WB No. 248: The 22′ power catamaran SEAHORSE is meant to carry six people—and their kayaks—on excursions to distant paddling grounds. She’s also adaptable to other uses, such as a support boat for waterfront parks or a power launch for rowing clubs.
In flat water and lightly loaded, SEAHORSE will reach her cruising speed of 5 knots with just 10 hp. But because the boat will carry a heavy load and much windage in her cargo of kayaks, a 30-hp motor is specified.
SEAHORSE’s two hulls take the simplest of forms: straight-sided and flat-bottomed. They’re built of commonly available lauan marine plywood. The loaded kayak rack and bimini top will make steering a challenge in a crosswind; this challenge is partially addressed with a bow board, the equivalent of a sailboat’s centerboard.
The boat’s construction is simple: Chines, stringers, and sheer clamps are sprung to plywood bulkheads, and the boat is planked in sheet plywood. The cockpit layout is adaptable to a number of configurations; the concept shown here uses tiller steering for the outboard motor.
- LOA: 22′ (6.71 m)
- Beam: 8′ 51/2″ (2.58 m)
- Draft (1/2 load)
Bow board up: 10″ (25 cm)
Bow board down: 2′3″ (68 cm)
- Boat weight: 680 lbs (295kg) approx.
- Half-load displacement: 1,455 lbs (599 kg)
- Full-load displacement: 2,020 lbs (916 kg)
- Power: 30-hp outboard
See more details in Designs: Sketchbook, WoodenBoat issue 248.
Do you have a boat concept you’d like to see Laurie McGowan and Michael Schacht develop? If so, send it to Sketchbook, WoodenBoat Publications, P.O. Box 78, Brooklin, ME 04616, or email it to firstname.lastname@example.org. Your letter should be no longer than 500 words.