‘The thing that hath been, it is that which shall be; and that which is done is that which shall be done: and there is no new thing under the sun’ – Solomon


Above: this Austin Exasperachun design is seen here vane racing – these full-sectioned designs remained competitive into the early 1980s, though the scow-influenced shapes required more expertise to successfully trim the vane steering gear than did conventional skinnier designs. During the 1970s model designer Eric Nuttall was experimenting with this (centre) cranked and balanced unstayed una rig – fast in some conditions, the unstayed rig could not hang on upwind with the devastatingly efficient and close-winded stiff and narrow designs that were now hitting their stride. A modern interpretation of HB Tucker’s original 1940s Duck scow (top right)


reduction of drag in other areas, ie a reduction of displacement, or a big gain in righting moment and thus driving force. It works well in boats that gain most of


their righting moment from the low vertical centre of gravity (VCG) offered by a bulb keel, ie where the crew has a minor effect on righting moment. Large boats and obviously model racing yachts with no crew fall into that category but small keel- boats don’t. Most of their righting moment comes from the weight of the crew on the rail and, because they are essentially sailed as upright as possible, and as the righting moment benefit of the bulb only materialises with heel, the right- ing moment benefit offered by the bulb rarely comes into play… and all you are left with is the extra drag. Not good. Today’s ‘modern’ IRC Quarter Tonners


universally do not use bulbs (nor did they in IOR guise). The Davidson-designed Black Fun sported one for a while but, as calculations and the VPP indicated that it was slow, we replaced it with a solid lead fin and the boat started winning again. Moving onto rigs, Manfred Currey did


much research work into rigs in 1923 using the Junkers wind tunnel in Dessau. In one experiment he filled in the gap between the sail and the mast with plasticine and noted a big improvement in performance. Double-luff sails carried to the deck give just that advantage, though whether Manfred went on to use that knowledge and produce double-luff sails is unclear. Others certainly did as the first patent is dated 1926. However, Roger Stollery used them on his champion model Ten Rater in 1968 and the concept is used now in the lower rigs of the Marblehead class, Ten Raters and others. However, it becomes very difficult to make double-luff sails set properly in light air so the big no1 rigs are usually conventional. Again I am not sure when kicking straps


or vangs were first used in full-sized boats but they were used as early as 1910 in models, Bill Daniels using one on his


schooner Prospero to control one of the mainsails that was particularly tall and thin and difficult to control. Varnished Terylene sails, which were


smooth (not necessarily an advantage) and non-porous, were being experimented with for models by a guy called Peaks in Wales in the mid-1940s and they were in almost universal use in models by the mid- 1950s which is comfortably before Tery- lene (Dacron) appeared in full-sized sails. Another innovation, the modern swing


rig, was invented by Roger Stollery in the late 1960s. They have the advantage over conventional rigs in some conditions, in that both jib and main rotate about the mast so that, no matter what the course, both are deployed optimally in relation to the wind. Thus, in classes with no spin- naker, the full allowed sail area is working downwind when, with a conventional rig, the jib would not be working unless it could be goose-winged. Even then, because of the angle of the jib stay some of its area is lost and its force vector is not in the direction of travel, so some of its potential force is also lost – though it does help to lift the bow in the manner of a modern full-sized asymmet- ric. Also, because the swing rig is partially balanced, sheet loads are much reduced. A similar semi-balanced una rig was


developed by Eric Nuttall in the 1970s. By cranking the mast forward just below the gooseneck and having the base of the mast enter the boat at a forward angle, the axis that the mast rotates about can be made to pass a given distance behind the leading edge of the single sail such that the forces generated by the sail are acting only a little behind this axis and the rig becomes almost perfectly balanced about that axis. This reduces sheet loads and, because part of the sail goes to windward of the boat centreline when eased, the boat is also better balanced downwind. This habit that model yachting has, of


being ahead of the game, was appreciated by the journalist and racer Jack Knights who, in 1979, persuaded Peter de Savary


to fund Project Acorn (from little acorns do mighty oaks grow). The idea was to assemble a number of model yacht designers plus an up-and-coming dinghy designer, Phil Morrison, and use their inventiveness to produce ideas that would make a Twelve Metre faster. Each designer produced a legal 10th-


scale Twelve Metre design that was then built by Guy Winder of Winder Boats in western red cedar and subsequently sailed under radio control. Additionally, some of the hulls were later tested in the tank. The advantage of radio sailing models as opposed to tank testing is that the radio model is free to react to the forces working on it whereas the tank test model is, in most cases, artificially restrained. Thus even today such things as performance in waves can often be far better judged in a sailing model than in a tank. A number of ideas were generated,


perhaps the most significant being the use of wings on keels. Remember, this was the early 1980s in the run-up to the 1983 competition which Australia II won using a winged keel. Peter de Savary’s British syndicate had the same idea, which con- tributed significantly to the Australian victory, but never used it. They even went to the trouble of asking for a ruling as to its legality which is why, when the New York Yacht Club protested the keel of Australia II, as it had already been declared legal, they lost (oops). Similarly, in the last Cup one idea that


helped win the competition for the New Zealanders, the double-cranked foil which reduced total wetted surface area by about six per cent for the same lift forces, also came from the world of model yachting and Moth sailing. Twice now, perhaps three times, there have been ideas that were used and honed in model yachting, long before they were used full size in the Cup and which were pivotal to winning the competition. There are others. Perhaps we should start using them? Dave Hollom, West Yorkshire


SEAHORSE 57


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