Osmosis \ blisters - acute?

[boatpoker]

I hesitate to give advice when the OP seems inexperienced and may be panicking over a cosmetic issue however if his description is accurate I'd want a pro to look at it very soon. I'd be particularly concerned about the state of the rudder, rudder stock and stock web arrangement.

[Lizzy Belle]

Originally Posted by morven55

Your logic is always sound, and you give good advice, as usual; at least in my humble opinion! :] Having said that, the description given in the OP's first paragraph is the sort of problem that, at the very least, requires some in depth investigation.

Aww, thx *blush*

And I completely agree with you, sorry if I worded my post poorly and it came across otherwise.

As the OP described it, I fear it's a very serious case. But w/out at least some pics, it's hard to say. I've seen people go in full 'panic mode', saying pretty much what the OP posted, but in reality there were a couple of blisters on the hull. For the OP's sake, I'm hoping (probably in vain ...) that's the case here.

To cybber:
Can you provide a few pics so we know what situation we're talking about?
Any updates as to an expert coming by?

[Sailing55]

Originally Posted by Lizzy Belle

Aww, thx *blush*

And I completely agree with you, sorry if I worded my post poorly and it came across otherwise.

As the OP described it, I fear it's a very serious case. But w/out at least some pics, it's hard to say. I've seen people go in full 'panic mode', saying pretty much what the OP posted, but in reality there were a couple of blisters on the hull. For the OP's sake, I'm hoping (probably in vain ...) that's the case here.

To cybber:
Can you provide a few pics so we know what situation we're talking about?
Any updates as to an expert coming by?

We're OK... you seem to be the eternal optimist, which is refreshing. I have reached the point where I hesitate to talk about [my] boat to others because of the high probability of negative feedback. At least here on CF there is a high percentage of well thought out replies by people speaking from personal experience, and it is highly appreciated.

I just hate to think of someone [OP] buying a boat for a LONG ocean voyage and being faced with a problem such as this one. "Covered in blisters" may indeed be an over reaction, but...

[Sailing55]

Originally Posted by Lizzy Belle

Aww, thx *blush*

And I completely agree with you, sorry if I worded my post poorly and it came across otherwise.

As the OP described it, I fear it's a very serious case. But w/out at least some pics, it's hard to say. I've seen people go in full 'panic mode', saying pretty much what the OP posted, but in reality there were a couple of blisters on the hull. For the OP's sake, I'm hoping (probably in vain ...) that's the case here.

To cybber:
Can you provide a few pics so we know what situation we're talking about?
Any updates as to an expert coming by?

And, just to clarify, what I am suggesting to the OP, and anyone with blisters, is to get qualified advice and opinion just for peace of mind, if nothing else.

[Dave22q]

I might be wrong but my understanding is that there is not one reported case of proven structural damage much less a sinking from blisters. Not one. My searching has turned up lots of hysteria but no factual accounts. Can anybody correct me or are blisters really just a cosmetic issue?

[Don C L]

I believe I read in a thread awhile back about a keel with blisters deep enough to cause slow, persistent leak into bilge. I have a question for OP, what kind of lay-up does the hull have? There was a post about a Cheoy Lee and I saw from a friend's Cheoy Lee, that had blisters, that the Lloyd's way in the old days was a thick hull made mostly of mat. In that case the depth of the blisters varied quite a bit. In the Op's case the depth sounds limited to gelcoat and/or first layer which I think is roving, is that right? If so that sounds less serious but I still can't make the call, sail or no. Given what I have seen of blisters, and how long they can sit, I'd probably go. By the way, I have noticed that immediately after haul-out you may not see any blisters, but once it is out for a few days they start to show up, not sure why. I have also read that blisters are found in mat but not roving. But then I saw photos of blisters purportedly in between layers of roving. This post probably doesn't help at all!

[Sailing55]

Originally Posted by Dave22q

I might be wrong but my understanding is that there is not one reported case of proven structural damage much less a sinking from blisters. Not one. My searching has turned up lots of hysteria but no factual accounts. Can anybody correct me or are blisters really just a cosmetic issue?

If a fiberglass hull is designed to be x inches thick for structural purposes, would you consider it to be a problem if some of those layers either were dissolving or delaminating? Would you consider that to be cosmetic or structural? If a hull is designed to be constructed of either solid glass or composite [cored] materiel would you consider it to be a problem if ANY of those cores or layers were compromised or rotting or dissolving?

In order for your research to be valid you will need to provide statistics for [cause of loss] for all the vessels that go missing every year and are presumed to be lost.

Hysteria is one thing, common sense and maintenance is another. Just because someone cannot google any verifiable cases of loss due to osmotic blistering does not mean that it is safe and prudent to cross an ocean in a vessel "covered in blisters" without verifying the extent of damage.

[Sailing55]

Originally Posted by Don C L

I believe I read in a thread awhile back about a keel with blisters deep enough to cause slow, persistent leak into bilge. I have a question for OP, what kind of lay-up does the hull have? There was a post about a Cheoy Lee and I saw from a friend's Cheoy Lee, that had blisters, that the Lloyd's way in the old days was a thick hull made mostly of mat. In that case the depth of the blisters varied quite a bit. In the Op's case the depth sounds limited to gelcoat and/or first layer which I think is roving, is that right? If so that sounds less serious but I still can't make the call, sail or no. Given what I have seen of blisters, and how long they can sit, I'd probably go. By the way, I have noticed that immediately after haul-out you may not see any blisters, but once it is out for a few days they start to show up, not sure why. I have also read that blisters are found in mat but not roving. But then I saw photos of blisters purportedly in between layers of roving. This post probably doesn't help at all!

Every observation is helpful, and yours is as valid as any.

Apparently the root cause of the problem, at least in many of the '70's vintage hulls, is not the fiberglass, but the resins used. From my understanding the problem began in the early 70's during the first "oil crisis" due to the fact that petroleum played such a large part in the manufacture of resins. And it seems as if the gelcoat, and inner and outer layers of glass are not really affected, just the inner layers of the different combinations of roving/mat/cloth. I'm not a glass expert, by any means, but I have seen a lot of blister repair and spent time working with a shop that specialized in that sort of repair. Some blisters are easily repairable individually, some are so severe that the entire hull has to be peeled mechanically.

[boatpoker]

Originally Posted by Dave22q

I might be wrong but my understanding is that there is not one reported case of proven structural damage much less a sinking from blisters. Not one. My searching has turned up lots of hysteria but no factual accounts. Can anybody correct me or are blisters really just a cosmetic issue?

Yes, there is lots of evidence of structural damage. Take a look at the photos in this thread from the trawler forum. If that's not enough I can dig out dozens of photos from my own files.

[accept]

Hi out there

I must tell I bought a sailing boat in UK some years ago. A survey who made a bad work. I knew there were blisters and got price down for professional treatment. Treatment company could not get moisture low enough after molding and then it came up they the balsa core was down to keel. My surveyor did not notice or gave me a hint of this problem strong enough.
Later we found out that the ship had been ashore on a reef and all balsa was too wet.
So the osmosis came from inside instead of outside.http://www.cruisersforum.com/forums/...ies/danger.gif

For me it was an expensive lesson……
Good Luck

[Muckle Flugga]

Originally Posted by s/v Moondancer

We crossed the Pacific, Panama to New Zealand, last season and we have just got out of a very good boat yard, Bay of Islands Marina, in Opua NZ. It has excellent boat builders and with the weak NZ$ skilled workers are about $50/hr.

However, crossing the Pacific is 7,000+nm and 60 to 70 days at sea and of the 200 boats we know that crossed, last season, there was a high failure rate. One sank from structural problems, one lost the rig, there were 2 rudder failures and several others had serious rig and engine problems.

Latitude 38 - 'Lectronic Latitude

I personally would get the boat fixed properly and delay the Pacific.

70 days at sea crossing the Pacific is more stress than many coastal cruiser boats experience in a life-time of sailing the bay! The boat that sank was 1,500 miles off-shore and had been subjected to days of 'bashing.' Repair facilities are non-existent until you reach Tahiti which is 4,500nm from Panama!

Good luck but remember that you should never be in a hurry to get into trouble at sea!

Good advice and I concur. In fact I would say the attrition rate you stated was likely well below the actual one (though I know you weren't trying to draw a graph!). Perhaps you meant to say that 200 boats cross (probably rather more), and out of the subset that you know there were those damages and failures. Of 200 boats (just for a number) crossing the Pacific in any given year, I would expect around 5 to be completely wrecked, sunk, abandoned or otherwise lost. Many more are damaged severely in one way or another. It has to be said, however, that the majority of that damage is done at close quarters, and usually dragging anchor or by striking reefs underway. But there is a fairly high incidence of rudder failure, rig failure, and usually a hull failure or two, underway as well.

Just so you know, however, the $50 NZD per hour you mentioned rather pales by comparison to the $64 NZD per DAY you will pay for a skilled foreman of an excellent team here in Thailand. I love Opua and the work is generally high quality there and in NZ, but the price is a big draw up here.

[Clivevon]

Hi. Hope my experience is informative for you. 18 years ago I bought a 1981 boat with osmosis, at a good discount which more than covered the expected cost of repair. However once we started stripping back the problem was more deep seated. You could strip off the outer layers of laminate over a lot of the hull using just a paint scraper. Difficult bits needed a wood chisel. Seems the makers had put white pigment in the first couple of layers to back up the gel coat colour, without realising the powder was hydroscopic. Once peeled, the boat took two summers in the north Mallorca sun to dry out supposedly sufficiently to rebuild (no artificial aids though). The boat was supposed to be rebuilt with glass cloth using the WEST system epoxy resins. I was mostly absent though and had no surveyor supervision. Both big mistakes with hindsight.

Twelve years pottering around at weekends and holidays later, now back in UK, I still own the same boat. Blisters appear again all over underwater hull. NO big deal - just get it done again. BUT on investigating, large areas of the previous layup done 12 years ago could be peeled off in sheets using a wood chisel, right down to the hull as it had been peeled last time. You could still see the pencil grid marks where they had been measuring the moisture content!

What came off had never bonded properly to the hull. It was not cloth or rovings, but chopped strand mat. I get the best surveyor I can find this time. Turns out that epoxy resin should not be used with CSM because it doesnt dissolve the powders they use in CSM to bind the mat together.

So a bit more peeling and use the Hotvac system to dry the hull. Didnt work - even repeated 5 times over several months with regular intensive steam cleaning. Hull would not dry. so used more peeling and also shot blasting - twice. By this time have taken off maybe a quarter to a third of the hull, with one weak spot having blasted right through.... Thankfully its a 1972 design and a heavy built boat.

As I understood it, surveyor opinion (two respected independent sources) was that the hull could sit there til doomsday but would not dry out until all the uncured glycol in the original layup was removed, at which point it would dry out in a couple of weeks.

That is what happened to us. After the last blasting and another Hotvac, the moisture readings dropped dramatically to acceptable levels allowing a rebuild. This time indoors in temperature control using surveyor specified materials (CSM and vinylester resins to get the hull back to designed strength, with final layers of cloth and epoxy.) and allowing proper curing conditions and intervals.

Costs - a lot but a lot less than it would cost me to go out and buy another similar boat. The devil you know, I guess. If this lasts 12 years it will see me out anyway. The surveyor supervision of the job was worth every penny.

Time for the work - with other refit jobs - about 18 months.

Was the hull structurally weakened by the osmosis? HECK, YES.

Do you have a problem if your osmosis blisters are just in the gel coat? Going by my experience - you dont really have a problem, do you.

You need to find out what your problem is - superficial shallow blisters or deep seated delamination.

Whatever you do - you need to thoroughly examine and fix that rudder - even if it means a complete rebuild. Is the internal web still properly attached to the rudder post?

It doesnt make sense to own a boat anyway - you've got to be a bit obsessed, in my opinion. Guilty as charged.


Hope my saga helps you consider the possibilities and solutions.

[cybber]

Hi and thanks everyone.
We have learn a lot about osmosis the last days. It sounds alot worst on the man on the boat yard's than what it really is.
It is most on the lower part on the long keel, we open up s few and look in to it. And it feels OK to sail a way.
And, I did know that the boat probably would need a epoxy treatment some day, hop that day would bee more in the future.

The Thailand thing sounds nice, please tell me more.

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[Lizzy Belle]

Originally Posted by cybber

And, I did know that the boat probably would need a epoxy treatment some day, hop that day would bee more in the future.

Happy to hear it's probably not as bad as it sounded in your first post, but ..

I am a little worried, to be honest.

Is the rest of the boat sound and well maintained? Did you get a survey before buying?
Cos the surveyor should have told you *exactly* what was going on with the osmosis .. and many, many other things that will need to be in top condition for the trip you have planned!

[cybber]

The rest of the boat is sound, new rigg, new sails and everyting else have get a share of TLC.
And it is an old Swedish boat with a lot strength, built for the oceans. It's a OE32.

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