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That's right - osmosis never sank a boat
Posted: Thu Feb 13, 2003 1:18 am
by Nick
At least, as far as I know. Anyone want to contradict me?
If your boat had serious osmosis the profile of the blisters would show through any paint job.
The blisters would be in the gelcoat on the outside of the hull, I've never heard of osmosis on the inside of the laminate.
Borrow a moisture meter and take a few readings - it might help to put your mind at rest.
Check out
http://www.bluemoment.com/osmosis.html for more information.
Nick 
Sorry..
Posted: Tue Dec 27, 2005 10:56 pm
by Silkie
but I think you are wrong. In fact, IIRC, the process can be faster in fresh water due to the greater density differential between the water outside the hull (fresh water being less dense than salt) and the fluid in the blisters.
There are several good articles on
BlueMoment's Osmosis Links Page as already suggested by Nick.
Posted: Wed Dec 28, 2005 1:12 am
by Magna Carter
Serious Osmosis will result in thousands of blisters, far too much to hide with paint, or in some cases, several extremely large blisters (the size of dinner plates), so again, v hard to cover up......
Posted: Tue Jan 31, 2006 8:56 pm
by DaveS
If fresh water has been sitting inside for some time you can expect to get a high reading from a moisture meter. I was caught by this when selling my last boat. A cockpit locker filled with rainwater over the winter which then overflowed into the hull, resulting in a surveyor's "high mosture reading" observation which in turn was translated as "hull riddled with osmosis". Complete bllx but it certainly dropped the price I got.
Posted: Wed Feb 01, 2006 5:36 pm
by claymore
I used to run a sailing centre on a reservoir where the water catchment area was very peaty.
We used GRP Wayfarers as the bulk carriers and I bought 3 from Porters when he started building them. They all had to go back after a season on their moorings as huge blisters had started appearing. A surveyors report commented that the high Ph content in the water had almost certainly contributed to the osmosis.
Re: comprehensive car insurance - nbgk
Posted: Sun Jul 05, 2020 11:33 pm
by Shuggy
If I had a TVR or Lotus that was suffering from osmosis are you saying you would insure me? Love a bit of car insurance spam on a boating forum...