The Model Yacht: Volume 7, Number 3 – Winter 2003-2004

LINCOLN MEMORIAL POOL, WASHINGTON, D.C. NEWSLETTER OF THE U.S. VINTAGE MODEL YACHT GROUP VOLUME SEVEN, NUMBER THREE Winter 2003-2004 NEWSLETTER OF THE U.S. VINTAGE MODEL YACHT GROUP VOLUME SEVEN, NUMBER THREE Winter 2003-2004 Editor’s Welcome This issue is long on plans and short on photographs, which I suppose is reasonable for our Winter “building and dreaming” issue. We have something for the schooner fan, lines of a previously undocumented M boat by Gus Lassel, and lines of a “R” Class design modified to rate as a Traditional VM. Since this is our biggest issue for renewals, a few reminders of things that make life easier for us. Next to your name you will either see two numbers or the letters “C” or “L.” “C” means you are receiving a complimentary issue. “L” means you are a Life Member, and the two numbers are the Volume and Number of the last issue we think you are entitled to. In that issue you should find a reminder and an addressed envelope, but sometimes we miss one, so if your “number is up,” please send in your dues. Our policy with regard to member’s privacy is very stringent — we do not give out a member’s name and address to anyone at any time for any reason. This does complicate the process of members finding each other, so in the new renewal form you will be able to designate that you are willing to have your name and address given to other members seeking fellow VMYG’ers in their area. Space prevented us from covering the results of the 2003 Schooner Regatta, but there is a terrific web page that does more than we ever could: Ebbs and Flows The President’s Message Vintage Membership VMYG annual membership is $20 for three issues of our newsletter – “The Model Yacht”. US VMYG lifetime membership is $100. Members then have access to technical assistance and vintage model plans. Plans will eventually include those electronically scanned, plus those to be made available in future through American Model Yachting Collection (Houk Archives) at Mystic Seaport Museum Library. VMYG “how to” book and video package on plank-on-frame construction is available separately. To subscribe to or renew our newsletter and services, please send $20 check (payable to US VMYG) or cash ($100 for life membership) to: John Snow, c/o US VMYG, 78 East Orchard Street, Marblehead, MA 01945. For detailed information, you can call me direct in Marblehead @781-631-4203 or visit VMYG Web Page URL: www.swcp.com/usvmyg Traditional Sailing Craft/Scale Model Coordinator A reminder that John Atwood is our new Traditional Coordinator. John’s contact data: John Atwood 9701 River Road Newport News, VA 23601 Phone: 757-596-9701; URL:www.pittelli.com/schooner/ events/2003/usvmyg. Email: john.atwood@tea.army.mil Earl Boebert Page 1 2004 Museum Of Yachting Model Yacht Activities 2004 VM and Traditional Sailing Craft/Scale Model Regattas John Atwood is our facilitator working with The Mariner’s Museum staff in Newport News to stage both of VMYG’s 2004 national championships. Dates are September 16-19, with racing on Museum’s 165-acre lake. Museum will host wine and cheese reception Friday and regatta dinner on Saturday evening. In addition, VMYG will also support AMYA Region 3 J Class Championship as part of this event Thursday and Friday. More details on our 2004 mega-event should be available shortly. 2004 Museum of Yachting (MoY) Activities I am personally coordinating with AMYA and MoY in Newport, RI on series of MY events and out-reach activities for 2004 MoY season: May 15-October 31. We are looking for volunteers to help construct this exhibit with MoY in late April in Newport. If you have interest in helping, while learning more about heritage of sport of MY, please contact Earl Boebert or myself directly. Vintage Etcetera VMYG Long-Term Goals and Service VMYG will be conducting brainstorming sessions to identify ways we can improve our support to members. This will initially include redefining and possibly expanding our mission statement to make VMYG more appealing to larger target audience from yachting community and public. Thus, look for possible article on this subject in next newsletter, which would elicit suggestions/comments from members on improvements to services we offer and how to better promote our message in US and world-wide. This will then be followed with prioritized set of action items to implement over time. MY Design Plans Preservation – VMYG remains fully committed to scan select, older MY design plans into electronic format for future preservation. Our initial effort of scanning 20 notable MY designs from Houk collection is complete. Another approach being considered is use of retail copying outlets, such as Kinkos, for this process as well. Test run with sample set of plans will be conducted in near future to determine feasibility and affordability of this option for long term application. John Snow Overview In collaboration with the Museum of Yachting (MoY) in Newport, RI, the American Model Yachting Association (AMYA) and US Vintage Model Yacht Group (VMYG) are creating a six-month series of model yachting events for the Museum’s 2004 season from May 15 to October 31, 2004. This effort will integrate AMYA radio-controlled (R/C) racing with specific out-reach opportunities, and feature a formal exhibit – “World of Model Yachts” to provide a chronological and educational baseline through modern and vintage models, objects, plans and graphics. With over 50 models anticipated, this will be largest, organized exhibit in the world ever devoted to the sport of model yachting and its historical influence on full-scale yachting. The AMYA-VMYG team and Museum of Yachting objectives: • Educate the public and yachting community on the rich history of model yachting and its competitive aspect from 1870s to present, and • Demonstrate how organizational and racing relationships between full-scale and model yachting contributed to the evolution of yacht design and technology. 2004 AMYA-sanctioned Museum of Yachting events will feature J, East Coast 12-Meter and CR-914 class sailing models, given their classic designs and the Museum’s mission: • May 22-23, “Model Yachting for Youths” Mentoring Event with CR-914s on Ft. Adams State Park opening weekend, • September 4, Labor Day weekend J & EC12M Invitational Race as part of MoY 25th Annual Classic Yacht Regatta, and • October 9-10, Columbus Day weekend J & EC-12M Regional Championships. Scratch-built J Class models average nine feet in length and 80 pounds. EC-12M models are available in shorts kits and ready-to-sail at 56-inches long and 27 pounds. These designs are based on America’s Cup yachts from the 1930s to 1980s, and will highlight the sport of model yachting in the context of renowned, full-scale sailing designs. CR-914 Class models are 36-inch, kit-built models having a Page 2 1990s America’s Cup heritage and will support a season-long, R/C sail-mentoring program for youths and adults. AMYA Marblehead (M) Class 50-inch developmental racing models will capture a 75-year perspective of yachting design technology with an evolutionary cross-section of M designs exhibited. There will be motorized models displayed for a historical snapshot on vintage model powerboats as representative of other types of model yachts. These 1900s to 1960s era wooden gas/steam-powered model speedboats designs average 40-inches in length and will depict the sport of tethered model boat racing. Other Museum of Yachting Model Yachting out-reach activities will include AMYAVMYG team involvement in the 30th Anniversary WoodenBoat Show at Ft. Adams from July 23-25, along with various on-site model demonstrations, lectures and workshops. The AMYA-VMYG team vision working with the Museum of Yachting is to broaden the appeal of model yachting by interacting with audiences, young and old, not usually found at today’s model yachting venues. Museum of Yachting Model Yacht Information 2004 Museum of Yachting Model Yacht activities will be promoted by Museum, AMYA and VMYG Web sites, magazines and special announcements. For Museum information call 401-847-1018. 2004 Model Yachting leads are Pete Maxson, AMYA Region 1 Director, and John Snow, US VMYG President. They can be contacted at 585-637-3603 and 781-6314203 respectively. Additional Museum of Yachting Model Yachting details as they become available will be found at the Museum, AMYA and USVMYG Web sites. Email:pmaxson@rochester.rr.com Email:jsnow@drc.com Museum URL:www.museumofyachting.org AMYA URL:www.amya.org USVMYG URL:www.swcp.com/usvmyg John Snow Yankee III Update Background “Yankee III” is a 36 inch LOA model, based on a design by John Black called “Yankee Jr.” which in turn was based on the famous J Class yacht “Yankee.” The model is the subject of a book I am writing, to be illustrated by M. de Lesseps and, with a little luck, to be available by May. The objective of the book is to guide beginning builders into the joys of constructing and sailing a boat of traditional, full-keel form. The fourth prototype of the boat is complete and passed her sailing tests with no problems to date. The hull is fiberglass over lightweight structural foam, a choice dictated by the need keep weight low. The rig is made from aluminum arrow shafts and the sails from rip-stop nylon. Every effort has been made to make the construction as simple as possible. Double-Header Rig I kept the basic dimensions of John Black’s rig on “Yankee Jr.” He used a single jib on a boom, which never It looked enough “like a J” for my taste. The double-headed rig used by “Yankee” after 1934 had two loose-footed sails with the jib overlapping the staysail. Normally, the sheets for such sails must run out at right angles to the stay, or the sails will pucker, wrinkle, and otherwise not set properly. Such sheets will carry back behind the staysail stay (in the case of the jib) and the mast (in the case of the staysail), and require complicated mechanisms to insure that the sheet on the leeward side is the one that is controlling the sail. I took John Black’s basic sail plan and replaced his single jib on a boom with a “cheater” double-headed rig. This rig achieves much of the look of an overlapped jib without the complexity of dual sheets. The secret is 1/4 inch by.030 inch battens in the sails at the point of sheet attachment. I got this idea from the 1895 article by Franklyn Bassford that we reprinted some time ago. The battens work something like an “inverse wishbone,” in which the battens rotate around the stays and maintain the shape of the sails. This permits simple sheeting where the jib sheet runs through the same screw eye that holds the staysail stay and the staysail Page 3 sheet runs through an screw eye just forward of the mast. The sheet adjustments are simple arrangements of a loop and bowser at the point of attachment to the sail. I was pleasantly surprised by how well she sails with this arrangement; if anything, tacking is more positive than with the single jib and there appears to be no loss of speed. Radio Layout The sail servo is an unmodified high-torque servo used mainly by the R/C car community for steering, and has a 90 deg range of motion. The arrangement shown in the diagram and the pictures, where the receiver and sail servo are mounted to the deck and the rudder servo is “slung” on plywood mounts between the sheer strakes. The battery box carries four AA batteries in a row down inside the fin. The batteries are protected against moisture by placing them in a plastic bag. The on/off switch is mounted to the battery box. The hatch, then, needs only to be large enough to permit the battery box to be removed and replaced, either when changing batteries or turning the receiver on and off. A strut under the sail servo takes the compressive force of the mast when the stays are tightened. Access to the radio gear and the steering linkage is gained by removing the deck. The disadvantage of this is that there are a lot of screws to take out. The advantage is that the sail servo and its associated sheeting can be tested as a unit on the workbench. I tried every variety of goop and gunk to seal the deck without gluing it permanently to the hull. I finally found some stuff called “Stick Tack,” used by museums and col- lectors to hold things to shelves. It is like a sticky “Silly Putty” and never hardens. It also does not lose its “stick” after being soaked in fresh water for 24 hours, and is the perfect removable sealing material. Earlier prototypes had a variety of conventional sheeting arrangements where the pull of the servo arm runs the sheets in and the pull of the wind on the sails runs the sheets out. With just 450 square inches of area, there is very little force from the sails to keep the sheets tight. Often they became slack under the deck and fouled the sail servo arm, which was made vertical to get the heavy sail servo down as low as possible. The final version uses the scheme shown in the diagram. A single “racetrack” sheet runs in 1/4 inch plastic tubes around the underside of the deck, surfacing for a short distance between two fairleads. The sheet reverses direction through “Linville Blocks,” a nifty device invented by Jim Linville. This is a piece of teflon tubing run through a foam or balsa block. These are superior to conventional blocks for small diameter line because there is no possibility of the line jamming between a sheave and the body of the block. The sail servo applies force to run the “racetrack” sheet in the “out” as well as the “in” direction. The individual sail sheets then only have to be pulled through screw eyes on the deck, a very lowfriction proposition that allows the sails to respond to even the faintest of winds, and there is no chance whatever of the sheet fouling under the deck. Page 4 Earl Boebert Page 5 Fairleads Rudder Servo Lead Sheets Strut Mechanical Layout Receiver Sheet Control Servo Arm “Linville” Turning Block Servo Arm 3.5” Throw Sail Servo “Racetrack” Sheet Trim Batteries Ballast Sail Servo Hatch Mast Sachem This racy staysail schooner came from the design team of John Alden, famous for his Malabar series, and his colleagues Charles G. MacGregor and Aage Nielson. She was not, as is usual for schooners, designed as an ocean racer or cruiser but was built to rate and race under the Universal Rule, the same rule that governed the famous J boats. As such she was given a low freeboard to reduce windage and narrow beam to reduce her rating. Built in 1927, she won 10 of her first 16 races. Like most designs to the Universal rule, she was intended to sail at high angles of heel to take advantage of her long overhangs. She may have been a little too tender, for she was rerigged first as a sloop and then as a yawl. She was lost in a boatyard fire in 1950. As a scale model she would be over canvassed in most conditions, but even under shortened sail that fine, easily driven hull should show an impressive turn of speed. Earl Boebert Page 6 Page 7 Scale: 1/6 Full Size for a 50 inch LOA Schooner LOA: 65’81/2” LWL: 44’ Beam:12’4” Draught:8’7” R/C Vintage Marblehead (VM) Rating Rules Traditional Marblehead Division Background The United States Vintage Model Yacht Group (US VMYG) was formed as a Special Interest Group of the American Model Yachting Association (AMYA) in 1994. The Vintage Marblehead (VM) Group was established as a key element of US VMYG program at its inception. Local and national VM regattas have been held annually since 1995 A Vintage Marblehead is defined as a Marblehead model yacht having the characteristics of a 1930 to 1970 Marblehead model yacht. A builder may choose to restore an existing boat or build a new boat based on an existing vintage design. A builder may alternatively formulate a new design based on the design characteristics typical of these early Marblehead model yachts. These rating rules modify the earlier Model Yacht Racing Association of America Marblehead (MYRAA) class rules with supplemental restrictions aimed at producing comparable racing performance at vintage regattas. As a development class, the Marblehead has undergone a significant evolution over the forty year interval and in order to achieve comparable racing performance, the VM Group has been divided into two design divisions: Traditional VM & High Flyer VM. The two divisions may be raced together or separately, as numbers permit, with separate trophies being awarded to the top finishers in each division The Traditional Division covers roughly the first half of the forty year development period. Traditional Division boats are characterized by short waterlines, integral skeg and rudder arrangements, shallow draft, and low aspect ratio sail forms. The High Flyer Division boats, covering the second half of the period, have deeper keels, full waterlines, taller rigs and balanced spade rudders. The determination of which division a boat belongs to depends on the boats design characteristics as set forth in these rules. Design dates, while helpful, are not used as a criteria for assigning boats to divisions as records have proven to be inadequate for this purpose. The Traditional Division Vintage rules are based the MYRAA Rating Rules for the Marblehead 50-800 Class as revised to June 1, 1939: 1. Formula 1.1 Overall Hull Length 50 inches plus or minus a quarter of an inch. 1.2 Total Sail Area Shall not exceed 800 square inches. 2. Prohibited 2.1 Sliding or adjustable keels 2.2 Centerboards 2.3 Leeboards 2.4 Bilge-boards 2.5 Bowsprits 2.6 Overhanging rudders 2.7 Outriggers, pontoons, or twin hulls 2.8 Movable or shifting ballasts 2.9 Prognathous keels (no portion of the leading edge of the keel appendage, including the lead, may project forward of any portion of the leading edge above) 2.10 Metal fin keels 2.11 Materials with density greater than lead 2.12 Carbon fiber or Kevlar in the hull rudder or rig 2.13 Fabric or film decks 2.14 Mylar sails 2.15 Swing rigs 3. Garboards 3.1 Hollow of garboards shall not be less than one inch radius and may be checked by use of a disc two inches in diameter, applied to the garboards at a convenient station. 4. Ballast: 4.1 Total Ballast: Total ballast shall not be changed during a race or a series of races. 4.2 Inside Ballast: Inside ballast must be fixed. 4.3 Page 8 Ballast Weight & Displacement Page 9 George Olson is restoring what we believe to be a later Lassel boat. The design and fittings are close what we know to be Lassel’s work, and the construction also uses the cold-molded method developed by Ted Houk and Lassel. We know that Gus designed at least one boat, called “Sun Wind,” later than his famous “Sun Kiss,” but we have never come across drawings of it or any of the other Lassel M Class designs of the 1950’s. Given the uncertainty about the name of the design, George has dubbed it “Sun Daze.” He has taken the lines off the boat and placed them in a CAD format as shown here. He has reinforced the inside of the hull with fiberglass and is planning on sailing the boat some day at San Francisco. As it stands, these lines represent all we know of Lassel’s boats of the early 1950’s. The “Sun Kiss” heritage is clear, along with the influence of “Rip Tide” on the forebody. The small “balance tab” on the rudder is also of interest. With a spade rudder she should be a real contender in the VM High Flyer Division. Scale: 1/6 Full Size There are no restrictions on ballast weight or total model displacement. 5. Draft Maximum draft of a Traditional VM model yacht fully rigged and ready to sail shall in no case exceed twelve inches. The intent of this rule is to require conformity to the keel design of early boats and in so doing also indirectly limit rig height. 6. Hull 6.1 Construction and Materials Hulls shall be primarily constructed by the methods and materials of the period as follows: Hulls shall be constructed of wood including plank-on-frame, horizontal lifts, vertical lifts, or laid-up fiberglass. Molded fiberglass hulls shall be comparable in weight to a wood-constructed hull from the same design plan. Fiberglass covering of wood is permitted as a method of sealing and strengthening the basic wooden hull. Modern adhesives are allowed to produce a stronger hull that is impervious to leaks. 6.2 Hull Shape and Configuration There are no restrictions on load waterline length, beam, freeboard or tumblehome. 6.3 Bumpers Bumpers are mandatory and are limited to one half inch overhang. Bumpers shall not be included in the overall measurement, whether built-in, recessed, or otherwise attached to the model yacht. 7. Rig 7.1 Types Bermuda, Marconi, jib-headed mainsail, Gaff, Gunter, Wishbone, etc. may be used. 7.2 Alternate Rigs Alternate rigs are allowed, provided the total sail area does not exceed 800 square inches. Details of such rigs must be comparable to the original sail plan. 7.3 Head Stay Height Height of the jib head stay above the deck shall not exceed 80 per cent of the height of the head of the mainsail above the deck. 8. Mast and Spars 8.1 Materials Mast and booms shall be constructed from material of the period: namely either wood or aluminum. 8.2 Height Height of the head of the mainsail above the deck shall not exceed 85 inches. 8.3 Diameter The greatest diameter of mast and spars is limited to three-quarters of an inch. 8.4 Configurations: Hollow masts and spars, permanently bent masts and spars, and rotating and bipod masts are allowed. Measurements of raking masts are taken exactly the same as vertical masts. Masts and spars are not included in the sail area measurement. Any increase in sail area by the use of a bent mast and spars shall be measured as a bow and added to the sail area. 9. Sails 9.1 Construction and Materials Sails shall be constructed by the methods and materials of the period as follows: Sails shall be made of either single panel or multi-panel sailcloth. The body of each sail shall be made of woven cloth, such as cotton, cotton/synthetic blend, Dacron, or Nylon. No material other than woven sailcloth is allowed for tablings or corner reinforcements in the head tack or clew of any sail except reinforcing tape. Roach of sails shall not exceed two inches. Rounded foot of loose-footed sails shall not exceed one inch. Mainsail battens shall not exceed four in number and four inches in length, and shall divide the mainsail leech into approximately equal parts. Headsail battens shall not exceed three in number and two inches in length, and shall divide the headsail leech into approximately equal parts. Headsticks or headboards shall not exceed three-quarters of an inch across the base for headsails and mainsails. No other wire or Page 10 other stiffening shall be put in the head of sails. 9.2 Calculation of Sail Area the rudder shall be scored with the High Flyer Division. 11. Radio Control Only the rudder, headsail and mainsail sheets may be adjusted by radio control. High Flyer Vintage Marblehead Lu ff Luff The High Flyer Vintage rules are based the MYRAA Rating Rules for the Marblehead 50800 Class as revised to 1954. They are identical to the Traditional Rules except for the following: 10.2 Rudder Shape Dia Diag g The measurement of sails is as specified in the 1958 MYRAA Handbook. Only the actual sail area, excluding roaches and rounded edge of loose-footed sails is measured. The attached figure indicates the layout for triangular sails. The luff is measured from the lowest point on the tack of the sail to the bottom edge of the headstick or headboard. If the sail has no headboard, the measurement is taken to a point at the head of the sail where the width of the sail is three quarters of an inch. The diagonal is measured from the aft edge of the clew to the closest point on the luff. The sail area of each sail is given by: Sail Area = (Luff Measurement X Diagonal Measurement)/2 The sum of the areas for the jib and mainsail must be less than 800 square inches. 10. Rudders Balanced spade rudders are allowed in the High Flyer Division in keeping with design methods of this period. A boat that is Traditional in all respects other than using a balanced rudder shall be scored with the High Flyer Division. 10.3 Draft Maximum draft of a High Flyer Model Yacht fully rigged and ready to sail shall in no case exceed 16 inches. The intent of this rule is to allow conformity to the keel design of later vintage boats and in doing so permit taller rigs. 10.1 Alternate Rudders It is forbidden to change rudders during a race or series of races except in bona fide cases of damage. 10.2 Rudder Shape The rudder for a Traditional Division VM shall be keel or skeg mounted in keeping with design methods of this period. It is permissible to enlarge the area of the rudder from its original size in order to achieve acceptable steering with radio control. Balanced spade rudders are not allowed. A boat that is Traditional in all respects other that Vintage Insignia and Sail Numbers All Vintage Marblehead Yachts shall be officially registered with the VM Group Secretary to obtain an official sail number. Sail numbers shall be three inches tall and of ¸ inch thickness and shall be affixed to both sides of the mainsail between the second and third battens parallel to the leech. The VM group insignia consists of a nested “V” above an “M” as shown in the attached figure. The letters are 1 1/2 inches tall and 1 1/ inch Page 11 wide with a thickness of 1/4 inch. The “V” is separated from the “M” by 1/16 of an inch. The “M” should always of the color black and the “V” may be in a color of your choice to perhaps match the numbers color or a hull color. The insignia need be only placed on the starboard side of the mainsail in the upper quadrant. Construction Excellence Awards At each National Regatta all VM yachts present shall be judged for construction excellence and up to three awards presented to the owners of the top three boats. A VM need not race in the regatta to be included in the construction judging. These awards are presented in addition to awards presented for the top racing finishers. The owner of each yacht entered in the construction judging must be either the restorer or builder of the yacht entered in the contest. ing the position of the c.l.r. the sailplan can be disposed to give a vessel which consistently trims well without a marked tendency to head into, or veer away from the wind. For racing purposes, the disposition of the sailplan with respect to the c.l.r. has a marked effect on the beating characteristics of the vessel. The relationship between c.l.r. and the sail plan can be described with a simple diagram (Fig. 1). The actual c.l.r. will, of course, be Charlie Roden Simple Model Yacht Theory Editor’s Note This admirably concise treatment of basic issues of balance and trimming appeared in the British magazine Model Ships and Power Boats for February, 1952. Author A.M. Colbridge’s explanation of how pitch turns into yaw is basic to the understanding of balanced hull design, wherein changes in angle of heel do not cause the boat to pitch. As a result, the boat maintains a straight course in varying wind. This is essential in a free sailing boat and a source of easy handling in a radio one. Trimming On any yacht hull there is a theoretical point where, if a side load is applied, no yaw will result. In other words if a line were attached to this point and the yacht pulled bodily sideways it would move sideways without turning or yawing in one direction or the other. This point is known as the centre of lateral resistance. For the simple theoretical analysis of yacht rigging and trim the centre of lateral resistance, or c.l.r., is of great importance. Know- Page 12 below the waterline and actually corresponds to the centre of the (effective) side area of the underwater body. For all practical purposes the effective side area may be taken as the projected side area, as given by a side elevation of the hull. The balancing point of the sails is known as the centre of effort (c.e.) and its actual position is determined with reference to the centre of pressure (or effort) of each of the individual sails, and the respective areas of these sails. We will deal with the method of finding both the centre of effort and the centre of lateral resistance a little later on. First let’s consider the effect of their relative positions on trim. In almost every trim, except running before the wind, the reaction generated by the effect of wind pressure on the sails can be resolved into a component force dead ahead— the driving force which carries the yacht along— and a sideways force which causes the yacht to heel over and tends to displace the hull sideways through the water (see Fig. 2). This latter reaction is resisted by the side area of the submerged hull and it is a very important feature of design that the actual drift resulting should be as small as possible. From what we have already seen, however. unless this sideways force is acting through the centre of lateral resistance it will tend to swing the yacht off course, in one direction or the other (see Fig. 3). The resultant wind pressure of the sails acts through the centre of effort and thus if the c.e. is in front of the c.l.r. the hull will tend to swing out of wind, or the vessel will be “carrying lee helm,” as it is called. Similarly, if the c.e. is behind the c.l.r. the hull will tend to head into wind or carry “weather helm.” Only if the c.e. and c.1.r. coincide will there be no yawing tendency. Now it is not possible fully to analyse this effect in simple terms, for as the yacht heels over, as it will in the wind, both the position of the c.e. and c.l.r. may, and usually do, change. For example, a “theoretically balanced” yacht with the centre of effort in line with the centre of lateral resistance would show marked weather helm under actual sailing conditions. This is explained in Fig 4. Assuming, for the sake of simplicity, that neither the c.e. nor the c.l.r. change their respective positions, as soon as the yacht heels the actual c.e. is moved outwards from the c.l.r. and so the actual applied force is some distance from the centre line of the vessel. The applied forward component of the resulting wind force, in other words, has a definite moment arm with respect to the axis of symmetry of the hull it is moving forward through the water. This gives the effect of weather helm, tending to yaw the hull round into wind. To offset this it is necessary, therefore, to have the centre of effort in front of the centre of lateral resistance, thereby introducing lee helm in the original set-up to counterbalance the weather helm (Fig. 5). The required amount of lee helm can be calculated for each individual design, but is an extremely tricky problem and quite beyond the scope of this present article. If the reader does require data of this nature then certainly one of the most reliable sources is to analyse the respective positions of the c.e. and c.l.r. of existing yachts of similar design and the same class which are known to have a satisfactory performance. Knowing the effect of c.e. and c.l.r. positioning, too, is a pointer as to how the performance of an existing vessel might be improved, simply by readjusting the sail Page 13 areas or by altering the fore and aft position of the mast to reduce the ”unwanted” helm inherent in sailing. A yacht with lee helm for example, will be difficult to make sail close to the wind in beating, whilst a yacht with marked weather helm may require too much rudder power to hold a beat. Another point to be borne in mind. too, is the effect of pitching or longitudinal trim (Fig. 6). If the vessel is initially set up correctly with lee helm and the yacht balanced on the designed load waterline, trimming by the bows (shown exaggerated in the diagram) will move the c.e. forward with respect to the c.l.r. and introduce further lee helm. The same sort of effect will be produced when the vessel pitches in a sea. Trimming by the stern will have the opposite effect. Longitudinal trim, therefore, is extremely important, and if the effect of “trimming by the stern” or “trimming by the bow” is examined in conjunction with the facts already discussed the possible advantages of movable ballast which can be adjusted in a fore and aft direction for trimming for different weather conditions will be apparent. Of course, a similar effect can be achieved by modifying the proportions of the sails used for different conditions. The subject is a vast, and an interesting one. Another Source of Full-Size Plans Adrian Brewer offers full size plans for interesting boats. Besides the nifty 48 inch LOA Gaff Cutter illustrated above, he has plans for a 36 inch racing yacht, a 27 inch sloop by F.J. Camm, and the 40 inch schooner by Camm that we featured in our Winter 2002-2003 issue, as well as an interesting assortment of fittings. URL:www.floataboat.com.au A.M.Colbridge (1952) Funky Foam Sheet This material showed up recently in craft stores. It is a 2mm thick foam sheet that appears to be closed cell foam. In any case it passes the “soak test” for gasket material around hatches, and solves yet another annoying problem. Bits of Oakum Industrial Grade Turnbuckles Nor’Easter Press Member Christopher Curioli has moved “Down East” with Mary Safford Curioli and established the Nor’Easter Press in Eastport, Maine. This traditional, small press will specialize in the publication of professional, reference, educational, and trade books in maritime related areas. Chris came upon the VMYG through the books of M. de Lesseps. Our best wishes to Chris and Mary Safford Curioli in their new venture. URL:www.noreasterpress.com These hefty little brass turnbuckles, along with many other items applicable to model yacht rigging, are made by Carl Stahl Sava Industries, an industrial supplier of cable motion components. They have a $100.00 minimum order requirement, so we have laid Page 14 in a supply and offer them to members for $12.00 a pair plus $4.50 postage per order, to the Editorial Address below. The picture shows the size relative to a large A.J. Fisher turnbuckle (lower item). They’ll look fine on a traditional M, a 50 inch schooner, or an AMYA J Class boat. 300 lbs pull strength, range of length 1 5/8 to 2 1/8 inches. Our thanks to member Fred Abbe for discovering these. URL: www.savacable.com Bumper Material Making bumpers for M boats and other class yachts can be a bit of a pain, especially if the boat has a complex stem. Micro-Mark now offers a urethane rubber that can be cast in rubber molds. Even better, it can be colored with the pigments used for resin casting. The stuff is called TCR-40 and is stock number 82987. URL:www.micromark.com Earl Boebert The Model Yacht is published three times a year by the U.S. Vintage Model Yacht Group. Copyright 1998, 1999, 2000, 2001, 2002, 2003, 2004 U.S.V.M.Y.G. Reproduction for noncommercial purposes permitted; all other rights reserved. Editorial Address: 9219 Flushing Meadows NE Albuquerque NM 87111 Email: boebert@swcp.com Phone: 505 823 1046 Officers of the U.S. Vintage Model Yacht Group: President: John Snow Eastern Vice-President: Ben Martin Midwest Vice-President: Al Suydam Western Vice-President: Dominic Meo, III Southeastern Vice-President: Thom Mclaughlin Vintage M Class Coordinator: Charles Roden A Class Coordinator: Rod Carr U.K. Coordinator: Graham Reeves Canadian Representative: Doug McMain Historian: Earl Boebert Archivist: Jim Dolan Snipe Junior Editor’s Foreword William F. Crosby was the editor of The Rudder magazine and designer of the celebrated Snipe class of one-design racing boats. In this 1932 article he gives detailed, step-by-step instructions for building and sailing a 20 inch LOA model of his most famous creation. This is a perfect class project for elementary students or as a “Grandparent’s boat.” The lead in the keel can be replaced with thick brass, and I’m sure our readers will be able to perform the other substitutions of modern materials. Snipe Jr. The popularity of the original Snipe design and the fact that hundreds of these little sailboats have been built and sailed, has led to the development of this practical sailing model. The original Snipe was not a model but a Marconi rigged knockabout 15 feet 6 inches long adapted to one-design racing. Snipe Junior is practically the same type hull modified to meet the needs of a good sailing model and so simplified that almost any boy or girl can make it successfully and for little or no money at all. The original Snipe was equipped with a center-board but practical experience has shown that a center-board will not work successfully on a model of this type and so a fin keel with suitable lead weight has been added instead. The rig is somewhat higher than on Snipe and other minor changes have been made in the shape of the hull to make it a better sailing model. The type of boat is known as vee-bottom because, instead of having the usual rounded shape, the hull has a distinct knuckle that starts at the bow and runs clear through to the stern. This is called the chine and gives us a boat that is straight sided from the chine to the edge of the deck and from the chine down to the keel. If you will look at the sections of the model or of Snipe, you will see that the bottom has a distinct vee to it and is therefore called a vee-bottom. The drawings explain practically everything necessary for the construction of this little model, which will be 20 inches long when you have it finished. Follow each operation by number, taking each one up in turn and Page 15 Page 16 before long you will have some very definite results. The mast and sail are of the most modern type and we would not advise changing them. The most important thing is to have a good suit of sails, made of balloon silk or some similar light, strong material. When in place, these sails should fit just as perfectly as you can get them. Wrinkles are not tolerated in a racing sail, as they seriously affect the efficiency of the sail and consequently the speed of the boat. No rudder is incorporated in the design for the simple reason that it complicates things and is not absolutely necessary for successful sailing. If the boat is built exactly according to the plans with the sail and mast exactly as located and the keel in the proper place, you will find that Snipe Junior will sail back and forth across the lake in great shape without the necessity of carrying the drag of a rudder through the water. The only time that a model really needs a rudder is when it is running directly with the wind, and since a rudder for this work entails a very complicated steering apparatus on deck, it is believed that the model would be better without it. Absolutely no rudder is needed for all ordinary sailing. For the bottom part of the hull, which is made from a solid block, the best thing to have would be a nice block of what is known as pattern maker’s kiln-dried white pine. This is splendid material to work with because it is soft and will work nicely and will finish off as smooth as anyone could wish. The side pieces may also be made of the same material as well as bulkheads, stem piece and stern. The deck may be made from the same kind of wood or anything else that you happen to have handy. Sometimes it is possible to get large pieces of cigar box wood (Spanish Cedar) and if you can get this, the sides and deck will be very pretty when finished off with a little varnish. A thin piece of Philippine mahogany will also do very well and it is not as expensive as you might think. Some kinds of plywood are also suitable. In putting on the thin side pieces, securely fasten them to the stem piece first, using 5/4 inch No. 0 flat head screws, and then bend them in place slowly, fastening along the chine and to the bulkheads as you go. In order not to change the shape in any way it might be wise to work on both side pieces at the same time. The material should not be over 1/8 inch thick or there may be difficulty in bending it around. Soaking a piece of wood in water for several hours will make it somewhat softer and more pliable and may help you a lot. The fin keel may be made from a piece of 16 gauge sheet brass or iron, cut to the shape as shown. The lead weight on the bottom may be made in several ways but the easiest method is to make a wooden piece the exact shape that the lead will be, cover it well with paraffin, and then, using plaster of paris and the shape, make a half mold of the shape. Allow this to dry and harden for at least twenty-four hours because pouring hot lead into a wet mold may cause a serious explosion, sending the hot lead all over you and everything else in sight. Page 17 Melt up the lead in a frying pan and, after removing the wooden form or pattern, pour the lead into the mold. When it has cooled sufficiently, remove it and you have one side of the keel bulb finished. Now make another plaster of paris mold, using the other side of the pattern to make your mold so that when completed the two halves will fit together. Pour the lead and allow it to cool—after the plaster of paris has dried for twenty four hours. When you have the two halves complete, smooth them off with a fine file or wire wool so that they are both exactly alike, nicely stream lined and absolutely smooth. You don’t want any bumps here because they may cause your boat to lose a race. The two pieces are then held together in a clamp or vise with the metal of the fin keel between them. A hand drill is used to drill two holes, one at each end, through the lead and the brass keel, and through these holes small nails are driven, the pointed end cut off about 1/16th inch away from the lead and holding a hammer against the head of the nail on one side, the other end is tapped with another hammer until it is thoroughly riveted over and the lead is secured in place. The holes through the metal should be just large enough to permit the nails to pass through when driven. They must not be loose or wobbly. The entire hull must be sandpapered off carefully until you have an absolutely smooth surface. The nail heads (1/4 inch brads), for fastening the side planks in place, may be countersunk a trifle and the heads covered over with putty, Plastic Wood or some similar composition. Take particular care where the edge of the deck comes over the side planks. If the boat leaks here when heeled over under sail pressure she will surely fill in time and possibly sink in the middle of the lake. Smear Ambroid or some similar material along the Page 18 edge before the deck is fastened down so that the joint will be absolutely watertight. As an alternative for the brad fastenings, you might use 1/4 inch No. 0 brass flat head screws which will make a very pretty job that may be varnished when complete. The hull, when sanded down perfectly smooth, may be painted in any way you wish. Some of the lacquers used for touching up automobiles are very good, as they will lie smoothly on the wood, and if a couple of coats are given, with a light sandpapering between the first and second coats, you will have a real “racing finish.” The deck may be sandpapered and coated with a light coat of good varnish. Don’t make the mistake of putting on thick coats of paint. It is far better to use two or three thin coats rather than one heavy coat as the paint will not crawl but will finish off much smoother. The stays from the mast to the deck are made of No. 22 copper wire, which is passed around small screw eyes in the deck at the spots where they are supposed to come down. The jib is sewed directly to the jib stay. For the sheets from the point of the jib to deck and from the end of the boom to deck use light linen thread. Don’t use heavy, clumsy cord for this. In sailing the model, remember that she will do her best when going across the wind. By this it is meant that if the wind is from the south, your model will sail best from east to west or from west to east. In sailing on large bodies of open water. the model should be tended with a rowboat or you can attach a light cord to the bow, permit her to sail out to sea across the wind, and then, by pulling Page 19 gently on the cord, she may be turned about and will sail back to you. Of course, you must take in the light cord slowly so it will not retard her speed too much. Don’t try to sail in too much wind. The best breeze is one that just barely ripples the surface of the water Heavy breezes cause a model to lie way over on its side and will sometimes cause it to turn around and start back to the place from which it was started. In order to sail at its best a model must be carefully balanced. There is a very definite relation between the location of the keel and the mast and if one is exactly balanced so that the pressure is just right. the model will sail a perfectly straight course. On some models the mast and sails may be moved forward or aft an inch in order to make this balance correct. and in Snipe Junior we have made the mast step so that it may be moved a little one way or the other. The balance has been very carefully figured out on paper and on several models already built it has been found to be almost exactly right for light breezes. After you have tried your model a few times, you will discover by experiment. just where the mast step should be to have her sail properly. One of the chief faults of most model skippers is to have the sails, and particularly the jib too tightly pulled in or trimmed. Allow a little slack in the cord that holds the jib in place so that the jib can flow off in a nice curve and so that it draws properly. The end of the jib where the sheet is tied should be almost out to the side of the model. The same thing applies to the mainsail and where it is fastened. It should be allowed to swing out a little so that the boom is about over the edge of the deck. If pulled in too tightly, she will not sail properly and if too slack or too far out the model may tend to get out in the middle of the lake and sail around in a circle while you may wait on shore for hours for her to come back. There are many ways to race models and some of the large model yacht associations have worked out complicated courses and systems of point scoring. Probably the easiest and simplest way to race such models as Snipe Junior would be to select some small Page 20 body of water or lake where the models could be sailed directly across wind from one side to the other. The start could be made on one side by one boy while another waited across the lake to turn the model around when she reached there and so back to the start. At the start all models would be lined up and held by their sterns and, at the signal, released with a gentle push. Don’t push them too hard as they will not carry their momentum and may possibly turn right around and come back to you. The best model racers do not push their models at all, but permit the wind to take the boats out of their hands when the starting signal is given. A race may be just once across the lake, it may be over and back or it may include several round trips, according to the time available. In turning the boats around to return on their next laps, do not take them from the water. Simply use a short piece of wood to turn the bow so that it is facing the other way. Never push the model when doing this, as it is against all racing rules. If you have your model properly built and properly balanced so that it will sail correctly she will sail back and forth across the lake with the minimum amount of attention and as a consequence will have a splendid chance of winning races. This process of balancing is one that takes time, and while the drawings show the boat very carefully balanced, there may be minor changes in your boat that may necessitate some rebalancing before she sails correctly. The process is one that takes time and patience and if your model does not sail properly the first dozen or so times, it is up to you to experiment with the location of the mast step and the trim of the sails to see that an improvement is made. It is not an easy job to have a small model balance perfectly but it can be done, and when accomplished the results are well worth while. A perfectly balanced model will win races. Possibly you may not understand what is meant by balance, and in order to make it clearer, we will briefly outline what it means. The pressure on the sails caused by the wind would cause the model to go sideways faster than she would go ahead were it not for the keel down underneath the water. This keel serves two purposes: the lead weight serves to hold the model upright and prevent capsizing and the area of the metal causes a back pressure against the water when the pressure is applied to the sails, thus preventing the boat from sailing sideways. There is a very definite relation between the amount of pressure on the sails and the amount of pressure on the side of the keel, and the sails center of pressure is called the center of effort. The center of pressure on the keel is called the center of lateral plane and in a successful sailboat the designer has worked out by mathematics the locations of both centers and so placed the mast and keel that the center of effort comes in a certain relation to the center of lateral plane. If the center of effort is too far ahead of the center of lateral plane, the boat’s bow will tend to fall off or be pushed away from the direction of the wind, eventually causing the boat to turn around and start off in the other direction. If the center of effort is too far toward the stern, the boat will swing her bow up so that it faces into the wind eventually will swing over on the other tack and head back where she came from. By moving the keel of Snipe Junior forward or aft a little it is possible to bring the center of lateral plane into different relation to the center of effort, and with care and a little head work you can get the balance so fine that the model will sail a straight, true course clear across the lake and back. Naturally, a model that sails the straightest course and does not go off on another tack every once in a while is going to be the model that will win all the races and careful balancing is well worthwhile. Page 21 William F. Crosby (1932) Page 22 This design began as a “R” Class boat to the Universal Rule, modeled at 1 1/2 inches to the foot. The “R” Class and the Universal Rule were explained in our Winter 2002-2003 issue, in the article on the Seattle “R” Boat “Pirate.” The design is by Thomas Darling, who also did the popular “20 Rater” design, and dates from 1926. The original boat was 55.375 inches long. Scaling it to 90% allows it to qualify under the VM rules. The sail plan has been further reduced to just under 800 square inches by the VM measurement rule given in this issue. She would have a displacement of 13.8 lbs and a draft of 7.6 inches, which would make her a light air boat, but a dangerous one under those conditions. Building her down to that design weight with radio gear would be a bit of a challenge and might require the use of advanced materials like the structural foam I used on “Yankee III.” The molded rubber we mentioned in “Bits of Oakum” could be used to make a bumper without doing violence to her lines. The sail plan is shown with the reduced dimensions and if the mast is set 20.5 inches aft of the stem the CE and CLR will be placed as the designer intended. Don’t let that short waterline and full keel fool you. She’s designed to heel immediately almost rail down and stay there, at which time her “sailing length” will be close to 48 inches. And with a slightly larger rudder she should be much more maneuverable than a fin and skeg boat in the Traditional Division, where she clearly qualifies. 25.6 28 50 56 Not to Scale Scale: 1/6 Full Size for VM 10.5 31