After eight months of work last winter, we launched two kayaks in May. A Great Auk and a 14 foot Great Auk. The fiberglassing and epoxy went well. We did two fill coats of epoxy and three coats of spar varnish. None of the weave was showing. All appeared well.

After using the boats a few times, we started to get bubbles under the fiberglass on the hulls. Some bubbles are about an inch in diameter, while one or two have grown with use up to ten inches or so. Some appear to have water under them. There are about 18 bubbles total. They got larger the more we used the boats. The bubbles are under the water line, none on the decks.

Two questions: the cause and the cure.
Do you think there were pin holes in the epoxy that did not get filled and water has gotten in under the fiberglass?

I thought I would cut away the bubbles, let the wood dry, patch with fiberglass and epoxy. Perhaps sand and do an additional coat of epoxy and varnish over the entire hull to prevent more bubbles.

Any suggestions would be appreciated. We're bummed that after all that work, we've got to drag them back into the shop and repare them, when we should be out using them! Thanks again.