Today I was in the yard, trying to re-arrange the overly-exotic zinc arrangement I have for all my bronze rudder hinges. The lowest hinge on the hull has a zinc that is drilled into the hull with a wire that goes to the hinge. Today I pulled out the 1/4" stainless fasteners that went through the hull at the bottom of the full keel and some water came out.
That can't be good.....
For reference, we're talking about a full keel boat, where the bottom portion is supposed to be solid, thick glass, with lead (and metal stuff) encapsulated into the keel. The bit that these bolts came out of is supposed to be solid glass and lead, yet a few tsb of water came out when the fasteners came out.
Is it possible that this was just the water trapped along the length of the bolt itself? Or.... by drilling through the gelcoat on the outside, did the previous owner expose non-waterproof fiberglass to water that has now soaked it up? (please excuse my lack of fiberglass knowledge, I'm a recovering wooden boat owner).