Down the starboard side (which had the worst pulpit leak) the wire to the navigation light had been attached with stainless screws that pierced the balsa deck core. I thought that the rusty look was from condensation. Nope, it was water trying to get out of the balsa that had leaked into the core from the leaking pulpit mount. The interior screw holes were all drilled oversize and I found no rot. I will dry out, fill with epoxy, and then find an appropriate fastener system.

A floor heating pad is placed on the deck with foam insulation above it. The heater gets up to about 160-170F, which is hot enough to kill dry rot spores in the deck, but not hot enough to damage the fiberglass laminate. It is moved every couple of hours to allow the heat cycling to drive moisture out and dry air in.

The wood appears to be okay, but I'm digging it out enough to replace with epoxy putty and protect the balsa core once it dries out in a few months.

The deck hatch was removed to find saturated balsa core. It is so wet that the wood has a waxy translucent look, kind of like rotten celery. There was a bead of caulking around the inside and the outside of the hatch. The outside caulking had failed (or the screws) and the inside caulking had kept the secret.

Down the starboard side (which had the worst pulpit leak) the wire to the navigation light had been attached with stainless screws that pierced the balsa deck core. I thought that the rusty look was from condensation. Nope, it was water trying to get out of the balsa that had leaked into the core from the leaking pulpit mount. The interior screw holes were all drilled oversize and I found no rot. I will dry out, fill with epoxy, and then find an appropriate fastener system.

The hole closest to the hull had to be drilled out from above. This shows the mildew/rust that was likely caused by water in the balsa deck, not condensation on the interior.

The next balsa core issue was the foredeck. This is the worst of the bow pulpit mounts looking from inside, looking up from the V berth. I could tell that there had been moisture on the through bolts, but I thought that it was from condensation on the inside. That could be part of it, but there was also wet balsa surrounding these fastenings. I bored them out from the inside to check for moisture, allowed the deck to dry out, and provided an epoxy core when refastening.

Psychrometer in the boat shows high humidity at first with the garage heat at 68. It later fell to 64%. Still, it is going to cost me $75 a month to heat the garage and dry out the boat. (Update: two weeks later it was down to 54% in the garage.) (Another update: my heating bill was up by more than $100).

M

Down the starboard side (which had the worst pulpit leak) the wire to the navigation light had been attached with stainless screws that pierced the balsa deck core. I thought that the rusty look was from condensation. Nope, it was water trying to get out of the balsa that had leaked into the core from the leaking pulpit mount. The interior screw holes were all drilled oversize and I found no rot. I will dry out, fill with epoxy, and then find an appropriate fastener system.

Marco Flamingo
Oct 26, 2015

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