Design № 29
12' (3.7m) single handed trapeze racing dinghy
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Every so often something new and better comes into the sport of sailing. And there always is a need for it. Many new skippers like to start right in on all the excitement, but that need is greatest for those who have gone so far in the normal type of single handed sailing craft, and would like something more demanding and thrilling to sail. The 3.7 offers the obvious excitement of single handed trapezing, which gives ordinary sailing a whole new dimension. And for light airs when trapezing is not possible, it is still a quick, responsive, and pleasant boat to sail. Sea Spray boats test (May 1971) described handling characteristics and all round performance as excellent.
The 3.7 is a single handed trapeze centreboarder, with hard chine, rounded sections, full bow, straight run, and generous beam. The rig is set well aft - 4 ft. from the stern with 1 ft 9 inches of rake. This makes for easy trapezing with no bow dipping tendencies. The overall length was decided on as being the nearest metric conversion of the optimum of 12 ft. This also makes the boat easy to store and tow, or carry on a roof-rack. It is also suitable for sailing both on the sea and on restricted inland waters.
The cockpit is self-draining, and the boat is easily righted if capsized, emptying out immediately. Lighter and heavier skippers are able to compete on even terms, because they may select fuller of flatter sails, possible with a stiffer of bendier mast. Building had been sept simple for amateur construction at home. Plans are detailed for construction in timber using sheet plywood. The hull is fully decked to the mast step with 15cm (6") side-decks aft. With the self-draining cockpit, the whole boat should be watertight and unable to take any water or be swamped. The rudder is hung from a 25mm square (1 inch square) alloy transom beam, and has a lifting blade. Blade and centreboard profiles are of minimum area and work efficiently. A daggerboard is used for simplicity.
The high aspect ratio is set on an 18.3m (20ft) mast. The sail is fully battened; sail adjustments are kept at an economic level, and no standing rigging can be adjusted while the boat is being sailed.
Suitable Crew Weight:
Hull Weight (with fittings):
8.8 sq m/95 sq ft
55-80 Kg/120-180 Lbs
48 Kg/106 Lbs
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