Fiberglass deteriorating- unknown reason

[mystro]

I purchased this boat a year ago and never really noticed the hull blemish below the water line until I took the boat out of fresh water moorage yesterday. A friend suggested it may be salt water damage to the gel coat..I have no clue, has anyone here seen this damage on fiberglass before?

 

[gcboat]

Re: Fiberglass deteriorating- unknown reason

Appears to be osmotic blistering. Do a Google search and see if you can find a comparitive picture. Is the entire hull like that? Also, what is the brand name? Year?

 

[tashasdaddy]

Re: Fiberglass deteriorating- unknown reason

boat pox.

 

[Mark42]

Re: Fiberglass deteriorating- unknown reason

You might want to keep your boat away from other boats for a while until you know what the cause is and if its terminal or not

It does look rather even, maybe damage from a strong cleaner by previous owner?

 

[mystro]

Re: Fiberglass deteriorating- unknown reason

Appears to be osmotic blistering. Do a Google search and see if you can find a comparitive picture. Is the entire hull like that? Also, what is the brand name? Year?

It's a 1972 Seaswirl and the only place this blistering appears is on the lower transom below waterline, I took it to a custom hotrod shop which does alot of fiberglass and they had not seen this before but took some scapings and didn't think it was too much of a concern but they remained puzzled..they said it almost looked textured but were sure it wasn't...what I'm seeing in regard to Osmotic Blistering or Boat-pox seems very close..thanks for the discription.

 

[Gary H NC]

Re: Fiberglass deteriorating- unknown reason

That chip in the gelcoat in the lower left of the picture may have allowed the transom to soak up water over the years also.I would investigate if the transom is rotted .It may need much more than cosmetic work..

 

[ondarvr]

Re: Fiberglass deteriorating- unknown reason

If the only area with these small blisters is this on the back, then it's most likely a repair, or that area was touched up with a brush after gel coating and before the skin coat. Small blisters like those indicate actual gel coat blisters, they can be in the gel coat or between layers of gel coat, Laminate blisters are larger. Gel coat is commonly blamed for having blisters, but they are normally in the resin, you just see them on the surface so people call them gel coat blisters.
They don't really do any harm, but they don't look good, you can try sanding down a small area and see how deep they go, the only cure is to sand it down and respray that area.

 

[mystro]

Re: Fiberglass deteriorating- unknown reason

They don't really do any harm, but they don't look good, you can try sanding down a small area and see how deep they go, the only cure is to sand it down and respray that area.

I found an article which backs up your comment and maybe it's wishfull/hopefull thinking on my part but it seems to make sence, how do you guys feel about it:

http://www2.yachtworld.com/mustangyts/mustangyts_5.html

 

[ondarvr]

Re: Fiberglass deteriorating- unknown reason

Most of what he says is fairly accurate, Fiberglass laminates do absorb water though (most plastics do) and that's a test it needs to pass in some markets for it to be approved. The "starch" he is talking about is the binder that hold the mat together and it can cause blisters, but is not always the cause, it's just one of many possibilities. Your blisters don't look to be in the laminate though, they look like they're in the gel coat and it's much easier to fix the problem if they are. Gel coat blisters are normally very small and tightly packed, Laminate blisters are larger and and may be inches or more apart.