Hi Josh,

I would answer question #1 with both a yes and no. The seam is an inward flange hull deck joint, bonded and sealed with 5200 adhesive or similar. This would seem to be just one lap joint, but it is more like three. The deck was created in two major layups, the second of which added the balsa core. Same for the hull. Even a slight compromise in that area will cause water to wick to the core. The water source could be the portions of the hull deck joint that are not covered by a well caulked toe rail or portions of the joint without toe rail, but only if the 5200 was compromised. The bigger issue are the fasteners that penetrate all of these layers. If the FRP to FRP joint near these fasteners has a slight compromise, this would provide a path to the core, whether the water source was the 5200 sealed lap joint, or more likely, the bolt hole itself. The bolt holes are the source for my boat as well as others I have seen.

Bottom line is that caulking the joint can't hurt, but further investigation might be in order. As far as caulking the other items, butyl tape might be a better choice. However, I may try an experiment by blue tapeing off a very thin fillet area on a test piece, then applying a very thin fillet of 5200 and see how that performs over time and how much effort will be required to remove it a year later.

GL,

-Chris