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NOVEMBER 1957 “a » om i 4 a. * of meee a a w TOP surT 64 MUFFsur8 LEACH we – wm. – ee “tae ene See ey = ee MEZAN ee, ws OM Mas – _« pane, ” mS ba a a Ae An ALL MAIN SAM ODMENSIONE TO BOTTOM OF I” HEAD BOARDS EEi ae. wh sd 1OP SUT MAIN. LUFF. 78” LEACH #2”. FOOT 25° JIB LUFF $5” LEACH 85° FOOT 19-5″ : ws ‘om erent ZL OLLOWING the 1956 British Championships at Gosport the writer returned home with the knowledge that three of his designs had finished in the top eight boats. Calypso, a Commando design, first, Serenade, a Roberta design, second, and Commando _ seventh. Calypso had also won the Y.M. Cup and Wingand-cup. On the face of it everything might have seemed very rosy had it not been for a couple of facts. These were as follows: Firstly Moonraker II was in third place seven points behind the leader. Secondly the conditions had been a reach on the first day and light to moderate conditions for the remainder of the week, which favoured a moderate displacement boat. Thirdly Moonraker II had dropped her first 10 points on the reach. Fourthly Ronnie Jurd was not 100 per cent. happy with his boat notwithstanding her win. A battle had been taken up, where Mr. Daniels had left off, against the cult of the 60 pound plus heavy boat. The writer had endeavoured to produce a design which could UNTERMATIONAL % CLARE OEBIGN WOR 5 +a! ‘0 Un LEAD : match the heavy and still maintain a moderate ® di et Nas I . ee. warren, pirate vee BM. Priest nears MAKER PLANS SERVICE ZI SH peed GH alll S displacement of 50-53 1b. This had been done with some success in the Yeoman, Roberta and Commando designs which could defeat or stand a very good chance of defeating the heavies both on beat and run in a wind strength of between five to 10 miles an hour. Below five miles an hour the Turner monsters had a habit of ghosting along and winning races to windward because once started their momentum carried them through light patches when a boat 10 pounds lighter would slow up or stop. On a run the lighter boat would usually win because it got going before the heavy, and although the heavy would pick up a bit of ground, neither Fleetwood nor Gosport lakes were long enough for them to quite overhaul the lighter boat. In a hard top suit wind and upwards there was never any doubt that the Moonraker creed were the better boats on the wind. The author remembers sailing on a hard long one leg plug at Fleetwood during practice before the 1955 championships with Commando against Moon- . raker, and lost every time. The writer, being honest about his boats and with himself, promptly, in September last year, set to work and designed the large Commando type Saxon on 55 in. L.W.L., and 56 1b. displacement, which was heading the way of all the rest and well on the way to yet another heavyweight design. But something had to be done to increase the sailing range of Com- 540 NOVEMBER, mando so that she stood a better chance of an even race in harder winds with the heavies. On paper there are three ways of making a boat good in hard weather. Fig. I was the Daniels conception in the famous Glengarry. The basic needs are a large beam, shallow body, and light displacement, and one other stipulation, that they must be sailed nearly upright for the following reasons, as shown in Figs. I, II and II]. When a boat is heeled to almost rail down a certain part is taken out called the “out wedge”. Now the force of the wind acting on the sails of a boat beating is split up and one component acts vertically downwards, which tends to submerge the hull. In practice this means 10-15 per cent. of the “in wedge”. In the type of hull form shown in Fig. 1, if the boat is allowed to heel to the rail-down position, notwithstanding the 10-15 per cent. depression, the “in wedge” is vastly greater that the “out wedge”. Now, as a boat always displaces her exact weight of water and as she now wants to increase her cubic volume by putting more in than she takes out, or in other words her displacement, she can only do one thing, and that is to rise bodily out of the water as she heels until her heeled displacement equals what she was in an upright position. The rest is logic. Her water line becomes shorter, her freeboard and windage become greater and she slides off to leeward, as most must have noticed at some time when watching a flatfloored, shallow bodied boat which was overpressed in a strong wind. The writer has compiled graphs of good all round “A” boats over the years, and has found that the required sail area for boats broadly varies in a straight line graph. It is not intended to be dogmatic and rigid over this rule as, of course, the water lines of the boats considered must be reduced to an equal. Further, a vee sectioned boat requires less sail than a flat floored boat. However, if allowances are made a straight line graph can be drawn showing the minimum sail area required for any waterline beam to give a good all round performance. This graph will be found to include Roberta at 13.6in. beam and 1,510sq.in, and run right up to Moonraker at 1,640 sq.in. Plotting other points it will be found that Tinker Bell, 1948 Champion, has more sail than she needs, Serica too little and Glengarry notwithstanding her 1,750 sq. in. too little. The more the beam the more the sail required. The Glengarry type of hull calls for a large beam, light displacement and large sail area. Under the “A” Class rating rule these conditions can only apply if a 541 wea 1957 Ohe ighlander Caneéet B. H. PRIEST, M.I.Mar.E., DISCUSSES IN TWO ARTICLES THE DESIGN WHICH HE SKIPPERED TO VICTORY IN THIS YEAR’S NATIONAL AND INTERNATIONAL* ‘A” CLASS CHAMPIONSHIPS * The publicity Officer of the Model Yachting Associa- tion informs us that: “At the committee meeting of the M.Y.A., on September 28th, an appeal was heard against the ruling of the operating skippers and the O.O.D., that the race for the Yachting Monthly Cup be declared void on account of the weather conditions prevailing which prevented an even number of rounds being sailed. The appeal was that the decision was not a valid ruling in the prevailing conditions. In support of this appeal it was stated that no other competitor, gaining all the remaining points available, could obtain more than 94 points against the 10 points of Mr. Priest, had he obtained no further points. The race could therefore have been stopped without any previous arrangement. “The appeal was upheld and Mr. Dick Priest was declared the winner of the British Championship and the Y.M. cup, also the Wing and Wing cup for the fastest time downwind”’. mL MODEL MAKER) Deck view of Highlander shows sleek lines and top class workmanship, standard. on Dick’s boats Like all yacht designs this concept The also has its disadvantages. design is usually good in a light breeze and can drive through a lop to windward in a blow. Owing to the body depth required to make a large “out wedge” the displacement of the boats must be on the high side. The result is that in moderate winds where wave making resistance is becoming the largest factor in the total resistance they are not so good; also due to the deep vee section they rarely lift and plane on As an all round type the run. they are, however, vastly superior short water line is used and in fact Glengarry’s L.W.L. was 48in. Her sail was too small for light airs and her L.W.L. too short to deal with a 1957 “A” boat of 54 in.—S6in. L.W.L. in a nioderate breeze, although in a blow, even _ [ \ \ y \ ee OUT WEDGE 7! 2 OUT WEDGE 60:5% “OF IN WEDGE / ‘GLENGARRY’ TYPE : year’s Championship, and was in the writer’s — IN WEDGE 16-708″ | “A. OUT WEDGE 10-00″ to that shown in Fig. I. The idea is not new, and apart from the Saracen design is well known in the Tucker Tango design and Jill, by Bill Daniels, which sailed so well in this OF IN WEDGE iN WEDGE 13-708 5 fp 1. er [7 TYPE today, she would take some beating owing to her ability to carry sail and, due to her shallow body, her low wave making resistance. oT Wee eek OF IN WEDGE : 1N WEDGE 16-308″ _| ee a TURNER 6218. A_ BOAT opinion the best boat to windward, in really hard weather, on view. Red Sabre, the Andrews design, is another of the type whose record in the 1955 and 1956 Championships was most The idea has been carried out with success in such boats as the Alexander designed Heather Glen and Scamp. The second method of dealing with a hard wind is shown in Fig. II, which is the mid section of the author’s Saracen. The concept behind this idea is to have a deep narrow hull, and by so doing close the gap between the “in wedge” and “out wedge’, so that when heeled the hull will tend to settle deeper in the water and not climb out. This type of hull has a low initial metacentric height which rises as the boat heels. The result is that the boat takes an easy heeling angle in a light breeze, but the more she is pressed the stiffer she becomes. impressive. Highlander on the bank (that’s Nordlys in the background) gives good idea of elegant profile 542 NOVEMBER, The third method for dealing with heavy winds is shown in Fig. III which is the mid section of the Turner designed Moonraker type. The idea is, as might be expected, a compromise between the Fig. I type and the Fig. II type. The Turner concept was to make a boat of an easyish section so she would heel with a light breeze and arrange things so that the metacentric height neither rose nor fell as the boat heeled. The “in wedge” is smaller than the “out wedge” by a fair amount, so Admiral Turner arranged a large displacement hull of smallish wetted surface, a slim keel and over 1,600 sq. in. of sail, the conception being that they would ghost along in light weather and fs 7 be able to look after themselves in a blow, due to their great weight. The concept was brilliantly successful as the records of Seri, Aktis, Actinia; Tinker Bell, Moonraker I and II, and the new Nordlys show only too well. Like all other designs they have their weakness, but even so it is not very noticeable. The weakness is beating in winds of 5-10 m.p.h., and running undér all conditions, where their great weight and short run are not the best types for fast running. It must be remembered that three points are gained for a beat, and only two for a run. Ninety nine per cent. of all other designs are compromises between types I, II and III, and what is gained in one way is lost in another. (To be continued) From left to right: Moonraker II and Orchid, both Admiral Turner designs, and Commando. Orchid, in top suit with a hard blow, appears to be trying to sit on her run. Centre picture by Model Maker, other two by Dick Priest. Picture on page 541 shows Highlander and Firebird in third suits, battling their way upwind in heavy conditions at Fleetwood. One of Highlander’s notable points is the ability to point high in the wind and yet still keep moving. The photograph, incidentally, is a graphic demonstration of total i ion of th edge”! ait —_—- SLOT-RACING DE LUXE-—continued from page 539 desire to give everyone a turn in the various lanes, though not important with only “company” cars racing. It can be avoided by cutting through the common surfaces between tracks, and had in this instance been done—the extra slots being painted over with gold paint to disguise the breaks. Another useful point we noted in the hodge-podge transformer and what-have-you hook-up, was the use of a low voltage lamp to act as overload warning light and current balancer—very valuable to people who are always going to fit cut-outs and don’t until their favourite mechanism goes up in a cloud of ably mechanical modelmaker’s workshop and an ancient though still serviceable Rollo Elf 24:n. lathe. As to the absent Ken Wallis, his workshop is extensive—in an attic at the top of the house—but was not used for building this layout, since he was abroad when Findon and Trevor decided to get cracking. The only turning operation really necessary would be in preparing the guide pegs, though of course, luxury usage such as skimming armatures, drilling gearbox brackets making wheels and stub axles, would all make life a lot easier. smoke and a bad smell! Whilst expense has been, well, almost no object in producing this layout, an extensive workshop has definitely not figured anywhere along the line. Elleston Trevor possesses a Wolf Cub electric drill, the usual modest hand tools found in most reason- Verdict on slot racing: great fun, wonderful “dicing” superior to raised rail layouts; harder work preparing circuit, but any and every prototype, irrespective of ground clearance, can be built subject only to room for the electric motor. We hope to get invited along again when we have built a model suitable for the slots! 543 Sn ed a eR a eS ih i le7 ‘il MODEL MAKER TROPHY, 1957 Bournville, Sept. 21-22 fewer than seven of the eleven yachts were from Mopet Maker Plans Service: these included the winner, Tega, built from Macdonald’s Saida design, and three to Priest’s Witchcraft lines, of fourteen was unfortunately reduced to eleven when three boats scratched at the last minute; nevertheless, the entry compared favourably with other centralised regattas and proved just a comfortable number to handle under the conditions prevailing. Running over September 21st and 22nd, contestants had to face a frustrating, almost windless Saturday with odd rain showers and only occasional promise of any breeze, and a downpour followed by a reasonable, if fitful, wind on the Sunday. It was particularly gratifying to see that no sailed and despite the unco-operative weather eight heats were completed on the Saturday. The round and the first heat of the second round were completed by Sunday lunch-time, and a freshened, though still flirty, breeze in the afternoon set things moving at a brisker pace. Heading picture shows winner Tega and Puffin; below, left, Myth and Volante; right, second-placer Gretel and Red Witch. Opposite page, top left, third boat Hustler against Myth, right, the winner sailing Cortie. Bottom left are Puffin and Gretel, centre Cunimar and Zoe, and right, a procession of boats including Corbie, Tega and Bombay Duck 554 ere entry Volanté, gg satisfactory being = VERY A boats for the 1957 MopreL MAKER Trophy these by Harry Andrews, who had only acquired the hull a short time previously, Zoé, fresh from her win of the Brighton Corporation Trophy, at Hove, the previous week-end, and Red Witch. There were two Festives in Cunimar and Corbie, and Myth, from the Macdonald Mithras plan. The last-named suffered from the very light winds, as did the two Tucker Ducks sailing. The two remaining boats were Hustler, an Adams design, and Gretel, a fine performer of doubtful parentage, built without drawings and since much modified to “look right” by its present owner. A target of two complete rounds was set customary cash award Place | No. | for Name the _ | furthest- Club 1006 | Tega … exe … 3 4 848 Hustler 1097 | Volanté ie ae .. | E. Breeze £3 .. | H. E. Andrews 5 6 7 654 | Gretel 912 Pay 883 Puffin… 633 8 9 938 1007 Il 900 10 761 ens Cunimar | Corbie Myth. a Bes _… : Rarikay Duck Red Witch … | E. Cooke/D. Cinpetts:. .. | R. Harris 3 … | A. Penn 52 … | E. Edwards… … | Designer Ist Round | Total Birmingham … | Macdonald … ese 40 79 Nottingham Poole.. ae … | Adams … | Priest… met th igs a 30 304 56 554 … | Daniels ine ate Bournville … Birmingham | Bournville J. Sills/J. Woollam … | Bournville … … M. D. Jeffery … … | J. Sixsmith Southgate … Birkenhead … … | R. Waite Nottingham … | V. Crean Te Widdows (scorer) and all others who helped to make the event so successful, including “Ananed, Ltd.,” tea suppliers extraordinary (see view on right!) Skipper | Z travelled entrant was split between the visitors from Poole and Birkenhead. MopeEL MAKER warmly thanks Mark Fairbrother (organiser and O.O.D.), ecorae Leeds (starter), Mick on? ; Sn AS The lead established by Tega was never seriously threatened, and the main struggle centred round the 3rd, 4th, and 5th places. Apart from one or two re-sails, the race ended as the breeze dropped at about 5.30. Apart from the trophy, the winner received a magnificent set of carvers and a cash “bonus” for the top-scoring MODEL MAKER design. Second prize was an electric soldering iron and third a Surform plane. Mates received handsome plastic cigarette boxes (designed, incidentally, by Gretel’s skipper) and the 1957 Poole… “i ee … | Hybrid … | Priest… … | Tucker … | Daniels … | Macdonald … | Tucker … | Priest NS Sy sae ree NOVEMBER, a “ee ‘as ae … wee ae ai 36 es 23 os 26 Be ay = rm 33 12 14 18 lot 69 55 50 44 38 334 30 28 MODEL MAKER _IN RESPECT OF Y2 SUBTENDING VALUES 50° TO probable limits of any suitable main section. Yachtsmen are very conservative in their ideas but I confidently prophesy that concentric circular sections will become more and more popular (if only as a basis for modification into sections of more conventional type). 74 ° oO S82oe 8283338823838 28 Peay SBS mie, Pu ati o% 50” 52° eet See Me ee : SN DS se MN No Oo row ener ANGLE Is © MAIN SECTION COMPARISON | ae w/L BEAM oe by Guy Blogg DIVIDED BY_|_ The mathematical calculations involved in designing a DEPTH IS 1 2 SIN@| ~~ 6 ers eee s Ade N sth er WHEN HALF Wee Sy 54° ea os 62° at \-cosQ yacht on the system of concentric circular sections are so simple as compared with the art and experience of a successful designer of more conventional types, that he is inclined to shun the more mechanical method of designing for fear of losing the demand for his art. A remarkable feature of yachts built to this system is their planing efficiency. Even those with as low a main section beam/depth ratio of 2.97 (i.e. 68° angular value) appear to rise from the water and plane on their mid sections maintaining their fore and aft trim with no tendency for their sterns to descend. Whereas a concentric circular canoe-body retains the same immersed shape at all angles of heel, the conventional types change the shape of their immersed canoe-bodies at every angle of heel and I suggest that few skippers appreciate the fantastically unsymmetrical | | ‘S T 64+ 66° 68 N ° 70- ww Me – NX ° 72 NX N ° N 74 Te shape of a yacht’s main section is probably her most important feature. I think it is remarkable, however, that no specific method is generally used to indicate more precisely the proportions of this shape. I suggest that the ratio: Beam on Water-Line shapes assumed by the immersed heeled bodies. Proportionate measurements are all important (L.W.L., beam, depth, etc.). A clever designer cannot produce a winner if he is tied down to unsatisfactory Depth (Canoe-Body) would signify quite a lot to an experienced yachtsman as soon as this method of description was frequently used, The character of a circular section can be completely described by specifying the value of its subtending angle which determines the value of the ratio above suggested. For the sake of interest and convenience I append a graph which readily shows the value of this ratio in respect of any circular section of which the angular value is between 50° and 74°, which I think are the measurements. The only sure way for the ingenious and clever designer of miniature yachts to establish a reputation is to exhibit the performance of his creations after a considerable period of tuning up. The most successful boats are not those of best design. They are boats sailed by the best skippers who have patiently observed their performance and tuned them up to a high degree of efficiency. I suggest that the skipper who concentrates patiently on one boat will learn far more than the fellow who plays about with several. eA, WITH Re RATIO OF w/t BEAM TO DEPTH SECTIONS atte down Mr. C. H. Verity’s article (March, 1957), I am only giving the subject as I have found it in the past few years of study. It is stated that when a vessel is heeled, the intersection of the old line of buoyancy is by H. E. Penny OTING that the “Trig. Class for Designers”? has again emerged, I would like to put forward the actual method of finding the “power to carry sail of a vessel’’, For this purpose the sail is taken as a plain area, say “‘A” sq. in. Then let: (1) C.G. of this area be the ‘‘centre of effort’’, (2) C.G. of the under water profile including rudder be “‘centre of lateral resistance’, Please note that the area of the sail is as projected. From the diagram it will be seen that with the force of the wind and the resistance of the water a couple is set up equal to P lbs./sq. in. x A sq. in. X X in. = Ibs./in., this couple tending to overturn the vessel; the moment tending to right the vessel is WGM Sin o. WGM Sino =PxAxX. If the sail area, wind pressure and positions of COL and CE are known along with GM, the angle of heel can be found. 1.¢. WGM Sino =PxAxX HCP WGM eA CX T do not wish to seem as though I am trying to run the ‘“‘metacentre’’, this is only for so very small angles of heel. The fact is that there is actually a number of positions of M as the heel is increased, causing a curve of metacentres. So to take moments about this ‘‘M” in the condition of large heel is wrorg, as its true position is not known. It is because of the above statement that when inching experiments are conducted the angle of heel must never be g-eater than 5°. 558 ~~ THE “POWER TO CARRY SAIL” —— — MODEL MAKER UCKER’S ON SPINNAKERS, TA LKS ENTRIES has little following in England though popular North of the Border. The classes in which this falling-off is apparent are, therefore, the 10-R., M-Class and 36in. I venture to think that it is worthwhile to consider why there has been this falling-off, and what steps can be taken to maintain the prestige of these Championships. The Editor of the “M.Y.A. News”, Mr. Mark Fairbrother, attributes poor entries for these events to the plethora of “Open” Races, District Championships, and the like, but I feel that this is only a partial explanation. Other suggested causes are:— (a) When a big entry is received, either Divisional Sailing has to be resorted to, or the race spread over TOPICAL: © Gustoiu Ne S j ba. my report of the Fleetwood Regatta, which appeared in the October MopEL Maker, [ stated that the general standard of handling was better than ever before. I did not imply, however, that there is no room for further improvement, because there enough days to ensure a full tournament. (b) In order to enable competitors to enter without certainly is. For one thing, in the very heavy quartering winds that prevailed for much of the meeting, many skippers came to grief by the use of the wrong size and type of spinnaker. In such winds, a flat spinnaker, set well forward, is both safer and more efficient than a big balloon spinnaker. Far too often the latter overpowers the yacht, and she broaches violently, and flounders on her beam ends across the course, totally unable to recover herself. A yacht planes when she is driven at above her normal top speed, the bows rising on the inclined plane of her entry. With a quartering wind, there is a considerable discrepancy between the water pressures against her weather bow and lee bow. This discrepancy increases as the vessel’s speed increases, and when a certain point is reached, the pressure under the lee bow throws her head violently to wind- ward and she broaches uncontrollably. Under these circumstances the balloon spinnaker flogs wildly and prevents recovery. Nor must it be overlooked that in a heavy wind a balloon spinnaker exerts tremendous power. This pressure, contrary to general belief, does not lift the boat’s bows, but being exerted so high above the hull, tends to depress them. What makes a boat plane is’ not the pressure of the sails, but the speed at which her entry encounters the water head of her. Hence with a quartering wind, a less powerful spinnaker is needed than when the wind is dead astern, especially in heavy weather. In very hard winds boats can be sailed closer than in light, but I still noticed quite a few yachts were rather pinched. It is a fact that often a very closely sheeted yacht will not only foot faster but fetch higher, given a trifle easier trim. The reason is that by travelling faster she increases her lateral resistance and decreases her leeway. The art of sailing to windward is largely a matter of striking a balance between pointing and footing. During this blowy week, many yachts were overcanvassed at one time or another. Here again is a matter that calls for individual judgement and know- encroaching on working days, Bank Holidays are often selected. Travelling with a boat and luggage at these times by rail is most unpleasant, and the roads are jammed with cars. There is no doubt that Divisional Sailing is unpopular, but is a necessary evil when the time allocated to an event is insufficient to permit a full tournament. On the other hand many cannot afford to take time off from business, other than their summer holidays. Moreover, many married men, particularly those with young families, hesitate to sabotage the family’s holiday to indulge in their own hobby. I feel the first point we should decide is whether for our National Championships we want quality or quantity as regards the number of competitors. Are these events intended to find the best boat and skipper in each of our Classes or as a sociable get-together?. If we intend them to be real Championships, 1 suggest we have been working along the wrong lines altogether, especially now that the various districts are properly organised. Here, then, is a concrete suggestion of how these events could be organised. their Class Championships hold (i) Let all Districts in the first half of the season, say before the end of June, and instead of giving prizes, present the skippers of the first two boats and their mates with return tickets to the venue of the National Championship for the Class concerned. If the boats are to be taken by car, a cash equivalent can be given the car owner towards the cost of the journey. (ii) The entries for the National Championships would be confined to the two selected boats from each Division. This would limit the entry to about a dozen boats but these would all be picked skippers and boats, representing the best in the country. It would not necessarily bar out entries from other countries but these should be limited to two per country. ledge of the boat concerned, and the skipper has often to decide whether it is more profitable to be over-canvassed during squalls, or under-canvassed during lulls. * * In spite of the increasing popularity of the sport of model yachting, entries for our National Championships have fallen off badly during the past season or two. The sole exception to this is the A-Class event which continues to attract a satisfactory and representative entry. The Model Yachting Association recognises five classes of yachts—A-Class, 10-Rater, 6-Metres, MClass and 36in. Restricted Class. Of these the 6-M. 568 (iii) The various Championships should be two-day events, sailed on Saturday and Sunday, starting positions be reversed on the second day, one round per day. This would enable races to be got through very comfortably. Further, these races would be a far more attractive spectacle to the onlooker than crowded events where several pairs are on the water at once, as it would permit spectators to follow more closely the fortunes of individual yachts, markup score-cards, etc. We all know that many clubs hold waters by precarious tenures against the clamour of paddle-boat and canoe owners, but a spectacle of this kind is far more to offer a local authority than double the number of unselected entries, since this would offer really the best of its kind, and in a form that would be attractive to the lay onlooker.
