OK, I think I found the problem. Took the kayak into the garage, put it upside on some sawhorses, and positioned a lamp inside the bow, cockpit and stern areas. I have pinholes through some of the wire stitching holes; probably around 20 or so, scattered up and down the hull, but mainly on the lower two chines (not higher up on the hull side or the deck).

Now first, I found this pretty odd. Like I said, I was pretty particular about filling those holes - however, the general failure of maybe 25% of the holes indicates that I possibly screwed up the epoxy mixture somehow. But it's also odd that the hole appeared through both the inside and outside layers of fiberglass cloth and fill coats of epoxy. I do store the kayak outside for now - I'm in the NE, and it has gotten pretty cold, which potentially could have affected weak epoxy. Or, because the pinholes are clustered around and under the waterline, the water pressure pushed the holes open.

Any other theories about why the holes are failing?

Anyway; I know adding more fill coats won't work, because after I initally finished the kayak (with 3 fill coats on the outside), paddled it and noticed the leak, I added another two fill coats.

So, what are my options?

- I could drill out the holes, and refill them with thickened epoxy
- I could simply slap a small cloth patch over the area

Any other suggestions?

I do plan on sanding the kayak next spring, adding another final fill coat or two, and then varnishing the boat. So, I could do an "ugly" temporary solution, and then something more permanent next spring.

Probably the best way might be to sand down to the cloth, drill out the holes, fill the holes, and then reapply the 3-5 layers of fill epoxy coats; but that will likely wait until spring.

Well, at least its not a major crack, hole, or leak along a seam!

TIA
Ed