7+ years without bottomcoat

Mar 23, 2025
11
Catalina 250 Lake Somerville
I’m going to check out a boat at Watt’s Bar lake in Tennessee. Current owner has had the boat for 7 years and has not painted the bottom during that time. I’m assuming there will be hard growth on the bottom of the boat.

If the bottom is covered in hard growth, do you have any idea what the remediation process will look like? It’s a 27 ft boat. If the hard growth is into the gelcoat or fiberglass, does that mean that there will certainly be blisters?

I know it’s impossible to say without looking at the boat. But I would like to be armed with information so that I can properly negotiate with the seller when the boat is hauled.
 
May 17, 2004
5,570
Beneteau Oceanis 37 Havre de Grace
Hard growth and blisters are separate issues and not necessarily related. Not repainting the bottom will almost certainly allow significant growth, but won’t have a direct impact on blistering. Being in the water with no dry time could lead to blisters if the gelcoat was susceptible to it and an epoxy barrier coat were never applied.

Growth is pretty easily taken care of. It can be pressure washed or scraped off when first hauled, or scraped off later (with a bit more elbow grease). Blisters are a little more work to fix, depending on how deep and numerous they are.

My bigger concern would be that if the owner hasn’t repainted it in 7 years, what other preventative maintenance have they skipped that could have bigger impact? I’d be especially careful to look around spots like chainplates and other bedded fittings for evidence of leaks or rot.
 
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Jun 14, 2010
2,294
Robertson & Caine 2017 Leopard 40 CT
To clean it you would need to haul out, scrape (floor scraper would help) then power wash, then use acid based bottom cleaners such as Mary Kate ON AND OFF.
You won’t be able to survey the boat until that’s done. I advise you to negotiate this work be done by the owner or have him hire it out. You should not commit to buying until you know what you’re getting.
 
Oct 19, 2017
7,953
O'Day Mariner 19 Littleton, NH
My bigger concern would be that if the owner hasn’t repainted it in 7 years, what other preventative maintenance have they skipped that could have bigger impact?
:plus:

Any significant failure in regular maintenance and general seamanship like that is a very good indication of deeper problems. Maybe the only neglect that boat has suffered is the bottom, but it's doubtful to me, as well.

The boat is in freshwater? Even if the bottom has never been painted, has it never been cleaned either? A good cleaning at the beginning and end of seasons might be enough to keep growth at bay.

-Will
 
Jun 28, 2019
4
Catalina 470 130 Middle River
If the bottom wasn't taken care of then most likely neither was the top or the inside. The hull will have high water content sitting for 7 years without an opportunity to 'dry out.' I wouldn't go near that boat without a haul-out and water meter reading just to start.