wrote in message
. ..
The hole is to big .Can't find a hatch cover big enough.
Decided to get
20x15 cover ,existing hole is 19x18. What is preferred
method do fill the
gap? Also need to extend a deck by 14 inch any advice?

Stop beating around the bush. Take it to a fibreglass shop
and ask them.

Joe Kovacs
SV Sea Breeze
Cooper River Marina Charleston SC