Paul Stomski built the hull of his sit-on-top from conventioanl plans. The only modifications were in the cockpit cutout, hatch cutouts, and the seats.

You can do the same with almost any other design you find, be it stripper or stitch and glue.

The basic premise is that you have a large cockpit. You can do this with any kayak design by constructing the deck according to the plans, and then using a saw to cut squarely across the deck from sheer to sheer (gunwale to gunwale if you are building a canoe) bulkheads at both ends of the opening seal the forward and aft areas, and support the deck. These bulkheads also serve the same purpose as a thwart on a canoe, and keeps the sides from caving in on you. If yo have a real large are cut out, you may want to put in an interior chine or gunwale on each side -- again, this would act like it does on a canoe.

The base of the cockpit is lined with plastic foam blocks that are glued in place and covered with a layer of glass cloth and epoxy resin. With an application of heat, either from a hot wire, a butane cigarette lighter, or a blow torch you can carve these foam blocks to provide a contoured seat and foot rests. You can also drill out areas for scuppers, cup holders for your drinks, a livewell, custom areas for holding your tackle boxes, or SCUBA tanks, and/or just about any other shapes you desire. Just remember to make these shapes a bit oversize, as the openings will shrink a sixteenth to an eighth of an inch when you cover the foam with the glass cloth and resin.

The sealed foam will add a tremendous amount of flotation to your boat. At the same time your seating will be higher, so the center of gravity is going to be higher, too. You may want to keep that in mind.

Consider using a stitch and glue pattern and make it from lauan plywood. The basic hull costs will be low, and you won't feel too bad about cutting away so much from the deck.

Hope this helps.

PGJ