: What causes this and what is the best way to fix? I know there have
: been discussions on this before. This boat is stored in a barn
: with a cockpit cover on it. It is used primarily in a fresh
: water pond for rolling. The okume was sealed and then the glass
: put on. In the fillet area, the fillet was put on and the glass
: put over it while wet. I looked down into the foot area and
: there are patches there too. It was also painted with urethane
: for protection.

Your hull interior was not waterproof.
Over the years your hull interior is suffered water intrusion which has caused the wood to expand and contract
braking the epoxy bond and delaminating the glass. Sunlight and hull flex probably made this worse.

To fix this sand or strip the old glass with a heat gun and patch the area. If other areas look good apply a couple coats of new epoxy to
the sanded (rough up) surfaces.

To prevent this;

#1 Your wet-out of the interior of your hull must be done right. Add a seal coat and then wet-out your glass, or know how
to wet-out glass and dry wood at the same time with warm shop temperatures and small batches of thin epoxy with slow hardener.

#2 You must add one fill coat to the weave, to waterproof the interior of your hull.

#3 Varnish areas which will receive sunlight.

All the best,
Rob