: I have started to revarnish my tern,As I started sanding noticed a dark
: pattern matching size and placement of 3-1/2 in. foam bulkheads,Anyone
: seen this befor?

Could this be water vapor that has over time been trapped in the composite?

Epoxy is not completely, totally water vapor-proof. At the West Coast Sea Kayak Symposium a couple of years ago, Pygmy had their demo boats arranged along the shoreline. At the end of one day, no one remembered to open the hatches to let the boats vent and dry out overnight from a full day of being in the water. The next day, you could tell exactly where the bulkheads were, because the enclosed areas were noticably darker on the outer surface than the cockpit areas.

What I can't remember for sure is if, or how long, it took to clear up after someone opened all the hatches. I'm pretty sure it did clear up, I just don't have the specific memory of it.

If it does clear up after, say, a day or so, you open up and expose these areas, I'll vote for the vapor theory. If it doesn't go away, then I'd look for something else. If it clears up, I'm wondering if this might be a good reason not to use foam bulkheads, as there are probably long-term consequences to having moisture trapped in the composite matrix. The foam seems to be trapping the vapor.

Since seeing this happen, I've always tried to be diligent about cracking my hatches after having the boat out for a day, and I've never had the problem myself.

Pete, in Snohomish, WA.