I've just experienced something similar (also after many many hours) and share your frustration - I have 2 problems identified - there may or may not be value in sharing them with you.

1) Before glassing my hull I put some acetone on a rag & ran it over an area about 1.5' in diameter all for the purpose of highlighting the great grain effect to a friend one evening when I shouldn't have been in the workshop in the first place (wine & boat building don't mix). Dumb move - while the surface looked fine, the acetone was still there in the wood when I glassed the next day & it left a visable dark mark - I put the hull outside in the sun to cure (a few months later and upon the advise of a local fiberglass expert) - it became apparent I had a problem with the cloth lifting off the wood - we sanded throught the glass and found the epoxy still sticky and very much separated from the hull. (sanded hull, patched it and reglassed) -

2)-we put the deck out in the sun to cure for about 2 hours and noticed small white spots along the centerline ridge (ridge has 2" wide French banding set 3/32" into the cedar - running the full length of hull) that appear to be under the cloth. - must have been air pockets from epoxy starvation that showed only when the heat expanded them.
Lesson's learned - 1) make sure I've got lots of epoxy on the ridge where gravity's effect will be most noticable - special care needed when using inlaying banding that creates a flat surface on the centerline 2) I will never ever again put any chemical substance on the hull before glassing 3)I will build a second boat and try not to make the same mistakes as there is no way to get under the cloth & repair the white spots without reglassing the entire deck - which I think would be very difficult given hatchs, cockpit etc are all in place. ie: I've accepted the errors of my ways, and am doing my very best to treat it as learning curve stuff and am prepared to move on. (we start varnishing this evening). good luck
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: 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.