gel coat blistering

[DBattt]

I was looking at an add on a 2005 nautique and saw a strange pattern in the gel coat and the response was that it had blistered from sitting in the water too long.......never knew nautiques would do that is that common? Is is easily repaired and if so is it costly??? The boat is a 2005 air nautique for 19,900 sounds like a steal but the gel coat issue and price tell me there is more to the story.....please advise....the dealer is miami marine in florida

[shag]

I have actually seen that before. IMO it only happens when boats are left in water a LONG time. Also, being in Miami - good chance it's a salt boat. Not trying to knock it, but if it is, it needed to meticulously maintained.

[TxJole]

Blister are not good. I did a bottom job on an 1979 33' Chris Craft with thousands of blisters. Some looked small till u opened them and found they were the size of a dinner plate under the surface. It was a week worth of fiberglass work 8 hrs a day. Pop the blister let the acid in them dry grind them to clean fiberglass then fill with glass and filler then bottom paint or re-gel.

[swc5150]

I was looking at an add on a 2005 nautique and saw a strange pattern in the gel coat and the response was that it had blistered from sitting in the water too long.......never knew nautiques would do that is that common? Is is easily repaired and if so is it costly??? The boat is a 2005 air nautique for 19,900 sounds like a steal but the gel coat issue and price tell me there is more to the story.....please advise....the dealer is miami marine in florida

It sounds like the price may reflect the condition, as you could be walking into a nightmare? I know of an '87 SN 2001 that has been sitting in water since it was new, and the gel is fine. An '05 must've been sitting in some harsh water to cause blisters so soon (IMO). Personally, I'd walk away.

[Chexi]

I believe that whether or not a boat will blister depends on imperfections in the fiberglass, ratios of resin to hardener and how well they are mixed, quality of the resin, etc. Some boat manufacturers are better at this than others, but there is probably no manufacturer that is completely immune. Some boats can sit in water indefinitely and never blister. Others will blister if they sit in water for a moderate amount of time. However, there is no way to tell beforehand that I am aware of. I don't know if the water itself (harsh or soft, of salty, etc.) has any impact.

[flaudia402]

We kept our last boat - a '01 Mastercraft Xstar in the water during summers since we didn't have our dock built at the time (was pulled out at the end of summer, stored in the garage on a trailer), and believe it or not, after just two summers of doing that, we developed osmotic blisters. It didn't affect the boat in anyway. They were tiny, no bigger than a few centimeters in diameter and you couldn't see them (hull was navy blue) unless you got really close and ran your hand over the hull. Our lake is completely fresh water, but turns out the humidity + the lake water created an environment for the water to travel into the fiberglass and develop the blisters. It drove me insane because I'm OCD as **** when it comes to that stuff.

[TRBenj]

I believe that whether or not a boat will blister depends on imperfections in the fiberglass, ratios of resin to hardener and how well they are mixed, quality of the resin, etc. Some boat manufacturers are better at this than others, but there is probably no manufacturer that is completely immune. Some boats can sit in water indefinitely and never blister. Others will blister if they sit in water for a moderate amount of time. However, there is no way to tell beforehand that I am aware of. I don't know if the water itself (harsh or soft, of salty, etc.) has any impact.

That is correct... I have boat that was stored in the water all summer for 10+ years and it doesnt have a blister on it. Our former '92 developed some blisters a few years after we sold it... and that was lift kept for all but one summer. Sometimes its just luck of the draw.

They are mainly cosmetic though- the blisters will not cause a structural issue with the boat.

[pzthk6]

Blisters will happen to any gel coated surface left in the water over time. Gel coat is porse, and over the years due to regulations on the environment, this porosity has tightened. Initially you would think this is good, but actually if and when moisture enters in newer gel coats it is harder to escape. There are several factors that will have an extreme impact on whether a boat blisters or not no matter who the manufacturer is. Ph level of the water, thermo cycling of water temp, if any acids have been used to clean, etc.
Acids are a major no-no when it comes to gel coat. Even the popular "On-Off" product will burn your gel coat and excellerate the blistering potential (because it is an acid base).
Typically salt water environments will produce less blistering due to the density of the water vs. fresh water (less likely to enter the gel in the first place). But on the other hand. salt water environments have more aquatic growth potential on hull bottoms (thus why bottom paint is common in salt water). This growth if not cleaned off regularly will then turn the tides and cause blistering.
There is a lot more science to the whole subject than most people know. I have been and always will be a proponent of people with a gel coat hull to get a hoist. Otherwise bottom paint your boat and know you will have to repaint every so often.

[xrichard]

The best source for information on blisters:

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