a B-zillion cans of that GREAT STUFF Insulating foam squirted under water into a trash bag for easier removal.

Seriously, I watched a guy do this with the blown-in polysterene insulating foam. A insulation truck pulled up and a long hose went down into the water where the guy had rigged plastic bags inside the cabin. It was a submerged lobster boat instead of a sailboat but I'd assume it's the same. Water out, Air in.

The nice part about being a pessimist is that you are constantly being either proven right or pleasantly surprised. - George Will
"It's not that liberals aren't smart, it's just that so much of what they know isn't so" -Ronald Reagan