- Description of contents
APRIL 1975 Skipper Ability. The factors listed last month are enough to indicate that the R/C skipper has a lot to think about during a race, and the fact that the skipper is constantly in control obviously puts greater emphasis on skipper ability. Simply steering to windward you may find quite difficult, after experiencing the luxury of a good vane on a well tuned yacht, because it is quite easy to lose a good windward position if you lose concentration for a few moments. Rounding the leeward mark can be quite an art in itself, and some skippers can regularly pick up a couple of places just around the marks. The use of good racing tactics (which necessarily take into account the rights of way rules) will often compensate for inferior hull speed. In a sense, this is very good news for the designers and the R/C skippers, because there must be many conceivable designs which will have, to a large degree, the criteria I have listed and there must be many vane designs which can be quite easily adapted to R/C. Thus, the skipper with the less than ideal R/C yacht may be able to compete effectively by concentrating designs at Central Park or nearby clubs, I will have to rely on my memory of racing each at least once and on comments from other skippers in whose judgement I have confidence. I have not listed them in any order of preference, and I honestly do not have any favourite at present. (I have just acquired a nicely built LJ 50 from Rod Carr who campaigned it for part of last year until he started experimenting with the Yankee, but i am sure I would have been equally delighted if a Warrior or a Yankee had become available to me in the same way at the same time. I am fairly confident that all three designs will be built and in competition next year at (CPMYC.) In the AMYA Nationals in Toronto in 12-14 mph. winds and among 43 entries, Stan Goodwin placed first with his original wooden Warrior I (not significantly different from the production fbg. hull, he says), Sandy Littlejohn (reportedly with some very bad luck) placed fourth with his LJ 50 and Rod Carr tied for sixth with the Yankee. With skippers of that calibre it is impossible to sort out the boat as a factor in the success, but I The R/C Revolution in Model Yachting Part Two Commercially available Yankee hull went into production January 1975. Flared bow and deep narrow fin are evident in this picture of one under construction; note hardness of bilge and apparent width of transom against fineness of bow. on improving on his talents as a skipper, by practising his manoeuvres and by studying tactics and sail control by browsing through some of those marvellous books on big boat racing. (My current favourites are: C. J. Marchaj, Sailing Theory and Practice, Dodd, Mead & Company; Yves-Louis Pinaud, Sailing from Start to Finish, Stein & Day; and Paul Elvstrom, Expert Dinghy and Keelboat Racing, Quadrangle Books.) I do not intend to demean the expert vane skipper, for we have all seen talent overcome speed in vane races. What I am saying is that skipper ability is relatively more important in R/C racing and that we are likely to see more R/C races won by the better skippers than by the fastest boats. Of course, that assumes that the best skippers will be using boats reasonably satisfying the criteria I have listed, because such boats will have the handling characteristics which will allow the skipper to use his abilities to the best advantage. No use knowing that it is a good tactic to hit the windward buoy on starboard tack if the skipper knows that his yacht is so slow to tack that he cannot afford a short tack to gain that strategic advantage. Three American R/M Hulls. There are at least three good R/M glass fibre hulls commercially available at reasonable prices in North America: (1) the Warrior II, designed by Standley Goodwin of Marblehead and modified by Chuck Black of San Diego; (2) the LJ 50 (also known as Boomerang and Boomer) designed by Andrew Littlejohn of Altadena (California); and (3) the Yankee designed by Chet Purdy from the Washington, D.C., area. Since we have no experience with any of these By Larry and Niel Goodrich Central Pa rk M Y Cc 7 s U “7 S A . . . suspect that most R/C skippers would find any one of the three quite pleasing, although curiously each is quite different from the other. For detailed specifications and more precise information, you can write to the manufacturers at the addresses given below, but here are my personal impressions of each. The Warrior was originally designed about 15 years ago for vane, and Stan won the MYRAA Vane Nationals with it in the late 60s. It is a very good looking yacht, a rather conventional displacement hull with clean round lines leading to a maximum beam of 94 in. and tapering to a rather narrow transom. Displacement is about 204 Ib. all up and it uses a modified flipper keel which seems to work well, although, to me, it looks rather ugly in the production model. Stan explains that he likes a very stiff stable hull on which he can put the highest rig allowed. With his 85 in. rig Stan is known here in the Northeast as virtually unbeatable in light, medium or heavy air with his Warrior; but, after all, he designed and built the boat, has been modifying it and racing it for at least 15 years, makes the best sails I have ever seen and is a marvellous tactician, regularly crewing on keelboats out of Marblehead. Those high aspect sails, which Stan feels are a very important part of his success, are very difficult to make well and very tricky to race with. Thus quite a few Warrior II owners use lower rigs and seem to be quite happy with them. This might make a good choice for the novice using a moderate rig as well as for those who think they can manage the tricky high rig. (4761 Niagara Ave., San Diego, Cal. 92107) The LJ 50 was designed exclusively for R/C, and vane NUNES MODEL BOATS sailors may at first feel uneasy about its full lines and its low weight. Looking down from above you get the impression of a wedge, a rather narrow high bow running back to a maximum beam of 114 in. tapering to an 8 in. transom. Waterline seems to be about 48 in., hull draught is very shallow and the lines are very flat aft. The keel is a fibreglass shell of rather modest camber, angled rakishly back at about 60% and gets thicker and wider at the bottom—very handsome lines—but has no bulb. Instead, the shell is intended to be filled with shot. Although its original specifications called for a displacement of 16 lb., at which weight it is reported to be quite stiff, I intend to experiment with it at 14 lb. on Rod Carr’s suggestion from his experience last year. It carries a very simple rig with a very large jib and a main with a 58 in. luff. This design is extremely manoeuvrable (some might think unstable), very fast to accelerate and is undoubtedly best on the reaches. Some report having difficulty getting it to point as high as the best yachts without a smaller flatter jib than recommended, and for light weather work it is apparently important to keep it light. Several experienced skippers I know think this would make a good choice for either a beginner or an expert. (LJ 50 hull ($40), keel shell and some other add-ons available from LJ Yachts, 430 Wapello, Altadena, California 91001, U.S.A.) Perhaps the most unusual and most experimental of the three American designs is the Yankee which will, I am told, be available here in a glass fibre hull-keel combination for about $50 in January from Leisure Products, 6926 Braddock, Annandale, Virginia 22003, U.S.A. The most unusual feature of the prototype I saw was the bow. It is very fine at the waterline and flares up to the deck where it looks like the deck of a ferry boat. As the hull goes to windward the flared bow creates a kind of tunnel effect with the bow wave lifting the bow, a most unusual sight to see. It has a very shallow hull draft and its lines aft are very flat. Although quite light, the hull seems stiff enough with its deep narrow keel and small bulb. The rig is simple and quite low. In an early race in Philadelphia last spring, Niel and I independently spotted this design as the most interesting (although it lost to a Warrior II and an LJ 50) for it pointed well and it showed surprising flashes of speed off the wind, suggesting great promise if everything could be put together. This yacht impresses as very experimental at this stage, particularly suited to the experienced builder-skipper who may have to work out a few bugs until he is really satisfied, but it is a handsome little yacht with a lot of potential. (I have written about hull-keel kits because they save a lot of time in the building and seem to me quite reasonable in price by our standards, but perhaps I should mention that each of the three manufacturers, I believe, do offer a more or less full kit or even a completely assembled model. A full kit will get you into a much higher price bracket, perhaps $150-200; and in that range you might want to consider the Vortex Soling-M kit which has been very popular in AMYA circles. (Vortex Model Engineering, 210 East Ortega Street, Santa Barbara, California 93101,U.S.A.)) Unless there are three equally good approaches to the ideal R/C design, which I doubt, then at least two of purchased in kit form for about $35 from Harris Engineering, 7628 Dunston Street, Springfield, Virginia 22151, U.S.A.; and it can be easily assembled in a couple of hours by a novice following the very clear instructions. Its 6 volt motor works through a gear box (believed to be from a humidifier) which reduces the rpms enough for the rotary arm to make a 180° turn in 5-7 seconds under load, a speed Niel and I think just about perfect. It comes with a Tufnol arm you can cut to size—we use a 44 in. arm, double the line and get 9 in. of travel which we like for Ms and 10Rs. Limit switches are used to stop the arm at each end of the arc, and a double-pole-doublethrow switch is supplied for the reversing switch. Niel and/or I have used this unit for the equivalent of an entire season and have not had any breakdowns attributable to unit so we consider it very reliable. The Neptune, developed by the Minuteman MYC, can be purchased for about $50 fully assembled from Lester C. Conner, Jr., 755 Central Street, Framingham, Massachusetts 01701, U.S.A. Its operation is very similar to the Little Herc, but its engineering is somewhat more sophisticated with case-hardened gears permanently sealed in a watertight case and its limit switches are adjustable. It comes pre-wired with a reversing switch plate which you simply glue onto a servo. In half a season of racing I have become very attached to this unit and do not plan to give it up until something much better comes along. The newest and most experimental of the three SCUs is a proportional one developed late last season by a CPMYC member and is available ready to hook up for about $40 from Robert Vega, 116-47 233 Street, Cambria Heights, New York 11411, U.S.A. It is fully proportional, very simply and neatly designed and uses a gear box from a commercial source to turn a small drum. All you have to do is connect the battery lead to the power source and connect a rod to your servo. The latter job may be trickier than it sounds because getting the right linkage for your particular brand of servo may take quite a little fiddling. I have not used this unit myself, but it is very popular with a number of CPMYC members, who swear by it despite the fact that it is rather noisy—sounds somewhat like a coffee grinder. All three of the units are quite light, comparatively compact, easy to install and have adequate torque for an M or 10R. The Neptune should have enough power for an A, and Harris Engineering offers a heftier version of the Little Herc for the same price for the larger boats. It may be simply a matter of personal prejudice, but Niel and I prefer the non-proportional rotary arm SCU, despite all the work which has gone into the design of proportional winches. It seems to us that if the boats are so far away that you cannot see where your sails are, the fault is not in the SCU but in the layout of the course and that nobody is really in control of his yacht under those conditions. We have abandoned drums and use rotary arms for two reasons: (1) rotary arms do not need the tensioning devices necessary to prevent fouling with drums; and (2) the fact that the arm travels in an arc means that line travel slows at both ends of the are which makes it very simple to get very fine tuning for closehauled work. these designs (and possibly all three) may be on the wrong track; but developments in this area are relatively slow and any one of these designs gives promise of remaining competitive at least for the next few years. (I am fully aware of Roger Stollery’s report of the hapless American tourist with an LJ 50 (or Boomer) who challenged, and lost to, the first three placers in the MYA R/M Nationals.) (Many American hobby shops carry the Dumas SCU, the type with a jockey riding on a threaded rod, and it has been popular with many skippers. In addition, Andy Littlejohn of LJ Yachts, at the address given above, reports that he has developed a lightweight SCU which he offers for about $40; and, although I have not seen it, that should be well worth looking into.) Three American SCUs. We are fortunate in North America to have commercially available at reasonable prices at least three good SCUs. The Little Herc can be Speculation about the Future. So much for the hard information. For those who like to speculate about the future, as I obviously do, here are some ideas worth 176 APRIL 1975 LJ 50s built from fbg. commercially available American hulls designed specially for R/C by Andy Littlejohn of Altadena, California. The hull is designed so that in pointing it heels and rides to windward in the “V” formed by the side and half the bottom and so that off the wind it rides upright on its shallow flat bottom as this photo demonstrates. exploring. Frank Soto and Niel and I like the idea of the “goosier’’ boat, easy to manoeuvre, quick to accelerate and easy to “read”’. (Visibility is a real problem in R/C a good deal of the time, making “‘reading’’ what your yacht is doing difficult.) This suggests we should try for much lighter designs, say 12-14 lb. for an M, with flatter planing lines more like the modern dinghies but with narrower deeper keels and small bulbs to retain enough stiffness. Many skippers will try to use a slightly tender boat which heels quicker in a new breeze and is easier to read. There will be considerable experimentation with removable keels of different weights for different winds. (Rod Carr and D. J. Robinson are among those working on this.) Some Central Park members have seriously considered fitting models with centreboard trunks which would allow the keel to be raised and lowered or moved fore and aft. We are likely to see at least several skippers develop really superior sails in the form of highly efficient unirigs. (Steve Van Ness of Central Park has two very interesting unirigs, John Ball of Ontario has been very successful with his, and D. J. Robinson is experimenting with one suspended from an aft mounted mast.) Indications are that conventional sails will see a trend to more seams to provide built-in airfoil, and we are likely to see experiments designed to make the sails easier to read by the use of stripes or colours. Some really effective telltales have been developed and their use will become universal. It will not be long before some ingenious R/C enthusiast figures out how to set a spinnaker by radio, but until then skippers will probably go to fuller bows to prevent so much diving downwind. If we can ever get rid of that movable ballast rule, it would be fun to experiment with shifting ballast by radio. (It would be quite easy with one of those rotary arm SCUs with a weight on the arm rigged to turn a full 360°, but you would have to be pretty quick on the control to avoid capsizing.) And I would like to see someone develop a simple speed DREADNOUGHT (continued from page 179) a heavier gauge wire along the top of the pins, as the rails were collapsible and were simply hinged uprights with cable or rather wire rope passed through them. I couldn’t drill holes through the pins (!) so I just took a turn round each pin, keeping the wire taut with my right hand while keeping the wire on the pin with the forefinger of my right hand. My forefinger needed medical attention at the end of it all but the finished job looked quite good. I only soldered the beginning and end of the wires to avoid blobs of solder and when completed, I carefully pushed the wire up or down the pins to get them parallel and relied on the paint to keep them in position, which it has done. I should mention that the appearance of H.M.S. Dreadnought changed over the years in a number of ways, but I have made her as near to the 1906 appearance as possible. If making the anti-torpedo netting gear seems to be too much of a chore, it can always be left off, as it was discarded in 1917. However, if this is done, the bridge, fire control and mainmast will need altering also. The anti-torpedo netting one would imagine to be an awful thing to cope with in real life. One can imagine 177 indicator you could put on the yacht to tune before a race. It seems to me it could be done by a mechanical device (a drag line attached to a bendy stick on the transom) or by some electronic device but weight would be a problem there. Niel and I have been talking about a sail plan which would be radical for model boats, and if it is successful we may have a report on it later. (The author would be pleased to receive correspondence addressed to him as follows: L. V. Goodrich, 295 Henry Street, Brooklyn Heights, New York 11201, U.S.A.; and suggests if a response is desired that the writer make it easier for him by leaving large margins or space between paragraphs so he can answer on the original letter.) sailors getting tangled up with the netting and falling overboard and the Lord knows what shambles developing, but in reality, it was so cleverly designed that it could be lowered in a minute or so and raised in not much longer. In the original ship, the flag deck, that is the one round the base of the for’d funnel, from which the flag signals were hoisted, was surrounded by railings. To reproduce this was too daunting for me, but I noticed that in some photographs, the Navy had secured canvas dodgers to the railings, and so I cut narrow strips of ply to represent this and painted it a lighter shade of grey. The original ship had four screws, but I found this too difficult to reproduce in a model of this size and contented myself with the two inboard screws, immediately forward of the rudders. “Inclination trials’ and other “trials alongside’ were carried out in the bath, and with great satisfaction it was noted that she sat down nicely to her correct water line, = was completely stable without having to add any ballast. “Steaming trials’ were carried out on Elstead Moat near Guildford and were as highly satisfactory as were the original trials in 1906. ee MODEL BOATS American Radio X Class Championship Eee National Championship Race was held on Sunday, October 20, 1974, at Conservatory Lake, Central Park, NYC, hosted by the Central Park MYC. The cold fall day restricted the spectator crowd well below the 3,000 who witnessed the RM Nationals in May, but the 5-7 mph winds, gusting higher, kept the yachts moving briskly around the modified Olympic course. A total of seven races were run, each consisting of two laps around the course and lasting 20-30 minutes so that the skippers were actually racing a total of about three hours. Although CPMYC Commodore Frank Soto with his hard chine Wilcock Maree III was a decisive winner, only 74 points separated him from fourth place Alan Wasserman with his Lewis Whirlwind. The father and son combination of Larry and Niel Goodrich placed second and third. Larry placed first in 3 of the 7 races with his X-Rated, designed by Harry Kellman, and could have won overall but for a rudder servo breakdown which cost him 10 points. Two top contenders, John Tucker and Steve Van Ness, suffered from repeated radio interference and finished much lower than expected, and Fred Frey was handicapped by battery failure in the later races. OOD Noel McIntosh and his assistants were able to work out frequency assignments in such a way that all nine entrants could race in one fleet, and this put the skippers to a real test of skill because most were used to racing in fleets half that size. Nevertheless, there was very little contact and protests were at a minimum. The event was covered by NBC and the film clips were shown on television during the half-time of a nationally televised Above, typical R/C sailing: bunched up abreast of each other are Hussy (X344) X-rated and Jon Elmaleh’s Zebra. The trailer (X342) is Bob Vega’s Maryann. Below, nine yachts jockeyed for position and a telephoto lens from across the lake focused in on 5 yachts rushing for the starting mark, left to right, Big Pepper, Zebra, Hussy, Froh Schlaf, and Joan. The background is a bonanza in that it shows some CPMYC skippers and kibitzers: L to R starting with grey haired geezer with sun glasses Frank Soto, bearded with cap John Tucker, hair flowing Bob Weeden, bearded with sun glasses Charley Noble, steward with armband Richard Synek, behind him Madelaine Tucker—Spouse, pointing to something Jon Elmaleh, with hat and shades CPMYC Secretary Sarah Ann Nack, transmitter in hand Bob Vega, and bearded profile Alan Wasserman. Photos Carl Brosius football game. The American X is an experimental class for monohulls of any size carrying no more than 1,000 sq. in. of sail. In practice the Xs are very much like 10Rs, and four of the entries had hulls from English 10R designs. It is expected that most of the X skippers will upgrade the sail plans on their Xs and race in the 10R races CPMYC has scheduled for 1975. CPMYC has dropped the American X from its future race schedules and substituted the International 10 Rater for many reasons, some of which are: X Class fleets in the USA appear to be gathering dust and show no sign of revival; design plans for Xs have never been made public and therefore are not readily available for use in construction and an increase in their National registration; by comparison the 10R is more competitive against A class yachts and can be sailed in “Open” R/C races which are becoming popular as a means of getting non-affiliated skippers together with organised clubs. The main lesson learned from this race is that any breakdown in R/C equipment can be disastrous and it is Psn 1 Name Hussy Skipper X-Rated Big Pepper 5 6 Zebra Froh Schlaf J. Elmaleh J. Tucker 8 8 Joan — S. Van Ness F. Frey 4 7 Coccinelle Maryann were hard chined. Curiously, less than half of the skippers used telltales of their own. It was remarkable how often after 20-30 minutes of racing, the OOD had to sight along the finish line to decide between two very close yachts, and it was noted how often in the racing the relative positions changed over the full course. Those with good starts usually placed well, but a good start did not guarantee getting to the windward mark first. Design F. Soto 2 3 important to be consistent throughout the series of races. Although he never placed first, Frank Soto won with 3 seconds, 3 thirds and a fourth. All of the first four yachts showed quite good manoeuvrability and acceleration, the first three weighed under 25 lb. and the first and third Wilcock **Maree III” H. Kellman “Little X”’ L. Goodrich N. Goodrich unknown American X Lewis “Whirlwind” Witty “Excalibur”? unknown American X Tucker/Daniels ‘““Diamond’”’ unknown American X unknown American X A. Wasserman R. Vega 180 Points 19 244 252 264 35 524 56 61 61 APRIL 1975 SHIPS’ FITTINGS—No. 2 The Anchor Windlass BY P. N. THOMAS [SHE anchor windlass was at first a simple drum round I which several turns of the anchor cable were taken, and the drum was turned by bars placed in sockets in the warping drums. Mechanisation took the form of a single gear reduction operated by removable handles or the Armstrong’s Patent Windlass in which the up and down movement of two handles was converted into a rotary motion by a system of ratchets. The sailors must have been very relieved when the owners saw fit to instal steam powered anchor windlasses. Depending on the size of the windlass there were either one or two gear reductions. As with the winch the “‘gipsy”’ and the warping drum could be operated separately or at least the “gipsy’’ could be uncoupled to allow the warping drum to be used alone. This clutch is operated sometimes by a handle which is clearly visible or else by a lever which cannot be seen easily. There is a band brake but the power required to hold the anchor cable needs a screw operated brake. Where a vessel was required to ride at anchor for long periods a cable-stopper was used to take the strain off the windlass. This was located at the top of the hawsehole where the chain cable went down through the deck. Where a stopper was not fitted a *Devil’s Claw’ might be used; this was a claw which held the chain links and was lashed back to the frame of the windlass itself. The photographs show a typical anchor windlass in common use on many small steam vessels and a cable stopper. Also shown is an old windlass which I saw lying on the beach at Carrara, near Via Reggio in 1964 and shows the old up and down windlass of the Armstrong type. The single gear reduction windlass was very common and was used especially on tugs and coasters. The spindle at the top could be moved to the right to engage the gear and by placing handles on the ends, the windlass could be turned over by hand. Very slow work! The double reduction type was used on larger vessels. There’s no hand gear on this size—if the steam failed the only way to get rid of the anchor was by slipping the cable and leaving the anchor behind. The warping drum is shown here on the intermediate shaft, but may equally well have been on the final shaft giving slow speed of operation. If you get hold of an old Naval Manual of Seamanship you will find diagrams for laying out anchors, anchor cables etc. M.Y.A. RULES sails away’’. In other words, a turn at the bank must now rely entirely on the pole on the bow, or a hand turn, without the customary additional touch on the stern. 10 Rater Class Rating Rules, page 3, rule 6, Spinnaker, The only definite changes in racing/rating rules for 1975 M.Y.A. events mainly affect the R/C sailing rules which are being reprinted in entirety (should be available as this issue appears but price uncertain—probably 35p inc. post from M.Y.A. Publications Secretary, c/o Model Boats) but there are minor alterations to some other rules, not at present being reprinted. Owners of rule books may add to end of sentence: 1, the height above which the spinnaker may be hoisted . . . ‘‘and shall be clearly marked on the mast” Marblehead Class Rating Rules, page 2, rule 6, Rigs, add to para (e) “The height of the jibstay is like to amend as follows :— Rules for Free Sailing, page 8, rule 10, Handling Yachts which come to shore, delete from para (b), To Tack— defined as the point where the line of the jib luff intersects the front of the mast” Page 3, rule 11, Roach of Sails, add to para (b) Rounded foot of loose footed sail is not measured, ‘‘but shall not exceed one inch’’. *“and may then, and only then, be steadied on her new course with the pole or hand against the lee quarter as she 181 EE MODEL BOATS An Epicyclic Vane Gear Geoff Draper discusses the advantages of such a gear, which has many possibilities a idea for this vane gear originated during a pond- side discussion in 1964. It was suggested that the moving carriage vane gear might be improved by using an epicyclic gear train. Although a scheme using this system was drawn up several years later, the idea was shelved because I could not find suitable gears. Comparatively recently I saw small plastic epicyclic gearboxes advertised with Pile motors and my interest was renewed. The Editor kindly suggested sending me one to play with. A test-bench model was made which not only proved the idea to have practical possibilities but indicated certain advantages over the more familiar moving-carriage vane gears. The possibilities offered by epicyclic gear system are far in excess of anything required by a simple vane gear. (By arranging for the elements to be driving, driven, or locked stationary a number of gear ratios can be obtained from a single train). It is basically a planetary gear system but for our purpose the above definition means that we can obtain a reverse drive on the output drive (essential for a vane gear) and in addition a mechanical advantage can be given to the feather. As the input and output share the same axis it allows the gear to be mounted on the rudder post (no need for linkage arms etc.), but the most attractive feature is its balance. The sums of the various elements are virtually symmetrically disposed about the central axis, thus enabling the whole system to be balanced on the rudder pintle bearing. Fig. 1 shows the system in simple diagrammatic form with the planet- carrier held stationary, Looking at the diagram in Fig. 1, with its application to a vane gear in mind (and a little headscratching—at least on my part) certain conclusions may be drawn. It will be noticed that it includes a ring gear with internal teeth and two planet wheels (there could be more or one less—four would complete the balance). However the incorporation of these extra elements does not help as it increases weight (and inertia) tending to produce side loads on the bearings when the yacht is heeled, though this trouble may be minimised as will be seen later. It will also be noticed that to obtain reverse drive the output has to be taken from the annulus and not the planetcarrier—which is the more usual set up. However, by taking the drive from the annulus it gives a 2 to 1 feather rudder ratio and 3 to 1 feather/moving carriage. This latter aspect proved to be a windfall, the importance of which was not immediately apparent. In effect it means that when the vane feather takes up an angle of 36° in the self-tacking position the moving carriage only revolves through 12° either side of zero. Furthermore when weather-helm is applied to the system the planet wheels following the direction of the vane arm tend to return to the zero position. This may sound somewhat involved but the result is that only a small segment of the system is in use, the size of the slice depending on the gear ratios used. Fig. 2 shows how only a small portion of the annulus and one planet wheel need be used. One then has the choice of designing the vane gear using either the balanced Geoff sent over from his home in France a mock-up using a Pile gearbox. Box at top indicates gear could be mounted flush with deck. Other views, related to sketches, show clever adaptation. 186 APRIL 1975 ANNULUS 100 a PLANET WHEELS —25 :| ANNULUS —~ ; — 1% L PS ANE T WHEEL Ise = SUNWHEEL PLANET CARRIER Tr wy r A _= J OUTPUT FROM Fig.l. system or the more unbalanced ‘“‘segment” version, each having its merits. One virtue is shared by both. As the annulus revolves with the rudder post it can be used to locate the indicator dial which will give readings for the vane angles in both the self-tacking and “plain” conditions. It would appear that the version shown in Fig. 1 would produce the better vane gear providing it was well en- gineered and the size and weight of the moving parts were kept to a practical minimum. Could one hope for an overall diameter of the annulus in the region of 13 in. for a Marblehead yacht? Using the segment version the diameter of the annulus could be increased considerably—anything up to 2 in.? I once came across a bag of Tufnol bevel gears in INPUT TO SUNWHEEL , = ANNULUS Dev, VANE ‘es we@ EL alan Be SUNWHEEL (eS eS i | LE ore OUTPUT (fo2 = FROM ANNULUS CENTERING LINE 187 ee TH LOCKING ae & “) i tie DEVICE MODEL BOATS The Pile gearbox with the vane dial removed. A metal baseplate has to be fitted to the box underside and an arm through beneath the gears; the sunwheel also has to be drilled for a tubular bearing. gybing of the boom actuates the self-tacking mechanism, and although one may lead the crossed gybing lines to Bonds of Euston Road, so one never knows, it might even be possible to obtain a Tufnol epicyclic gear train! In common with other moving-carriage vane gears the SAILBOARD arms on the moving carriage in the usual manner, I have suggested a pin in slot linkage to a revolving post fixed to the deck. Both the gybing line and the guying lines are led to this post, thus leaving the vane mechanism virtually divorced from other inhibiting factors. This system worked perfectly well on the ‘tmock-up” and as it was installed beneath the deck it left the dial flush and only the vane spindle protruding, making for a neat installation. Finally, although the little plastic Pile motor gearbox can be adapted to suit a small yacht (4 M?) it is by no means easy to do. If anyone fancies experimenting with one, a word of advice—the one marked 3 to 1 is the most suitable as this ratio refers to the sunwheel-planet carrier ratio. An ultra-simple sailing surfboard capable of Ts simple model should give a lot of fun to 10-11 year olds—several were made last summer and proved very successful at the seaside and on local ponds. They really can move in a good wind. Four can be made giving juniors lots of fun from one sheet of 3 x 36 in. x ¢ or #- in. balsa, plus a small tube of cement, a couple of lolly sticks, cotton, paint, and foil for the sails, so they are not exactly expensive! Apart from the simplicity, the main features are great stability and the scope for hull decoration, which can be as elaborate as the builder desires; teachers will appreciate that this is the bit the boys enjoy! Secondary schools who have used the Splinter design (Feb. issue) for 3rd or 4th year pupils may be tempted to try Sailboard for their Ist years? Construction Stage 1 HULL. Study the plans. From your9 in. x 3 in. piece of balsa cut 4 in. strip from one long edge and put aside. This will form mast later. Mark a line across the board 14 in. from one end. Draw round a tin to mark the round end and remove waste with a sharp knife or single edge razor blade. Glasspaper ends smooth. Now cut the hole for mast as shown, right through the board, also cut slot for keel about +; in. wide so keel is a tight fit. Both these slots should be on the centre line. Cut slit each end on centre line for rigging as shown. Next, the nose of the boat has to be bent up. Cut along the line drawn across the hull halfway through the thickness only. Break the board across this line and bend up front. Run some balsa cement along the crack and smear smooth with finger. If rounded end broke right off when you tried to crack the board, cement it back on and sup- port end until dry. This joint must be strong. Stage 2 MAST, From the } in. strip originally cut from board a 54 in. length is required. Top end has to be narrow for 1 in. as shown. Push mast into slot and cement. Ensure that mast is upright viewed from front and leans back towards stern slightly. Now pull cotton through slit in bows, pass round mast twice on top of “step” then down through slit in stern. Pull taut and cement under each end, after snipping off all but 4 in. Stage 3 PAINTING. Hull is now complete and can be decorated, your artistic talents can be let loose! First it is best to give a coat of clear varnish all over to seal the wood. Hang boat up to dry. When dry the main 188 colour can be applied all over. Any paint can be used (even emulsion) but of course the more glossy the finish the faster the boat will go. At least two coats of the main colour should be given and any decoration you fancy put on after in a different colour. The simplest is a broad arrowhead as shown on drawing but do whatever you like. Remember a careful paint job will make all the difference. If you really want class, think of a short name and paint it on or use transfers. Stage4 SAIL. Paper is no good if it gets wet so we don’t recommend it. From an aluminium foil sponge or cake case cut out a 4 in. diameter circle. You can draw round a tin the right size. Cut off 1 in. as shown so you have a shape like the setting sun. Cut a small slit in centre of straight edge. At each corner poke a small hole and tie a piece of cotton about 9 in. long. Cut a small hole in top centre of sail and push the sail down onto mast as far as the step. Pull cotton rigging through slit at stern and draw tight so that sail is evenly curved. Cement ends under as before. The cotton in front of mast should rest in slit in bottom centre of sail. Stage 5 KEEL. This is simply a 2 in. length of lolly stick pushed through slit cut for it. It is only necessary to put keel in when the boat is actually being sailed, otherwise the boat can stand on any flat surface to be admired. Sailing Any clear stretch of water will do. Note which way the wind is blowing and place the boat in the water with the wind behind it. Two or more boats will make a real race of it. If the wind is very strong or changes direction quickly the boat may capsize. This will not matter much as the sail is waterproof and the boat cannot sink. Have fun! APRIL 1975 MODEL YACHTING ASSOCIATION 1975 FIXTURES 9March 9 M 10R 29-31 31 6 April M A A Championship National Championship Trojan Cup Mayoral Cup 20 A Southern District 27 27 18 May 36 in. 10R M 17-18 18 18 25 25 RA RM 10R RM RM 25 RM Championship Open Race Guildford Fleetwood 26 1 June A 10R Nyria Cup Timpson Trophy Gosport Wicksteed 27-28 27 RA M Spastics Cup Bonar Cup 14-15 RM National Championship New Forest 28 4-5 Oct. M 6M Woodhouse Trophy National Championship Witton 12 A Spastics Cup Gosport 12 M Southern District Team Championships Guildford at Hove 19 26 10R 36 in. Lever Cup Southern District Fleetwood 26 15 M 10R 22 RM 22 10R Midland District Championship Wicksteed Southern District 3-9 10 24 20-25 M 26-1 Aug. A RM-R10R International Regatta R/C “Sail in” M Midland District Team Championships World Championship World Championship 24 RM Southern District Team Championships New Forest Midland District Championship Cleethorpes Silver Ship Eastbourne Southern District 26 31 A RM Bilmor Cup Open Race run by Guildford & Reading at Queen Mary Gosport Tamplin Cup and Currey Mug Nylet Trophy Midland District Championship Midland District Championship Southern District 31 31 6-7 Sept. 14 14 RM A 10R A M Open Race Little Portugal Cup National Championship Jack Roberts Trophy Wicksteed Cup Fleetwood Gosport Hove Fleetwood Wicksteed National Team Championship Birkenhead Rick Pond Dovercourt Gosport Fleetwood Championship Gosport Championship Mayoral Cup Mayoral Cup 27-28 Fleetwood Northern District Championship Fleetwood Southern District Team 28-29 36 in. 29 5-6 July M A Hove Corporation Trophy National Team Championship RA 21 21 Fleetwood Championships National Championship 12-13 Poole Gosport New Forest Bournville Witton National Championship Hove Dovercourt Hove Fleetwood M 12 Poole 6m RM A Sailing Club Championship SAIL COTTON RIGGING ly |—-178″« 1/4″ MAST CEMENT | | i | 3/4″ ——1.1/2” SAIL . KEEL FROM LOLLY STICK, DO NOT GLUE A SIDE VIEW ) \ CEMENT” | FRONT VIEW \\UNDER HOLE FOR MAST TINFOIL SAIL 189 Li Gosport Fleetwood Fleetwood Midland District Championship Witton POSITION OF | Witton Midland District Championship Bournville Wellworthy Cup New Forest NOTE STEP IN MAST ea Fleetwood Fleetwood Gosport New Forest Run by Portsmouth
