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Poe RANE Sree MODEL MAKER & ¢ mI MODEL BOATS 1965 British Open MARBLEHEAD CHAMPIONSHIP Photographs by G. Gelinaud (CHRIS DICKS sailed Tinpot superbly to win the Above, Graham Wyeth about to pole off ‘‘Pinky’’, one of the new Foxtrot twins from Southampton. Below from top to bottom, ‘‘Anne IV”? and ‘‘Daredevil’’ starting off downwind; centre, ‘‘Tinpot’’ and ‘Dragon’? on their last beat to windward; *‘Nimbus II’? off to a good start against ‘‘Melior’’ from France. championship for the third time against a fleet of 23 boats, which this year included eight from France. The number of entries and the efficiency of the Hove organisation made it possible for a full tournament to be sailed in the two days. This made the sailing more enjoyable and interesting than the Divisional sailing which is usually necessary for this event. However, the resails, gear failure and sail changing, brought about by the second and third suit breezes, gave the O.0.D., Mr. Frank Jennings, the difficult task of completing the tight schedule in the time. The French team from Reims were unaccustomed to the rough weather, since their sailing waters are inland, and they had the greatest difficulty, at first, in coping with conditions. But on the second day they had ironed out many of the problems and were sailing very well. SATURDAY The Mayor of Hove started the racing at 10.30 a.m. in a brisk south westerly breeze giving a second suit guying beat and spinnaker run. The wind increased during the day, but dropped back to second suit strength by teatime. After the day’s racing, a dinner for the competitors and their French friends was held at the Hove Town Hall, and was attended by the Mayor and TAAYOTOES of Hove as well as officials of the M.Y.A. SUNDAY At 10.15 a.m. outstanding resails were completed in a top suit westerly breeze, before the day’s programme of 12 heats was started. The wind backed to the south west and increased during the morning, so much so that starting at the leeward end had to be made from the side to avoid damage to the boats. It was then possible to lay the finishing line on one tack, although sometimes a short guy was necessary. Towards the end all eyes were on Norman Fish and Chris Dicks, either of whom could win. On the last beat Tinpot was sailing Dragon II from weather and had to get these three points to win. At the halfway stage Tinpot was in a commanding position to windward and two or three lengths clear of her rival, when suddenly she broke tack in the rough water. Chris’ fear that the vane gear had become dis- connected was unfounded and fortunately for him, 454 NOVEMBER 1965 L. to R. ‘‘Hyperon’’, the most consistent boat to windward. Centre, Norman Fish catching his Foxtrot ‘‘Tempest’’; note his unusually tall spinnaker which he used all the time and preferred to the fuller shapes others were using. Right, Derek Reed stopping ‘‘Hyperon’’. the guy tacked Tinpot back again and on to win the championship by a narrow margin from Norman Fish’s Tempest. It was encouraging to see such variety of design especially among the» first six, which were all different. Many of these completely opposing types boat is not all that is needed to win a championship; Chris Dick’s Witchcraft Tinpot lost only one run, and he must be congratulated for such consistency downwind. His success bears out Priest’s dictum that oe ane points are as important as those to windward. put up surprisingly similar performances at times. For example, one could not but admire Dave Bateup’s powerful 23 lb. Duck, Hyperon, smashing Another interesting boat was Nimbus II, a 16 lb bulb keeler, built in glass fibre and sailed by her designer, Mr. Arnold. It has a warped plane hull form with a very fine entry and long flat run. It did exceptionally well for its weight and was one of two to take three points off the most consistent windward boat, Hyperon. After the conclusion of the final heats the prizes were kindly presented by Mrs. Steinberger, wife of the M.Y.A. Chairman, There were prizes for the first four and a trophy for the first French boat, that of Mr. Douillet. A surprise presentation was made to “le petit garcon”, aged seven, the youngest of the French party, for behaving so well throughout the weekend. her way to windward and yet be impressed by the effortless way that Derek Reed’s slim 20 lb. Araba, much less powerful by comparison, sliced up to weather just as fast and with no fuss. Also the Bewitched, The High Priest, on her first outing ploughed to windward extremely well, although disappointing off-wind. Those boats able both to plane fast and survive the rough water at the leeward end, were the most successful downwind. Of these Tempest and the other Foxtrots and the prototype bulb keeler Daredevil were the most outstanding. However, a fast Zz = a ©) os _ Le Dragon Campionissimo Renee Aigle des Mers Etoile II Dragon IT Melior Polux Anne IV Araba Manor Lady Tantivy Hyperon Jade Gallivant Tinpot Brandysnap Tempest Daredevil C. Lagarde M. Sourmail D. Cheret J. L. Mague S. Douillet R. Cheret F. Cuiller D. Goyard R. Mackarel D. Reed G. H. Bain R. Dunning D. Bateup F. R. Shepherd Miss E. Blick C. Dicks Miss A. Stollery N. J. Fish R. P. Stollery The High Priest T. Moss Nimbus IT Pinky Perky D. C. Arnold G. Wyeth C. Edmondson Y.C. du Foyer Remois Y.C. du Foyer Remois Y.C. du Foger Remois Y.C. du Foyer Remois Y.C. du Foyer Remois Y.C. du Foyer Remois Y.C. du Foyer Remois Y.C. du Foyer Remois Fleetwood Hove & Brighton Guildford & District 25° 47 0 66 2 3 6903 90:5:5. 94:35. 99833)5 Bury 1034:5:5 LI5915 5) 1165/59. Guildford & District Clapham Hove & Brighton 1218 35 M3245, § Portsmouth 14605. 5° Eastbourne & District Southampton Southampton 225 22000 3 03 3~.5 2 0..2-3 03000 2-4°3’0 0: 3 3000 3225s s_ LAS4 S’S” 14635 5 146555 “35 4406.55. 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(07353-35520 5250550 3 3.00 320; 0:22 2-2 56.13 (393224235. 0.210935, 55 = 50-303 1 330:0 =2/0- 3° 35°95) +S 0000 000 284 0.000 00:0) 47: 5350702 eSealou6s 1533: 2 Ses Op 4 I24GS 5-5 1317°S’5 Fleetwood Hove & Brighton 3 35.0 2°73 3:0 0:-2):0°0′ 220000000 00 952.5 35’S 3-2 53000 1022: 5° 3 22-2250 200 937 573.3) S20 75) S53) 2 0.5. 973 S15 -.5. 235 5S S55 3 1S Hove & Brighton Guildford & Distriet a <8 9 MODEL BOATS NOTES FOR THE NOVICE MODEL YACHTSMAN PART I! MOVING CARRIAGE OPERATION, YACHT DESIGN, & FEATHER SIZE BY A. WILCOCK UR attention can now be directed to the bridle which gives the tack motion, the guys and the centering line. First the bridle. This should be of nylon or terylene so as not to be affected in length by being wet or dry. It requires to have just a degree of slackness about it so that when the boom is moving over and pulling there is no binding at the eyes or pulleys. Three methods are illustrated. (a) in Fig. 36 where the beating sheet is hooked to a cord link to an eye on the centre line of the boat and the two halves of the bridle come from the top of the link. (b) Fig. 37a where a horse (possibly existing) is used and the two halves of the bridle are attached to the runner, and (c) Fig. 37b where a plain bridle is used and the length carefully adjusted, with the kicking strap to the boom tight, so that it has just the right amount of slack. The latter is the simplest, but has the disadvantage that it is so easy to adjust the kicking strap for some other purpose and then find that the bridle is bind- ing. The author would therefore recommend (a) or (b). The guys are simply light elastic bands connected at one end to the cross arm of the gear and at the other to bowsies on side jack lines, so positioned that there need be no pull on the elastic, ie. it is out of action, or when moved forward there can be considerable pull, i.e. the guy is in action. Both are out of action on plain tacking. With this type of gear the author recommends a centering line to a forward tail on the quadrant, so that if the wind fails the rudder is centralised immediately. With the earlier types of gears described it has been desirable to apply the centering action to the gear body because of the pin and slot linkage to the rudder, but that limitation does not apply to the Fig.38 push-pull arrangement. This centering elastic should be shirring elastic, nothing heavier, it only has to centre the rudder when the wind fails and anything stronger means that the vane has to continually waste steering power “fighting” this elastic. Now to using the gear. Let us start with any plain course. In these cases the carriage is locked and the vane set to the angle for the course, see Fig. 5. Either the beating sheet or running sheet is used as appropriate. The gear will transmit positive lee or weather helm. Gybing lines should be set as described in an earlier section if the course is anywhere near a run. For a close beat where a tack or a guy may be required the vane/counterweight assembly is set fore and aft over the scale (VANE aft) and the carriage released by sliding the lock back out of engagement. If the carriage tacking stops have been set as described earlier the gear is all set for port or starboard tacks with both guys slack, and for turning from one tack to the other. If one is sailing on the port tack, ie. wind over the port side, and on turning the boat to starboard when it comes to shore, wishes it to guy back to port tack then the starboard guy is tightened —hard for a short guy and less so for a long guy and depending on the strength of the wind. Clearly for a guy from starboard tack to port tack the other guy is used. When sailing with the gear broken the wind in the mainsail holds the carriage firmly against its stops and LEE or WEATHER helm is applied positively as was the case with the gear fixed. There is nothing more to it. It is as simple as that. The influence of vane gears on yacht designs Before commenting on design features of vane gears in general, to facilitate your own experimenta- tion we will devote a short section to the influence of the introduction of vane gears on yacht design and hull design in particular. As was mentioned earlier, the practical application of vane steering gears had to wait many years because of the gaff rig sail plan and the short waterline, large sail plan, designs that were usual. The Bermudian rig gradually became more popular in the 1920’s. We should therefore look at designs of that period. Here again the form of steering then used by model yachtsmen, the NOVEMBER 1965 Braine gear, had been in use many years to influence hull designs. These may be described as cutting away the centre of the skeg, deepening it, and fitting a tall slim rudder as shown in Fig. 39. Note the forward angle of the skeg. It took some courage for a skipper of the old school to modify a good boat, by the old standards, to this extent to prove that it would perform still better with a vane gear on it, but it just had to be done to get the best out of the new gear. If your boat has these old features don’t be afraid to tackle the job, it will be well worth while. One reason that these old boats still put up such a good performance when modified is that the hull in other respects was so beautifully balanced. The vane gear operates on all courses and operates on wind direction and not strength. It is capable of exerting a much smaller force, relative to the Braine, and consequently a much more tender hull design is required. This is done by having a much smaller fin. In fact this is reduced as much as one dares without losing too much by drift on beating and reaching courses. The skeg is cut away from behind the fin, which gives a freer flow for the water to get away when driving on the beat well heeled, but a small skeg is positioned immediately in front of the rudder, serving to part the water and give it directional flow about the rudder as well as providing the rudder base bearing. Since a rudder and skeg combination well aft will give a good turning moment for little force, it is now usual to place the rudder as far aft as the water line of the design will permit. Because hull balance with a continually effective steering gear is not so important, and so many full sized craft are clearly unbalanced, there seems a current tendency to pay less attention to this feature than was so necessary in the past; only time will tell whether this radical change has been justified. Since a balanced rudder (without a skeg in front) should theoretically require a smaller controlling force for the same turning moment on the hull there would appear to be scope for experimentation here. The author is aware of one such successful design, but the same designer failed to achieve a satisfactory performance on other boats, so while there is a field for experiment it is not an easy one. The high aspect ratio Bermudian rig sail plan has been developed concurrently with vane steering and while perhaps not directly related to the introduction of vane gears, the new lateral planes of 465 i Fig.40 = hulls of good balance since the gear was not nor- mally used on the beat and designs having a large lateral plane, particularly in the fin and skeg, were usual. This feature was necessary to counter the power of the Braine steering on other than the beating course. To this end, also, the rudders were long horizontally and shallow. If they had been otherwise, a puff of wind would have turned the boat off course. The shape of the rudder and the slipstream of the water past it smoothed out irregularities, but the large lateral plane and long solid skeg made the boat sluggish to turn. These features are illustrated in Fig. 38. These were the conditions when the vane was introduced. It took a long time for designers and skippers to realise that radical changes had to be made to designs to meet the requirements of the new gear. Many a vane has been thrown in the pond, to the author’s knowledge, in disgust at its inadequate performance, when, in fact, it was the hull design that was unsuitable. Many old boats are performing wonderfully well today, having been modified by J AA hulls, tall sail plans and related or interdependent. vane gears are inter- Design features of vane gears This section is one of odds and ends, hints and tips. It is in no particular order since as the author sees it there is nothing particular to give it order. Perhaps what you have been hoping for are some ideas on vane sizes, that is, the feather, more than the gear itself. One might expect that its size would bear some relationship to the rudder it has to operate. This is undoubtedly so, but the ratio of areas can vary quite widely and is influenced by the length of the arm carrying the vane and the proportions of the rudder, rather than its area. A tall narrow rudder will operate effectively from a relatively small vane on a long arm or a larger vane on a shorter arm. The rudder size has almost certainly been given by the designer of the hull. Starting from there it is suggested that with a long arm, a vane of six times the area of that of the rudder would be about right while on a shorter arm, eight times would be required. What is a short arm and what is a long arm? For a 36 in., 2} in. would be short, 34 in. long. Marblehead 3 in. short, 4 in. long. 10 rater 34 in. short, 5 in. long. “A” Class 4 in. short, 6 in. long. The vane or feather should be made of obeche, 3/32 in. thick for the smaller ones and 1/8 in. for the larger. With the thicker material some aerofoil shaping can be given, while for the thinner material remove the square edges. As to the shape of the vane, one has only to look at those at a Championship match to realise that either it doesn’t matter a great deal, or we haven’t yet settled what is the right shape. On the average a six to one ratio of height to width is of the right order and a little shaping can be done to make it aesthetically more pleasing. It is much more important to have a balanced vane/ counterweight combination than some mathematically calculated vane size. It was stressed in earlier sections the importance of being able to set the vane (feather) in the balanced position. This is stressed again now. The author is in favour of using a feather with a straight vertical front edge and shaping the aft part if you wish. Suggestions are given in Fig. 40. The vertical front edge is believed to create a good low pressure area on the lee side and this, together with the direct pressure on the windward side, gives a good operating torque. The vertical forward edge also enables one to see at a glance if the feather is in the correct position for balance. It will be noticed that the “boxkite” and “aeroplane side vent” types are included. These are seen perhaps as experimental types, too liable to damage in a collision for everybody’s fancy but as types which are effective they should be recorded. Their purpose is to reduce weight by more effective form, so if you are going to experiment bear in mind that the size (total area of surface) should be less than the conventional feather for the same power.
