Believe I'd go for a rather large hole
> in the hull and fix a holder on the inside with a piece of flexible
> plastic that craft people use to cut up and sew back together with yarn.
> Comes in sheets about 8"x11". Has "strips" going up
> & down and crosswise. I believe the larger hole will help with the
> airation.

Sounds like a description of "Plastic Canvas", a plastic grid material used for a process simailar to cross-stitching designs. Most craft stores will have plastic canvas in several sizes, at least 8/inch and 10/inch grid. Good luck, TNX, Scotty