Re: Moisture around chainplates
A warning to I-28 owners and possibly others. The fiberglass-covered plywood partial bulkhead to which the forward starboard chain plate is attached is exposed to deck leakage around its chain plate. It can be completely rotted away inside the fiberglass coating with no indication of the problem from probing the exposed edge of the plywood you see inside the head cabinet. Also the bottom shelf of the head cabinet is structural, tabbed to the hull and bulkhead, and is also part of the head countertop. If this area has any rot, then it is likely that the chainplate attachment is compromised.
I spotted all this when I sighted down my hull from the dock and saw that there was a 24" long vertical inward dimple developing which corresponded exactly to where the chainplate partial bulkhead was tabbed to the hull. Although the tabbing and deck was preventing vertical failure, the rotted cabinet/countertop and bulkhead had allowed the entire chainplate structure to move inward as the rotted plywood deformed. It was taking the hull in with it. When I drilled into the fiberglass covering the chainplate attachment I found that the plywood had basically departed. Fortunately Islander builds stout boats and the fiberglass covering the plywood chainplate bulkhead is about 1/4" thick on both sides and well attached to the hull. My fix? I removed all the rotten wood including the cabinet shelves and what I could reach in the chainplate attachment after drilling 1" holes through its fiberglass covering and pulling out the rotted wood. I replaced the cabinet shelves/head countertop and tabbed them back to the hull. This sealed the bottom of the now empty chainplate bulkhead which I dried internally using a heat gun and acetone (NOT SIMULTANEOUSLY!) and then injected epoxy paste to refill it.
Fellow I-28 owners, please check your forward starboard chainplate attachment - the one in the head cabinet - because it may not be as strong as you think. Drilling a small hole from the side may be the only way because my exposed edge was solid for about 1" in before it disintegrated. Which leads me to wonder what's going on under all that vinyl on the port side? Does anybody know what that looks like?