To enjoy sailing, the boat has to be appealing, easy to handle and speedy. Our 30 years of design experience has always been aimed at doing just that and now we want to put all that experience into a small keelboat to bring that within reach of disabled sailors.
This powerful hull shape is needed not only to enable speed but, more importantly, also to give maximum stability. Because of the limited mobility of the crew we need to make sure that the boat can sail as upright as possible. We do this in two ways. One is called form stability, having a wide boat gives us this, and the other through a low centre of gravity combined with a high ballast ratio (weight stability). This design has a keel with a low centre of gravity bulb at the bottom to maximize this. The result is a boat with a limit of positive stability close to 130 degrees. This means that the boat can capsize (90 degrees) and when pushed further down another 40 degrees it will still come back upright. We consider this vital for safety in the event that an unsuspected gust or wave hits and turns the boat over.
Another safety feature incorporated in this design is the four watertight compartments. Each combination of 2 compartments carries enough buoyancy to keep the boat afloat, which means you can have a breach comprising 2 compartments, and still be safe. These are very stringent safety requirements and not unlike those applied to the round the world racing yachts and although these small boats will never venture offshore, we still feel that one wants the peace of mind that we have made the design as safe as we possibly can.
With the help of 3D modeling we have managed to create a modern sleek design with totally developable surfaces, which means that it can be completely built out of flat panels. Even the bulb, which has a complex hydrodynamic shape and its requirement to be made out of a high-density material (steel in this case), can be simply made combining shapes CNC cut out of a flat plate of 12 mm steel.
This bulb weighing 110 kilos (242 lbs) represents a ballast ratio of over 60%, which is in part responsible for trying to keep the boat at optimum heel angle of less than 20 degrees.
It is important to limit the amount of heel as much as possible as the sailors will be sitting in a seat which can be angled either way up to 20 degrees so that they can sit upright in most sailing conditions adding tremendously to sailing comfort of the crew.
The rig is a freestanding mast made out of two sections of aluminum pipe. These are standard size extrusions, which should be available in most countries. The principle of the rig is the same as that used so successfully on the international Laser Class (GRP one man dinghy) where the lower section is a thicker tube standing in a recess made in the deck and the top section being a thinner tube, which slides into the lower tube for support.
This way it creates a tapered mast which will bend more at the top than at the bottom, releasing sail pressure when a gust hits the sail. The length of all the spars needed has been optimized around two six meter (20ft) sections of tube, which are standard lengths.
Total Weight under 200Kg
The total weight of the boat including ballast is designed to stay under 200 kilos (440 lbs). This will allow it to be towed on a single axle trailer by a standard family car.
The boat also has a single lifting point to allow for it to be hoisted quickly in or out of the water without too much hassle. There are different sail combinations possible to adapt to the level of competence, crew and performance. Sailing either on mainsail alone, mainsail and jib and or mainsail, jib and spinnaker, this yacht is going to be an excellent performer.