Model Maker: Volume 2, Issue 21 – August 1952

is cae I by i : Novice 50 — New Car for .5 cc. i “First Steps in Model Yacht Beane : Rotating Masts =: lan Moore’s 5 cc. Racer Building a 1 c.c., Engine Pt. II]: fee Series on 25 mm. (TT) Gauge Model Railways s, : a Rolling Stock of the East Kent Railway : The gener _ Model Buildings that are Different : for 0 Gauge: Gar Preeouppe—Ulesr. Anan a ieee E - First Steps in LEAD anyone who understands the first four rules of arith- metic can tackle designing, and that all the necessary calculations can be done on both sides of a postcard. For our purposes this is almost literally true so don’t DRAWING be discouraged on this score. WEIGHT HE sport of model yachting consists of three separate yet integrated parts, designing, building and sailing. Each demands a different skill and yet each is necessary and complementary to the other, and full enjoyment of the sport can only be appreciated by those who have a knowledge of all three parts. Nearly all men in the sport can sail a boat and many can build, but there are very few designers. Although many men have definite ideas of what features constitute a good boat they lack the skill to put their ideas on paper, and thus their ideas are lost. I think the main reason for this is that there is a widespread impression that yacht designing is a highly mathematical process and not to be understood by ordinary men. To dispel this idea, I quote the late Dr. Harrison Butler, a very talented amateur designer of small cruising yachts. He has said that In these articles I hope to take you step by step through the processes of designing a model yacht, and we shall not use any more arithmetic than simple addition, subtraction, multiplication and division. I do not propose to go into complicated theory to any greater extent than is necessary to understand any particular point under consideration. Tools All jobs require tools and fortunately in designing the tools are simple and easily obtained or improvised. To make a drawing we must have paper, and the most useful for our purpose is graph paper, squared into inches and tenths. Using this, the framework for our design is already drawn for us, and the squares are used for calculating purposes. This paper is obtainable in sizes 30 in. x 20 in. and, more occasionally, by the yard. Two sheets will be required for a Marblehead or’a 36 in. Restricted, but if you are contemplating any larger class yacht, you will need four sheets in order to make two, each 60 in. by 20 in. Good quality pencils are necessary, and they are now obtainable. Use a soft one, HB or F for preliminary drawing, for much rubbing out will be necessary, finalising the lines with a 2H or 3H. To draw the long curves you will need two drawing ‘‘splines” or battens and five drawing weights. Make the splines of lancewood, or of boxwood, of straight grain, about 3 ft. 6 in. long, the stiff one to be about x in. x } in. and the other % in. square. Commercial drawing weights cost a fair sum, but can be made at home quite easily, and the sketch (Fig. 1) gives you the idea and main dimensions. PEAR CURVES FRENCH CURVE A piece of baize should be glued to the base so that the paper is not marked. Weights can be improvised even more easily, and one famous designer was using the loose weights from a baby scale when last I saw him at work. You may wonder why I specify five weights. The reason is, that this number accurately placed provides the correct type of curves for a yacht. Three weight curves are to be avoided, while curves requiring more than five should never appear in a yacht. For drawing short curves found in the body plan and in the ends of the buttock lines on the sheer plan, a set of “‘pear curves’’ is necessary, but they are both expensive and hard to get. “French curves” must be used if you cannot obtain the “pears”. Both 530 August MODEL PROP YACHT DESIGN CB CCAP CP PUCPCPIOPLCPOPLELDPILPLLPLOPLCLPLELDPLOLPO LP OPP. POPPIOEP I OFOE EF OIE OF OY OEE ae” OP OE OE a OO a.OKC OI OOO OO OA COA CAA ET VPI OV OVO RRR types are shown in Fig. 2. Finding the areas of surfaces bounded by curves forms a large part of designing, and in this series I have confined myself to counting squares for this purpose (another reason for using graph paper), but if you can afford it, a planimeter saves a lot of time. This gadget looks like a rather curious pair of compasses, and by anchoring one leg on one corner of the area to be measured and moving the other round the lines bounding the area it automatically does a sum in calculus, and records the answer on the scale at the hinge. They are usually calibrated to read directly in scales of 1 in. to 1 ft., so if you get one you will have to adjust your answer to the scale you are using. I have illustrated one in use in Fig. 3. In addition to these special tools you will need an accurate straight edge and a 1952 set of 45 deg. and 60 deg. set-squares, a pair of compasses, and a 2 ft. rule. You will also need a drawing board or table of size suitable to the paper you are using. This completes the list of tools. Reading the Plans Before we can start to draw our own plans we must obviously know how to read a set of plans, or “‘lines’”’ as they are called, and to know what all the curves on the various drawings mean, and we will now look at the drawings of Polaris. All yacht plans are drawn in three planes of reference. The ‘Sheer Plan’’ shows the profile of the yacht, and the lines of the buttocks drawn on planes set at equal distances out from, and parallel to, the centre line of the yacht. The water lines and section lines appear on this plan as straight, horizontal and vertical lines respectively. The “Half Breadth Plan’ shows half a hull looking directly upwards from underneath, and shows the shape of the deck line, the load water line (L.W.L.) and all the other waterlines spaced at equal intervals up and down from the L.W.L. On this plan the waterlines appear as curves and the buttock and section lines as straight, horizontal and vertical lines respectively. The third view is the “Body Plan”. This shows the shape of the various cross-sections of the hull, spaced at equal distances along the length. In this drawing the waterlines and buttocks appear as straight, horizontal and vertical lines respectively. It will be seen that by reading these three drawings together we can obtain a very accurate idea of the shape of a yacht or of any individual part of it. The long curved lines opposite the half-breadth plan and the diagonal lines of the body plan call for explanation. These lines are used to check the fair531 OPT OW SF BBO eV PLLPLPOPO eeoao = EO Ss. PPL I I FE SE FE FY S& Pa EY EOOYa. POT POPOTBOPoruBoerD ness of all the others, and they are the views of the cut surface of a hull if it were sawn in a fore and half direction on the plans indicated by the diagonal lines on the body plans. It will be realised that in order that all these lines accurately show the shape of the hull all points of intersection must be the same on all the drawings, and in your drawings you must exercise great care to see that this is done. The sail plan and the curves of areas will be discussed later. Classes and Proportions A study of the yachts in your club house will make you realise what effect a rating rule has upon the shape of a yacht quite apart from its size. Closely restricted rules like the ‘A’ Class rule and the [.Y.R.U. rules have produced boats which, provided they are built over a similar period, look very much like each other at first glance, while the 10-Raters and Marbleheads, particularly the latter, show wide differences in form. This is because designers have to take advantage of any loopholes in the rules to get the fastest boats possible. The rule makers know this and frame the rules so as to leave as few loopholes as possible. The “Length and Sail Area Rule” of which the model 10-Rater alone survives, was killed in the full sizes because it had such few restrictions and tie yachts became uninhabitable racing machines, twice as long on deck as they were on the load waterline. The old model 10-Raters were the same, and it was only the necessity of having a powerful hull to support modern sails plans which has caused them to become a reasonable shape again. It is obvious, therefore, that our first consideration must be the class to which we are designing, and What proportions are necessary in order to get a successful boat in that class. Here observation and experience must be your only guide. Check as many designs and as many boats as possible, and then decide what main dimensions you are going to use. Remember, however, that it does not usually pay on a first attempt to stray far away from the accepted MODEL MAKER Three typical mid-sections are shown in Fig. 4. if No. 1 is that of an old-fashioned 10-Rater, and without the fin keel is very like that of a modern racing dinghy. This section produces a very easily driven hull, but unless very deep is a light displacement section. No. 2 is a typical modern cruising yacht of fairly heavy displacement. This produces an easy, sea kindly hull, which sails at a moderate angle of heel with reasonable initial stability, but a boat with this section takes a long time to attain maximum speed because she creates a deep wave system and the deeper the wave system the more energy is needed to attain maximum speed. TYPES OF MIDSECTIONS dimensions of the other boats in the class, for the other designers have probably found what propor- Oddly enough, she is probably faster in light winds than No. | because her fuller hull has less wetted surface, and at low speeds it is surface friction which retards a boat more than wave-making. The graph illustrates this point. No. 3 is the type we are mostly concerned with While it is true that long sailing length means in length our models, and you will note that it combines the that in true also is it higher potential speed, sea-kindly shape of No. 2 with the speed potentialimost rules has to be paid for by sail area, and in the “‘A’’ Class and I.Y.R.U. classes by extra dis- . ties of No. 1. All models and most full-size racing yachts have sections of this type. placement as well. Hence all designs must be a I must now introduce you to the “‘Metacentric compromise between these three factors. AdditionHeight” (denoted “‘M”’ on the sketches in Fig. 4). ally these latter two classes restrict sailing length by This can be termed the measure of initial stability indirect measurement of overhangs. and it will be seen that in Fig. 4 (1) it is very high Midsections low angles of heel, but falls rapidly as the heel at midThis brings us to a consideration of the increases, while in Nos. 2 and 3 it is low to start section, the most important line in the design. It with but remains fairly steady at all reasonable angles is upon the shape and size of this section which of heel. This is the condition we must strive for in mainly depends the displacement, the initial stability, our designed mid-section. and how soon the boat attains her maximum speed. tions pay best. MODELLING BRITISH PROTOTYPES ‘‘Manxman’”’ has argued for a change to 24 mm. scale whilst keeping radii the same and thus achieving broad sweeps and nearer-to-prototype running. This is a very nice prospect for those who have the space to play with, but there are many modellers with all the component parts for a layout stored away because they just have not got the space to lay down even the smallest of country stations. Let those who have the space decide for themselves; I am concerned with a whole new group of people who before the advent of 24 mm. scale either had never started railway modelling, or had become what I call ‘‘stored-layout modellers” (they build to store and not to run) simply because they have never had the space for a layout. This series of articles will I hope, give them an idea of the possibilities which exist in 24 mm. scale. IN (Continued from page 525) The inevitable question will doubtless be asked, “Why, if you are reducing your scale from 4 mm. to 24 mm. do you not go all the way and work in 2 mm. scale?’’ The answer is, I think, perfectly straightforward. In 2} mm. there are, even at this early date, a certain number of commercially produced components which are made for this scale, and with careful planning certain 4 mm. mechanisms can be adapted for use in home-built locos. In 2 23 MM. SCALE mm. everything, as far as I know, has to be made by one’s self or for one’s self (a comparatively expensive process) and commercial mechanisms are too big to be used. The mechanism question is vital to a good number of modellers, I fancy. Nearly all the fraternity will not draw the line at fiddling, makingdo and improvisation, but there are comparatively few modellers who do not (rightly or wrongly) consider making a mechanism beyond their powers. Added to all this, the reduction of scale by $ mm. makes a vast difference to the skill needed to produce the models—a divergence out of all proportion to the apparent small reduction in scale, and the model maker has to acquire not a little of the watchmaker’s skill and cunning. The scope of the articles will, if sufficient people are interested, be wide and fairly comprehensive. Baseboards and Tracklaying will be covered, as weil as Motive Power, Rolling Stock and Lineside Details. Working drawings (full-size for this scale), detail and constructional sketches and notes on construction will always be given. I hope they will be of use not only to the man who intends to build his 24 mm. layout from scratch, but also to the Rokal owner who wants to turn his original set into a fully detailed layout. 332 MODEL MAKER ROTATING MASTS wow % LEWIS ONE of the chief offenders in lowering the efficiency of the available sail area of model yachts is the mast, the reason being that considerable turbulence in the air flow is induced and the sail cannot therefore produce the thrust that a more nearly laminar flow would make possible. The degree of turbulence will depend on the size and shape of the cross motion of the mast (Fig. 1). It will be seen that the greatest turbulence is created on the leeward side of the sail, this being most unfortunate as the greater part of the driving power of the sail is derived from this low pressure side. The first obvious way of improving the flow of air is, of course, to reduce the diameter of the mast to the minimum. The trouble then arises with the complex rigging required to hold up the mast straight and the attendant difficulties of setting up the mast when travelling from one venue to another. It is my opinion that the extra windage involved in complex rigging goes a long way to offset the advantage gained in improved air flow over the sail and the above-mentioned practical trouble imposes definite limits as to how far one can go in that direction. Another device which achieved some popularity about 15 years ago was the Bipod mast. With this mast the sail was carried on a wire stay supported between two small section spars which were stepped on each gunwale and joined at the top. Thus there was no mast to interfere with the air flow (Fig. 2) I experimented for some time with a mast of this type on a 36 in. restricted yacht and found that it was necessary to move the sail plan forward to a considerable extent. This indicated an improved efficiency in the driving power of the mainsail, but due to several faults which are listed below it was not possible to judge whether the overall perform- ance of the boat had been enhanced. The main faults in the system were : 1. The extra weight of two spars as compared with one reasonably slender conventional mast. 2. The higher centre of gravity of the two spars detracting from the stability of the hull. The difficulty of maintaining sufficient tension in the wire stay to prevent it taking up a curve and spoiling the set of the sail. Probably the most effective way of reducing mast interference with the rules of sail area measurement as they are today, is by making a mast of streamline section. It is a waste of time using such a mast unless it is allowed to rotate and take up alignment with the sail (see Fig. 1 (c) and (d)). Rotating masts have been used on certain full-size yachts for 3. some years, and we must look to them for the lead in this technique. 540 August In the rotating mast schemes used by Uffa Fox, before the war on the 30 sq. metre class, the mast was mounted on the deck or a AREA OF TURBULENCE. ball and cup fitting and the shrouds were attached to the mast near to the leading edge. The windward shroud, being under the heaviest stress, applied a twisting movement on the mast which caused it to swing into approximate alignment with the sail. I tried this system on a 10-rater and immediately came up against several problems, the main one being that the shrouds needed to be set up so tightly in order to provide adequate support that there was insufficient give in them for the mast to rotate of its own accord. This ruled out the basic idea of the Uffa Fox system, and it became obvious that a gooseneck with movement in a vertical direction only was necessary, and to use the driving force of the sails to rotate the mast. This is not ideal for, to obtain maximum efficiency, the mast should rotate through a greater angle than the boom. I, ROTATING STREAMLINED FIG.|.__ COMPARISON _OF_MAST SECTIONS, The first attempt, which was to some degree sucThe cessful consisted of the system shown in Fig. 3. mast was wooden and of rather small dimensions; POD _MAST. being % in. x 4 in. as it was felt that the minimum size of mast would always be advantageous. The mast step, consisting of a brass plate with a row of countersunk holes in it for adjusting mast heel, was plugged with brass and similarly drilled. A single rustless ball bearing was placed between the keel and the step. The mast was held up entirely by two shrouds, a forestay and twin backstays. This form of bearing for the foot of ‘he mast seems to be foolproof, for even I have never had any trouble with it MAST TUBE EYE FOR DECK PLATE WITH HOLES FOR ADJUSTING MAS KICKING ‘STRABL 352 BALL BEARING. FIG. NO. 5.___ DETAIL OF MAST _ HEEL FITTING. coming unseated despite deliberate misuse. EYE FOR BACKSTAY. The shrouds, being fastened to eyes near the leading edge of the mast, and the forestay carried from a bridle with a similar bridle for the backstays, produced a beautifully simple rig which looked as though nothing could go wrong. Troubles soon be- came apparent and began the very first time 4 BORE pRASS- TUBE TO RECEIVE DIA BRONZE ROD the boat was made to sail before the wind. It is now obvious that in the running position the mast receives very little support from the shrouds in a fore and aft direction and that only the backstays are effective in preventing it from going over the bows. Furthermore the strains imposed have to be carried FIG.NO._6._ HEAD FITTING LINE OF SAIL. a Gr S ae – across the smaller dimension of the mast, i.e., 4 in., and the amount of bowing of the mast needed seeing ® NO _TURBULEN: LINE OF SAIL, ANG OF LE BOOM Eanes However, they -——-—— OF Boat, £ did their job and the mast never broke, althoug h top suit was carried in very heavy winds in order to try and break something and sort out the weakest link. When I finally did have a failure it occurre d in a hook which attached one of the shrouds to the mast. ©BOAT OF DIRECTION ge i to be believed. It was therefore decided that diamond stays be fitted from the hounds to the heel. The spreader had to be built short in order to pass inside the shrouds, and really the diamond stays were not as effective as desirable. DETAIL OF MAST FIG. 7. SiPARISON —— It was found to possess an old crack in the MAST A Ni metal, but the result of the failure was interest ing 541 OF MAST ROTATING AT MA? ROTATING HAN THROUGH GREATER BOOM “8° 1952 a MODEL… MAKER in that due to the sudden release of the compression forces in the mast it sprang up clear of the boat and alighted safely in the pool alongside the hull. I thought that the heel of the mast might have skidded off the ball bearing and dug into the deck. Having proved that the mast could be made to stand satisfactorily under heavier weather conditions it was found that the greatest trouble occurred in very light airs. Again the trouble was when reaching or running, for when the wind fell away the boom had a position tending to return to a fore and aft position. Of course this was hopeless under fluky conditions and something had to be done. A number of experiments were carried out with different forms of masts and fittings. There were two main faults in the first system which now seem quite obvious, of course. These faults were: — 1. The points of attachment of the shrouds needed to be modified to minimise the ‘‘winding up” effect of the shrouds as the mast rotated. The tendency for the shrouds to untwist was quite powerful and returned the boom to a midships position except in. winds of over about 6 m.p.h. 2. The mast heel bearing, the point .of attachment of the shrouds and the backstay attachment were not in alignment, and some different arrangement needed to be devised. The latest result so far is the system of rigging as shown in Fig. 4. Here it will be seen that a modified form of mast heel fitting is used so that the actual centre of rotation is in front of the leading edge of the mast. There are several advantages in this fitting, not the least of which is that the tube over the bearing forms a very convenient spinnaker socket, and as it is on the axis of rotation the thrust SWIVEL FOR “ore ay ———— | PULLEY, MAST BAND WITH SHROUDS ANO FORE: rotation. The shroud problem seems to have been solved by joining them together and hooking them to a simple mast band by means of a single hook into an eye on the leading edge. The shrouds are given a very slight drift aft, say about # in., so that the mast can rotate a considerable amount before bearing up against them. The mast head fitting consists of a simple socket arrangement into which a piece of } in. bronze rod carrying two small ballraces is plugged. The swinging arm is simply clamped around the outside of the ballraces. Do not braze the 4 in. rod into the fitting as it will be softened too much to stand the strains when running before the wind. With the above arrangement it is possible to position the three swivelling points in alignment and to assist in this direction the mast is given a straight taper up the leading edge. The mast is made of sufficient cross-sectional area to make elimination of spreaders and diamond stays possible; it is a solid pine spare 14 in. x 4% in. thick, and tapers down to # in. x # in. at the head. The diameter at the heel fitting is 44 in. I realise that this is a heavy spar, but it is serving well for experimental purposes. It is intended to make a hollow spruce mast 14 in. x 44 in. when time is available, with a considerable reduction in weight. With the present rig the boom is neutral with regard to swinging back to the centre line over an arc of about 100 deg., i.e., 50 deg. either side, and this does seem to be the answer to light weather sailing. The mast must not be set up with too much rake or the weight of the boom will cause the same un- wanted effect. I am trying out the rig on a new 10-rater, and it has proved capable of standing up to considerable misuse and strong winds, but it is rather difficult to measure the value of increased performance. It may be necesBACKSTAY (BRAIDED FLAX) sary to equip Halceyon with the rig to see exactly what difference it makes. STAY HOOKED ON. However, previous experiments on boats of known performance have convinced me of the follow- aoe aiite ae re BACKSTAY ARM: of the spinnaker boom has no reacting effect on mast ing : — DIAMOND _ STAYS 1. The sail plan needs to shifted further forward. SYAINGESS STEEL, BALL BEARING. be 2. The mainsail sets better on a rotating mast due to its greater fore and aft rigidity. i 3. There is less tendency for the jib to backwind the mainsail. iP 4. There is a definite improvement in downwind performance. 542 August 1952 mer as winds are usually non-existent, and thereby obtained some reduction in their rent. They are concentrating on their remaining summer time allocation of Sunday mornings. After twenty-two years of active existence this is a retrograde step to be deplored, but to some extent forced upon them. However, the club members still retain their enthusiasm and hope to maintain their position in the south, MODEL YACHT CLUB NOTES On their usual summer visit to Exeter they were able to collect 58 pts. to the home club’s 24 pts., with Commodore Pinsent in the fore, as usual. L. Bending of Exeter was top individual scorer of the day with 27 pts., and Trixie gained Paignton’s best with 24 pts. Members are now busy fettling up their craft for the Gosport A Class Championship in August. Birkenhead M.Y. & P.B.C. We haye received a very friendly testimonial from Commodore A. R. Andrew, whose Floreana won the National By “Commodore” Marblehead Championship at Birmingham. i “I had a very happy time at Birmingham, as I always do,” he says; “they are a grand lot of sports, having known them since the L first race for the Macdonald Trophy, when the late Mr. ea encouraging sign for model yachtsmen everywhere must undoubtedly be the appearance Savage won the cup and I was second. I have been to their club nine times and always find them willing to give all a good time.” Commodore Andrew goes on to say that Birkenhead now numbers over one hundred members, with quite a large number of new 10-Raters this year. They boast four designers, and quite a large number of builders though, strangely enough, only Mr. Andrew builds ‘“bread-andbutter” yachts. In addition to his M Class Floreana, he built Flora, a 10-Rater for Mr. Blackshaw, which came in second in last year’s championship, and which he has high hopes of seeing first this year. Midland District 50/800 Championship Ten entries came under starter’s orders, restricted to two each from Bedford, Birmingham, Bournville, Leicester and Nottingham at Valley Lake, Bournville, on Sunday, June 15th, to compete for the second annual Rolffe Trophy. of the M.Y.A. News in printed form under the new editorship of Major G. B. Lee, Racing Secretary of the Y.M.6m.0.A. While reports can be just as interesting in a duplicated format there is no doubt of the great value and increase in status that a properly printed publication provides. While this first new-style number was necessarily devoted in the main to introductory matter we were pleased to see a letter from Admiral Turner, taking up the cudgels on behalf of designers old and young. The Admiral raises a number of pertinent points by demanding which style of boat he should copy for the future. If we may, as outsiders, enter into a discussion of this sort, we would urge the worthy Admiral to close his eyes to this and that sort of boat which may have achieved some transitory success in the -post war years, and settle down at his board to produce a Turner design as he has in the past. We are sure that such a boat, uninfluenced by fashion, based solely on sound design principles would, in capable hands, be able to hold its own. That advice, too, is offered, for that matter to all designers—let them produce only designs that they are confident will be a little better than the best, and from that basic design refine and refine until they have the boat of their dreams. A light fitful breeze veering N. to N.E. gave some trouble to competitors in the first four heats, owing to fluky airs caused by surrounding trees and shrubs. However, it settled down after lunch from the north with an all-round improvement in the sailing. Sheer sailing ability contributed much to the winner’s success in the shape of Golden Eagle (J. Lapsley, Nottingham) with 34 pts. He was followed home by the two Bedford boats Wanda (D. Green) 29 pts., and Wilhelmina (G. Dixon) 28 pts. Best local boat was J. H. Cunningham’s Cunimar (24 pts), which, incidentally, is a modified version of Model Maker’s Festive design by Bill Daniels, Doncaster & District M.Y. & P.B.A. The Northern District 36 in. Restricted Class Championship took place on June 22nd on the Barnby Dun water (some 250 yds. long). This was the first major event to take place on this water since the club took it over earlier this season by arrangement with the N.C.B. A silver cup has been presented by the Yorkshire Evening Post, who have also provided another for purely club competition. The event began inauspiciously with heavy rain, but this Eastbourne M.P.B.C. We were recently down at Eastbourne to watch trials of E. G. Cock’s radio controlled Admiral’s Barge, on the water shared by the club and the Eastbourne M.Y.C. On the Sunday morning some fine A Class boats were out, doing fortunately cleared up leaving a stiff breeze at the begin- well in almost non-existent wind. ning, which moderated later, and fell away during the evening. Sixteen boats came under starter’s orders, and produced eight hours racing to decide the winner, H. Short of Bradford with Bjax (41% pts. out of a possible 50). Second place also went to a Bradford entry, H. Chadwick’s Curlew II (38%), and third to J. Palin, Birkenhead, with his Myra. This last effort was particularly meritorious as the entrant is only 14 years of age. Best ucal club place was Vice-Commodore L. Aldam, who came fifth with Katinka. Thorne Sea Scouts gave valuable assistance by manning a field telephone between starting and finishing lines, and by mating two of the winning boats, a tribute to their Lt.-Commander J. Farrel, Commodore of the Doncaster Club, who acted as starter with Chairman John S. Reeves. Readers will recall that the Doncaster Club will be organising the second Model Maker trophy race in 1953 on these waters for 36 in, Restricted Class yachts. Paignton M.Y.C. We hear from Commodore Donovan Pinsent that the club has given up Saturday evening racing during the sum- It seems that here is an opportunity for the two clubs sailing the same water to get together to form one powerful combined club for their mutual benefit, rather than exist by mutual tolerance. Local authorities are keen to support their activities, and between them they could be a big force in local sport and entertainment. Bournville M.Y. & P.B.C. Bournville Shield Open Competition, July 5th, 1952. Yachts of the 36 in. Restricted Class were entered for this trophy by City of Birmingham, Coventry and Bournville clubs, and although a fresh variable wind veered disconcertingly from N.E. to S., competition was keen. By sustained skill and effort Ron Harris, Bournville Club, who sailed Argo, obtained maximum points. Next in order of merit with a creditable score was Albert Thornhill, City of Birmingham, of Enigma, a close third being with his yacht Chance. Leading 1 Ron Harris 2 Albert Thornhill 3 George Leeds 543 George Leeds, scores: — Argo Enigma Chance skipper Bournville, 35 pts. 27 pts. 25 pts. By W. J. Daniels and H. B. Tucker ; 3rd (revised) Edition. Published by Chapman & Hall, 37 Essex Street, Strand, W.C.2. Size 9% in. x 74 in., 239 pages. Thirteen half-tone plates, 18 folding plates (17 in. x 9% in.), 144 diagrams. Cloth bound with gold blocked title on spine, half-tone, two-colour dust cover. Price £3 3s. Od. HE advent of the Third Edition of Model Sailing Craft by Messrs. Daniels & Tucker at last gives the model yachting fraternity an up-to-date textbook covering the whole of the sport in detail. This book is rather more than just another edition of the previous well known pre-war volume, and can in fact be considered as a completely new book. Of course, there is much in it that appeared in the previous volumes ; this being justifiable as the general principles of designing and sailing have not changed, but latest developments have been incorporated and the book is completely modernised. Possibly the first things that one looks for in this book are the designs, and we find one A Class, two 10-Raters, one 6-Metre, one M Class and a 36 in. R. It is by examining designs that the student can obtain the greatest knowledge and understanding about hull form, and if any budding designer can achieve the beauty of line to be found in the designs published in this book then he is a genius indeed. It is pleasing to find that the Sharpie 36 in, in the first editions has been superseded by a very attractive 10-Rater of true Sharpie type with constant chine angles. It will be interesting to see some of these boats sailing, for I am sure that this design, properly sailed, will prove that there is little difference in performance between a good Sharpie and the more normal typé of round-bilged hull. The construction of this boat is very simple and being explained in detail, should be a very suitable task for the novice. The chapters on design will be of interest to pro- fessional as well as amateur designers and contain all the relevant information necessary to produce a good and well balanced boat. The authors do not attempt to make a science of design, but make it obvious that it is an art to which mathematics can only be a guide. It is perhaps a pity that when dealing with the drawing of the lines that it is recommended virtually to base the character of the hull on the main diagonal, as the beginner may have some difficulty in visualising how the main diagonal should appear. Admittedly, this is a matter of opinion, but some people find it easier to draw in a tentative L.W.L. and quarter beam buttock, and use the main diagonal as a check on the lines as they are developed. I doubt whether any two designers go about the job in the same sequence, and I should not like to enter into argument with Mr. Daniels over this point, as he is perhaps the finest designer the model yachting world has seen. There is some excellent writing on vane steering, Braine steering and the combination of both. All model yachtsmen would do well to read this as many of the faults to be seen in the performance of yachts are explained and the remedies given. The authors are not blind to the fact that radio control may enter into the model yacht racing sphere and whilst not dealing with it in a technical sense, give a useful guide as to the effects it may have. There is a very useful chapter on glues and their various types and methods of application. In fact, it is difficult to think of any subject connected with model yachting that is not fully covered by this book. All seriously interested in the sport should possess themselves of this volume and those who are fortunate enough to have one of the earlier editions should add this edition to their shelves, as there is so much new information contained in it. The price is 3 guineas, which admittedly is expensive, but considering the amount of technical knowledge and experience that has gone into this book, it is very good value. 570