: To be quite honest with you I never gave this a thought. I guess I'll have to
: look into something. Will the trapped air create that much pressure to
: cause problems?

all our wood kayaks to keep their good finish etc, depend on perfectly good epoxy, perfectly applied on perfectly readied wood, perfectly everywhere.

so you have an air pump waiting to work back there, on hot days it's pushing and cold days it's sucking. if there's any tiny failure or bump on the exposed thin stern etc, etc, what do yo think could happen.

one thing that could happen is nothing, and to some obviously has. but what other thing could happen?? and then what would you have to do?

why worry?, jam in a pc of rubber plug from the hatch and pull out periodically and see if draining anything. put in the very high pt., so you could drain all upside down and yet doesn't fill unless hatch filled or rollig around.

a thought anyway

-mick