12-foot Sailing Diesel Inboard Lifeboat/Skiff Sosume
Tim designed Sosume to be a shore skiff and lifeboat for the original 56-foot Tropic Bird. She was built of foam-core epoxy and fiberglass; a construction that made her lightweight and unsinkable at the same time: the hull alone had 684 pounds of bouyancy in the foam.
This didn’t count the two watertight compartments which added another 280 pounds of bouyancy to the hull.With a total of only 208 pounds of metal in her structure (we’ll get to that in a bit), she would float about halfway even with her entire bottom holed and leaking.
Sosume was powered by the roller-furling sails on 2 unstayed fiberglass windsurfer masts you see; but also by a 4-horsepower inboard Yanmar diesel, directly connected to the propellor shaft. She had a homemade Kort knozzle around the specially-machined propellor that made her more fuel-efficient and faster, and also tended to keep lines out of the propellor.
This boat accomplished the following goals:
- Fuel-efficient shore boat that could easily hold eight average people for short hops.
- Could sail longer distances to save fuel, such as across the inside of an atoll, or between islands in periods of good weather.
- Did double duty as a ship’s lifeboat in the event of shipwreck or capsize: with 4 5-gallon jerry jugs of diesel onboard, she had a 400-mile range under power, and an unlimited range under sail.
The boat in the background was the same hull shape and size, just adapted for use with an outboard motor at the customer’s request.