Blisters

[quasimodo]

I'm  buying a 323, it has blisters on the hull. My question is 1. is this a serious problem?  2. Do I need to remove them (Costly) or can I leave be?  3. If  I choose to have them removed what is the best method. Thanks in advance for your consideration.

[Valor]

Hi,
I guess the question is do you have a few or an infestation and  how bad are they? Do you have a picture?

Michael

[Dolce_Vita]

My feeling is that if the hull has already shown that it is subject to blisters, it will only get worse over time.  So you want to get to it sooner rather than later.

The general treatment for blisters is:

• Strip the hull down to bare gelcoat.  You can trade money for time by having it soda-blasted, or do it by hand.
• Dig out the blisters and fill and fair with an epoxy-based fairing compound
• Apply four coats of an epoxy-based barrier coating, such as Interprotect 2000.  Alternate gray and white to insure complete coverage at each coat.
• Apply two coats of a contrasting color bottom paint.  The first should be done within 24 hours of the last barrier coat to get a good bond.
• Apply two coats of the final color bottom paint.

There's more details about timing of each coat, temperature, hard paint vs ablative, etc, but that's left "as an exercise for the reader"
It's a lot of work, but it will deal with the blisters once and for all.
This is a lot of work, but it will eliminate the blisters once and for all.

[selene]

There are many types of blisters, so it may be worth getting an expert to look at them.  Typically the Pearson layup is very good, so the problems are likely to be shallow.  In some cases - if you are lucky - the blisters are caused simply by too many layers of bottom coat, without correct sanding between layers.  If you are less lucky...the deeper they get, the more difficult to repair.

As a rough guide, if the blister pops fairly easily, it is likely in the paint.  If it required some effort, and has a vinegar (acid) smell, it is likely to be deeper.  Be careful, as if it is deep, it can be under pressure, and spray acid at you!!

A friend bought a boat where all the blisters were in the paint. He burst them, leaving small depressions - barrier coat sound underneath - and, after putting the new bottom coat in, kept sailing.  It wasn't pretty, but he wasn't racing, so a few depressions made no difference to him!

The best process is as outlined by Ed - starting with a soda blasting, and then the next steps should be clear.  If you are lucky, repainting could be all that is needed.  Otherwise grind out, dry out, rebuild, fair, repaint.

Good luck!~