Research indicates they were caused by poor saturation of resin into the initial layer of woven matt FG against the
gelcoat. typical larger ones are 3/16 ' deep.
Layup would have been better if they had used a saturated 'chopper gun' layer against the
gelcoat instead of the woven mat . This would have avoided the voids . Pure
water comes out from the
blisters with no smell or color. This seems to indicate that they were not caused by poor resin mix. Boatyard says caused by voids in mat behind gelcoat. if left unrepaired they might cause
delamination as they are so close together they could join together eventually. One can only speculate -but these might have been prevented with a barrier coat as they all developed within the pat 5 years and
boat has been in
Florida salt water continuously for past 30 years. Oh Well!!