The leaks were from the hull deck joint on the starboard side. I stripped the vinyl hull covering from the inside area between the head
and the stateroom and found 4 empty screw holes that were obviously leaking. It was inline with the rub rail. It appears that the holes were from when the hulls and deck were joined and my guess is that they screwed into small blocks to suck the two parts
together after thickened resin glue was applied. The screws were removed but were never filled (really sloppy workmanship). Then the outside gap at the join was filled with a white sealant like 3M 4000 but the buffoon who did the job was holding the caulking gun at the wrong angle so only the top edge actually sealed. It was solid but 20% of the inner face and 95% of the bottom edge were cold joints and unsealed, wicked the water in and to the unsealed holes and then inside. The whole rub rail acted like a big rain gutter supplying the screw holes.
I cut out a generous chunk of the sealant exposing the top edge of the hull and part of the inner vertical face and refilled with 3M4000 Fast Dry (2 caulking cylinders worth). That has cured and the rub rail will go back on tomorrow using butyl tape as a primary water seal.
I will reinstall the hull liner and decide later if I will replace it with Frontrunner fabric
(it's warmer and easier to maintain than the original sponge vinyl).
Tomorrow, I will remove the wood panel in the stbd stateroom to access the heater wiring
that, I hope, lies behind it. To trouble shoot the heater, I need the thermostat connection to the wire loom to access the heater to get any fault codes and that is buried behind that panel.
I'm afraid Linda won't come with me to see the start of the Race
(r2ak) this Thursday early AM without a heater.