Valve
Theoretically possible, but the pressure differential needed to open it – a few inches of water – would mean that you’d need a very light spring holding it closed. It’d probably be hard to make it reliable at a reasonable cost.
Sailboats use venturi bailers that create low pressure and draw water out when the hull is moving at a reasonable speed.
I’m about your size
and even the 14 foot SOTs can be quite different. I paddles a WS Tarpon 14 that always held 3 or 4 inches of water in the footwells. I bought a 14 foot Manta Ray that holds no water in the footwells. I’m in the weight range of both, the designs are just that different.
Scupper plugs are the temporary solution, but you’re going to need a wetsuit or drysuit to paddle a SOT up there year round.
jim