gauged on, and working toward the keel to conform to 7, % Al Va S00 * | a a 9 a] rp r | 4| 3 ‘ite Stern Lae £Wie \ Sey < s X ‘ Ks ~S || a "6 15) 4 B 2 7 owe FIGURE 23 the shape shown in Figure 26. This figure also shows the way to take %-inch No. 2 roundhead screws and enough in the keel to use the calipers to measure the thickness properly when doing region to hold the No. 2/56 brass bolts. a job of this kind. ridges left by the tools. This hull should weigh 27.5 ounces with Figure 25 gives one a good idea of the way the hull will appear at sheer line when all hollowing out is finished. Sandpaper away all the the deck beams and the rudder port or tube fitted. Work carefully when hollowing in the region where the Get out the deck beams, dressing the stock straight, smooth, fin and the rudder port are to be located and secured, as there and square, and marking the face and the edge for recognition. must be enough material left for a landing about the rudder port Measure and lay out a center line, and label it. Lay off 4 inches 17 on each side of the center line and square marks on the four surfaces. Now get out a deck-beam mould. True one edge and use it for the bottom of the mould. Find and mark the center line. As the extreme beam of the boat is 8 inches, the chord of the arc will be 8 inches and the height of the camber 34 inch. Therefore the simplest way to lay out this curve will be to sweep an arc of a circle through these three points, and the curve for the beams will be laid out. Shape the edge of the beam mould.to this curve, and sandpaper it smooth and fair. Apply the beam mould to the stock for the deck beams, so that the center lines on the mould and the stock for the beams correspond, having the working edge of the mould flush with the working face of the stock. Line off the lower face of the deck beam. Move the beam mould up % inch, being careful to see that the beam thickness will be uniform, and mark off the upper face of the deck beam. Repeat this process on the other edge of the stock. Figure 27 shows the appearance of the finished beam mould, and the way it is applied to the stock. X shows the thickness of the deck beam. Two Station No.9 FIGURE 24 deck beams are required for this boat. Shape the sides of the boat at the sheer line to the right camber to receive the deck. Take pains with this job. If you are careful, shaping these surfaces so as to make a good joint between deck and topsides, the seam will remain tight. Stretch a center line from bow to stern. Gouge down at each station and obtain the proper camber, using the beam mould to test the shape. The method of doing this part of the job is illustrated in Figure 28. After grooving down at each station, remove FIGURE 25 18 FicurE 26 the waste wood between the stations, using the block plane and the spokeshave. This will remove }@ inch from the sheer height, but when the deck is installed your boat will be back at the designed height and have the right amount of freeboard. Fit the deck beams to their proper places. the spar and sail plan. Refer to Locate the center of the mast, measuring from the stem head. FIGURE 27 One beam goes there. Find the center of the rudder port or tube at the deck line. The other beam is fitted here. Bean MOULD q id Gauge in 14 inch at the sides and lay out the sockets for the beams. Dig the sockets or mortises deep enough to allow the top faces of the beams to come down flush with the topsides. A sharp 14-inch chisel will function very well when digging out the sockets. Use a 14-inch chisel to fair the bottom of the recess as you fit the beam in place. Center the deck beams properly and mark them to length. Saw cut them to length, and fit the ends snugly into their respective places. Secure each beam at the ends, using %4-inch No. 2 flat- head wood screws. Bury the screw heads well by counter boring, to permit trimming the faces of the beams, if necessary. The after beam will have to be removed when the rudder port is fitted. Figure 29 shows how the deck beams appear when secured in the sockets, and the way the deck lands on the topside. Read the chapter on ‘“‘How to Make Fin Keels and Cast Ballast,” in which the process of getting out the fin for the 36-inch sloop is fully described, and the chapter on “How to Make Fittings.” FicureE 28 This latter will tell you about manufacturing the rudder port, and the other parts required. Work the fin keel to the specified shape. Cast the ballast on the fin, and smooth it carefully. Make the rudder port, and fit it to the landing left inside the hull. Set the flange in white lead, and secure it with roundhead screws. Locate the knife mark denoting the place for the FIGURE 29 forward edge of the fin keel and set the fin in its position, Mark the flanges. Dig the mortises or sockets for the flanges and fit the keel so that the flange faces come flush with the surface of resemble the real thing most. The stock for the deck should be longer and wider than the finished dimensions of the boat. With material sized this way, allowance is made for the necessary trimming to the flare of the hull. In other words, the proper shapes at each section of the hull can be carried out according to the plan if sufficient material is left on the deck edges. Make sure you have sufficient stock fore and aft to carry out the lines of the boat, and mark the location of the rudder port. Bore a %4-inch hole for the tube, and lay the deck in place. Secure it temporarily in place with wire brads, and mark 3 inch on side of the hull. Trim the deck to these lines and shape the edges fair. Dress the top and bottom faces of the deck smooth and clean. Sandpaper both faces, using No. 1 sandpaper, and finish the top face (which is to show) with No. oo sandpaper, oiled. The holes for the %-inch No. 2 flathead brass screws are laid off 1 inch apart, starting from the center line of the hull, at the bow. Bore all the holes, being watchful that each one takes the proper angle to prevent the fastening from coming out of the side when the deck is secured to the hull. Twist drills for metal, turned by a hand-drill, are the best tools to use for this job. The holes across the stern are spaced 1% inch apart. Give the under side of the deck and the inside of the hull three coats of thin spar varnish, allowing it to dry thoroughly. Inspect the joint of the deck and the hull for fit. Remove the A 40-inch Keel Sloop deck and if everything is found to be right, apply white lead or varnish to the edge of the hull and the deck, and replace the latter. the hull. Bore for the bolt holes. Press the deck down at the lowest point of the sheer, Embed the flanges in white bore the holes for the thread of the screw with a brad awl, and lead and bolt the keel in place. Clean off any white lead squeezed secure the deck with the screws, working fore and aft on one out when setting up on the keel bolts. side of the boat. The material used for the deck may be white pine, or white- After driving all the screws on the first side, fasten the second side. This method of procedure will prevent wood, as specified in the bill of material, or mahogany or white any unevenness or buckling taking place in the deck. holly may be used, as the builder prefers. The first-named woods screw heads sink slightly below the surface of the wood. These give good satisfaction, and are easy to work, and when finished holes can be puttied or, in the case of a large boat, plugged 20 Let the later. Remove the superfluous white lead or varnish that squeezed out as the joint between deck and hull made up. Trim the edges of the deck, following the shape of each section of the boat accurately. Sandpaper the boat, removing any finger marks or other soiled spots. You are now ready to line off the deck planking, if this finish is desired, and to proceed with the painting, the making of the spars, the fittings, the sails, the rigging, and the installation of all gear and parts. In Figure 20 are shown the plans for a 40-inch racing sloop. This hull has been rigged as a schooner, too, and performs very satisfactorily. A boat of these dimensions is not too small, and is easily carried about, if one wishes to use a miniature for pleas- ure sailing or racing, when traveling. The bill of material for this craft is given in Figure 21. Go over the plans carefully, as previously instructed. This form of hull is one which is known as a real “‘keel boat.” It will be necessary to build a solid or multiple block, by gluing three pieces of stock together. Dress the blocks 4, Band Cstraight, smooth and square and mark the faces and the edges for recognition. Mark the ends on each of the pieces “bow” and “stern.” Mark the blocks 4, B, and C. Note that block C will have its fe inch dimension in a vertical position in the assembled large block. Before proceeding further, draw in the outline of blocks A, B, and C’on the sheer plan. Employing this method will enable you to locate readily the top of the lead line on the block. Lay off the lead line. Saw cut on the lead line, using a rip saw, and dress the two surfaces smooth, straight and square with the plane. Fit them so that they make a close, tight joint. Join the two parts of block C in the following way: Apply a coat of hot glue to each of the surfaces of the joint. Put a single thickness of newspaper between the top and the bottom pieces and clamp them together. Allow the glue to dry for twelve hours. A joint of this kind is used by pattern makers, where it is desired to have members of a pattern separate easily. The pattern for the lead keel can be worked to shape, when secured in this manner, and removed later, when you are ready to mould and cast the ballast. Check your three blocks and make sure they will come together properly when glued up in their permanent position s. Gauge a center line on each block. We will employ a different method of obtaining the heights and the half-breadths in this instance, as no table of offsets is given. Using a pair of wing-dividers, we will pick the dimensi ons directly off the full-size plan and prick them off on the prepare d blocks of wood. Lay off the forward perpendicular and the after perpendicular on block 4. These are the points of the L. W. L. farthest for- ward and farthest aft, or stations 3 and 15. The L. W.L. is 2634 inches long. Lay off stations 4, 5, 6, 7, 8, 9, 10, II, 12, 13 and 14, using the dividers to space the points equally. Now lay off stations 1, 2, 16 and 17. Stations o and 18 are at the ends of the 40-inch block. Secure blocks B and C to block 4 tempora rily, as shown in Figure 22, using 14-inch wire brads to hold them in Block C is shown secured with its face flush or even with the edge of block B, to enable the worker to pencil the position. station marks in a continuous line from the deck line to the bottom of the keel line. Mark all the stations on the faces and the edges of blocks 4, B and C, after taking the blocks apart. Figure 22 shows the stock marked, and ready to be glued up. Apply a coat of waterproof glue to each surface of the joints, and assemble the blocks. Be careful that the station marks and center lines correspond and are in proper relation to each other. When clamping the blocks, use hand screws to hold the work together. Allow the glue to dry for twelve hours. The builder should have no trouble obtaining a waterp roof glue as there are several brands now on the market. A casein glue of recognized brand is recommended by the author. At stations 8, 9, 1o and 11 bore a %4-inch hole. Hold the auger bit at right angles to the edge of block C when boring these holes 21 and bore through block C and well into block B. Your keel-bolt holes are now finished and will show inside when the hull is hollowed out. You have been instructed in the method of making templates. Use the method previously explained and make a template for the keel in the fore body as shown in 3, Figure 18. Station No. 9 is the midship section in this boat; therefore the fore body extends from station 9 to the bow. Make a template of the keel for the after body as shown in 4, Figure 18.. Mark off the shape of the keel line, fore and aft, using these two templates. Outline the keel on each side of the block. Pick off the sheer heights with the wing-dividers and prick them off, working up from the load water line. Circle the spots. Lay off the sheer line as you have been taught to do for the 36-inch boat, by the use of the spline or the batten. Mark both sides of the block. Lay off the half-breadths by the same method, and mark off the deck outline. A template can be used to mark off the shape on deck, if you care to make one. Saw cut to the keel line fore and aft, first, and then cut to the sheer line. The bandsaw can be used, if you have access to a mill, or a turning saw will do the job. Dress these surfaces smooth and fair. Replace the center lines, and carry the station marks across the shaped surfaces. At this stage of the work the block will appear as shown in Figure 23. Tack back in place the slab left after shaping the sheer, and saw cut the half-breadth shape. Dress the side surfaces fair and smooth, using the spokeshave and the plane. Replace any of the station marks that have been cut off, and number them all along the center lines. Lay out the shape of the bottom of the lead on the block. Push a 14-inch dowel into each hole bored, to reinforce the joint at the lead line. These can be withdrawn later and will serve as cores for the holes when casting the ballast. Using a 44-inch inside gouge, cut a groove down the rudder post or back edge of the deadwood. Fit a piece of %-inch O.D. brass 22 tubing to the groove, so that half of its section is contained in the groove. Bore a hole to receive the 44-inch tubing which will serve as a rudder post. The rudder post should be left %4-inch wide. Make the section or station templates, Nos. 1, 2, 3, 4, 5, 6, 7; 8.0) FO El, 22, 195 Tay 15,10, 17 and 08. Remove the waste wood on block B as shown at 4, Figure 24. Shape the block at station 9 so that it approximates the tem- plate shape as shown at B, Figure 24. Take inside and outside 14-inch gouges and with them groove from the sheer line to the keel line until template No. 9 fits accurately. Repeat this procedure, working toward the bow and the stern. A finished section groove is shown at C in Figure 24. An inside gouge, having a rather flat section and about 1 inch in size, will assist greatly in removing the waste material between stations when cutting the grooves. Model the outside shape of the hull fair, using the gouge, the chisel, the spokeshave, the block plane, and a half-round file, where necessary. Do not go below the section guide marks with the cutting tools. Sand out all the tool marks, employing No. 1% sandpaper, and finish the surface smooth with No. 00. Shape the transom and sand it fair and smooth. Now separate the pattern for the lead ballast from the deadwood by inserting the sharp cutting edge of a chisel at the after end of the joint, and giving it a sharp tap with the mallet. Scrape the top surface of the ballast pattern and the surface of the deadwood clean and smooth, thus removing all traces of the paper joint. A block, 134 inches x 134 inches x 12 inches, should be secured to the hull to permit the worker to hold his boat in the bench vise preparatory to gouging out the inside. The appearance of the block A, when fastened to the boat, is shown in Figure 25. Lay out the lines for gouging or digging out as described in the first part of this chapter. Hollow the boat out, doing the Be sure to leave an adequate landing for the flanges of the rudder post or tube. Figure 26 shows the proportions of the skin thicknesses at the several points and the way the required amount of material is left at the sheer and the bottom center line of the hull. The way to measure the hull thicknesses, by the use of the calipers, is also illustrated in this figure. Work the topsides to shape, ready to receive the deck. out, make and fit the deck beams. Lay Two deck beams are re- quired for this boat and are located at the center of the mast and at the point where the rudder port comes through the.deck. Figures 27, 28, and 29 should be studied again when performing these operations. Refer to the chapter on ‘“‘How to Make Fin Keels and Cast Ballast,” for information relative to the preparation of the lead keel. Smooth the top surface of the lead carefully with the plane. Cut the 10/32 threaded bolt stock to the proper lengths, and secure the bolts in the lead. SUGGESTED TOOL KIT Wood-working Tool List 1 jack plane, 14’’ (smooth bottom) 1 smooth plane, 8’’ (smooth bot- tom) 1 block plane, 6’’ (adjustable) 1 iron spokeshave (adjustable 1 firmer chisel, 14’ 1 firmer chisel, 14” 1 firmer chisel, 1’ I inside firmer gouge, 14” outside firmer gouge, 14’’ Put a lock nut on each bolt, after turning the first nut down as far as it will go. Varnish the inside of the hull and allow it to dry before in- stalling the deck. Get the deck out to the approximate shape and clean it up thoroughly on the top and the bottom faces. Varnish the underside. Secure it to the hull when properly fitted. Proceed to shape the deck edges to conform to the hull, sanding thoroughly wherever needed, and line off the deck planking. Putty all recesses, allowing the putty to dry hard. paper all putty flush with the surrounding surfaces. boat, sanding carefully between each coat. Sand- Paint the Make the spars, Ca A washer is to be used under each nut. inside firmer gouge, 14” outside firmer gouge, 14” backsaw, 10”’ crosscut handsaw, 18’ No. g ripsaw, 20’’ No. 7 turning saw (20”’ blade) keyhole saw drawing knife, 8” blade pocket knife (two-bladed) T-bevel, 6” blade circumference rule, 24’ combination try and miter square, 12” marking gauge pair wing dividers, 6’’ leather modeller bradawl (small) bradawl (medium) set of plug auger bits No. 4 to 0. ball peen, 6 oz. mallet (round 3’ x 5” head) putty knife cabinet rasp, 8’ half-round cabinet file, 8’’ hand screws, steel spindle, adjustable (block t firmer chisel, 1’ | Place the lead and set up the nuts. spokeshave makers) Apply white lead to the top surface of the lead and to the surface of the deadwood. 1 1 I I 1 6 cutter) 1 wooden ee job in the manner previously mentioned. I 1 ratchet brace, 6’’ sweep I rose countersink Metal-working Tool List 1 12 I 1 1 1 I 1 1 1 1 1 1 1 1 1 3 I I 1 I hacksaw frame (extension) hacksaw blades (fine), 8’ cutting pliers, 6’ round-nosed pliers, 4” hand drill set of twist drills (for metal) pair snips, 12/’ soldering iron, 4 lbs. set of jewellers’ taps and dies file knife, bastard, 6”’ file, round, bastard, 6” file, round, smooth, 6” file, square, smooth, 8” file, regular taper, 6’ file, slim taper, 6” file, mill fine bastard, 8’ file handles (wood) pair calipers, outside spring, 4’” pair calipers, inside spring, 4” drill and wire gauge center punch Drawing Tools or Instruments t bottle India ink 1 ruling pen t architect’s scale 1 pair dividers I automatic screwdriver the fittings, the sails, the rig, and install all the gear and other 3 nail sets,(small, medium, large) parts. 1 claw hammer, 13 oz, Note: Several wooden splines dressed to desired dimensions. 23 3 Rage re ASN e ay ee ALY FR-Boar - Scare ~—/*=/~—0" Huse ————————— 20 2 SPARS, Sas, FITTINGS ~ 4 oz Balas r—_§_—— $1.95 oz DiSPLACEMENT — 87.95 oz Mew Yor. afases R= saan > fi en = 296 Original drawing, 1” = 1’. here = 36” in original plan. 12” Sia: T ial sp 3g a tie > a a scott le eT ; ae L- we | att og – 1 t= et abe __j.= 4 c -7 — > Forward Keel line ZI | | ° y Oo 28 point | for is 356 / me ® fh ‘ FIGURE 34 é 32″ 6 BOARD Ficure 36 wn – Es = eesi | ; cael 1 oO FIGURE 35 : t oa Caen ~~ iG = ie = en Beart Mopto ° ae “1 foot Thickness at keel \ feel Ss 43 waste wood curve +4 ny \\. ° T i- 7 a Daag oo = = |rae a NY 4 | 1 : U want FIGURE 33 ° (rain Ihea I ars 44 ” I-77 | : Pann marae 6 aS 2g ” “8 2 X fa eae OS ee “6 we zal) Cie Landing for rudder’ 7 7 ; Y ee 5% inch from the side at the sheer, and 134 inches in from the Sandpaper the deck clean and smooth, using oiled No, oo sandpaper, ready to lay off the pattern of the deck planking. transom or station No. 17. Start hollowing the inside of the hull, using the gouges. The Figure 37 shows a pattern or system with the planks laid parallel skin should have a uniform thickness of % inch, except at the to the king plank, 4, and the plank sheers, B, following the sheer, the keel, and the landing for the rudder-port flange, as shape of the boat. shown at E, in Figure 33. The keel outline, inside, is shown at the king plank and the ends are “‘nibbed”’ into the plank sheers. C, in Figure 33; and the proportions of the thickness at the Figure 38 shows a system in which the planks are laid parallel sheer, bilge, and keel, at B, in Figure 34. to the plank sheers, and the ends are nibbed into the king plank. Sand out all the gouge marks, using No. 1 sandpaper. Give In full-sized yachts, the material of which king planks and plank sheers, or covering boards, are generally made, is mahogany or the inside of the hull two coats of spar varnish. Lay off the location of the deck beams. The intermediate planks are laid parallel to These are fitted at teak. The planks are of the finest grade white pine. Figure 39 the place where the forestay touches the deck, at the center of shows a pattern of planking known as the “herring-bone”’ sys- the mast, and where the rudder port comes through the deck. tem. The deck beams are recessed into the hull at the sheer line, as are employed to construct the decks on the most expensive described in Chapter II. yacht hulls. Secure the deck beams in place. Dress the sheer line to the deck camber or round-up, using a These ‘“nibbed” systems, and this ‘“‘herring-bone” pattern When properly laid and carefully finished they present a very attractive and beautiful feature in a boat. spokeshave and plane, and testing frequently with the beam Lay out the deck planking, using a spline or batten to give mould, as shown in Figure 34, at B. Apply the deck to test for you the required guide for the marking tool. A leather modeller a tight, accurate fit. will serve very well to make the seams in the deck. When the Place and secure the rudder port, using white lead between seaming is finished, sandpaper any burrs or rough edges away. the flange and the landing, and fastening it in place with 14-inch Give the deck a thin coat of white shellac. Mark the seams with No. 2 roundhead brass screws. India drawing ink. Fasten the half-section along To finish the deck, apply three coats of the stern post with 14-inch No. 1 flathead screws. File the heads spar varnish, rubbing down between coats with fine oiled sand- to take the shape of the brass half-section. paper. Cast the lead ballast, bore for and place the keel bolts, soldering them securely in the lead. Bolt the lead to the hull, and trim the ballast to conform to the proper shape. Smooth the down between coats until a satisfactory surface is obtained. Make the spars. Make the sails. and secure all the fittings. ballast carefully. Dress the faces of the stock for the deck. face perfectly smooth. Paint the hull, applying the paint in thin coats, and rubbing Sandpaper the top Give the underside two coats of spar Set the deck, using white lead or heavy varnish in the joint, Trim the deck to conform to the shape of the hull at the sheer. Place of the center of the rudder head, and the jib traveler 214 inches forward of the center of the mast. The chain plates are placed 134 inches aft of the center of the mast. varnish. and fasten it with 14-inch No. 2 flathead brass screws. Make the fittings. The main traveler goes 3 inches aft forestay hook. Locate and place the Bore a hole in the deck to permit the passage of the screw at the bottom of the hook. This large hole can be filled with plastic wood or plugged and then covered with a small 29 and turn the 14inch screw eyes int o the boom and Jib club, for the sheets. CHAPTER Rig the shrouds an d the forestay. St ep the mast, set up on the turnbuckles an d rig the main and Jib sheets. In doing each partic ular job, refer to the chapter which treats of that job if furthe r information is des ired. |[y BUILDING A HULL BY TH E RIB-FRAME AND PLANK METH OD OF CONSTR UCTION frames or timbers, and planking to fo rm the skin, and the deck. There are severa l ways of arrang ing the planking in boats built in this way. In the “longitudi nal planking” syst planks are hung em, the or placed edge to edge, and their edges follow the diagonals used in the body plan of the boat, approx imately, “Diagonal planki ng” js somewhat the same as longitudin planking, the ed al ges butting toge ther, but the pl an ks cr sections at an an oss the gle, gene zontal. “‘Lap-strake rally about 30 degrees from th e hori. planking” is the meth od employed Canoes, dinghi for es, small ra cing craft, an d lifeboats. The plank edges lap as do the siding-board s on a ho Figure 38 use. It makes a strong, tight job, and is useful where a cra ft is kept out of water for long periods of time. In the “R ibband Carvel” method the planks are hung edge to edge, an d a batten or ri bb an d is fitted over each se am on the inside, be ing secured wi th screws. Th system holds is the boat firm ly together an d a lighter fr ame can be used. It is us ed motorboats. ALT 30 FicureE 39 So arranged in light racing ma chines, and high -powered The “double-pl anki that the seams ng” system em ploys two skins, of the inne r skin middle of each pl ank of the outer. will come in the Cloth, and heav y paint or Se th | aayehe ee | | | 3y” 3″ Is —| ea Whe a) a en > — ee SI0E Plank <7” i” i | ee One 4 Inco SQuares Over one-half reduction 4 45 6 eae ies St 4k " SLooP 'T. xs Zhewies 287 = Bboy, DESIGNER 34” here Figure 39A aT The plans for the 28-inch sloop Twin kle show a very simple form of planked hull, having spla yed sides and a half-round bottom. Practically all of the sizes and shap es for this craft can be obtained by laying off a panel and divi ding it into 1-inch squares, as shown in Figure 39A. The shap es for the stem, moulds and transom are given, with all allo wances for the thicknesses of the side planks and the bottom planks having been made. As the shape and size of the side planks have been taken from an SAIL ¢ SPAR PLAN 28"SLooP actual set of moulds, they can be cut to shape from this lay- out. The stem and transom are made of ¥%-inch stock. The ma- , terial from which the moulds are made is 38-inch stock. The side planks are worked out of ve-i nch material. The bottom planks and the deck are made of ¥-in ch stock. White pine is employed throughout, as this wood works easily and is comparatively light in weigh t. As this hull is to be constructed in an inverted position, a mould-board is employed for moun ting the stem, moulds 2, 4, 4, §, and the transom. enough. A board 7 inches x 30 inches will be large It must be free of all wind and warp, and be straight from end to end. Lay off the overall length of the hull, and the station for each mould, obtained from the sheer and half-breadths plans. Moulds numbered 2 and 3 are secured in place forward of the station marks and the moulds number ed 4 and 5 are secured aft of thei r marks. The moulds are to serve as perm anent frames, therefore it is recommended that all lines necessary for construction such as center lines, the sheer lines and the lines for the deck camber be laid out on each before it is secured to the mould-board. Lay out the center line and the rabbet line on the stem. Cut the rabbet to an approximate dept h before securing the stem in place. 32 Ficure 39B Twinkle i £.we ‘R' Boar Scale — f"=1" Is" Leagth OA. Length LW.L. I75*% Brought Soil Area 8.5” 1325/8 9" "62" Bsa —— Roting-—./g. a 2227 ; hanes Qurkig 3/8/26 eee ee ee 34 2¢-t_ = 30 NewYork Crty ease Scare— +: ” After cutting all parts to shape, mount them in position on planks, stem and transom in preparation for the decking. The the mould-board, for a trial set-up; and to enable you to obtain deck is fitted in one piece, and is fastened with screws as were > the necessary bevels at the stem, the mould ends and the tran- the bottom planks. som. All bevels for this job can be obtained by offering the Dress all surfaces true and flush. Reinforcing blocks and pieces can be fitted in the way of side plank up to the frame members. Mark off all bevels. Cut the bevels to shape, after the frame members have been dismounted. Now, re-mount all the frame members on the mould-board, bracing them where necessary to insure their proper positions. Offer the side planks up to the stem-rabbet, moulds and the transom. ‘Trim the several parts where necessary to procure a good solid fit, and prepare to fasten the side planks in place. Use 14-inch No. 2 F.H. brass screws to fasten side planks. Lay out their locations carefully, to prevent splitting. Now, fasten the planks, being sure that they lie smoothly against the frame members, and that no forcing is necessary. White lead can be applied at the rabbet and transom faying surfaces, as it is not expected the builder will find it necessary to caulk this boat. The layout for the bottom planks is shown by the broken fore and aft lines in the half-breadth plan. The center plank is fitted first, then the other planks are worked in parallel to it. These bottom planks are 1 inch in width. Bevel the stem, moulds, transom and bottom edges of the side planks to receive the bottom planking. Make sure the abutting plank edges are properly fitted and are fair. Screw fasten into each mould, the stem and transom, An *‘R” Model at Anchor. See Figure 40 and the side planks. Dress all faces, edges and ends of the planking, making them flush and true with each other, the stem and transom. Sandpaper all surfaces preparatory to turning the hull over. When all smoothing has been completed, unscrew the frame members from the mould-board. Trim the top edges of the moulds to the camber line and bevel the top edge of the side fittings, keel and rudder. The moulds can be lightened by hav- ing the middle areas removed as described for a ‘“‘web-frame” elsewhere in this chapter. In Figure 40 we have the plans for a model ““R” boat, drawn to a scale of 114 inches = 1 foot. This boat is admittedly fast, a steady craft under sail, and an all-around performer. She is 37 Orrser TaBLe ~R- Boar Scare /f$’=/-0″ PLANKED Boar For —— Stations —— 0 2 3 4 s 6 7 93 lo “ 43 id is eer Half Breadth | o|o\2\ol2[o] /[2) 3[2/3/o|sl213\4l’3|s’o’2 s21i{s}slal statetsts[atslale erolat aztotsiz{a12et Waterline No.3 above ” o}ols fol/|2{2\2 Wien if a] 1 | 3) 2[o][4]/j2] 5\0]/ [5.2/0 4 /\2\0 [2/2/2[3|3)2] 4/3 /3] 5/2 |2]5/3!3 | élols |si3i3 [sj2|/)4/3,2/3)31/ NS Water line No.| below “ o2iu fi iy ” u «4 4 u 5 a A 4 a a a ik 0 lol Sheer Height la Buttock No.l ZiA3lolsio 3/3)7| s\slo Ors] si2}o} 2jolo} /[3|2]) 4) //3 jol3|ojajo|2 4) @\ 412130 0/3| 4] //0|2| /\o|7 [0|3|/ jol2iojolo|2 /\olo[o[3|3/o|3|olojz|o 13|2|2| 32/0 15|1|3|4 1.0 Ti 2\o| 113 3 0} 3|3}0/3|3/0/3|0{o|\2/0 17\0|1\4\3\3 0]3| 1 {ol2| 3 ]o\2/0 «8 4 48| 2\3| 5|2)3 Olt folrl2 0/12\/9j0|2|0 jolz2jo /o|2\o]oO|2\olo|3\ol 7s |ol|3| sii if] Jlol/ jol3|/ joj2z\olo|2 |Olo|2|olo|2\0|o/\2/0 31110101313 [Ol s[2|/|2]o}] a/ |2] 3/0] 2) 3/2lol3]/|2} aloo l|2i1i2| ss jojolol2|/i/ |oj2ii|2 slzis lol sl2} sj2is}2io}3} 2j2joj2j2i1 f2iris jij2j2joj2i3jols|3|s|3lo 3lolofolils}slifejel2{a]sj2i3]sj2jo fol3alrfolsiol2isjo 4) 0\0|2/3|3|/\O|2| oO oo|/\0}/ |2)0|0| 3\0|2| 4| 21] ViOlo] 7/3|2 (8 0/3 |8\2/0/4// 3 /O;Ojo| Tilol3 sjoj2i{2iiit Siilolilsls lolol 2fojal3]i[3l2] 2aisl2| aj2[al¢gis|/j4i3{2is|1j2 [5|3|2j{2/3|3{olo|s jojo|s lololt Transon 2iili|3lols 3 ras £ Ls at ) Note ams L.WL. used os base-line 4\/\|o| 7\2\0 o|2/3| 6] 3/3 Weller 4|0\0|2/0\010/3|/ [ol //0| //0/3| 20/3) 2/313) 3)2//13/3)3/4)0\ / j4/0|/ |o3/ol/o0)/2/3/ 3 et Lire 24 2\2]6/ 7/0 4 olr|4lololsl3i¢{3i2|2]al2|o|als|s| alols] slolo[2]3[sl2]s lz] 2/3] 4 |2)/3/0]/2|/3/o] 2/3|1 [2/3] 2] 2/3/3] 3/0} 7 | 3/3| 0} e|3\o Q lad 7i2\/ 513]/| 6\Z10 2|0/2/3\3/1/4/3]o| S/0(3] 5| /| 0/4) 3/3 |Ziol/|si3\2 6 «4 Keel Hal¥ Breadth EI Fn m AP 8|3|0| 8]3\0 S’s isl saisi2 als li 14i2j/{ S111 31S [3 |/ | $1312) 512] 3 || sloldioji2 ZAI 13) 1) 131311131312) 3171/3 |2jo| 2} 01 4/3 a “ : 0 (3|2{[2\0/3 slalalaiviaisicioleiaiel asic eieins tedieiaio tia 3\0|2 Load Water Line G Ly 8iilolvizio 7\2\0 (measure up and down) Stations spaced ——— 3-3-0 Waterlines _« 1-0-0 Buttocks by /-2:0 Overhang (ford) ——— 8:30 FIGuRE 41 Overhang (att) ———-8:3:0 New York City u/u/3o large enough to hold her own on pond or open water, at the same time of a size to be easily handled and transported. With a few slight changes the craft can be made to rate as a “D” boat, under the M. Y. R. A. rules. The accompanying photographs should give the reader an idea of how the finished prod- for this are given in the Offset Table under “Keel Top.”” uct will appear in her element. these last two mentioned lines are found in the Offset Table, The first step in the construction of this boat will be to obtain a full-size set of “‘lines.” She can be “laid down” from the “Table of Offsets” given in Figure 41. The method of using this data has been explained in Chapter II. Exercise great care in the performance of this part of the work, as all shapes will depend on the accuracy with which you enlarge the plan. too. 38 After the lines have been enlarged the line representing the top of the keel can be drawn in on the sheer plan. The figures Draw the lines representing the ‘“‘keel half-breadth” in on the halfbreadth plan. Now lay in the “‘rabbet line.” The figures for The course that the rabbet line will follow is plainly shown by the broken lines in both the sheer and half-breadth plans in Figure 40. The outlines of the keel top and keel half-breadth are shown in Figure 42. The rabbet line is also shown at F in Figure 42, as it appears when looking at it from the side, and from the bottom. Model “R” Boats Racing on Lake Winnepesaukee, New Hampshire. Builder and Owner, Dr. Charles Thomas An “R” Boat Close-hauled. An “R” Boat Close Reaching 39 FIGURE 42 The next step is to get out the keel or backbone of the boat The keel must be built up, as shown in Figure 42, to insur getting the grain of the wood to run in a direction most suit able for strength. A section of the keel is shown at B, Figure 44 Note that the keel consists of four distinct members. 4 is th keel proper and includes the stem in this instance. B is th stern post. C is the knee or deadwood. or fashion piece. to one another. D is the horn-timbe Observe how the different members are fitte The keel butts against the stern post, the horn timber lands on top of the stern post, and the knee is dove tailed into the keel and the horn-timber as illustrated. Make a template for each member of the keel. These tem plates can be made of heavy card or Bristol board. Select th material you desire to use. If the boat is to be planked wit white pine or cedar, and is to be finished bright, use oak. Shoul you desire to use mahogany, baywood, or indoako for planking A Quartering View of Budédles, “R” Boat. Designer, Owner and Builder, Thomas Darling 40 use pieces of straight-grained Honduras mahogany. : Materiz should be medium hard, free from knots and checks, and we FiGurE 43 Figure 44 seasoned. If white pine is used, increase the dimensions given here, 20 per cent. Label the pieces of material with the names of the several parts. Draw a center line from bow to stern on keel top and bottom. Apply the templates, and draw the outlines using a hard, sharp pencil point for marking. The stem head is allowed to project 1 inch for setting up on mould-board. several parts, and assemble them. Shape the Use a waterproof glue to secure the members, at first. FIGURE 45 Bore the holes for the keel bolts as shown at /, Figure 42. Groove the stern post, and bore the hole to receive the rudder Observe that the keel bolt at station No. 12 will help to port. secure the several parts when driven. Get out the transom. This member, shown at E, Figure 42, can be made of the same material as the keel, or may be made of a wood with a color which will contrast with the planking material. Lay out and mark the sheer line and the rabbet line. Make sure that you have enough extra material to permit work- Now bore for, and drive drift bolts through the deadwood, or knee, and stern post, as shown at J, in Figure 42. These drift bolts are made of No. 40 brass ing a taffrail on the transom, and for camber or crown of the wire. ing this shape. Lay off, number and mark for recognition the sheer line at the stem (see G, Figure 42), each station or section, the L.W.L. and the rabbet line. Square the station marks across the top and bottom of the keel, and mark the plumb lines on each side. deck. Refer to H, Figure 42, and to R, Figure so, when study- Fit the transom to the horn-timber of the keel, cutting a socket to receive the timber end. This is shown in Figure 42, and Figure 50. Secure the transom to the keel, using glue, and 34-inch 4] Lwl IF Shear Line = 3 4 1/3 Mould FIGuRE 46 No. 3, F.H. brass screws. The screws can be driven from the top of the transom, as they will be covered by the deck later. If there is fear of leakage at the joints of the several members of the keel, stop-waters can be bored for, and driven as shown by the circles in Figure 42. These will prevent seepage of water. They can be made of -inch white pine. Stop-waters are hardly necessary in a boat such as a miniature because the hull is hardly ever left in the water long enough for this action to take place, although it is well to know about this method of preventing leakage. Lay the keel aside until the moulds are ready. The next job is to get out the moulds. Study Figures 43, 44 and 4s. These figures show how allowances must be made for the thicknesses of the planking and the frames or ribs. Refer to C and D, Figure 44, especially, for this information. Study Figure 46 to obtain an idea of the way allowances are made at the top of each mould, to permit it to rest in the proper position, on the mould-board. Proceed in this way: Drawa line 1 inch above the sheer line, 42 | at the stem head, parallel to the L.W.L. from bow to ster This line represents the top face of the mould-board as show in Figure 46. Each mould, or section shape, must be made larg enough to extend up to it. Draw these extension lines at eac section on the body plan. As the frames and planking will k 1% inch each in thickness, 4 inch must be removed from th moulds to permit the frames to lie in place, and that the con pleted hull may conform to designed measurements. Take pair of bow compasses, and set them to 4 inch. At the poir where each water line touches the section or station outlin strike an arc. Now draw a line, from sheer line to keel, tanger to these arcs, and the outline of the mould will be obtaine: Pick up each mould shape by tracing on strong onion-skin pape working from the vertical center line. Keep in mind the fac that for a boat to be a consistent sailer, both sides of the hu must be made the same shape. Make a template for each statioi It is recommended that poplar, 3 inch thick, be used fe moulds. This material should be well seasoned, and free of win: Plane a working edge on the stock, and mark for recognition. Mark the center line of the mould on the working edge, and on each face. Lay out and cut each mould to shape. Be sure to mark the sheer line, and load water line on each one. Number each mould. The mould-board is next in order. Procure a well seasoned, straight piece of stock, and dress it on four sides, cutting it to these dimensions: 114 inches x 3 inches x 61 inches. Lay off seventeen stations on the mould-board, number each one, and gauge-mark a center line. Its appearance is shown in Figure 46. Now, set up the moulds. Use a small block in the angle formed where the mould and the mould-board meet. Drive two screws into the mould, and two screws into the mould-board. This method of fastening will prevent the mould swivelling or shifting. Moulds 3, 4, 5, 6, 7 and 8 are placed forward of the station marks. Moulds 9, 10 and 11 station marks. are placed so that they straddle the Moulds 12, 13, 14 and 15 are placed aft of the station marks. It will be necessary to determine where the bearding line will come. This line is formed by the meeting of the inner faces of the planks and the side face of the keel. Refer to B, Figure 46. The simplest way to obtain the spots for the bearding line is to draw a cross section of the keel at each station, as shown in Figures 43, 44 and 45. Cut the rabbet, using a piece of planking to measure its Bevel the keel at each station, first, and then remove the waste wood in the areas between, afterward dressing the depth. surface between the rabbet line and the center line of the keel, fair and true. Replace the station marks, wherever they may have been cut away. Notch out moulds 3, 4, 5, 6, 7 and 8 forward, and 13, 14 and 15 aft, to permit keel to drop down in place. Bevel the bottoms FIGURE 49 of all moulds, and fit the backbone into its true position. A split block holds the stem head in place, and a block is fitted 43 under the transom to support it. Fit and secure blocks in each angle formed where the moulds and the backbone meet. Getting out and bending the frames are the next jobs to demand attention. The frames for this boat are 4% inch x 4% inch. For a larger boat % inch x 3% inch is recommended. The frames are to be spaced at each station, and one in each room between. Ash, oak, or elm are the best materials to be employed for these members of the hull. It should have clear, straight grain. After steaming or boiling for about two hours .they can be readily bent to shape. Tack them to the moulds, temporarily, with 14-inch brads. After they have cooled and set, remove them from moulds, number each one, and lay them aside. It will be necessary to make provision for the lower ends of the frames. Sockets can be cut so that they are “boxed” in as shown in Figure 43 and Figure 44, or a through mortise can be cut, allowing the frame to pass directly through the backbone. This arrangement is shown in Figure 45, and at M, Figure 47. The last-mentioned method cannot be used where the sections are too V-shaped. The moulds must be notched or recessed to take the clamps and stringers. The clamps are pieces running from the stem to the transom, located a distance equal to the thickness of the deck beams and the deck, below the sheer line. They are 34 inch x 34 inch yellow pine. The stringers are pieces running from just under the clamps at the stem, to just under the clamps at the transom. Use 4 inch x 38 inch yellow pine for these parts. They are located midway between the clamps and the keel top amidships. Each mould must be cut out to receive them. When fitted the clamps appear as shown at F, in Figure 44, and at C, in Figure sr. The stringers are shown at E, Figure 44, and at S, Figure 51. Fasten them at stem, transom, and timber heads with screws. The plank fasteners will pass through the clamps and stringers at other points where they cross the frames. Check all parts carefully for fit and alignment. Secure frames 44 FicurE 50 i FiGuRE 51 ‘ = TITS FIGURE 52 in place using glue and screws at heels. Use brads to hold frames The plank nearest the deck line or sheer is known as the “sheer strake.” in place on moulds. Before the planking can be fitted the frames must be bevelled There are other names such as shutter, binders, etc., but we will This work can be ac- not consider these, because our method will be to put one plank Apply a batten to the frames as the on after the other, beginning with the garboard and finishing to allow the planks to lie snug on them. complished with a file. broad,’ and the next one is the “second broad.” waste wood is removed, testing for an accurate, fair fit. Most of at the sheer strake. this bevelling will have to be done on the forward and after frames. There are several things to be borne in mind as the planking The hull is now in frame and ready to receive the skin or job progresses. Each plank must fit its neighbor without forcing of planking is most practical for a boat such as this, and is the or strain, butting up to it with an absolutely tight joint. If the plank ends are forced upward or downward, hogging or drooping one generally employed. will surely take place. planking. It can readily be seen that the longitudinal system Pattern-makers’ white pine, cedar, indoako, baywood, or mahogany will prove to be satisfactory Each plank should be worked out in pairs as the job goes The materials should be % inch, full, forward, and each should be “hung” or fastened in place on in thickness, straight grained, uniform in color, free from knots the boat at the same time. Proceeding in this manner, all chance and checks, and well seasoned. of undue strain can be avoided. woods for this purpose. Each plank should be in one length from bow to stern. The plank nearest the ballast is called the ‘“‘garboard.” The one next to the garboard is the “first Wherever the turn of the section requires that the plank be hollowed out to allow for a good snug fit to the frames, this 45 ba I Greatest Girth #9 Station Divided by num ber of Strakes -=—____.. Diminish Scale (10 planks required ) Girth SE Station wh . ~ fg NM old IN s ee XN XN Vv ) N Pd a led al ‘ iS | Divided by number of Strakes=7” —| FicurE 53 hollowing may be done with a “violin plane,” or the hollow may be made with coarse sandpaper. Great care while working will repay the builder, in large measure, later on. The fastenings recommended are Japanese round toothpicks. Ordinary straight brass pins are sometimes employed. At the plank ends small 14-inch brass screws will hold very well, as there solid wood is found. A No. 51 twist drill will serve to bore for the fastenings, although the size of the toothpicks obtained may make it necessary to use a different size. Refer to Figure 52, study the layout of the planking and note that thirteen planks to a side have been used. A good idea of the direction in which the seams of the planking will run can be obtained by a study of the diagonals in the body plan, although it may be necessary to make some changes as the planking goes forward. Notice that the fifth plank from the sheer line is about at the water line, its forward end about at the turn of the stem, and its after end terminates at the knuckle, which is made by the joint of the horn-timber and transom. The girth, or measurement of each section from rabbet line to sheer line, is different. The problem is to divide each section girth up, so that the same number of planks can be fitted. When taking these girth measurements remember to keep the top edge of the sheer strake ‘g inch below the sheer line mark. This ve inch with the 5 inch which will be removed when bevelling, 46 will bring the top arris of the deck edge down to the sheer line. The garboard should be laid out first. Measure up 258 inches on station No, 12. Take a thin, pliable batten and adjust it fore and aft so that it lays fair and true along the frames, getting it as nearly parallel to the water line as possible. Do not force the ends of the batten, but let it lie naturally. Mark the frames. This will be the top edge of the garboard strake. Now, to obtain its shape, to enable you to lay it out on the planking material. There are several ways of doing this, such as cutting cardboard templates, pressing stiff paper against the rabbet line, then cutting away until it fits, etc. manlike way is to take a “‘spiling.”” ployed by the boat builder. The surest, and most workThe spiling method is em- Study Figure 55. A thin batten, narrower than the plank to be worked out, with a length governed by the length of the plank, is secured to the frames or moulds. The center of each frame or mould is lightly marked on the “spiling batten” and numbered. Set a pair of wing dividers, or for this small job, a pair of bow dividers, with their points apart equal to a greater distance than the space between the edge of the spiling batten. and the shape to be obtained. Keep the points of the dividers parallel to the center line and prick off a “spot” as shown at zo, Figure 55. Do this at each station. Circle the spot, that it may be readily located again. Remove the spiling batten from the frames, and secure it to the plank- lee Sooooh SS Sprling __Gatten Sheer Strake FIGURE 55 9 i 3 ONS FIGuRE 54 ing material. See Figure 56. Tack the spiling batten to the plank. Draw the station center lines on the plank. With the dividers set as before prick off the spots at each frame number. Line off the edge of the plank, using a thin batten tacked in place, as a guide. The end shapes of the planks can be obtained by offering them up to the rabbet, and marking, when the plank is tried in place. Do not be alarmed at the peculiar shape the plank edges may show when lying flat on the bench top. Watch that the edges show fair, with an even sweep, when they are : F3 8 2 Spiling 9 Batten = Plank Ficure 56 tried on the frame of the boat. Cut the garboard planks to shape, and fit them to the rabbet, carefully. Varnish the rabbet, and apply varnish to the plank edge. Fasten in place. Lay out the “first broad.” Measure up 34 inch on station No. 9, apply the batten as before. The top edge of the first broad should end at about station No. 5. Allow it to run natu- rally in the after-body. Sight for a true, fair sweep. Obtain the shape, line out the plank, cut in shape, fit and fasten in place. Use a liberal quantity of varnish on plank edges, and dip the toothpicks into waterproof glue before driving. If it is decided to use pins as fastenings, anneal by heating and quenching in water. FIGURE 57 47 Now, lay out the sheer stra ke. at station No. 9. as ‘“‘diminish.” It is also to be 34 inch wid e The taper on the planks, fore and aft, is known A “diminish scale” is sho wn in Figure 53. Suppose the remaining space or girth to be filled in at station No. 9 is 838 inches, and is the grea test girth. Three strakes, the gar. board, first broad, and the sheer strake have been acc ounted for. Ten strakes remain to be laid out. Lay off 836 inch es on a pliable batten. If this measurement js div ided by the number of strakes required we get 34 inch. 32 Inch. Mark the 836 inches point Take station No. 5 as an average least girth section, and suppose there is a 534inch space to be covered at that point. Lay off 534 inches on the batten, and divide by the number of strakes required. Mar k this point $4 inch. Divide the distance between the point mar ked 43 inch and the one mar ked 3% Inch into seven equal spac es, and label them 38 38, 39, 2, 33, and 23 as shown in Figu re 53. If the end of the scal e is placed against the top edge of the first broad, the scale being applied at any frame between stat ion No. 5 and station No. 9, the num- ber on the scale touching the lower edge of the sheer strake will give the width for each plan k, at that frame. Another method of laying out the taper or diminish of plan k- ing is illustrated in Figure 54. To make this scale draw a stra ight line as X—Y. Scribe a sémi circle with a radius equal to the width of the plank at the grea test girth, 34 inch. Suppose the width of plank at station No. 3 to be 3% inch, and for the plank at station No. 15 to be-%4 inch. Erect perpendiculars at 4 and G and where lines of these lengths cut the semicircle labe l the points 3 and 15. Divide the base line into six equal spaces, and erect perpendiculars as shown at B,C, D, Ban d FE.’ Acmeasure ment for stations 5, 7, 9, I1, and 13 can be taken off, marked on the plank, and lined out. In this way the shape of the second edge of the plank is obta ined, and the plank given a uni- form, fair diminish. Of course, it is necessary to sight the batten, when lining out, to detect sud den kinks, and very unusual shapes. 48 Finish the planking, mak ing tight joints in all sea ms, especially if the boat is to be finished bright. Remove temporary fastenings as each plank goes on. Before putting on the sheer strake glue filler pieces between all fra mes at the clamps. Make them wide enough so that they will come up to the she er line. The se are shown at F, Figure 49, and at F, Figure 50. Dre ss them off flush with frames. The sheer line, or top of sid e should show a fair line when finished. Trim all fastenings flush with the surface ‘of planki ng. Plane off all irregularities and uneven ness at seams, dressing the whole surface of the boat wit h care. Sandpaper, firs t using coarse, and finishing with a very fine grade. Giv e the outside of hull a priming coat of var nish if she is to be bri ght, or paint. Turn the hull over. Fit the breast hook. This member js shown at B, Figure 49. Trim the top of the tra nsom to shape, being sure to allow for pro per deck camber, and for a rail if one is to be fitted. This is shown at R, Figure 50. Fit the deck beams, as sho wn in Figures 4, 10, and 14. Figure 57 shows the way to fra me for a hatch. The deck bea ms, 4, which are 14 inch thick and 1 inch wide, receiv e the carlines, B, which are 14 inch thi ck and ‘% inch wide. The carlines are dovetailed into the dec k beams. The hatch for this boat is located 2934 inches fro m the stem head, and the opening is 3TM inc hes x 5 inches. Stay passes through Deck beams are locate d where the head- the deck, and at the rudder hea d. at the Remove the moulds ver y carefully. saw cut them at the center line shows a “‘web frame.” mast, at the Fasten deck beams. hatchway, It may be necessary to to get them out. Figure 48 The moulds at the mas t may be cut away to form a fra me such as this, and will add greatly to the str ength of the hull at this point, relieving the strain caused by the thrust of the spar. If left in, be sure to provid e “limber holes,” shown at L, to all ow bilgewater to flow aft. Cast the ballast, and dre ss it to shape. Bolt it to the hull as OUUWIE AL fy EVIBUIG fitted for carrying. 44 FL 1s recommenaeca that a nanale pve ‘This should be bolted in. The keel bolts driven at No. 10 and 11 stations can be made long enough to hold the handle. Trim off the waste ends of all fastenings. the hull three good coats of varnish. Give the inside of Bevel the top edge of sheer plank preparatory to fitting the deck. Fit, fasten, and finish the deck. Fit the hatch. Figure 58 shows a cradle suitable to hold and show off the lines of a craft such as the one under consideration. The uprights 4 and B are recessed, following the shapes of stations 12 and 9. They are screw-fastened to the base C, 1114 inches apart on centers. CHAPTER V F. HOW TO MAKE FIN KEELS AND CAST BALLAST HERE are several methods of securing fin keels to hulls, In practice presenting today. Those found most efficient and the most workmanlike installed, will be considered. appearance when Brass, 34g inch in thickness, is the material most commonly used; but monel metal, or bronze may also be employed. In Figure 59 a fin keel is shown consisting of a plate, P, and two flanges, F. The flanges are riveted to the Of course, the top edge of the keel plate must be shaped to the bottom of the boat, and the flanges bent to Ficure 60 plate as shown. this fore and aft, or longitudinal shape. The flanges must also be bent to conform to the section shapes, or deadrise of the hull. Holes for the fastenings are drilled as shown. The fas- oO fe Q O ous 49 tenings may be rivets, round or flathead bolts, or screws. Should flathead bolts, or screws be used, it will be necessary to countersink deep enough to permit the heads to finish flush with the surface of the flange. This method of constructing and fitting a fin keel gives a very strong, satisfactory job. Figure 60 illustrates a style, or method, where alternate flanges are employed. The top edge of the keel plate is divided into five equal spaces, and the width of the flanges, F, laid off. Saw cuts LZ are made at each division mark, using a hacksaw. _—— — Wiesner The flanges are bent so that they will conform to the hull form, both longitudinally and transversely. Holes are drilled for fastenings in the flanges. Notice the five holes, H, drilled along the bottom edge of the keel. These holes are so placed, and are of such a size as to permit lead to flow when the ballast is cast, thereby binding or securing the two parts of the ‘“‘bulb” or ballast to the fin. This type of keel, having the ballast concentrated at Ficure 61 CS the very bottom, is known as a ‘‘bulb-fin.”’ A type, having ears, EZ, which run up and secure to the deck beams, is shown in Figure 61. A slot is cut in the hull, permitting R the plate P to enter. This method of fitting a fin makes a rigid job and will tend to strengthen the hull, as it ties the deck and the keel of the boat together, if properly installed. When making fin keels, always cut them to shape, remove all corners and arrises with a plate with a mallet. file, and planish the flanges and the Be sure every part of the surface is smooth and true. Remove all burs around drilled holes. Clean the metal carefully, polishing the bottom edge, and the surfaces against which the ballast is to fit. _ S Moulding the lead ballast is the next job to claim attention. Before starting this job, study Figure 62 and Figure 63. Plaster of Paris, moulders’ sand, and wood are employed for mouldmaking. oy, XA | Ete) Ficure 62 ~ Sr Figure 62 shows a mould constructed of wood, consisting of two members, 4 and B. It is made as follows:—lay out the fore and aft shape of the lead on each block—lay out and number the section shapes at the proper intervals——lay out the notches, or recesses, AX, to allow the keel to be clamped between the blocks, as shown in Figure 63. Make a template for each station or section shape, and gouge out the shape of the casting, in each block. Cut the recess for the keel in each block. Smooth the surfaces of the recesses for the lead and the brass fin carefully. Ay Pilot holes, large enough to take a 14-inch dowel, can be bored at each end, to insure the mould lining up properly, when fitted to the keel. Bore a 54-inch hole at X, Figure 63, for pouring metal, and small holes for venting at forward and aft ends of the ballast. | iii a gaan i C Di De Ps Se a i # i f an ae et a Bis Lean = Sth DS fe! i eee geese JB Ree ye ee ee aa gy Cal ee | i \ sh Tél ! ‘ Ne Feels d ss ll tO ee SIE ck mie er SE ed le TI dee oe) = . PS egies as, Jug oly se eo ol otic Mia Ean ee eo l we ‘%. oe be Coat the mould with a very thin film of plaster of Paris, to Ficure 63 prevent excessive burning, when the hot lead comes in contact with it. Clamp the fin between the two halves of the mould, as illustrated in Figure 63, making sure that everything lines up between coats with fine oiled sandpaper. properly. Melt the lead, testing it for the right degree of heat for pour- ing. The pattern for the lead ballast should be smoothed up very carefully and given three coats of orange shellac, rubbing down Use a pine splinter for this test. finished patterns. Figure 64 shows some The foundry method of making castings is The pine will char, if applied to the hot lead, when the right heat is obtained. Make sure to keep all moisture away from the lead pot and the mould. Should moisture be present, “splattering,”’ or even an explosion may take place. Now, pour the lead, allowing the gate hole to become completely filled, and watching for the appearance of lead in the vent holes, too. The metal should be poured in a continuous, fairly fast stream, as it cools rapidly. Allow the casting to set and cool. Remove the mould, and smooth the casting, using a file and sandpaper. The excess material left on the casting at the gate, and the vents, can be removed with a hacksaw. Making a ballast casting for a boat having a built-on keel, such as that designed for the ““R” boat shown in Figure 40, presents a somewhat different problem. As the keel or dead- wood really land on top of the lead, it becomes the fin itself. Ficure 64 Si nead screws, Wwemove the tCOp trom the DOX., Filace TN VDAaMAase pattern against the underface of the top, and bore the holes for ll ec % Z vy ® @ © me “ trl A jecs . Oo) a \ vit Kt. 1″ Aea .\ \ ge? 4 let ‘ 3 Ofa kK B.S.= Bow Sprir / > FIGURE 70 55 Label it 4. It should be straight. Plane the stock to size , making sure it is straight, squ are and smooth. cut to size. Lay out the length, and Gauge a center line on 4 surface and on each end. Label surfaces B, C, and D. and D surfaces from shape. X Lay out the curved tap er on B to the masthead. ance of a rectangular for m, derived from the pla nk boom orig inally used on lake scows. In D js seen a spar having a section similar to that used in the boom of the famous Cup Defender Plane the tapers to Ce Lay out curved taper on 4 and C surfaces. Plane to these taper marks. Refer to 2 in Figure 70, and use the method illustrated of drawing an octagon on the ends of the spar. By measuring a distance equal to one-ha lf of the diagonal fro m each corner (as shown at 4) and connecting the points with lines across corners. © Draw lines the whole len gth of the spar using the pencil and the finger as a gauge. Plane off the corners as shown at 3, Figure 70. The stick is now octago nal in section, along its entire length. Remove the corners aga in, all around, and it will be sixteen sided as shown at g. A small hollow plane can be used to comple te the work, but not having one, use a block pla ne, set very fine. Finish the spar to a tru e circular section by sandpapering , first with a coarse and finally with a fine grade. Hold the sandpaper in the left hand, and move the “> ® Enterprise with travelers fitted at intervals. These travelers permit the foot of the sail to ow out to leeward, the sail there- by attaining a more efficien t shape. There are some other spar spar back and forth wit h the right hand, giving it a rotary motio n during each stroke. The boom and the jib boom or club have a dou ble taper. True the material, cut the lengths, gauge the center lines, and Proceed in the sam e way’as when mak ing the mast. Ma rk the location of the out-haul holes, and drill them. Remember to have the surface of the spa r, nearest the sail, straig ht. Hollow spars are generally used on racing miniatures above 36 inches overall length. A spar made in this way holds its shape well, is Strong, stiff and has the advantage of being lighter than a solid stick of the sam e diameter. The saving in weight aloft, is particularly valuab le. Figure 71 gives the sect ion shapes of several types. At 4 is see n a circular or round spar. B shows an egg-shaped or modifi ed elliptical form wit h groove or track to take the sail slides. 56 a bulb-shaped C illustrates the app ear- Ficure 72 shapes in use on both full -size and miniature yachts such as the ““T,” the +, and the triangle, offering its apex to the sail edge. In E, Figure 71, is shown a longitudinal half section of a boom. This sketch shows how a hollow spar appears on the Note the solid places or dia phragms left when hollowing out. These are worked to strengthen the member and also inside. to offer solid wood into which fittings may be fastened. The location of fittings should therefore be carefully laid out when planning for the diaphragm s. The spar is made in two halves. Square up the material. Hollow the halves. Sandpaper the hollows, as this will remove ridges left by the gouge, and save considerable weight. Figure 72 shows a spar-clamping jig. The straight edge X is screw fastened to the board Z. The spar Y is placed against the straight edge, and wedged up as shown. Use waterproof glue and avoid crushing the spar when driving the wedges. Follow the same procedure when shaping as that described when making solid spars. After cleaning and sandpapering the spars, give them a coat Sand well, and apply three coats of good of thin white shellac. spar varnish rubbing down between coats. This will give a substantial and lasting finish. Lay out the holes and center-punch them. Drill the holes using twist drills for metal. Where holes are to be threaded, use a suitable tap, turning it in slowly. Before bending flanges or re- turns always anneal the stock. Use a smooth-jawed vise to hold the part, and work to the required shape with light even blows of the hammer. When joining the parts, clean them bright. Cover the surfaces to be joined with flux. Apply a dressed soldering iron and wire solder. The soldering iron should be heated until it readily melts the solder upon application. Dress the joint clean using a scraper and a file. Clean the fitting and polish, using emery cloth and steel wool. A brighter, smoother sheen can be obtained by polishing on a buffer wheel. Figure 73 shows the appearance of fittings suitable for service on a modern racing miniature. In z a bowser is shown. Bowsers are used to regulate the lengths of sheets and halyards. The diameter of the holes is governed by the size of the line used. A mast step is shown at 2. A notch is cut in the upright part to receive the heel of the mast. CHAPTER VII HOW TO MAKE FITTINGS HE fittings used on a miniature may either make or completely mar its appearance. They should be well proportioned for strength and appearance, harmoniously modeled and finished smoothly. Brass, bronze, or monel metal are materials which can be utilized for these parts. German silver is sometimes employed, too. Should the builder use brass, intending to nickel-plate the fittings, hard solder should be used where joints are made. Hard solder will hold under the plating heat. The general procedure when getting out fittings is as follows: Lay out the shapes. Cut to the outlines using snips, a hacksaw, or a jeweller’s saw. Dress the edges with a grinder and files. Holes are drilled, 1 inch in diameter, to lighten the fitting. Holes 4 are drilled in the deck flanges to take a 14-inch No. 2 roundhead screw. 3 illustrates the way a slot is cut in the heel of the mast to fit the step. The slot B fitting the step in this way, prevents the mast turning. 4 shows a forestay hook. 37 wire. The hook C is fashioned out of No. A 1}4-inch No. 10 wood screw E is drilled to receive the wire, and the head is ground off. The hook is soldered in as shown at D. A hole large enough to permit the passage of the screw is bored in the deck, and the screw is driven into the keel. The large hole in the deck is covered with a metal plate. 5 shows the way chain plates are made. No. Io screws, 114 inches long, are used for these. A slot, large enough to take the eye of the turnbuckle is cut as illustrated at F. The turnbuckle is secured with a threaded or riveted pin. 6 shows a ferrule. These ferrules are fitted at the forward end of jib boom, or main boom when a gooseneck such as the one shown at 77 is fitted. 57 Bows cr Go) momar eI © Mast STEP PLATE a i Wann 8 Ficure 85 Ficure vas will not hang as a plane surface, but will be concave when filled by the wind. In other words, the cloth takes the shape of a parabolic curve from luff to leech. This is the shape of a The shaded portions of the sails in Figures 80 and 81 show where the greatest bag or draft should come in sails bird’s wing. of this type. Broken lines in Figure 80 show proper curve when looking from the top of the sail toward the foot, the draft being near the luff and fading out into a flat leech. I advise making a template for each sail for a model yacht. This enables the maker to check himself when laying out another suit. If the first does not fit as desired, the template can be changed accordingly. Templates can be made of heavy wrap- ping paper or Bristol board. As the jib-headed rig is the most popular, let us consider its layout first, taking our measurements from Figure 80. These dimensions are for a 40-inch (overall length) craft. Draw the chord of the leech arc 49 inches long. The ends of this line will give the location of the head and clew. As some allowance must be made for stretching, allow 3% inch on foot and ¥% inch on luff. head, tack and clew. 86 Draw chords or straight lines between the The curve that is to be laid out on each edge is called a roach, and these roaches are what give the sail the desired shape. It is assumed that the spars are straight. If the mast, boom, or club has a buckle, you must allow an extra curve for it. Measure up one-third way along luff, and lay off 38 inch from straight line. Measure out one-third way along foot and lay off jg inch from chord. Divide leech chord into halves and measure out 2 inches for roach. Sweep a fair curve from clew to head, giving slightly more curve at top half of leech. Now sweep the luff curve in, and repeat the operation for the foot roach. Use a spline or batten for this purpose. Lay out batten pockets. These should be 14 inch wide, and three times the dis- tance of the roach from the leech chord. When laying out the template for the jib make the luf straight, allow the slightest roach along foot, and shape the leech as shown in Figure 80, 3%; inch being allowed for stretch on foot. Spread the sail cloth on an even floor or table top so that the 65 weave lies naturally without creases or wrinkles, securing so that it cannot shift. Place and secure template for mainsail, with leech chord parallel to the selvage, but far enough away to allow 34 inch for hem or tabling. Ordinary straight steel pins are best for this job as they make a very small hole in the sail cloth. Outline the template, using a very sharp-pointed soft lead pencil. Mark the place for the batten pockets, at leech and the inboard end. Now measure out beyond template for the hem allowances, 1% inch on luff and foot, and 3 inch on the leech. Remove the template and cut to these marks, using a sharp pair of scissors. When turning the “‘tablings,” as the sailmaker terms the hems, it will be best to do it the way he would go about it. Turn the leech tabling over roughly, for its full length. Place the point of the scissors at the head mark using the right hand, and with the left bring the crease on the leech mark. Now hold this much of the tabling by spreading the thumb and index finger along sail as shown and rub tabling with scissors, creasing to the leech pencil line. The scissors are held in the right hand and the fingers spread as in Figure 82. After you get started in this manner drive a pin in where the index finger would be and take a slight strain with the left hand, rubbing the crease with the scissors held in the right hand. This method will insure against distorting the natural shape of the edges, or stretching. Rub the tabling, singly, completely around the sail, and then place the raw edge in the crease which will give a double tabling when rubbed down. The tablings will now be % inch wide on the 8; inch on the leech. Tack the batten pockets luff, and foot, and in place. Do Vikevrise with any reinforcing or corner pieces that may be thought necessary for more realistic appearance and strength. The stitching down of the tablings is very important. Watch the tension of the thread, both top and bottom, so that drawing or puckering of the edges will not take place. Try it out first 66 Wik Cre oevane ON A WAStE PIECE OF SAIL CLOTN TOLACG WH HH LANE LtLartiy Run a row of stitching around the edge of tabling, as shown at a, Figure 83. Fold the corners at clew, tack and head so that no raw edges will show when sewing is finished. Starting 3 inches above clew on edge of leech run another row of stitching around the sail as 6 and c, Figure 83, ending 2 inches below head on the leech. One row on leech is enough, as it must be free and smooth for a proper set. More stitching would tend to draw or harden it. Sew batten pockets and corner pieces carefully, leaving a proper amount of slackin pockets so that they will not pucker the leech. Proceed the same way when cutting out the jib. Have the leech chord parallel to the selvage, allowing 34 inch for the tabling on the leech. Cut % inch outside of template for ta- blings on the luff and foot. Rub them up as on the mainsail. The stitching should be laid out as in the mainsail, two rows on luff and foot and one on leech. Let the edge row run around head and clew for 2 inches as on leech of main. Battens are not needed on this sail. If the instructions are followed carefully, a well setting sail with good draft and strong edges can be made. There are other methods of reinforcing edges. One is to bind the edges of the sail with a tape which has been creased double. This is done on larger sails. One must be careful when laying the sail edge in the tape that a proper relation between the tension of the sail itself and the tape is maintained. The tape should be shorter in length than the foot of the sail. In other words, slack sail is allowed. When the sail is stretched out along the spars this slackness will work out and the sail will be smooth. Another way, and one that makes for strength and snappy appearance, is to place a fishing line inside the tablings. Work the line out to the edge crease and run a row of stitching as close as possible to the line. Bleached or white materials can be tinted by dipping them into coffee or tea. They will then resemble Sea Island cotton. Should you tint your sails and they become partly wet when sailing, wet them all over before drying. ‘This will insure against unsightly stains and uneven fading, and the sails will hold their shape longer. If you are planning to lay out a sail plan similar to the one [here are several Methods OF bending Or securing Sails tO Spars. The most common is to fasten each corner and roll a lacing or thread about the boom and gaff, having hoops or rings on the mast. The principle of this arrangement is wrong, as the sail should not be in a fixed position on the spars. It should be allowed to come and go as occasion requires. Figure 84 shows a simple device which will allow the sail to be stretched out gradually and it can be completely slacked up when the boat is housed. The very smallest crochet rings are sewed to sail edges, as at R. Very small screw eyes or staples | aes i es Ficure 87 Ficure 88 shown in Figure 81, proceed as described for the jib-headed rig. Be careful to lay out the proper lengths for the two diagonals, y and 2, as these dimensions control the angle at which the boom and gaff swing. Make the head of the mainsail straight unless the gaff buckles, in which case you must allow for this condition. The luff of the topsail can have the slightest roach, but this sail should set rather flat. are driven into spars, as at S. A thin wire is passed through these, being secured at gooseneck, and made taut at masthead and outer end of boom. Staples can be made by bending pins * or using galvanized wire. A hole is bored in the end of the boom and an outhaul rigged with a bowser on under side of boom. Figures 85 and 86 show an arrangement that is neat and efhcient. A small aluminum tube, with an inside bore large enough to allow the passage of a bead, is cut lengthwise and spread. (Refer Figure 86, view 4 and C.) This makes a passage for the thread with which the beads are sewed to the sail edges, as shown in view B. The tubes are screw fastened to the mast, boom, and jib club. As the gauge of the tubing can be very light the weight will be negligible. Figures 87 and 88 show the jib and masthead rigging, using this device. The halyards, marked H in both figures, can be run down to deck if desired. Should the builder decide to use spars having a bulb-shaped track worked in them, similar to the one shown in Figure 71, glass beads can be employed to serve as slides. Bend your sail, hauling it out toward the ends of your spars gradually. Do not try to make it go out to the limit at first, for if you do, a “nigger heeled” leech will result. Pull out, exerting a fair strain each time the boat is sailed, and eventually it will be completely stretched. When through sailing slack your outhauls and halyards. 67 Witte lg Rinx RIGGING HE rigging for a miniature should be simple and reliable , and should be designed and fitted for easy and rapid handling. If these few items are borne in mind, the sailor will derive much satisfac tion, especially when sailing under cold conditions or from a skiff , as one must in open water racing. Rigging can be divided into two main divisions. Standi ng and running gear. The standing rigging serv es to keep the spars in the boat, and to hold the spars in shape, that is, to prev ent their springing or buckling. It includes the various shrouds and stays. Turnbuckles set up or haul taut the standing rigging. They can be procured in 34 inch, 1 inch, 114 inch and 1% inch sizes. Galvanized, bronze, or German silver wire can be employed for standing rigging. On the larger classes of miniatur es very fine aeroplane wire, or the wire used to hold cloc k weights Is sometimes used. The running rigging serves to hoist, spread, or trim the sails, when they are set. Very fine linen or silk fish- ing line will serve for running rigging, as it can be readily spli ced to the various spars and fitt ings. Running rigging includes the halyards, sheets, outhauls, laci ngs, and guys necessary to a miniature boat. The raw ends of all running rigging should be whipped or back-spliced to keep the line from unraveling. Har d- ware stores can furnish all kinds and sizes of wire , and fishing- tackle dealers handle several grades of line which can be used. Little will be said here abou t halyards and sheets, and how they are rigged, as they are sho wn in the chapter on sail making, A rigging plan for a gaff-hea ded sloop is shown in Figure 89. The stays which hold the mas t in a fore and aft direction are the headstay, 4, the jibstay, B, the forestay, C, the backstay s (one to each side), D, and the masthead runners or prev enters (one to each side), E. The arr angement of the shrouds, or stays 68 which support the mast in a lateral or sidewise directio n are pictured in the end view. Top mast shrouds are shown at F, main shrouds at G, and the lower shrouds at H. Eyes are spliced at the upper ends of all stay s and shrouds and slipped over the masthead, being fitted to enci rcle the spar. The bobstay is fitted at J. It is given greater purchase by the small spar or strut called a martingale. All stays are fixed, with the excep- tion of the backstays and runn ers. Set up as occasion requires. When These can be slacked off or the main boom js slacked off to leeward the lee runner and backstay must be slacked to permit the boom to swing outb oard. The weather stays are set up to brace the mast. There are few miniatures rigg ed this way today, although occasionally a person is foun d with a cruising turn of mind, who just wishes to knock arou nd, adjusting and manipulating a rig of this type. In Figure go is seen a simp le rigging plan for a jib-head ed The forestay, 4, has a ring fitt ed at the lower end. This ring engages the hook on deck. There are two shrouds, B, lead sloop. fairly well aft. They are set up by turnbuckles, D. When the turnbuckles are slacked, the fore stay ¢an be unhooked, the mas t unshipped, and the whole rig rolle d up for transportation. No. 22 wire is large enough for stays on a 36-inch boat. Heavier wire must be fitted on larger craft . spars must determine the size. The shape and weight of the Figure 91 shows a jib-headed rig having a jumperstay, J, fitted to prevent the backward spring of the mast. A strut, @y is installed to push the jumperst ay out forward and give it good purchase. This strut is one-eigh th as long as the distance from the masthead to the place wher e the forestay joins the mast. A turnbuckle, placed just abov e the strut, regulates the tens ion on the jumperstay. B shows a permanent backstay running from the masthead to the taffrail. It is also regulated by a turnbuckle. A backstay of this type is very effective when a boat Ficure 89 is reaching or running, as it steadies the whole rig and prevents weaving at the masthead. The boom end must be far enough inboard to allow it to swing freely from side to side. The lower end of the jumperstay is secured at a point two-thirds of the way down the mast. A jib-headed rig having a short jumperstay, 4, running be- FicureE 89 tween the masthead and FIGURE go the finger plate which secures the upper ends of the forestay and shrouds, is illustrated in Figure 92. The turnbuckle, B, controls the tension on the stay. A headstay, FP’, is also fitted on this boat. Such a rig as this is needed on large, or heavy boats, to insure the spar staying in place. Then, too, a mast must be supported to enable it to maintain 69 FicurE 93 70 Ficure 91 Figure 92 its designed standing position, otherwise the sails will not set properly or retain the desired draft. Methods of fitting spreaders and systems of rigging shrouds on masts for the jib-headed rig are shown at 7, 2, and 3 in Figure 93. It hardly seems necessary to explain them, as they speak for themselves. The reader can readily understand them, after having perused what has gone before. One of these systems of staying must be used for support in a high narrow sail plan, and the builder can modify them to suit his own particular problem. Four different types of bowsers are illustrated in 7, 2, 3, and 4, Figure 94. Bowsers can be made of metal, wood, or bone. At 5 an arrangement called the ‘Liverpool Boy,” is shown. This device is used to bring a boat about, or for tacking, when some distance from the bank, in pond sailing. It consists of a Y%-inch rubber band, 4, which may be flat or round, about 5 inches long and a sheet, B, the length of which is regulated by a bowser, C. The rubber band is hooked into the screw eye, E, placed just forward of the weather shrouds. The sheet is rove through a hole in the forward end of the band, passes through the hook-eye, F/’, and up to an eye screwed into the jib boom. There is an eye in each side of the spar, as shown at H. These eyes are located about 3 inches aft of the forward end of the jib boom. This gear is used in conjunction with the beating guy. The beating guy is a rig consisting of a rubber band about 8 inches long, having a rope eye at one end, and a lanyard with bowser at the other. The eye is passed over the outboard end of the main boom, and the lanyard with bowser is hooked into an eye on the weather rail. The tension on the guy draws the mainsail to weather, thereby swinging the boat’s head into the wind and eventually putting her about, and on the other tack. It is very useful when the occasion demands a short board to fetch a finish line. t= =I FIGuRE 95 = 71 OVERHAND Sf a RUNNING BOWLINE Two HALF ¢ WITCHES CATSPAW fia OOUBLE SHEET BEND B REEFKNOT CARRICK BEND Prats J A spinnaker, 4, is sho wn at 6. Piate II The spinnaker boom, B, is held on the mast by a gooseneck, similar to the one used to hold the main boom, hav ing a bell-shaped socket to receive the end of the boom. This arrangement permit s the spinnaker boom to be unshipped. C is the spinnaker guy and D is the sheet. A preventer is seen lifting. This stops the spinnaker boo m from Bowsers to regulate len gths are fitted on the guy , sheet, and preventer. 72 at E. OW THE BienT The method of riggin g a jib sheet and a mai nsheet is illustrated in Figure gs. Plates I and II show kno ts and splices the sailor s use. Plates IIT, IV, V, and VI ill ustrate and describe the way these knots and splices are made. ture or model This data should be of value to the minia- builder desiring to produce an out standi ng job, Knot reproductions are by courtesy of the Whi tlock Cordage Company. A rope’s end = should always ag rurae to prevent rig. 1 ‘ fraying out The best method is by ordinary whipping. This ig done as follows: First lay the end of a length of twine along the end of the rope. Commencing at the part farthest from the rope’s end, take six or eight turns around both the rope and The Oursipe CLincn is formed ! in CLINCH twine end visible the will (Fig. The ComMMON 3). Loop ¢ by close to the commencement be ; shown FIG. LOOP around the loop y and Z, we shall term ae au is toop is often called from 3 to To 1 BOWLINE haul e KNoT made backing ¢ behind a; qa bring j and ! over pass through at 2 is bight SIMPLE © CLINCH pull 6b around then BOWLINE The RUNNING BoWLINE is made by forming a loop, with the long end z © lying under the standing Part a (Fig. 1). EN Next bringthe the and taut. the bowline knot on part 2 just as, in the previous case, we formed ‘it over its own z down Fig. 2. FIG. 2 end ¢ over y and with it form al by part taut asin 4 we Ercut e FIGURE EIGHT part. This knot is when a running required. used noose is aR vi RUNNING BOWLINE A ‘SIMPLE CLINCH ig formed by closing up the initial loop to form a small ring and maki ng fast bya small lashing, or seizi ng, at d. RUNNING OR of a for uses, aS FIG,2 is a temporarily b before passing the end c A MIDSHIPMAN’s Hitcuis often HITCH To make a BOWLINE ON THE Ye BicHT: Using both parts of La A FISHERMAN’S BEND is made by taking two round turns around the object to which the rope is to be secured, and then backing the end around in the form of a half hitch under both the standing part and second by a half hitch as shown in diagram. This knot is often called a BucKET HitcH Hiren used instead of the BLACKWALL Hitcu, because it will hold better if the rope is greasy. It is made by first forming a BLACKWALL HITCH and then taking the underneath part and placing it over the bill of the hook. MIDSHIPMAN’S TIMBER 205 ¢H the TIMBER HITCH round turn. The end may be further secured of BLACKWALL under a, it will hold much HITCH more securely. should besupplemented by a Harr Hitcu FISHERMAN’S BEND way securing a rope to a_ hook, It consists of a HALF Hiren. AS soon as 4 receives the strain ¢ it jams the end part ¢. By taking another round turn at b sti BLACKWALL the rope together, commence ‘as in making the ! BOWLINE i diagram). S / FIG. 1. ordinary (see previous To finish, @&@ 2) ‘ open out bight ¢ and, Aya taking it in the direc- AAX i tion indicated by the (ASS dotted line, pass the whole knot through it and haul taut. It will then look like Fig. 2. FIG. 2 BOWLINE ON THE BIGHT SSSISSSSSSSSMSSSSNH The Topsam HALyYAarD BEND is seldom seen in deep-water ships, but often is used aboard yachts. It is begun in a manner similar to the FISHERMAN’s BEND, but three round 6 qsssmmnpsss Usssssssssssssany” FIG. 1 TOPSAIL ea turnsare first taken around a spar, the end being backed around the standing part @ and then led under all three turns, and finally again backed over the last two round’ turns and under the first ae in the diagram. is A SHEEP SHANE ing used a for shorten- rope. First take up desired amount of rope as shown in Fig. 1. Next, with parts a and b make a Hatr Hitcu around the two parts of the bight as pictured in Fig. 2. To make the SHEEPSHANK more secure, the bights a and b may be whipped or seized to the standing part FIG. 2 a SES b SSS AAAS Se SHEEPSHANK INSIDE CLINCH A RUNNING or CLINCH is formed end free oer soa must be pointed steadily in one direction, Tey by the dotted line, and OVERHAND Ficure tie a BOWLINE: Revert- quick Sige esti en The TimsBer Hitcu is a useful way of securing a rope quickly to a plank. When there is to be a long, continuous strain, or when the tim- down through the last made loop, as shown To tie an OVERHAND Knot place c through the bight 6 and draw taut A kept other of 4c ing to the original loop, 7 take part z in the right hand and y in the left. < Qa KNOT the in securing ratlines to the cLove shrouds. Its formation is HITCH shown in Figs. J and 2 Throw a loop over c, the end, as in Fig.J. Second, lead ¢ around behind a and pass it standing part, we shall call a". The portion included between 2 and 3, following The end ‘ HITCH future reference. The part from 1 to 2, known as the the “bight”. shall call ‘‘c’’ CLOVE : end again over y and then through the last loop formed, so that c lies BUNTLINE part 2. to the left is used in commencing most of the knots herein described. Its parts are lettered and numbered for COMMON ll FIG. 1 A oO pass the longer end c over y, bring cut off short and no 3 jam, but always ready for slipping at short notice. it up through bight b, and tuck the pulling part ‘‘c’’. Then BSssssswlly FIG. tightly A CiLove Hiren is prac. tically a jamming form of Two HALF Hircugs. It is chiefly used when a small rope has to be secured to a the A BUNTLINE HitTcu is commenced by making an Outsipg CLINCH. But instead of putting ona seizing, continue to take turns tightly around the rope and part ‘'b”’ of the twine. When the through to. HITCH lay the twine in the FIG. 2 form of aloop along the rope and over the turns already taken (Pig. 2). To finish, take portion of loop marked ‘“‘a’”’ and remainder manner OUTSIDEto the twine end (Fig. 1). BSS)b Next . similar brought around on top, away z from the bight. It is used for securing hawser ends, where the end should be in a position not J o loop is nearly used up, pull a INSIDE CLINCH, but the end c is a rope on HALF HITCH itsown standing part. It ig usually used for secu ring buntlines to the foot of a sail. A Carspaw is formed in a rope INSIDE by the of to TWO HALF HITCHES The formation of a HatF HITCH, and Two Harr HitcHes, may easily be cena by a study of the above, Puiate III two diagrams make a temporary loop for fastening on the block of a tackle. First throw back a bight. Then, taking hold of a and 6 @in either hand, twist them up. CATSPAW Bring together the two eyes and hook in the tackle. A DouBLE CarRRICK BEND is ‘ormed in exactly the same manner as a SINGLE CARRICK BEND, buta AY complete round turn ig taken /7 4 around the cross of the first rope (QH at c, and then led up again GhiNoa) through the eye b and finished off Wey as before. DOUBLE AY, Prats IV i . CARRICK WY BEND [fj 73 SPLICES. The Reer KNOT is verysimple. Itisused THE when a common tie is required. FIG. 1 FIG. 2 REEF KNOT Its for- mation may be easily traced by the above diagram Be sure to front of b, as shown, and the which is the desired size of the eye. Lay the three strands keep a in end c led in according to the dotted line The Common or SHEET BEND: In making a bend the ends of the two ropes are not used simultaneously as in forming a REEF 4 Knot, but an eye, or loop, is ~ first made in the end of one rope, as in Fig. 1, and the other rope's end is then led through in various ways according a FIG 1 to the bend desired. F In forming a SHEET BEND, pass- d rope’s end under secon and neath the eye at pointthea, loop. the 5 IG. the lay of the rope.) Then pass 2 FIG COMMON OR 3 SHEET BEND A Carrick BEND is used for : bending two hauling 3 lines together. First, with of each rope to their own respective parts as in Fig 2 CK CARRI izaS <— it over FIG FIG. 1 to the lay of the rope. Qua esses A SHortT SPLICE is used to join two ropes quickly when they do not have to pass through a block or First over a_ sheave. alternately between the strands of the _ other. Then tuck the rope a into the rope b in a similar manner to that described in an eye splice, and Spon lkewioe tuck the strands FIG. 3 4 BEND the strands of one rope go css Note before the fourth tuck that the strands are always tucked in the direction opposite FIG. 2 unlay the two ropes the and distance required clutch them together as in Fig. 1, that is, so that FIG. 2 Now tuck each strand again alternately over a strand and under a strand of the rope, and then taper off by halving the strands before tucking the third THE LONG SPLICE THE SHORT SPLICE ses on the other side of the rope time. And again halve the halves Sa the eye b, back FIG.1 the cross at c, and bring it up again towards you through the eye b. Then stop the ends t S = CSS ean first at a, bring up through é fy de 4 the strand on the left over the strand under which No. 1 strand istucked, and tuck it under the next. Last, put the remaining strand through the third strand ii 1 form a loop rope No. as in Fig. 1. Pass the second rope under the 74 strand of the the through standing part next to it (against 5 bring it up through H Then form with ita Harr Hitc It around ¢ and b. See Fig.if 2.the will then hold still better end c is passed around a second fig. 2 time standing part @ against the Now tuck the middle strand 1 F 1G. of rope b into rope a, as shown in Figs 2 and 3. THE CUT SPLICE SPLICE. THE An Eve Spuice is formed by unlaying the end of the rope for a short way. Next, form a loop 3 i 2 EYE The Lone Spice is very useful, for it permits a spliced rope to run through a block just the same as an unspliced rope. First, unlay the ends to a distance four times the length used for the short splice. Then clutch them together as if about to commence a short splice. Now unlay one strand for a considerable distance further, and fill up with the strand opposite to it of the other rope. Then do the same with Let the remaintwo other strands. ing two strands stay as they were first placed. The ropes will now appear as in To finish, tuck the ends the diagram. in as in the SHORT SPLICE, but with the lay of the rope, or so that the tuck will continually take place strand. the yarns in the strand, Pate V around the same Taper off by gradually reducing A Curt Spricge 1s made by laying two ropes in the position shown in Fig. to1. Leaving the ropes between a and @ form an oblong loop, tuck the strandstheof one rope into the other as done in Eve Spice. Splices are often served, or GROMMET To make a GROMMET, cut a strand about three and a half times the length.of the chia ccideloarien Dsl the rope carefully to keep in. the turns (of the strana pa cone caine strand to HG si abigele pe hie ys ds EE i 4 Ae i es original ‘ay soune until all the intervals are wormed, as is shown.in Fig. 2. FIG. 3 in Fig. 2. filled up, as Finish off the two ends as in the Lone Sptice, Fig. 3. Pate VI CHAPTER XI HOW TO DESIGN AND CALCULATE A MINIATURE YACHT ESIGNING and calculating a miniature racing yacht is a most fascinating phase of the miniature yachting sport. It is recommended that the novice study the plans of experienced designers, and build boats from these plans before attempting to originate lines of his own. Sailing miniatures, observing their qualities when in action, and making adjust- ments for improvement in behavior will also give the embryo designer invaluable experience for future efforts. The person showing ability in design is generally a combination developed by having had experience in building and handling boats, imagination or ability to visualize the results of the actions of a vessel when in her element, plus the knowledge of how to apply certain scientific principles. The successful designer must possess some originality, too. In short, the elements found in his make- ee —s ae ‘ie a et — a : toeA ie Pas — : ee The Aare " | | BSS 5 é PV Si tay ~~ TS eH TS cvs MAAS IN Hm SSS ca A = = = z — pS SS St - “20 ie ates ree a Lines of “Enterprise.” Her dimensions are: L.o.a., 120' 9!'; w.l., 80’; extreme beam, 21' 8''; extreme draft (without centerboards), 14’ 8''; displacement, 128% ot: tons; sail area, 7,583 sq. ft.; height of mast (over all) Se eS SS C we Li ieee iz SS ipa seas = a _ 5 ; SE FIGURE 96 up may be practical experience, natural genius or inherited talent, plus the faculty to employ scientific data. The model tank, laboratory, the field of experiment in hull The objectives to be attained are fitness to purpose or con- ditions, symmetry or harmony of proportions, and esthetic appearance or beauty. If these objectives are attained, a speedy form, sail plans, simplified rigging and fittings, and improved craft is produced. spar shapes, offer never-ending employment for the faculties of synonymous with beauty and speed. an individual interested in this branch of the sport. long sailing lines, moderate displacement, and small wetted sur- Sweet, clean, fair, easy-flowing lines are all Properly proportioned 75 | | i face, when powered with a proportionate amount of sail area, make for an efficient design. When long sailing lines are desired, they can be procured in two ways: first by designing with a long water line and fine ends , or secondly with a short water line and full ends. It must be borne in mind that a boat with fine ends will have an easier acti on in a disturbed sea than one having full bow and stern sect ions, when planning a hull to meet the conditions under which it is presumed she will be sailed. Easy performance means mor e power, too, as when the sails are kept “asleep” they function most efficiently. A study of the lines of Enterpri se, Figure 46, will aptly illus- trate the foregoing points. Her V-shaped forward and after sections give her a rather fine bow and stern, which coupled with her generously curved, well-proportioned midship sect ion, and full deck line at bow and stern “which give high kine tic stability and unusually long sailing length when driven jn a heavy wind and sea,” are prod uctive of a yacht very well suit ed to the purpose of defending the America’s Cup, in weathe r to be expected off Newport. That all the elements whi ch go to make up the design of Enterprise harmonize, is very apparent . The lines of Enterprise are here with produced by the genero us kind_ ness of Mr. W. Starling Burg ess, her talented designer. Figure 97 shows the lines and sail plan of Shamrock V. Observation of her sections will’ reveal the rounded or U-type. This shaped section will mak e more of a fuss than a shar per one, but is very efficient und er moderate wind and sea cond itions. Her lines are very sweet and artistically beautiful. They are included by the courtéous perm ission of Mr. Charles E. Nich olson, the designer of many famous racing craft. A rare opportuni ty is herewith presented to com pare the lines of these two famous yachts and to speculate on the reasons for the sweepi ng success of Enterprise. The same fundamental law s of yacht design apply to minia- tures 76 as they apply to life-size boats, with some exceptio ns. Ficure 96, Continued Let Construction plan, showing location of centerboards, winches, and the like Ficure 96, Continued One very important point to be remembered by the designer of miniatures is that the boat must be perfectly balanced. Whereas, minor defects in the balance of a large yacht can be overcome by the helmsman, this obviously cannot be done in the case of a miniature. In other, words, a miniature must be so designed and rigged, that when set on a course, provided her sails are properly trimmed, she will be able to sail that course truly. When a craft can perform this manceuver, she is said to be well balanced. To effect this happy state of affairs, the fore body must balance the after body, when upright, or when the boat is heeled under sail pressure. The relation of each section in the fore body to that one which corresponds to it in after body has a great deal to do with balance. It is pretty generally conceded that the areas of the sections in the fore body of a boat, when plotted, should give points through which a versed sine curve can be drawn; and those of the after body give points through which a curve can be drawn approximating a trochoidal curve. This is illustrated at 7, Figure 98. The curves are plotted in 77 this manner: The horizontal line W—L is the L.W.L. of the boat drawn to scale. For example, %-inch scale of a 40-inch L.W.L. would give a line 10 inches long. This line is divided into sixteen equal spaces as shown at J, 2, 3, 4.5) 0) 7) 8; 9; 10; II, 12, 13, 14, 5, and z6. At these points ordinates are erected. At the ordinate M—/A which will represent the immersed area of the midship section, a linear measurement equal to the area of the midship section in square inches is laid off. For example, the midship section has an area of 33.60 square inches. Using a j'g-inch scale would give 2.10 inches. Lay off this length on the line M—A and bisect the line to find its center. Now draw a circle having as its diameter the line M—4. This circle is known as the generating circle. Break the circle up into sixteen parts as shown at 7’, 2’, 3’, ’, etc. Draw horizontal lines from these points to the corresponding ordinates as 7, 2, 3, 4, etc. A curve, V.S., drawn through the points obtained in this way will be a versed sine curve. The trochoidal curve is drawn by laying off the horizontal distance from the center line M—A to the division mark on the circle, on an extended horizontal line, measuring from the corresponding ordinates. For example, the distance from the center line to 75’ is laid off from the ordinate 75 on the first broken horizontal line up from the line W—L. The curve, T, drawn through the several points will be a trochoidal curve. These two curves are geometrically constructed and are for comparison only. At 2, Figure 98, a versed sine curve, and a trochoidal curve are shown by the broken line. Superposed, for comparison, is a “curve of areas.” The length of each ordinate is found by dividing the actual area of the corresponding section by the 3/g-inch scale, and setting out a linear measurement, as described for the midship section, when developing the curves in 7. The degree to which the curve of areas should approximate the geometric curves is one for discussion. This example is for a hull when upright. Curves of areas can be drawn for any angle of inclination, 78 FIGURE 97 Lines, body plan and construction plan of “Shamrock V.” Reproduced through the courtesy of Charles E. Nicholson. “Shamrock’s” dimensions are: Length over all, 119 feet 10 inches; water line, 81 feet; beam 19 feet 8 inches; draft (without board), r4 feet $ inches; displacement, 134 long tons; sail area, 7540 square feet. Ficure 97, Continued 79 h. | ae IZ —| a oer re = i AMERICA a : . Buoyancy is the power which tends to keep a vessel afloat, or the upward pressure exerted on a body by the water. The “Center of Buoyancy” is the center of displace- ment, or the center of the upward or buoyant action. Counteracting buoyancy is gravity or downward pull or COLUMBIA a which the whole weight of a vessel tends to act downw ard : It may be considered as the point at which the whole weight of a body is : F . concen- j L. —_ i a S= : q ers VALKYRIE om a ft RESOLUTE (1 ere = pe ee a —F_P sie. i VIGILANT oe SHAMROCK VALKYRIE Ml — ATALANTA CS SHAMROCK =<. N eee —TM \ a qa eregerd | SS — L — ed hg sas ms RELIANCE | YY SAPPHO ~_— \ aan mea ad a eT i eer =F Tt an tJ SHAMROCK — { LIVONIA The “Center of Gravity” is that point throug h or toward the earth’s center. A ras XU \ MAY FLOWER aie <= | THISTLE eee lation each section will bear to the longitudinal center line of the boat, and where the greates Fs t buoyan cy may y be looked g yancy 80 abs: MAGIC and when carefully studied give the designer a good idea : SJ — of just how the area of each section is distributed, what re- aa GALATEA CAM BRIA = | if ral oe @ pressure. = i { GENESTA A cae (a Ss \ enone 8 SHAMROC PURITAN a Ss F } rats, are v.s. ee —_S== MISCHIEF See earn —- Ne DEFENDER FIGURE 99 WEETAME ay, coq / | | SE We = FIGURE 104 FIGURE I00 FIGuRE 102 FIGURE 103 FIGURE 105 81 9 ' 1 | | 1 ~ +--+ | 1.2 BILGE 1 Dia GoNAL | trated, and the distribution of the sever al members of the hull, spars, sails, fittings, etc., determine its location. Buoyancy and gravity must be kept in mind from the very start when designing, because they must be so related that they will tend to help the boat rather than hinder her. The location of the fin or keel of a boat will have a noticeable effect on her behavior. If the forwa rd or leading edge tends 82 | Figure 106 to cut downward or bore, this will act against buoyancy, and slow the boat up. The long lead ing edge for a keel is best. This desirable feature can be seen in Figure tor, which well illustrates the triangular form of later al plane. Such a form of lateral plane has the least tendency to cut downward. A study of the development and change in the style of lateral planes of the America’s Cup boats should prov e interesting. See Figure 99. A ; om en —see P Nor a boat to trim properly the “Center of Gravity”? must come directly under the “Center of Buoyancy,” or a vertical line. When this condition obtains a boat is said to be in equi- librium. AS % s Ne h A Ng < 4 N A exist in a longitudinal, as well as in a transverse direction, for a vessel to trim properly. It is desirable to have this relationship re- * A A D ¢ E main constant at all angles of heel, and at all speeds, for best results. Should a craft settle or “squat”’ by the stern, it may change her sailing lines, thereby improving her performance and speed, FIGURE 107 but most times it stops her, by what is known as “dragging.” a. ee ‘This relationship between the C.B. and the C.G. must PRR ei F The form or shape of the overhangs, when immersed, and their relation to the middle body of a boat must be carefully studied. They must be so designed that the forward and the after overhangs will balance the middle body, and each be en- abled to do its allotted work. ‘‘Tumble-home”’ is sometimes introduced throughout the middle body to further this condition, but it is not always effective in producing the desired harmonious A condition. If a midship section having the right outline productive of some initial stability and holding power is designed, the other sections can generally be so shaped that they will harmonize with it, and a sweet, clean-lined boat result. A H J G Initial stability is the term used to describe the ability of a Ficure 108 K ——— x 4 RS * h h ne ee x hull to float upright without ballast. ee Acquired stability is the term used to describe stability ob- ieee le = Ah M FIGURE I09 x A The designed shape of the hull determines this important attribute. tained by ballasting with lead on a keel, or the stowing of weight inside a boat, to keep her on her feet. a A g A It is well to clearly understand that a heavily constructed, thick-skinned hull will take less ballast to bring it down to its L.W.L. than a lightly constructed, thin-skinned hull. The latter type of hull will have a lower C.G. which is desirable, provided it isn’t overdone. Figure 1oo illustrates this principle. At (z) is seen the midship section of a light-displacement boat, with a deep bulb fin. 83 Such a form is driven easily, but with the low C.G. and high metacentric height MM, the boat will be quick on her return to heavily against this type of yacht. A is the more desirable. The hull form shown at (2) The C.G. and C.B. being closer together, with a lower metacenter, her motion will be more graceful and y . i D> AWN the upright, in a seaway or a fluky wind. This bad feature weighs dignified. She will heel over slowly and easily to the breeze, and be correspondingly easier in her recovery. This latter type will sail more on her side than the fin-keeler, in a given breeze, but it can be readily seen that this feature will not be to her disadvantage, all things considered. A FIGURE IIO When it is necessary to gain displacement to enable a boat to carry more ballast the sections may be broadened or thick- ened in the garboards, as bulkiness does the least harm there. One must bear in mind that roundness, easy curvature, long diagonals, and flat buttocks properly harmonized, will function well under nearly all conditions. Keep the ideas in mind, too, that the longitudinal form determines the amount and location of the ‘‘Center of Lateral Resistance’’—a long deep keel will make a craft slow in coming about—a short deep keel tends to make a boat quick in stays—lines which balance and harmonize at any angle of heel are most efficient, as the boat seldom sails on an even keel. Resistance is an important factor to be considered. It is caused by different wave systems, eddy making, skin friction, and air resistance. It has been ascertained by experiment that several wave systems are set up when a hull is moving through the water. The waves at the bow resemble a series of arcs, those along the middle body take the form of trochoidal curves, as do those at the stern. The hull must be so proportioned and shaped that these separate wave systems will synchronize and swallow one another up, or even themselves out. This neutralizes the disturbance of the water, as the yacht moves forward. ALLER Bopy Ficure I The fastest hull will be the one which disturbs the water least. A well-shaped hull, with a harmonious rig, will set up a steady the streamlines on the after body have their own effect as the system of waves, or pressure variations, and the boat will move yacht moves forward, these facts must be reckoned with. forward smoothly, making very little fuss. Eddy making can be prevented by streamlining the entrances how these different actions seem to neutralize one another, so and runs of all members such as appendages, rudders, struts, tion of the rig. The method of doing this is illustrated in Figure and the elimination of bulwarks and rails. 101. Skin friction can be prevented by reducing the immersed area Some- that a good approximation or fix can be arrived at for the loca4 shows the relation between C.E. and the C.L.R. which produces weather helm, B the relation which produces perfect or wetted surface to a minimum, sufficient to serve the design. balance, and C the position of the C.E. which produces lee Maintaining a smooth, glossy finish or paint job on a boat, will lessen skin friction, too. helm. This relation, that of C to the C.L.R. is the right one to be attained in a miniature yacht. It must be remembered Air resistance can be cut down to a minimum by streamlining that the bow-wave will tend to make the boat come nearer to spars, spreaders, struts, and doing away with all unnecessary the wind as she gains speed, therefore lee helm is a necessary rigging and cordage. Attention to this matter will make some condition. The amount of the lead of the C.E. to the C.L.R. difference in performance. varies in different types of hulls. The proportion of headsail area to that of the mainsail is a factor to be considered when drawing the sail plan. It is main- of the L.W.L. is effective. tained that the jib of a modern sloop, with 50 per cent of the area of the mainsail, does as much work as the mainsail. These straight edges, splines or battens, and spline weights (as shown in Figure 102), T-square, triangles, protractor, scale rule, slide proportions for the areas of the jib and mainsail, then, are theo- rule, proportional dividers, planimeter, set of drawing instru- retically ideal, and seem to work out well in practice. ments, set of ship curves (as shown in Figure 103), thumbtacks, It is a difficult matter to obtain the much talked of valve effect with the sails of a miniature, as they cannot be sheeted home effectively when they overlap.. If the draft is worked into the jib and mainsail properly, the leech of the jib can be fitted very close to the luff of the mainsail, without “backwinding” taking place. From 2 per cent to § per cent The tools needed when designing are: a large drawing board, tack lifter, India ink, and erasers. A planimeter (as shown in Figure 104) is a simple instrument to use, and a wonderful time-saver. If this device is not used when calculating, one of Simpson’s rules, or the Trapezoidal rule, must be employed. A composition batten or spline (as shown in Figure 105) is very Locating the center of effort in relation to the center of lateral resistance is a job which requires patience and great care. The theory of this feature of designing is that as the boat useful. It can be bent to any desired shape and will “stay put.” Reference to Figure 106 will give one an idea of how the lines of a yacht are drawn. The procedure is as follows: Determine works to windward the center of effort moves forward of the the length of the load water line, and draw it in. calculated position, and as the boat heels the center of lateral the length overall and how much overhang you will have for- resistance moves aft. As volumetric displacement is redistrib- uted to a greater or less degree (according to whether the yacht is of discordant or fairly harmonious design), and the action of ward and aft, and locate the points. Determine Divide the L.W.L. and the overhangs up for the required number of stations. Draw the vertical lines, extending them upward far enough to take in 85 the free-board of the hull, and downward to take the under- body, the half-breadth plan, and diagonals. Lay off the free-board at the bow and stern, and at the point Draw in the half-breadth plan at the sheer line, as the midship section, the bow section, at the F.P., and the stern section at the A.P., develop. mind when laying out the rake of the stern or rudder post. Some Lay in the shapes of all sections in between the ones already drawn, developing each succeeding shape from the one. finished. Draw the diagonals in the body plan, and develop them as shown by the “bilge diagonal.” These will be of great assistance in fairing. Lay the bow and buttock lines in. aoe will also serve designers fight shy of a rake, feeling that this introduces the to assist in fairing the design. possibility of the after body being dragged downward when the At this stage in the design, when all section or station shapes have been tentatively laidin, it may be advisable to do a little estimating. Calculate the areas of the immersed sections and compare them with the curve of areas previously laid out as a guide. If this has not been done, it will be worthwhile to do it at this point; to check up on the way the lines are developing, where the least free-board is to be located. Draw in the sheer line. Determine the extreme draft needed, or that the rule you are designing to will allow, and draw in the profile of the keel including the overhangs. It is well to have “rudder action” in helm is put down, and that lifting will take place when the helm is put up. Little harm is done, if any, by having a conservative rake, for if driving, or sail power and hull are in harmony, very little rudder angle is ever needed for proper steering, on a miniature yacht. Settle on the beam of the boat, and draw in the midship sec- tion. This section should be so placed that the after half of the L.W.L. will equal the forward half of the L.W.L. at any inclined angle. This section must not be too hard in the bilge, nor can it be too slack. A happy medium must be decided on. This phase of design is worthy of lengthy consideration. the water lines, and draw them in. Space Station lines and water lines drawn in with ink serve best, as much erasing can be done without the loss of these necessary lines. Lay in the bow section shape which is to be located at, or and to enable the designer to make corrections. Fair all shapes preparatory to the final calculations. Calculate the displacement. Calculate the rudder area needed for efficient steering, and draw in the shape. Allowing for the weight of hull, spars, sails and fittings, calculate the amount of ballast the hull can carry to bring it to the designed L.W.L. Lay out the “top of lead” line, after ascertaining where it will come by calculation. Find the center of lateral resistance of the under-water plane near the forward perpendicular. Keep in mind that the bow form must be full enough to help gain sailing length, but must and mark it on the sheer plan. also be fine enough to insure easy entrance. sail plan. Lay in the stern section shape which is to be at, or near the after perpendicular. Do not shape this too fine. Design this section to help sailing length, to prevent “‘squatting,’ and to Design the rig and find the center of effort. Draw the spar and sail plan, locating the C.E. in proper relation to the C.L.R. Check over the work, marking for ready recognition all lines, prevent the boat “slewing” to leeward, when she experiences sudden wind pressure; thereby causing her to shoot up into the stations, diagonals, buttocks, and views. wind’s eye. etc. 86 Mark it on the Calculate the design for proof, i.e., her ability to carry sail, Calculations The sum of each ordinate, plus twice the sum of ordinates Nearly all areas to be calculated in yacht design have curved outlines on one or more sides. These curves are generally parabo- las of the first, second, or third order. ‘The required areas can be calculated by one of Simpson’s rules, or the Trapezoidal rule. Explanation of Simpson’s First Rule numbered 4, 7, 10, etc., plus three times the sum of all other ordinates, multiplied by 34 the common interval equals the area. Example. which are 4.75, 5.37, 5-75, 6.37, 6.62, 6.25, and 6 inches. h Number of Ordinates Length of Ordinates I 4-75 To find the area of a figure as shown at 4, B, C, D, in Figure 2 107, divide the base line into any even number of parts and 3 The sum of the end ordinates, plus four times ordinates, multiplied by one-third the common interval 4 equals the area. and 6 inches. The area is found as follows: Number of Ordinates 2 Length of Simpson’s Ordinates Multipliers 4:75 I 4-75 4 21.48 3 5.78 2 4 II.50 6.37 4 25.48 6 6.25 4 25.00 7 6.62 2 6.0 Common Interval = 2’ % Common Interval = 34” 13.24 I 6.00 Sum of Functions Area = 107.45 X % = 107.45 214. , Ae = 71.633 sq. in. Explanation of Simpson’s Second Rule A= 22h (yi + aya + ays + aye + 3ys — Bye + Yn 43): 4-75 16.11 5-75 3 17.25 6.37 2 6.62 3 6 7 6.25 6.0 3 I 12.74 19.86 18.75 6.00 Sum of Functions 95.46 Common Interval = 2’ 34 Common Interval = 34″ 95.46 X %= > 7 Function of 5.37 5 I 3 86.38 Ordinates Function of Ordinates 5.37 A curvilinear area has ordinates spaced 2 inches apart, the lengths of which are 4.75, 5.37, 5.75, 6.37, 6.62, 6.25, I Simpson’s Multipliers 4 5 the sum of the even ordinates, and twice the sum of the odd Example. The area is found as follows: =3( + 4y2+ 2ys + 4ys — 4Yn + Yass} erect ordinates. A curvilinear area has ordinates erected at a com- mon interval of 2 inches, as shown in Figure 107, the lengths of Note. . = 71.595 sq. in. When using this rule the number of intervals may be either odd or even, but must be a multiple of three. The rule can be used with four ordinates. Explanation of the 5-8 Rule This rule can be employed to find the area between two consecutive ordinates as at H-E, and /J-z, Figure 108. The re- quired area H EJ J is found as follows: Area HET] = 2 (sy + 8y2 — ys) Fight times the middle ordinate plus five times the near ordinate minus the far end ordinate multiplied by #5 interval ‘“‘h,” equals the area between consecutive ordinates. 87 Explanation of the Trapezoidal Rule A= h (My + yet ys t ya t ys t+ yot+ yr t+ Mys). Divide the base line into any number of equal parts, and erect ordinates to curve as shown in Figure 109. The sum of one-half the end ordinates, plus the sum of all the other ordinates, multiplied by the common interval equals the area. Calculating Displacement When calculating the underwater volume of a vessel, one of the foregoing rules is employed to find the areas of the various planes. These may be the water-line planes, which are hori- zontal, as shown at 4, or the several sections or station areas, as shown at B, Figure 110, may be used. These areas are then taken as ordinates, and arranged as shown in the following Fore Boby table: Number of Section Area of Section Simpson’ s Multipliers Functions of Areas I 0.00 I 0.00 2 1.08 4 4-32 3 3-91 2 7.82 4 8.33 4 33-32 17.09 18.09 15.87 4 2 4 68.36 36.18 63.48 i 12.86 6 7 8 2 25.72 9 11.72 2 23.44 10 4.57 4 18.28 II 0.00 I 0.00 I Common Interval 14 Common Interval Ml Sum of Functions + —252 280.92 3-75″ 3-75 37 . % Volume = 280.92 X me = —— = 351.15 cu. in. Volume = 351.15 cu. in. X 2 = 702.30 cu. in. 88 AFreéR Booy FIGURE I12 .§ to .$5 are the figures generally used when planning boats which are expected to be seaworthy and weatherly craft. To approximate the displacement of a yacht, multiply the area of the midship section by the length of the L.W.L. and divide by .55. Calculating the Longitudinal Center of Buoyancy M Liw.k C.G. A . FIcuRE 113 Note that the areas set down in the table are half areas. obtain the full volume multiply by 2. To To find the cubical contents in feet divide: 702.30 X 1728 T728 Section Areas = .406 cu. ft. Now multiply .406 by 63 pounds (weight of one cubic foot of fresh water) and the displacement of the hull will be known. Displacement = .406 X 63 lbs. = 25.57 lbs. The prismatic coefficient is used to help determine the fineness of form of a vessel. It is the ratio which the immersed volume bears to the contents of a solid block, equal in length to the L.W.L. and whose cross-sectional area equals that of the midship section. Numeéer of Intervals from Midship Section Product for Moment I 0.00 5 9.00 2 8.64 4 34.56 15.64 3 4 66.64 5 46.92 2 133.28 51.44 I 51.44 6 Midship Section 136.72 fo) Fore Body 266.20 7 8 I 2 3 72.36 253.92 140.64 9 72.36 126.96 46.88 36.56 4 II 0.00 5 0.00 561.84 = Function of Displacement After Body 611.16 Fore Body 266.20 ste) H — 792.30 Functions of 3 @c.B. R Number of 144.24 Total 344.96 age IS = 2.12” linear distance of C.B. from midship section. List the number of sections as in column one. Multiply the areas of sections by Simpson’s multipliers (using the first rule). List the products as functions of areas. Multiply the functions of areas by the number of intervals away from the midship section and obtain the products for moment. Add the products for moments for the fore body, the products for moments of the after body, and subtract the lesser from the greater. The excess of products for moments is shown to be (344.96) aft of the midship section. Multiply the excess of products by the common interval (3.75 inches), and divide the product (1293.60) by the function of displacement 561.84, which gives the linear 89 distance of the center of buoyancy from the midship section. It is shown to be 2.12 inches aft, by this method. The greater moment is aft of the @ and the reading is 29.22. The forward moment reading is 15.73. 29.22 the result is 13.49. A Graphic Method of Locating the Center of Buoyancy Figure 111 illustrates a graphic method of locating the center Subtracting 15.73 from Dividing 13.49 by 27.43 = .49, and .49 multiplied by 3.75 (which equals the distance () — Y), gives 1.837 aft of “ q@”’; the midship section. As the mathematical of buoyancy. The upright curve of areas 7, is laid off on a base method of finding the C.B. gave the point as 2.12 inches aft of line which is a scaled L.W.L. the midship section, and this graphic method as 1.837 inches, plained. The way to do this has been ex- Curve 2 shows an inclined curve of areas. These areas were measured as shown at 7, on the leeward or “in” side of the boat. Owing to the apparent dropping away of the water 2 inches was used as a compromise for the ““R” boat Budéles. Cutting out the curve of areas area, and balancing it on a knife-edge should give the same result. to windward, due to the motion of the yacht, and the constantly The C.B. in an upright state and the C.B. in a heeled condition changing streamlines, a very uncertain and variable immersed should be in line with each other to avoid changes of trim, either body results. The weather or ‘“‘out”’ side is therefore neglected, by the bow or stern. in this graph. The curved broken line at 8 indicates the ap- proximate water line, to windward, of a boat under sail. The “‘moment curve” 3 is generated by projecting the points marked J, B, and C, horizontally, back to the line Y, as indicated by the darts at points 4’, B’, and C’. Lines are then projected from g through points 4′, B’, and C’ back to the stations from which they were originally projected, giving points 4?, B®, and C*. Draw a fair curve through the spots thus obtained, run- ning from 4 to 9 stations. 3 is the moment curve for the fore body, yacht upright. zis the moment curve for the after body, yacht upright. 5 and 6 are moment curves, yacht inclined. The area of the curve of areas is found, which multiplied by, in this case, horizontally 1’ = 2’, and vertically 1’ = 4 sq. in. is2x4 = 8. The areas of the moment curves are then found and the re- sult of the larger minus the smaller is divided by the curve of areas area. This figure is then multiplied by the distance (1 — Y, giving the center of gravity of the curve of areas. For example: Area of curve of areas = 27.43 sq. in. To find displacement in cu. in., 27.43 x 8 = 219.44 cu. in. To find displacement in pounds, 219.44 xX .036 = 7.87 pounds (fresh water). go Calculating the Longitudinal Center of Gravity The hull, keel and ballast, spars, sails, and fittings make up the weights, with which the designer of miniatures must concern himself. Their distribution or location, and weight, is to be taken into account when calculating the C.G. He must esti- mate or calculate the center of gravity, for each separate item. For this data in miniatures the C.G. of fittings, etc., can be obtained by balancing, or suspending the items. When the needed information has been compiled it is set down in a table: Outfit Item Hull Lead Sails and Spars Fittings Weight Moment from F.P. Product 4 lbs. 16 lbs. 2 lbs. 0.5 lbs. 19.00 18.50 76.00 296.00 29.40 9:37 18.75 18:75 22.5 lbs. 22.5) 418.87- 418.87 (18.61” from F.P. The sum of the products being divided by the sum of the total weight gives 18.61 inches aft of the forward perpendicular; centric height (distance between center of gravity and the meta- from which the measurements for the moments were taken. center), and Sine 25° = 0.42262 (the sine of the angle of inclination). Calculating Stability Figuring the stability of a vessel at given angles of inclination or heel, is a long, tedious process. For example: Displacement = 6.854 lbs. C.G.—M = 3 in. Sine 25° = 0.42262 There is a graphic method which will serve the designer of miniatures very practically, and save much time. Figure 112 shows the full-size immersed sec- 6.854 X 3 X 0.42262 = 8.6899 in.-lbs. tion templates of the fore body and the after body of a yacht, when she is inclined at an angle of 25 degrees from the vertical. Divide this product by the displacement to obtain the length of These templates should be made of stiff material having a uni- the righting arm in inches: form thickness. They are superposed, making sure that the in- 8.6899 _ tia 1.267 clined center line, and the inclined L.W.L. line up truly, and is having each section in its proper place from bow to stern. Secure them together with a light mucilage. The spot where they bal- Finding the Center of Lateral Resistance ance on a pinpoint will be the transverse center of buoyancy of the immersed part of the hull. Centers of buoyancy can be The center of lateral resistance may be said to be that point on a hull at which a string can be attached, and the hull drawn obtained in this manner for any degree of inclination. Another method of obtaining the C.B. is to suspend the im- sideways without the fore and after center line of the boat making mersed section template by its opposite corners X and Y, Fig- other than an angle of 90 degrees with the drawing agent. ure 112. practical way of locating the C.L.R. is to make a cut-out of the Drop a plumb line from the pin or tack used to hold the template at the corner. Mark the course of the plumb line. Repeat this operation, working from the other corner. The C.B. A immersed fore and aft plane of the yacht, reduced to a convenient scale, using stiff card or Bristol board. Balance this on the point will be located at the point where the two plumb line courses of the compasses, or a needle. intersect. quired point near enough to serve the purpose of the designer of Refer to C.B., Figure 112. miniatures. This method will locate the re- Refer to Figure 114. Calculating the Righting Moment Having located the transverse center of buoyancy, the righting moment or length of the righting arm R—A, Figure 113, can be ascertained. Erect the perpendiculars DE, and FH, which pass through the C.G. and the C.B. respectively. The metacenter is located at the point M, where the perpendicular FH cuts the center line, ¢. Now, employ the formula D x C.G. — M X Sine 25°. D = Displacement, C.G. — M = meta- FIGURE 114 gli FIGURE 116 FIGuRE I1§ Finding the Center of Effort of Sails Figure 115 shows the method of locating the center of effort by triangulation for a jib-headed rig. The line 4 is drawn from the head of the mainsail to a point half-way along the foot. The 92 line B is drawn from a point half-way up the luff of the main to the clew, and the line F from the tack to a point half-way up the leech. The point C is the theoretical center of effort of the mainsail. The center of effort of the jib is found in a like GLASS D – CLASS _MerEL_YACHT Scave – Furr Size LINES N°&T WALTER R. MANY,N.A. \ L Rudder 4 | o a QOOK SSS Deck.at Side Z VLA \a veok- Pion viet 365 S.MANSRIELD AVE.,__ ‘fb QS ANGELES,CAL. Phone- Oregon 5614 APRILS,I929 | Boy NLA. L_\ WK FIGuRE I17 94 [Beck – s 4 of Veck 4 Deck at Side Wa ter Line “ 1.3 fox) Load Water Line Lengtn overall SYinches Length on water line 38 « Beam,extreme Beam,water line Praught Veo Under Sail 4 ls | j . | PLANS AND SAIL AREAS, 6-METER : oe ) 4 MODEL YACHT | ‘ ‘ , i “| i i \ * \ te 4 i \ ( ‘ 1 $ n . ayer z ‘ i : \ ° \ ‘ eg \ i ) ‘ ‘ l fi 7) ) ; ¥ ae inal t 2 I f, th 4 Veh i eo § : rere a 4 a Fe Ot — ptt i a “Wh. : OWEST POINT OF SHEER SEC% – SECTION a | (> | [| 7 ot gh | YS eg es ( 2 Ae 10-9 ae EEE = ee 3 4 ov _.~-, <= es 3 . A SAN © AN AEN SECTIONS salar i < & » SECT ORD'SM."EARESLEERY MOM No a 4 mm : a Ps - 36" oh oe TLONG® Pos. C* LATERAL RES. (To WL at en | gt 9 0° ONTD| WATER LINES 1 APART at . ge gt gt ae ; ats 981" saron Baan le gs r oa a Sl me kee 1" WL. ee a wy: |b en = arc ill gt A WRT og * 556% ee- b ingFLiAd KEEL OP os RUDDER AREAS 69x16 = 10-9" RUDDER oy — Eh Le i Swi .- 0 ry Ada Wedee OELK AT IDES, ;——— | -##s SS a ee ee _| BASE | f ARE Ua) (Nv tek nicheeseS. fa. ---f-4---~-- Scatcha Wise ZZ gel = = See at \ L.c8, 1HeoKEEL veer OFausLEAD |Ice. ——————————— —— \ | f 138". L sacs edad gf tesco ts ed / SHECR AFT [TO UNDERSIDE OF DECK}-25 [3 » FORWARD 5 i ake , » LOWEST POINT OF SHEER = i, VERT AXIS7THRO CLR. | 5{2 [17-0 1234-0| 194 |1g: BASE | ¥Le 15|2 {is0 oe A = A lgalt 15-7 0 $1 |) Se [salt 11 ES 19 | 1212 [24140 $e a | FHO[ 21% | +t [5 , [STO ) - Sb terse2 (IS-2-37-9)* AeA3-6 Se -354! | | CLR LAT PE AREA Wee DEFT ANE. i peck INES — oe = — i + es 2. = 189 _ §=—306 po Oho : SSS ; F A > ~~~ ge Ae oe oor L / ! 7 / 13454 — ShSeen} Sa ne i ae Se \7 ] ee Wate . j 4 ; 5 gen «(CO7 a ae a Ens | ane SF a SEcri ye eo oNDy Nh Pt es: Seria t 7— 5: > a ‘ ad 10 Sei a8 __b8 ee | t 6 —— ee SS t nel a _ eet aL,Ata. Ye =197% Topwh ¥ —= == “Do — Tyee telew FP PpACoWALs eer eee panier ee Sw Hitman niniiineniraat i ONGONALY ue Saget aero eeeet an al 7 -.1 SSeSAaS css Oe a = wn i 98 3 Pw Lie: Le aoe at get BUTTOCKS |” APART — SECTIONS 3:6″ oy | aoe aurea eran Ficure 118 ‘ / TM A ( \@|| ! EAD FTG a ” hd Th Lene Ghd FAS MAIN: SAIL Sat| ORS TE: Perea y iil) FORE SAIL 48214-5225 ToP oF DECK AT SIDE a A ZI TLY ei wa LASS | uF ght “ é ” ° of ee), / MEASURED LE YY | we Y . Vs >” Wa AC) Lt LAH, li Wi / ra af 7 “CL” (Fw) wt. F a’WL. 3’ / f “| 7 4 ‘ 7 Z 195 30 B= viowbss ~ 3240. _ ToP oF DECK AT-S5 sec: i 2. ToIAL RATED ARLA,/0 48 ’ oh A WL. / \x 5’ WL. \l 7, / 6’WL. \ \ 7’WL. ‘ A SeSEC P BASE ‘B 28 38 4B van 0) SEE oe soo 22! 4s ne MAST SOLID FoR |” ABove OcCK~ | Y ott Ficure 118, Continued Bue \ SALT The ©, of the manner, as shown by the lines 4, B, and /. rig is somewhere on the line /, which is drawn between the C.F. of the jib and the C.E. of the mainsail. ‘This C.E. is found by obtaining moments from a point such as the forward perpendicular, and listing the moments and the areas of the sails in a table as follows: Sail Jib Mainsail Area Moment Product of Moment 248.43 9.125 2246.92 1076.75 26.625 28668.46 3091 5.38 1325.18 Multiply the areas by the moments, obtaining the products of moment. Obtain the sum of the combined sail areas, and the sum of products of moment. Divide the sum of the products of moment by the total sail area: 30915.38 _ 1325.18 23.32″ aft of F. P. This measurement is laid on the L.W.L. and a perpendicular erected to the line “‘E.”’ This is the C.E. of the rig. Figure 116 explains the method of finding the C.E. of a gaffheaded sail. Lines are drawn from the throat to the clew, and from the head to the tack. This breaks the sail up into four triangles ABC, BDC, EDC, and ACE. The centers of these triangles are found by the method explained for jib-headed sails. The four centers F’, G, H, and J then serve to locate the com- mon center of effort as shown I on Figure 116. Calculating Sail Area Sail area can be readily calculated by taking the triangles into which the sails have been laid off when finding the C.E., and multiplying the base of a given triangle by one-half of the altitude; then finding the total sum of all triangles. Calculating Amount of Sail a Yacht Can Carry It is usual to picture the wind pressure as acting through the center of effort, when the C.E. may be considered as the center of pressure. Transverse stability controls the amount of sail spread a boat can carry. The relation between the moment of the sails and the moment of stability must remain equally con- stant at any angle of inclination. To find the moment of the sails employ the formula—M.S. = S.A. X V.H. X W.P. Where M.S. = moment, S.A. = sail area, V.H. = vertical height of the C.E. above the C.L.R., and W.P. = wind pressure (generally taken as 9.6 oz. per sq. ft.). Divide the product obtained in the formula by the displace- ment of the boat and this will give the length of the righting arm R-—A, to balance the sail area. The lines of Yeo, Figure 117, are included to bring home to the reader the fact that a miniature can be designed to very closely resemble the large yacht. Note the comparatively long lateral plane similar to the Shamrock V idea, and the V-shaped sections somewhat similar to those of the Enterprise. Observe the manner in which the rudder has been designed to eliminate rake, and the outline of her under-water plane. Veo won the Cabrillo Cup, at Los Angeles, Calif., on March 16, 1930, and is said by her designer and builder, Mr. W. R. Many, to be a very satisfactory craft, smart in every way. The lines of Boojum, an English design, Figure 118, are in- cluded to further impress upon the mind of the reader the likeness in this boat to her life-size sisters. She has the long, natural keel of a large yacht, with the high sail plan of our modern racing craft, and should be a satisfactory performer. This design appeared in The Model Yachtsman, an English publication, during a design competition, and is included by their kind permission. The writer firmly believes that successful miniatures can and should be designed to approximate the approved conventions of Io! MIG AUCOILE Vial, 44S pracuce, It seems CO Nim, 1s tne only manner in which worthwhile information and data can be obtained to promote efficiency in future design projects. It 1s well for the designer to remember, when working to any rating rule, that power to carry sail is determined by wind pressure, plus the height of the center of effort; as opposed to the righting-moment, plus the location of the center of gravity , plus the displacement. CHAPTER Wind pressure can be considered as substantially the same at any given moment, for any size or scale model, within reasonable limits. Height of center of effort varies as the square root of the linear dimensions. The righting moment varies as the cube root of the dimensions. Bear in mind, too, XII RATING RULES ; RATING rule is simply a formula or method’ invented to determine the class to which a boat belongs. When classified by this means they are enabled to race or compete, on an equal basis. Rating rules are composed of several factors. These factors must be taken into account in one way or another, if the designer wishes to take advantage of everything allowed by a given rule, and still have his boat fit the class. Rules are formulated or developed to encourage a certain type of boat and to prevent extremes or freaks, by imposing penalties or taxing various undesirable features of a design. One of the first rules evolved taxed length only. This did not serve a useful purpose, as it was only necessary to increase beam and draft, pile on a large sail area, and then beat the boat of equal length, which had been considered fast. In England, a rule known as the Length and Sail Area Rule was drawn, and employed for many years with good results. This rule restricted length and sail area. Beam and draught were not controlled directly, by the rule, but the hull resistance due to increased bulk, without required additional sail area, automatically took care of these dimensions. Some very finely shaped, fast boats were produced under this rule. Io2 that a large yacht scaled down is generally over-rigged, and that this condition must be overcome by fitting a deeper keel or adding ballast. The sail can be reduced to correct this state of affairs, should it obtain. The Model Yacht Racing Association of America has evolved a rule for the rating of miniatures in classes, termed A, B, C, and D. A-class boats are the largest, and D-class boats are the This rule is very similar to the Uni- smallest, under this rule. versal Rule, which is widely used in the United States of America for large yachts. The model yacht clubs composing the Asso- ciation employ this rule, thereby assuring intercommunity racing on a fair, well-regulated basis, and with wholesome seaworthy boats. The rating is an arbitrary number, obtained by the formula, and not the length of the boat in inches. Mopet Yacur Racine Association Or AMERICA Tue OrriciaL Ratinc Rute ror Mopet Sattinc Yacurs (SLoops) A Class—Over 46 but not over 55-inch rating B Class—Over 38 but not over 46-inch rating C Class—Over 31 but not over 38-inch rating D Class—Over 25 but not over 31-inch rating Measurement for Classification and Time Allowance Measurement = 0.18 L 5 § S.A .037 for sea water, There shall be no limit on the actual dis- placement but the cube root of the displacement (D) shall never exceed 23 per cent of the L.W.L.; if actual displacement is less than the above limitation, the actual displacement shall be used in computing the measurement; if greater, then the limiting value of the cube root of D shall be used in the computation. The draught: the limit of draught of yachts shall be in inches; Racing length (L) in the formula shall be the ‘‘load waterline length” plus one-half the excess of the quarter-beam length, 16 per cent of the L.W.L. plus 5 inches, and any excess draught over and above the percentage of the “‘load water-line length,” shall be multiplied by 3 and added to the rating. All boats in the same class shall race without time allowance as given by the formula: Percentage = 100 — bY L.W.L. on a course of less than half a mile in length. On longer.courses, or when racing is between boats of different classes, the time allowed the smaller boat by that of higher rating shall be based The “load water-line plane” is to be the plane from which upon the formula: : all calculations are made for quarter-beam length, draft and 600 beam. Time = – ; “Load water-line length” (L.W.L.) is the distance in a straight 600 > r = allowance in seconds per 4 mile line between the points farthest forward and farthest aft in the established plane, and likewise “‘load water-line breadth”’ is the 3600 = the number of seconds in one hour I = the smaller yacht extreme breadth in the established plane. L = the larger yacht Any decided hollow or jog either at the point of measurement at the L.W.L., one-tenth beam water line, or quarter-beam buttock shall be bridged by a straight edge of a length equal Author’s note. Observe that 23 per cent is given as the root of the to one-half of the W.L. beam and the measurement shall be displacement. taken at the intersection of the straight edge and the extended stability, as the seaway, in which a model or miniature sails, is gen- L.W.L. tenth-beam W.L. or Q.B. buttock as the case may be. erally out of proportion to the size of the small craft, comparatively. The rule was drawn this way to help buoyancy and The sail area (S.A.) shall be actual measurement including roach in square inches; the jib may not be less than .18 of the total area. The sail area shall be limited to the product of L.W.L2 X 1.60. For each excess 100 square inches, or frac- Before attempting to design to this rule, communicate with the secretary of the M. Y. R. A. to ascertain whether revision has occurred. tional part thereof, 2 inches or the corresponding fractional part of 2 inches shall be added to the rating. The displacement (D) shall be the volume in cubic inches arrived at by weighing; the weight divided by .036 for fresh and The rule is self explanatory with the exception of the factor L. It is well to understand that the quarter-beam length is not compared with the L.W.L. length, but is compared with a percentage of it. The percentage is given as 100 less the square 103 Be OW. Bos < 42." t. "| Yo Geam lw. ee <¢ f, Biwi... KAN pain fo hI Q.8. 4. “ > 424% Y BWL, Ig B.W.L. e t FicureE I1g root of the L.W.L. length. Assuming the L.W.L. length as 42 inches, then the calculation would appear as: (L.W.L. = 42”) (VLW.L. = 6.48”) (100 — 6.48” = .935 or 9334%) (42.00 X .935 = 39.27’’ — or percentage of L.W.L. used) The percentage of the W.L. length as thus calculated is sub- tracted from the length of the quarter-beam measurement, and half of the difference (if any) is added to the measured load water-line length which is assumed to be 42 inches. The racing length is then obtained as follows: O.B.L.. = 42:¢0″ L.W.L.% = 39.27 ExcessQ.B.L. 104 = 3.23 1.61 2)3.23 L.W.L. = 42.00 Penalty = 1.61 Racing Length = 43.61 Figure 119 illustrates the way the quarter-beam buttoe k, incl the one-tenth beam water line is laid in on the sheer, half-breadt ’ and body plans. Study the method showing how the measure ments. are obtained, then go over the complete caleulation fi this boat as follows: 7 Pr) L.W.L. = 42.00” W.L. beam = 11,40” Sail area = 2730 sq. in. Displacement m Ate Mu, In, Jo Q.B. length — gag” : Draught = 12,0/ or 7 (W.L. beam = 11.40’) (11.40! X& ly @ Lig’) (igo! x (L.W.L.= 42’) (VW L.W.L. = 6.48) (% = 100 = 6.48 = (42” X .935 = 39.27″) QF GLAS3| MODELS MODES SOLE oo} 8R CAR S’s 90″ ApMpa “Le, 7 Rarity anormal disp. 11 Gud «eG WL 42″ + 1,61″ m | 43.61″ RL, (O.B.M. = 42,80″) 39.27″) (% L.W.L.Lie = pails anes a er Limit me iphipleon, whet iad = 3 23″) (Excess ded above imit|Helght af mast cep fy Peer 4 wedel fe inahasbagncnclet Lint Tn ‘ 4 excess or penalty = 2)3.23° Aout “ (Sail area = 2730 sq. 1n;) ! = 700 : (Vv 2730 = | 52.3 ) F (Displacement = 30 lbs.) y, eB teey ® 26 8 a JA pena were Z By ; fe) a = 834 cu. :in.) Wea if 9 ame a ey iy ona BS ao W834 34 = ———- |9.40 9-4 x a 3 nA oO 2 (L = 43.61) (V S.A. = 52.3) (VW D = 9.40) si t57O 7 9-4 Ww ex 25. bY es 14. 48399 1 \ ecstnincasainasee SO re St S20 Ce SSCS MORMAN | L..SHe ~—CIS:”S~C*~SS~—~C«SC*‘SYS:=—C awe 4 vet Ae “37 Least average Freeboard limit =.286 0+!” Limit Height of mast above Lil, = 2xLWl, ¥ Fee a ers aa 6 816| S7_| 2250) = a = S —4e|/700 ea i = psa S56 5HEL00 2 Y Rating = 1 Metre =37,37″= FERAL IST D= Normal Disp, tin curin. =(20LYWL4 1)F eae oma? & Taeotset som SarY Arey forral Warm DY 6 METRE MODELS ON SCALE 2”=/’ ~\e Tall 2100 2 7 osm e = y 170 60 58 Ks: % 26 a bag ink 2500—-G} f 2200/4 \b aon See 8-S ~S Sour 62) y RY ae MY aN is z roger 7 POT I 46″ R= a . 3800, = 3700 2100 – Z 4/00 aes S f a 4200 SC FicureE 121 = ; “| Characteristics Class B Zz by NORMAN.L, 00 Calculated MAN. SKENE, 4 & ey) 25 = v x + 38 : 59 40 4] #2 43 LWL. 44 4S 46 IN INCHES 47 48 49 30 S| G& S354 20 55 FIGURE 122 105 ’ har + 1) = ( hae VY eRe if YD is less than fatal + 4) then value of YD for formula 1s to be twice 5 The r” Yachting Monthly ”’ Cup. L.W.L. Measurement Certificate Y.M. 6-METRE MODEL YACHT. Clut : i O ub Nationality Designer S = Sail area = 50 % of the product of the Luff of mainsail A, measured along the mast from the top of the boom, where in its lowest position it cuts the mast to the top of the sheave of the halliard or black band on the mast » and the Diagonal B from the pin of the outhaul or black No. istrati <3 . Builder WHE Registration No band on the boom to the nearest point on the mast; plus 85 % of one-half the product of the of the mast to where the line of the luff of the Height I measured from the deck at thetheforeside and the Base J measured from the foreside mast, cuts extended, foremost headsail, when of the mast at deck to where the line of luff, when extended cuts the bowsprit, other spar, hull, etc., as the case may be. lbs. to the cub. ft.). All measurements ‘The model yacht must be measured in sea water (64inches (or lbs. avoirdupois, to the nearest are to be recorded in inches, square inches and cubic ounce) and all decimals beyond the 2nd place to be disregarded, excepting at* The above refers to triangular mainsails. . — > 1 : = M Reng Bulleele: oo nee eluate u : Aft Overhang _— Sum ot Overhangs … / % (| ) Rating = e) Game aaierene ( saliieds eceeveteSass ) _ B 10 =—-= ) Q.B.L. = Quarter Beam Length = ( waterline ( = 100— P = Percentage of L.W.L. allowed as Q.B.L. without penalty / W.L. =100 – ( = ( : P x L.W.L. Q = Q.B.L. without penalty = -—————-~— = ( 100 LIMITS AND PENALTIES. ) shu 106 = ( ys d+ ( )x( 12 ( ) ) ) ) and added (2) The lowest average freeboard (taken at centre and at forward and after ends of L.W.L. Actual draught = ( ). to the rating.) (Any excess in draught should be multiplied by three ) dr ( )+ ( ( ) = { Average Freeboard = 3 . . . (4) The height of sail plan is not to exceed twice the length of L.W.L. above water-line, ) Such height excludes the mast head and racing flag. ) ) = ( )+ ( D = Displacement in cubic inches = W divided by .037* 4 + (1) The greatest draught — .16 x L.W.L. + 3.5 = ( (5) Any deficit in freeboard or excess in height of sail plan is to be added to the rating. GENERAL REQUIREMENTS. is to be in the affirmative :— following questions the continuous, each offair, The answer tosheer concave curve? a Is the trim with largest suit of sails W = Weight of model yacht complete in fullorracing apparatus of any description carried including spinnaker and all fittings ) )+( ) To Determine %/D For Ratinc Formuta: on board for racing purposes = ( ESS b JS 4 : Eid 12/D_ = .28 YD + 1.0 Q.B.L. —Q = ( ( = ( ) = ( R = Penalty, if any, for excess of Q.B.L. = —————— 2 L = length for formula = L.W.L. + Ro the fore triangle J. = ( 2” to 1’) = 1 metre metres, Rating = %/S = 39.37 inches Distance of Q.B. Buttock from centre sum of overhangs —y—( L.W.L. == L.O.A. 1 = Load ( foreside of the mast to the (where cut by the line of the foremast headsail) the excess shall be added to the base of ) : Vi Sek ) )xX{ 2 from the spinnaker boom exceeds the distance bowsprit end ——> )B = Maximum Beam on L.W.L. = ( Height of 1/10 beam Water Line ) 2 aft line of the mast to the outer To DerrerMine Lenctu, L, For Ratinc FORMULA: L.O.A. = Length over all ………..- ( ) ….. ( Forward Overhang ) ………0-+ ( 2 + 85xX( ) ) = ( ) + ( = ( all allowed is I. Inand The hoist of Spinnaker cases, if the distance from the centre foreof the end ———— Centre Lire: 2 yx} ( – a Ausnebée Toba. Boutfacke 85x Ix J Ax 8 Quarter Beam Length. ae VA VA total area of mainsail and topsail if fitted of the largest fore triangle. — & [ i With other rigs the sail area includes the (neglecting, however, the area of any bow after leach of the mainsail) plus 85 %in the — = Lond Woler Line: To Dsterming ,/S For Ratinc Formuta: \ Scale, 2 ins. = 1 foot. ) )=( y—( yD — (—- + 4) = 2x ( ) yo =! : Are stem and stern profiles fair easy curves? a ee any hollows in the surface of the hull between the L.W.L. and the sheer ine? : Have all concave straight line? Has any concavity, jogs if or any, notches, if in profile where it cuts the L.W.L, been bridged by stem any, at plane of L.W.L been bridged by a Kor scaling down the other dimensions of the formula the following table will explain how it is done. B a straight line equal to ? Te 7! Max. Disp. tile Es fg Does the round of beam come within the Y.R.A. limit of } in. to the foot’ Is the number of battens in the after leach of the mainsail equal to or less than four? Are the lengths of intermediate Are the lengths of top Are the and battens 7.87 inches or less? L.Wiy anes bottom battens 5.90 inches or less? a battens equally spaced? Has any increase of sail area obtained by intentionally bent spars been calculated as a Min. Disp. aa Ao bow ana added to the sail area? Is the headstick of mainsail .98 inch or less in length? 1. = 2% i = ghee opt ee 4 Is the headstick of spinnaker 1/20 of the length of the spinnaker boom or less in length? Have the masts and spars which are not round been correctly penalized? L.W.L. Are the measurement marks on hull, spars and deck in order? ” has been measured in conformity Draft, 16% of L.W.L, + 1.75 = 1″ = 1° ADRs ales ia RNR SUD UN ee NERUNOSS aN NENY Official Measurers. | 1ol 1.= —_ w8%of YD+ > .6 = | Freeboard 28% of WD + ll 16% of L.W.L. + 3.50 = 2” = 1’ Now This is to certify that the model yacht ‘‘ with the above, and is in rating. MEASUREMENT. The Measurement Committee suggest the facilities for measuring mcdels in salt water. following as of’ interest to Clubs having no It may be taken that any model measured in fresh water and found to be within rating may be relied upon to come within rating and fulfil the restrictions laid down for this competition when measured in salt water, providing she be of normal form and within the restrictions as‘to draught and height of rig. Author’s note. Before attempting to design to this rule, communicate with the secretary of the M. Y. R.A. to ascertain whether revision has occurred. Figure 120 gives dimensions, area, and volume data on the ““B” class models of various sizes. The data herein contained will help the designer, materially, in arriving at his preliminary conclusions for a plan. His final project will be the result of his Explanation of Yachting Monthly Cup Rules effort on the drawing board, and the figures the lines produce, These rules are based on the measurements ofa full-size yacht: 6 metres = 19.68 feet. For a model it requires scaling down or The rule states that all models must not exceed 6 meters. Drawn to a scale of 2 inches = I foot, a model will be one-sixth the size, or 6 meters (19.68 feet) X “7 = 39.36 inches rating. Figure 121 illustrates, graphically, the characteristics of “R” boats, under the A. Y. R. A. rule, and is self explanatory. reducing. (19.68 feet) on a scale 2 inches = 1 foot. under the A. Y. R. A. rule. In Figure 122 very helpful data on the six-meter models is shown. ‘The several items are worthy of considerable study and thought. The dimensions of successful boats which have competed in the International Races at Gosport, England, for the Yachting 107 MODEL SIX METRE OR A CLASS BOATS: Dimensions L.O.a, L.W.L. Invader Crusader 43,0″ Beam (L.W.L)13!,0″ 45.0″ 13.7″ Vanity Berlin Bostonia 11 45.0″ 13,75″ Q.BeLe Penalty 0,25″ Freeboard | Draught L– Displace. 1035″ 10.65″ Sail area 2,080°” . Gertrude Daniel’s 69,43″ 72″ 47,5″ 45 78,5″ 43,13″ 46,0″ 46,11″ 46,17″ 46,88″ 43,13″ 1,19″ -85″ 1.01″ 4,28″ 4,09″ 4,25″ 4,28″ 10,81″ 49.56″ 10,80″ 47,79″ 14,56″ —_—-:13,15″ 14,62″ 14m 10,4″ 48.35″ 20,7″ 36,76 lbs 2,0057* 1,900%” 1,748.57″ 1829,81″ 20457″ 39.01 Ld 39,34 * 12,13″ 10.0″ 44,14″ 39.5 lbs. 51,12 lbs | 27.0 lbe 19.0 lbs | 39,27 39.04 _38 lbs 28.0 lbs 26,0 lbs a rionne 1 49,56″ 1,0″ 10,65″ 76,50 33,5 lbs 37,0 lbs 37,0 lbs 45.0 lbs 46,75 lbs Lead Rating 0.30″ 77.81″ Bunny 11 NAME OF BOAT 1750.57 . 1884,630″ riposa 60.0″ 45,5″ 13.0″ ibion 75,5″ ankee 47,52″ 13,6″ Doodle 11 76,0″ 49,5″ 12,5″ 10.5″ 11,3″ 1050 cu.” 40,4 lbs 20000″ sae 39,33 * 72,0″ 48,75″ 12.4″ 0,58″ 0,61″ 3,84″ C) 11,25″ 10,88″ 47.3 lbs 42,75 los 18327″ 1747″ 39.36 * ° 39,1 * Note – Boats marked * have participated in International Cup Racing at Gosport, England, as accredited representatives. “Invader” winner first race – 1923. “Albion” winner – 1930. FIGURE 123 Monthly Cup, are listed in Figure 123. These figures will help boats would have less displacement and sail area than the six- to if an outstanding boat is to be the result of his effort in designing and building. The data compiled by Mr. Norman L. Skene, author of Elements of Yacht Design, shown in Figures 120, 121, 122, 124 and Data on ‘“‘Scharen-Kreuzers” of the 22 square meter, 30 square meter, and 40 square meter classes are given in Figures 124 and 125. Much interest has been manifested in the 30 square meter boats, and they are becoming quite popular. The large boats produced under this rule have had a long, lean type of hull, with long overhangs, comparatively light displacement, and small sail area, as viewed in the light of the other rules. A 30 square meter model class would be very interesting. The Before leaving the subject of Rating Rules, perhaps a few remarks about the parent rating rules, i.e., the Universal Rule, and the International Rule, would not be amiss. They are the results of years of experience in rule making, both in America and in Europe. A study of these rules discloses the fact that the first rules were drawn with the idea of regulating size, giving the designer as much latitude in the matter of shape, as possible. the designer in arriving at some idea of what he must live up 108 meter models, and should be very graceful craft. 125, is included with his kind permission. VOCHANCNNNGVULENYS F, bm and fe accorehing fo rules Pee is mex, mt except wilh certain min mum increases in Disp. le ar + ~s sib ig “y ew Noasirneh cn aay me é ee aE draft e SLITS S| SAIL ARFA DISP. L, rg – nof exceed .f Centerboards not prohibited LIMITS GWEN in ENGLISH UNITS 22 SQ METER | 30 5Q.METER |40 SQ. METER E |fuck SizeelgEwze |Fuec sel SIZE FULL ma max| 236 774 \9F#7 Sx) S227 | 127/ 430 1722. in| 27/0 10.|| min 1S. 2S max| Pe5le | 4410 4| 6480 16| 30.0 lb, 2.62 | 1772″ | 2.95″ | 20.08″ | 335″ mIN. 4 SG SZ b, (when 62=2a,) min|* 204 b| 2560’||5/20″ | 27.00′ | 54.76″ | 3440′ | 6°80″ 763° * 6 30’ 5.62 min| 54s’ br ter £l. ” mm| 3.28″ ok mer BP ees *6.50′ |[70-90″| 6.77″ | 46.30″ [ 772″ &. SS , 6.93″ 6.95″ S.6F’ 6.10’ | 12 20°) C72″ T.4 3.61″ a | 1944″ SR bg min le £° 138″ (S” hs for gle a, min 22.9″ 8.26″ 26.8″ 905″ 50-7″ (0.25° 5S ge ° xo ee Wa pene okry min) 4.72″ + Sie” 50° a ac) 3658″ nl Hereht eh esr #101 4577 55U” 3.64″ 29.2″ S$” 7″ Oram. round masf $08″ || Arco of Cockpit max] 14.56″ || 23.66 27 02 2444″ 20:54″ SL2AS’ Hb [Mieclfhetsige” max| max] 338’ || 6°65″ S22″ /- in verplanel, min) [ |dt of fore A a taken where Om IS greatest fe +, (2Feierymin |* 36.15 || 6.02″ [¥40,79″| bmi rier. lin outside of ae Ge ) moy ra 6.57′ min} K b, nint* $62 by atleast bs! = 29, when Pus less than She, Free bd mark aa : |, = clear length of house rh plane / re y & t Is j 4 = LM, ‘ark ee ~o PLANE O f- J rom limit 2.08 $.48″ 7″ be L a Ne FIGURE 125 eS } “ ce” y ear 2 By 5 . 6.03″ SSE KS Sy * Based on other quantiles 1? the formule being at fimit values SKENE ie FicuRE 124 109 Competition in the several classes has served to determine which type of shape is deemed best today. The Universal Rule reads: A8L ae S.A. aca = art WL) cK [om ae ( TOO U. | ake 47 WL OL We )|- This rule, as has been pointed out in a previous paragraph, is in general use on this side of the water, and many wholesome, fine boats have been the result of its application. Notice the similarity between it and the M. Y. R. A. rule. The draft and displacement limits imposed by it, and the In- ternational Rule, are practically the same, the former rule per- mitting a little more draft. The formula relating to displacement and load water-line length are identically similar, although the International Rule has a more drastic penalty for a boat which is shy on the required amount of displacement. Both rules impose a limit on the height of sail, the Universal Rule basing its calculation on the square root of the sail area, and the International on the water-line length. The Vanja, Rail Down, at Fleetwood, 1933 The hull shape is controlled in the Universal Rule by the feature known as quarter-beam length, and in the International Rule by measuring the girths at the bow, midship, and stern sections and comparing them with their depths. In the former rule, Q.B.L. does not function unless it exceeds a certain percentage of the L.W.L. length. It is hardly worth a tax, for the little sail area to be gained, by invoking it. In the International Rule any craft, other than a double ender, with a plumb stem and plumb stern are liable to a tax if the shape of the sections and lines are not very carefully watched. This feature of the rule has quite effectively controlled the forms of overhangs, midship section shapes, and draft. Both rules have tended to sure everything is in working order. Note that all gear is smooth produce boats with lateral planes approaching the triangular and strong, and if chafing has occurred at any point, take care shape, having a long leading edge forward, and greatest draft aft. of it immediately, by refitting. The International Rule has a freeboard factor, which is nega- Carelessness in this regard has cost more than one race, and caused much damage. Oil all tive, and by an increase in the freeboard of a craft, other elements, moving metal parts, where friction causes binding or sticking. and sail area can also be increased. This applies especially to the steering gear. A tumble-home factor is Be sure that the tiller works easily, and that the rudder stock moves freely in also contained in this rule. In spite of the fact that both rules permit the production of the port or tube. Go over the steering device, watching the way very narrow boats, they are considered to be good, as they do the sheets function, that the rudder may be properly actuated, give the designer the alternative of producing a boat with great when the craft is in her element. sailing length, and a controlled sail plan, or a more conserva- Observe the way the sails set. Tinker with them until all un- tive type of hull, having greater beam, and a somewhat enlarged sightly wrinkles and unevenness disappear. A little experiment- sail plan. ing will teach the owner just how taut the outhauls and hal- yards should be. Remember the effect that heat, cold, and moisture have on your creation, and be prepared to meet these re- actions with the proper adjustments to overcome them. Go over the sheet leads (the eyes or blocks), making sure CHAPTER XIII HOW TO TUNE-UP AND SAIL A that they are properly placed to give freedom, and the right MINIATURE YACHT purchase, as this gear functions. Adjust all hooks, squeezing their points together, so they will not jump off at a crucial moment, and spoil all your well-laid plans. Keep the running lines and beating sheets laid out in their F a miniature is to be tuned up so that she will be at concert pitch, and be able to perform most efficiently, constant watchfulness and care must be exercised. The hull should be kept clean and as smooth as it is possible to make it. This state of finish can be attained only by rubbing down and polishing whenever any rough spots or unevenness appear. It is also well to remember to wash the hull, fittings, and gear very thoroughly with fresh water, after having sailed the boat in salt water. This will eliminate residue deposits, pre- proper places, clear of other gear. This will insure a quick re- trim, or ease of making adjustments when they become necessary. The stowage of gear in the hull is an item well worth watching. Wet sponges, spare sails, or spare gear, if they are carried, will change the trim of the boat, and may cause erratic action. It is best to keep all gear ashore, unless the racing rule makes it mandatory to carry it. After the miniature is water borne, observe the set of the sails, and their behavior or action. Study trimming the jib and vent corrosion, and help to keep everything in prime condition. mainsail, so that a proper relation exists between the two. Before attempting to sail the boat, and especially previous to The jib should not, under any circumstance, back wind or racing, go over the hull, spars, fittings, rigging, and sails, making back draft the mainsail. If it does, either trim the main closer III Chsehouled 8n Port Tack — Beating to Windward Z NS ese the headsail may correct this condition and keep the boat’s head off, enabling her to sail a steady course. Should the main- sail spill the wind or shake first, then the jib, the center of effort requires more lead over the center of lateral resistance. This can only be accomplished by moving the rig forward. Setting up on ~ pee Reaching bie Se oS Sis / a woo me “~ the headstay, thereby shifting the sail plan, may turn the trick. A condition of this sort will require experimenting to attain proper balance, and raking the mast in the aforementioned way is sometimes all that is necessary to make things right. Sliding mast steps are employed by some owners to locate the right posi- tion for the sail plan in relation to the hull. If a hull develo ps steering tendencies of its own, and after careful observation and experiment these seem insurmountable, it is best to lay the hull aside, and acquire one which is known to have recogni zed good qualities. Close hauled on Starboard Tack — Several suits of sails, having different areas to function in winds of varying forces, are an asset. It is often detrimental to a boat to lug a great spread of sail, when less will drive her just Beating to Windward as fast, and give her an easier, more comfortable action or motion as she travels through the water. Stort and Finish Line Figure 126 or slack off the jib, if the point of sailing will permit it. When the jib and mainsail are suitably sheeted home or trimmed, the wind stream from the former flowing onto the mainsail materially increases the efficiency of the latter. Marking the sheets, or the pin-racks, after the right trim has been attained will facilitate trimming again. These remarks apply to a properl y balanced boat. A she is balanced. little experimenting will soon show whether If the boat comes into the wind, the jib shaking first, trimmi ng T12 These suits should be carefully balanced and adjusted to the hull to be of most service. Separate spars can be made for each suit, or the sails can be made with slides; so that each suit can be set on the one set of spars. Having separate sets of spars, obviously offers the ad- vantage of doing away with unnecessary weight, alow and aloft. Figure 126 illustrates the several positions of maneuv ering, or principles of sailing a boat, in relation to the wind. If one is to become proficient in the art of boat handling, a thoroug h understanding of these principles is necessary. One should also be able to visualize readily the angle which each sail makes with the wind when the craft is close hauled on the port or starboard tack, reaching, and running. Note that after leaving the starting line it is necessary for the boat to come about to enable her to make No. 1 mark. Coming about entails swinging te “hy if = = H-0 4 a | fed t Lat. a“ ‘i Stem, 134” oak Stern, 134” oak Frames, 14” oak (at each station) Sides, 14” stock (one piece) Bottom, 3%” stock (laid fore ’n’ aft) + ol a L.wl. Skeg, 58” oak oe > LWL. Thomas Darling, Designer Scale, 34” = 1’ 0” – eee Metal Bands (at stem and stern) 10 SSS FIGuRE 127 the boat’s bow through the wind. Note, too, that the boat would you wish to reach is gained. gybe around No. 2 mark. the wind is broad on the beam, or about at right angles to her stern through the wind. Gybing entails swinging the boat’s A boat is said to be on the port tack longitudinal center line. A boat is said to be reaching when A boat is running when she is sailing when the breeze comes over her port side, and on the starboard dead before the breeze, or nearly so. tack when it comes over the starboard side. down the wind” is often heard. Tacking is simply The expression “tacking Instead of sailing a straight sailing a zigzag course, due to the fact that it is impossible to course when running, a series of tacks are made; thereby de- sail directly into the wind’s eye; by making headway, first, on scribing a zigzag course before the wind. the starboard tack; coming about; then making headway on euver is helpful and effective; when a heavy sea is running, the port tack. especially. These maneuvers are repeated until the point At times this man- 113 Before attempting racing, it will serve the sailor well to know his boat thoroughly; what she can and will do. When a boat is used for pond sailing, experimenting with the gye, becoming expert in its use, under the wind conditions obtaining in the locality where the boat is sailed, will repay her skipper well. Know how much tension is necessary for a slow tack, and how much is needed to bring her about quickly. Before a race, look the situation over carefully, and map out your strategy. When sailing to windward, you have the choice of sailing close to the wind at reduced speed, or sailing broader and faster, thereby covering more ground. You must learn to make correct decisions of this nature. Do not allow the performance of your opponent’s boat to disconcert you. Study your own craft, and get the most out of her. Another thing to remember is: if your boat can make the leeward end of the finish line with started sheets, sail her that way, as the speed attained will mean a great deal in deciding the outcome of a race. Do not attempt to pinch for the weather end of the line, unless al- lowing for leeway, or you know it to be absolutely necessary to overcome prevailing conditions. Figure 127 gives the lines of a skiff, which can be used to follow or sail a miniature. A rowboat similar to the one depicted here is needed when sailing on a large lake, or in open water. Following a large miniature boat will prove a much easier task if the individual handling her possesses such a light, strong, easily propelled skiff. She can be built of cedar or pine. The boat is designed to be a double ender, as it is often necessary to go astern in lively fashion. This boat will weigh under 100 pounds complete. If a club has in its possession an aerometer, it will be of great service to the people sailing thereabouts. The aerometer will indicate the prevailing wind force at all times; thereby assisting the sportsman to determine which suit of sails to set before getting underway. “PAIR WEATHER AND SMOOTH SAILING” 114