? Any thoughts?

Sit on tops would be complex in that they would require another step as equally involved as a deck or a hull. I haven't thought about this except for now, but the simplest procedure would be after designing:

build the hull and deck as usual

glass i/s and o/s

cut cockpit profile in deck. I visualize a fairly low profile side view with therefore a fairly simply curve area at the cutout. And I see the cutout as being U shaped, with a wide U bottom for my big butt and short U sides for my stubby little legs w/ maybe a blob at ea end for my size 13 snowboard boots.(prob not)

tape both halves together w/ packing tape in exactly the right alignment and shape.

strip vertically down from the deck to the hull w/ strips glued to the cockpit opening but NOT to the hull(use plastic or duct tape etc on the hull)

Sand the strips and glass over the deck edge and down to the hull making a flange over the duct tape (but NOT glassed to the hull)

Split hull and deck apart and glass inside the strips to the bottom of the strips

Now the complex considerations. How do you inside seam the deck and hull. One way is to use Ed Valley's great approach in leaving an upturn of glass on one side. Another is a modification of Jay Babina's approach. I am seeing these as both blind seams.(but this is not great but might work). The second approach is to seal the edges and outside seam only. And I guess the third is to use a front and rear hatch to stick yer head in to inside seam the old way. That way you could even inside seam the cockpit(in the first two, you just glue the cockpit flange down and glass across.

So you end up sitting on the bottom of the hull with some sort of seat just like usual. Or you could lift yourself up by fitting in some rigid foam or bring Lee over for some expanding ideas (whoops I mean foam) or do either and put some wood slats over to appear as if the bottom was woodish.

Problems I can see. future finishing or repairing of the inside. venting. Possible buckling of the whole yak at the centre(easily minimized at the deck) don't forget draining.

Some ideas anyway, I guess the strip would be easiest.

-mick