: Gore-tex might be nice, but 3-layer gore-tex is so expensive (like
: $15 a yard I think last time I checked, I bet you could get it
: cheaper if you shopped around). You might be able to do some
: fabric-constructed scupper-like things, especially with vinyl or
: those vinyl-ized fabrics. Imagine, if you will, a hole in the
: deck fabric, covered by a patch that's sealed on three sides.
: When a bunch of water dumps on the deck or you capsize, it would
: probably keep most of the water out, and it would allow a whole
: lot more air movement. Might not be water-tight enough though in
: really rough water (like surfing).

If you are not into rolling and whitewater you could simply have a vent flap held close with Velcro . . .