Blisters showing on topside

[Bigatlas]

Noticed something a bit unexpected while giving my 1989 Pacific Seacraft 34 a rinse after last 2 weekend's sail, there were small blistering along the topsides, just above the waterline. These aren't what you'd find on the hull below the surface, they're kinda higher up, right where you'd think the gelcoat would stay dry most of the time, well...the boat's been in a warm, humid slip for the past few months, so maybe that's part of it?
I always figured gelcoat blisters were mostly a below the waterline issue, so seeing them here has me curious and a little concerned, what could be causing this, who has an idea?

 

[littlewarrior]

Blisters above the waterline arent that common, but heat, humidity and trapped moisture can definitely cause them, especially on older gelcoat. Could be water getting in through fittings or just the boat baking iin the slip for too long. Any chance that area isn't draining or drying properly?

 

[Godofhunger]

Well to be fair, the boat is over 25 years old so time, sun, UV, weather and everything else may have weakened the bond between the gelcoat and laminate. Are they dry or wet? Have you tried to puncture one? If they're dry then it's cosmetic and I wouldn't worry too much about it.

 

[littlewarrior]

Well to be fair, the boat is over 25 years old so time, sun, UV, weather and everything else may have weakened the bond between the gelcoat and laminate. Are they dry or wet? Have you tried to puncture one? If they're dry then it's cosmetic and I wouldn't worry too much about it.

I agree, 25 years is significant. So it also depends on how your maintenance was during those years