Osmosis on GRP hulls

[Rick O'Shez]

Does anyone have any experience of this? I am thinking of buying an older used boat, probably something with a GRP hull.
How do you test a hull for osmosis? What are the signs, assuming there are no obvious blisters or damage to the gel coat?
And if a GRP hull has got osmosis, is it a big deal and can it be fixed? I read somewhere the problem is getting the GRP dry enough to paint on a sealing coat?

I have looked into getting a marine survey, though it looks like it could be tricky to arrange and they say the boat would have to be lifted out of the water to check for osmosis. Also the survey would be quite expensive relative to the amount I plan to spend ( maybe 10% of purchase cost ), and of course it would be wasted money if I ended up not buying the boat.

All advice gratefully received!

 

[Guy Threepwood]

Does anyone have any experience of this? I am thinking of buying an older used boat, probably something with a GRP hull.
How do you test a hull for osmosis? What are the signs, assuming there are no obvious blisters or damage to the gel coat?
And if a GRP hull has got osmosis, is it a big deal and can it be fixed? I read somewhere the problem is getting the GRP dry enough to paint on a sealing coat?

I have looked into getting a marine survey, though it looks like it could be tricky to arrange and they say the boat would have to be lifted out of the water to check for osmosis. Also the survey would be quite expensive relative to the amount I plan to spend ( maybe 10% of purchase cost ), and of course it would be wasted money if I ended up not buying the boat.

All advice gratefully received!

How old is older? is it a sailboat? Older is generally better, they used thicker, heavier, better quality construction- more resistant to osmosis and other problems. I would tend to forgo the survey unless it's required for insurance, tons of resources on the internet to learn about any problems to look for specific to your boat,and check them yourself.- save the money for all the other expenses of owning a B.O.A.T. - break out another thousand

 

[Rick O'Shez]

How old is older? is it a sailboat? Older is generally better, they used thicker, heavier, better quality construction- more resistant to osmosis and other problems. I would tend to forgo the survey unless it's required for insurance, tons of resources on the internet to learn about any problems to look for specific to your boat,and check them yourself.- save the money for all the other expenses of owning a B.O.A.T. - break out another thousand

Thanks, I tend to agree. I've been chatting to some GRP boat owners, and the general view is basically that most GRP hulls have some osmosis but don't worry about it.
I am not going to bother with a survey but will get a mechanic to check over the engine before proceeding. I've decided to focus on smaller boats, partly because I can get something more recent for the money I'm spending, and partly because it will reduce annual running costs significantly - moorings are the biggest annual cost and they are charged according to the length of the boat.
Buying a used boat is rather like buying a used car, it's not so much what you spend initially but what you have to spend to keep it working over a period of time.

 

[Guy Threepwood]

Thanks, I tend to agree. I've been chatting to some GRP boat owners, and the general view is basically that most GRP hulls have some osmosis but don't worry about it.
I am not going to bother with a survey but will get a mechanic to check over the engine before proceeding. I've decided to focus on smaller boats, partly because I can get something more recent for the money I'm spending, and partly because it will reduce annual running costs significantly - moorings are the biggest annual cost and they are charged according to the length of the boat.
Buying a used boat is rather like buying a used car, it's not so much what you spend initially but what you have to spend to keep it working over a period of time.

Yes, launching/ haul out/ winter storage is the biggest expense for me. And marine mechanics are way more expensive than regular auto mechanics, so the more work you can do yourself the better!

Boats do hold their value better, and they are way more fun.. being out on the water, you never feel like you are missing out on anything.

Be warned though you might find yourself praying at some point!

 

[Jake1001]

Interesting problem...any update ??

Does anyone have any experience of this? I am thinking of buying an older used boat, probably something with a GRP hull.
How do you test a hull for osmosis? What are the signs, assuming there are no obvious blisters or damage to the gel coat?
And if a GRP hull has got osmosis, is it a big deal and can it be fixed? I read somewhere the problem is getting the GRP dry enough to paint on a sealing coat?

I have looked into getting a marine survey, though it looks like it could be tricky to arrange and they say the boat would have to be lifted out of the water to check for osmosis. Also the survey would be quite expensive relative to the amount I plan to spend ( maybe 10% of purchase cost ), and of course it would be wasted money if I ended up not buying the boat.

All advice gratefully received!