Re: Partially filling a void
but the bolts pass through two layers of plastic
Can you improve on that description?? Are the two layers of 'plastic' part of the boat? GRP?
Depending on where/what it is exactly I'd probably fill it with long strand fiberglass filler aka 'carpatch'
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)