Last weeks windy trip north and motoring in the river showed my Mark 1's cockpit drains to nicely work in reverse to half inundate the cockpit floor.
We tried a few at-sea solutions such as rubbish partially blocking the cockpit side holes (making increased pressure against the outside wave slap ingress).
Seemed to work okay but now to do a better fix.
Thinking one way plastic flaps on transom side outlet.
Any others had a win on this or suggestions/pics?