Blisters - SAN 230

[jkallen21]

So I leave my boat in fresh water most of the summer. Consequently, the hull is showing some blisters on the sides. Not a ton, but enough that they stood out to me. I have read that they are cosmetic and can be fixed, but I've got questions:
1) do they only fix what is present now and more will show up later?
2) with the acid present in the blisters, I will not be tackling this myself so how much should I expect this to cost?

SAN 230
Thanks.
3) should I just leave it alone and not fret about it?

[Quinner]

Not sure that CC will fix under warrantee, worth a call or 2 to determine. Anytime you leave a fiberglass boat in the water for extended periods of time you run the risks of blisters, the only real way to prevent them is to apply a bottom paint on the wetted surface. Some hulls can soak for years without issues while others may get them very quickly.
Fixing or not is up to you, your dealer or a decent fiberglass shop should be able to give you costs on that
Good luck

[TRBenj]

2) with the acid present in the blisters

Wut.

If there was a way to prevent blisters from forming in the future besides resorting to bottom paint, I would imagine that would be a pretty common thing for people (or the factory) to do before a boat ever sees the water.

[nyryan2001]

There was a Malibu over on their forum that looked like it caught chicken pox. 100s of them. Very rare defect.

The general consensus is that some boats get them, others never will. And some with get them whether they are left in water for long periods or not. Folks tend to think its due to a defect in the fiberglas layup process.... either in the method of worksmanship.... or in materials that make a boat prone to this perhaps were not optimize or used in sufficient amount.

If this is the first time you have seen them.... unfortunatly there is likely more to come, so makes no sense to repair now. You have conditions in your gel and fiberglass that make these possible....its not just a one time thing.

Couple options:

Leave it as it and see if the "growth" "stops" in 2-3 yrs. If it stops, have it repaired then. I would think you are into a costly $1-2k repair to grind out and re-gel at the waterline and below if they spread across the hull of the boat and not just a few in a specific area.

Sell trade the boat now immediately and cut your losses now.

Or leave it as it and enjoy the boat for as long as possible. Good thing is all indications are that its purely cosmetic, unless trailer bunks crush a blister and water gets in there and then you are into a water intrusion potential fiberglass delam situation.

[jkallen21]

As far as the acid goes, I have read that the blisters occur when there is a defect in the fiber glass - and it only happens to some boats and not all because the fiberglass defect isn't always present. The result is that blisters full of acid appear on the hull when it is exposed to water long term.

[swankster]

Let it dry out over the winter a see what they look like in the spring. I had an old Bayliner that we kept in the water about 8 months out of the year. It got them one year and by spring they were gone.

[pzthk6]

Gel coat is not a sealed surface, and thus always water to penetrate and then exit/dry out. When left in the water for a long time, the molecules cannot exit and get stuck. Eventually this will blister. The number one thing that can accelerate this process from my experience is the use of hull cleaners that have acids. Even those marketed as hulls cleaners, are NOT good for your boat.
The acid is great at removing the scum on hull bottoms from sitting in the water too long, but literally burns the gel coat surface. You can even do this in your garage. Get a gel sample and use one of the hull cleaners that contain acid (or at an extreme use muratic acid like may shops do in bulk), spray it on the sample and just watch. It will start to smoke within minutes as it burns the gel.
Also, if the acidity level of the water that you leave your boat in is high, it will have the same affect over a long time.
Solution = boat hoist, dry storage or trailer
Never leave your baby sitting in the water more than a couple of days max.

[xrichard]

Best information I've seen from a respected source:

http://www.yachtsurvey.com/blisters.htm