websoldtoys 6:52pm, 24 July 2009
Well, I'm glad I insisted on seeing it out of the water.

To make a long story short ; it has osmosis. Lots of it. Big disappointment for me AND the current owners, who had themselves not seen the wet side since 2006, when it was fine and freshly painted. Three years without layups was apparently too much. Pics in my photostream, as usual.

The blisters are 1/4" diameter average, 1/2" tops. They will of course shrink when left to dry, but that's only hiding the problem. I wonder up to what size would temporarily go away when laid up to dry?

I was advised there would be a major price drop because of this (and the price wasn't too high to begin with), but I don't know if I want to take on this job at ANY price.

With blisters all over, the only way is a full gelcoat peel, wash, dry, then painstakingly smoothing the hull with a filler of choice, and painting over with epoxy. Given that I keep postponing similar work on my house, I'm not looking forward to that one... besides, I hear the drying process involved could take a whole year without expensive specialized ovens or other heated storage.

I could also buy it anyway, cheap as chips, and ignore the blistering completely, hoping annual layups will slow it down enough to get a few good seasons out of it. But I have no idea how long it will last before the blisters become a real problem (when they burst open I think). After that it would be worthless, so I wouldn't be able to justify investing in new sails for it. And I don't think it's that much fun to sail with the current tablecloths, even with the beard gone.

I thought this deserved a thread of its own. Major bummer for everyone involved. I really looked forward to shaking the seller's hand and sailing it home a few days after. But it was not to be. At this time I think it's best to walk away and look at the other fish in the sea.

Even that is difficult though - for every ship I pay more for than I would for this one, I would have to be SURE it doesn't have osmosis. That means not buying any laid up ship (it may be hiding temporarily shrunk blisters), and a floating one only after having it craned ($$$). Hmm...
Skykomish E29 9 years ago
you do suprise me, this is very rare to find an Achilles with osmosis. It also seems a very short period of time for such extensive bubbling to have suddenly appeared.
Still I think that you have perhaps made the right choice, as . the work involved in a complete strip back would far exceed the value of the boat.
Never mind I am sure that you will find the right boat for your needs, good luck
Apae01 9 years ago
Bear in mind that osmosis is more likely to appear with fresh water than on salt. And this one has been in fresh water for about three years, without ever been hauled out, not even for a fresh coat of underwater paint.

That's why I'm not really surprised about the bubbling, maybe it lay already dormant three years ago, already there but not yet really visible. i don't think the current owners had the boat tested for osmosis back then, or went especially looking for it.
websoldtoys Posted 9 years ago. Edited by websoldtoys (member) 9 years ago
Well, clearly I managed to find one. They do say the osmosis problem is worse in fresh water than in sea water - perhaps that's why you see less of it around the UK, and more in the Dutch lakes.

There's one more for sale besides Briseis that IS a salt water ship, though an early model and

Am currently trying to find out how safe it is to buy a dry ship off a shipyard. One of the worst things I could do now, is to pay much more for a better ship, only to find it has osmosis as well, when lifting it out of the water next winter. In that case I might as well have bought 473.

BTW agreed price on 473 was in the 2500 pound range, but that was before we found osmosis.

I just received an approximate quote of about that much for a full professional osmosis treatment, using gelcoat peeler, hotvac etc - with a 5 year warranty. Another yacht painter quoted about 1500 quid plus winter storage rate, air drying the ship between peel/wash and resealing. A few hundred more for a second round of filler to achieve a mirror smooth finish. Again, a 5 year warranty.

Specialized tools have brought down osmosis treatment prices a lot, apparently. It would still be a "patched up" ship afterwards though.
websoldtoys 9 years ago
Am now eyeing a GK24, a bit of an oddball but spacious, fast and a bit more modern hull shape. Not the A24's good ballast ratio, but 2 feet more beam helps compensate... even if it worsens the handling in short choppy waves somewhat...
santalars 9 years ago
It would be new to me that Osmosis can possibly occur in freshwater at all. I'm quite shure that it's a saltwater problem only as it's basically a process of equalisation of salt concentrations.

Also this is why lots of freshwater rinses are used as first step for osmosis treatment. This is to get the salt out.

I don't understand how osmosis should occur in freshwater from a chemical perspective, but I'm willing to learn.
websoldtoys 9 years ago
I read it on one of the better sites about osmosis, that it is even more of a problem on fresh water than sea.

The way I understand it... (but this is entirely my own uninformed explanation):

There are a lot of contaminants inside an osmosis bubble...

And very little outside, in fresh water.

So the water wants in, in an attempt to dilute the contaminants in the bubble just like outside.

Salt water on the other hand may not contain the same contaminants as the osmosis bubble, but certainly a higher concentration than fresh water.
Andrew Curry 9 years ago
Achilles dont seem to be prone to Osmosis are you sure the the blisters in your pictures are not a failed epoxy coating. I would like to see it scraped back to the gel coat to see whats really going on.
busy home [deleted] 9 years ago
I agree .. odd that the light blue is totally uneffected.
sailing bye1 9 years ago
I understood osmosis first became apparent in the grp liner of swimming pools especially where the water would be above 20 C for long periods, ie warmer climates where the water would heat up in the sunshine.
I am assuming the inland areas would have a temp rise above 20 C during the summer as most of the water would be retained.
websoldtoys 9 years ago
The light blue is above the waterline, that is why it is unaffected. The top 1-2 inches under the painted waterline are unaffected as well, because the actual waterline is slightly lower.

'Sailing bye' may have a point about water temperature, too.

Everyone who saw it in the flesh, agrees it couldn't be anything but osmosis. A failed epoxy coating will crack more easily, but these blisters are pretty strong. I pushed fairly hard on one or two and they wouldn't budge, which means they are deeper than the top few coating layers, they are definitely under the gelcoat and therefore without a doubt osmosis.

Some 'perfect laminate' GRP boats might never develop osmosis, even when fully saturated with moisture, but 30 years of slowly absorbing water and then 3 more consecutive years without layups (to fully saturate the laminate) is a very very tough test. Even with boats that are not known for osmosis at all, it's no scandal to see a few fail it.
websoldtoys Posted 9 years ago. Edited by websoldtoys (member) 9 years ago
Forgot to mention, after inquiring about repair costs, I made a low offer on 473 that was not accepted, so I've moved on and am looking at other ships.

There's one more A24 I haven't looked at yet, an early fin type like Briseis, only half the price. Might be a very good ship, though I'd prefer a bridge deck which is one reason why it's not at the top of my list at the moment.

There's a GK24 candidate and a Maxi 77, both slightly longer, wider and, according to SW handicaps, faster. The GK has a new mainsail, three more sails, six winches, rebuilt ('99) inboard diesel and such, the Maxi mainly has a low price to its advantage, with some minor work (window leaks... sound familiar?). Both are very spacious inside, discouraging taking a look at the third A24 just yet...
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