[C38] Hull blistering - ouch!

Steve.Ribble at gmail.com Steve.Ribble at gmail.com
Tue May 3 07:36:51 EDT 2011


HI Marci...sorry to hear about the blisters, they are a pain that just  
needs to be dealt with. As mentioned above, if you see a few, chances are  
there are others forming. That said you have two options, address the ones  
you know about and repeat the process for those that show up later, or sand  
blast the entire bottom and re-gel coat with vinylester (rather than  
polyester) fiberglass/gel coat.

I haven't noticed anything on my [1980] hull, but I had another hull  
(different boat/builder) from the same year that looked like it had  
thousands of thumbtacks everywhere below the waterline...and the only thing  
to do was re-do the bottom. As odd as it might sound, boat builders didn't  
know a lot about fiberglass in that era (it had only been around 15-20  
years) and their typical solution was to build hulls that were bulletproof.  
As technology progressed and lighter cored hulls became the fashion  
advances in fiberglass understanding found that polyester resins in the  
fiberglass would allow osmosis to occur, particularly in freshwater  
(possibly due to it's lighter density when compared to saltwater?). Once  
inside the hull material the moisture expands with the freeze-thaw cycles  
of the seasons and allows more room for more moisture/water to get in and  
repeat the process until you get something you can see on the surface.

I kept that boat for 8 years after the sandblasting and gel coat  
replacement done and never saw another problem...and I would have noticed  
because that boat had VC-17 for bottom paint and with a roller (like I  
used) it's really hard to get more than one coat of thickness because it  
dissolves the old coat when you put on the new (great stuff if you want to  
go fast, but not for saltwater...). Anyway, the point is that any  
imperfection would have been noticeable.

Oh, and regarding the drying out period, we blasted the boat in the  
fall/early winter and did the gel coat in the spring...it sat in a heated  
building in the interim. Don't know that you need to wait that long, but if  
the boat is in a dry environment and/or protected from direct exposure to  
snow/rain it is better it give it longer than you think it needs. Finally,  
if you go this route, get a few prices...for what I paid the guys that did  
mine I was able to also Awlgrip the deck and non-skid for the same price  
the first yard I talked to quoted me for the bottom alone (which was part  
of the "in the building over winter" thing).

Hope it helps, good luck.

Steve Ribble
Tittravate, #64
Boothbay Hbr, ME
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://catalina38.org/pipermail/listserve_catalina38.org/attachments/20110503/56e2a383/attachment-0001.htm>


More information about the Listserve mailing list