The rowing shell self bailers work very well. You just open them up when you need them, and they work off the ventri effect to draw water out of the cockpit when underway. They seal off very nicely when closed. You can get them from Maas Rowing Co. I think they run around 75.00. Stainless steel construction....
Water does come in when you stop, if you forget to close it up, but not disastrously quickly.

: These are made for single wall/shell installation. About all you'd have to do
: on a Mystery is cut the hole and install - and then remember to keep it
: closed except for short periods to drain while moving. You'd be reminded
: pretty quickly if you forgot!

: I have been thinking about these for sometime now and might incorporate one
: if I ever get around to building a stripper. Seeing one on the Mohican
: makes me think it's not so crazy - but then again Mohican is targeted as a
: flat water boat, and shells don't typically get too far from shore
: either... Not sure I want a hole on my hull that relies on a rubber seal
: and a mechanical latch if heading offshore.