Thanks for the ideas and thoughts Jim,

: My builds always hang over the ends.

Mine will too - started a 12' table with overhangs all the way round for clamps if needed

: Experiment if that makes you happy. I think most of us here dabble
: in changes.

Part of the fun as I see it.

: The butt joint will be plenty strong. I surf my butt jointed Pygmy
: Tern 14 often and have endo-ed it pretty hard with no problems.

That sound painful! I am very much a rookie paddler.

: I built Nick's surf kayak from plans. Instead of butt joints the
: plans call for replicating the puzzle joints by hand.

I have no "spare" wood within the kit pieces to try anything that overlaps, hence the idea of splines which merely connect and strengthen butt joints. I was thinking of working from plans but chickened out at the thought of the long curved cuts.

: Maybe you could draw your own puzzle joints on your project. Nicks
: surf boat has survived many endos, collisions with other surfers
: and abruptly ended side surfings where I simply ran out of water
: and hit the sandbar.

That certainly says they are strong - I guess I am what you would call a "flatwater paddler" at this point.

Thanks to all for your ideas and thanks to Guillemot for setting this up.