Those red vertical crease lines I have made with aim of panel development. As this kayak is 6 meters or 20' long it does not fit to one or even two sheets of plywood. So I divided boat already with purpose to have plates developed to sizes fit on sheet of plywood, and later in building process I thought to use straight joint line as mounting guide for all parts as it is done in Pygmy boats.

Little bit more tricky is deck, where I see is difficult to build good cockpit for all three paddlers, because front must be higher and rear side seems is better to have lower. So I decided to go for compromise as middle place is mostly for kid what we take with us in trips. But even then panel is twisted and I somehow cannot guess will it be possible to bend it like this. Don't know is it ok or not. Too less of experience unfortunately.