Rich wrote:

Father in law's boat is fiberglass with self bailing deck. Has leaked water
under that deck for years ... (snip for brevity) ...
There is no bilge plug or drain, because the bilge area is totally filled
with foam.
Any ideas about getting this water out?

A couple. None that are quick or easy. If there is truly no way circulate air in
there, your best bet is to take off the deck and rip out all the old foam. Or
you could start at the transom, and drill a hole forward thru the transom and
into the foam as far as you can, and put in a sealed hot dry environment, and
stand it bow vertical. That might take a good while.

I have lightened up several sailboats with waterlogged foam, but all of them had
a way to circulate warm dry air under the deck inside the hull. And it still
took a few months.

This is not entirely a joking answer, the best way to solve the problem is to
haul it to the landfill and buy another boat.

Fair Skies
Doug King