We have a repeating problem with our 1986 Hunter 31 'window': meaning the 30" long by 10" wide port plastic piece that is like a porthole but does not open. It cracked and broke in 2001 and we replaced it with what we thought was an exact replacement piece of plastic. It broke again last winter and when we (finally) got the new part we hoped all would be well. We installed it with fewer screws (as we felt the old one might have moved too much with the coach roof twisting a little as it does under sail. We used the black LifeCaulk and gently put the screws in just enough to hold the plastic down. It cracked about 8" from the forward narrow piece but did not leak, as that triangular part covers fiberglass gelcoat, not the window portion. Now it is leaking. I put some caulk around the outside edge and the leak has abated, but the boat has ugly white stuff on the window. There is some crazing around three of the screws. What was the original equipment kind of plastic and is there a company that already has the specs for exactly what we can use (already cut to size)? joe