Chesapeake 17 built in 2000. Tape over epoxy filets in the interior turning white. Still solid—not loose or flaking in any way. Should I be concerned?
If not loose or flaking you have nothing to worry about it other than looks. On that front, I would wipe it down with denatured alcohol and if it turns clear, I would then follow-up with a brush of unthickened epoxy. If it does not turn clear…it means the underlying glass is breaking down but if no flaking or other obvious problem, I would wait and focus on ensuring boat is put away dry. Otherwise your only other option is to remove the old tape and retape which I don’t think is worth the time and effort.
This is a standard occurrence in old boats. There’s 2 things that cause it and they each have different symptoms - sunlight exposure and mechanical fatigue.
If it’s sunlight, the outermost layer is breaking down. You’ll find a chalky powder or flakes on the joints or other places where it’s drifted to in the boat. This is the most dangerous in terms of affecting the longevity of the boat since the epoxy that holds the glass fibers together is actively breaking down. This can and should be fixed ASAP. The fix is exactly what Howard recommends - clean off the degraded material and apply a new layer of epoxy (don’t forget the varnish or paint to protect it from further UV exposure).
Mechanical fatigue is the case where Howard’s denatured alcohol test shows no results. That’s caused by the boat flexing as it’s used, creating microfractures in the epoxy/glass matrix. Eventually, the microfractures will merge and the joint will lose integrity, like a paper clip that’s been folded too many times.
If a boat is old enough and used frequently enough, it will eventually develop this problem. The good news is that the progression is slow. The boat that you’re seeing it in is a quarter century old. I started seeing it in my WD12, which gets very frequent use, when it was 10 years old. My wife’s 20 year old CH16LT has no trace of it because she paddles very infrequently in extremely calm conditions. I noticed it it in one CLC demo boat that was 6 or 7 years old. The CLC demo boats are used hundreds of times per year, year after year, so it makes sense that they would be the fleet leaders in fatigue.
Another piece of good news, visible in your photo, is that the bulk of the damage happens in the fillet, not the glass. This is good because a taped seam’s strength comes mainly from the glass, not the fillet. The fillet just supports the glass which provides the tensile strength. As long as the outer layers of the glass are good and it’s not peeling from the wood, there’s enough strength for lightweight kayaks like CLC sells.
Finally, if you want a quick fix that’ll be good for another 25 years (at least), just lay down another piece of tape on top of the damaged one. The boat will get a bit heavier, but the tape will provide extra support for the damaged joint and will reduce the flexing that is causing the problem in the first place. Alternatively, you can just add a thin layer of glass (4 oz or so) to the damaged area to accomplish the same thing with less weight. Or just live with it for now and take care of it when it gets worse. It’s a sign of an old, well-used boat and you should be proud that yours has made it long enough to show the signs of love over the years.
BTW, there’s more info about aging stitch and glue boats over at the Life of Boats blog that John Harris writes. It specifically mentions stress damage on a Night Heron and fixes.
Laszlo