Might have the Pox? No! Does have the pox. Advice please

[CalicoJack]

As previously mentioned our Neptunian ketch was hauled out with the intention of soda blasting and then cooper coating. Since then things have gone from bad to worse. The hull was covered in dozens of small blisters, the largest about the size of a small finger nail say 10mm long. A well respected surveyor was called and his meter showed that the readings were on the high side, but only just in the red scale, as opposed to the orange scale. Apparently we are lucky in so much as Tylers, the builders, used a clear gell coat below the water line, so that we can really see what is going on; I must say that it doesn't feel very lucky to me. There is in addition to the blisters wicking, which apparently shows how the moisture is travelling through the outer layer of fiberglass mat.

The surveyors advice was to get the problem dealt with sooner than later ie some time during 2014. The soda blasting has opened some of the bisters, but by no means all, although it could not go back in the water for the rest of the season without spending some money on filler, primer and anti-fouling. The other suggestion is to employ a professional to strip the gell coat, then let it dry and follow that by epoxying the hull.

Our problem is what to do? Are we just throwing money away by putting the boat back in the water and dealing with it in the autumn? Should we bite the bullet and go ahead and let the professionals deal with it; the down side being the cost and the fact that we will be without the boat for at least six months? Or is there some other cunning plan, that we don't recognise?

Your thoughts are much appreciated

 

[Easticks28]

Ignore it ( unless you plan to sell her in the near future) Treatment , as you rightly comment will cost a packet and deprive you of use for some months.
The Insurance companies seem not to regard ' the pox' as a structural risk. Although many boats have sunk with osmosis, here is no evidence of any craft foundering because of it as far as I know.
The problem is largely cosmetic, although there are many who will tell you otherwise. By and large, these are the same people who wish to get their hands on your wallet.....

 

[Deleted member 36384]

….. hull was covered in dozens of small blisters …… in addition to the blisters wicking ……

I don't agree that so called osmosis is largely cosmetic, there are some pretty horrendous pictures of sever osmosis and the complete delamination of FRP, which obviously weakens the structure. In addition, wicking can also be indicative of poor resin application to the cloth such that the cloth has been starved of resin, not wetted out correctly, again this results in loss of integrity.

Your question of course is how much integrity has been lost? Well, there is a big difference between 'dozens' and 'covered', so which is it? The moisture reading does not imply a serious moisture problem and a few dozen blisters, 10 mm long, doesn't suggest a serious loss of integrity. However, you mention that the blisters are 10 mm long, not round, are the blisters elongated?

Elongated blisters (perhaps tear drop shaped) and evidence of wicking may imply that the first layer of cloth was not wetted out correctly as opposed to a water/styrene reaction and osmosis. In this case, the remaining layers of cloth could have been wetted out sufficiently and are providing a better barrier against the water molecules flowing inwards, hence the surface blisters; little loss of integrity.

Is there a fluid in the blisters, that has been tested for acidity, smell and greasyness, if so, this may indicate osmosis instead of dry cloth space filled with only with water? If not it might just be age related moisture in dry cloth gaps - especially if the blisters are all parrallel and in the same area. If it was me, with fluid in the blisters and wicking, I would pick the worst spot that was accessible from inside and outside and then cut a core right through the hull. If the core looks good and only the surface shows a problem then I would not be too worried. If the core shows delamination or dry GRP in the middle then there is a serious structural issue. One reason for the blisters and low moisture reading is that laminate was so poorly constructed (large scale resin starvation) that it doesn't hold much moisture, the wicking wicks it all away except where you have blisters and below the blister, better resin saturated cloth. Go over your hull with a ball peen hammer, panel pin type, and tap the hull sharply, you should hear a distinct tap, a dull thud, could indicate further problems deeper in.

Your yacht is of the generation that is likely to have been laid up thick, so again this means that loss of integrity is probably not that much as there is ample redundancy of FRP. At the end of the day you have paid a surveyor, you could ask for a second opinion, for osmosis only by a different surveyor. Do you have any reason to doubt the surveyors professionalism?

I am an amateur, my opinions are based on internet trawling of osmosis as an old boat owner, so I could be well off the mark here and wrong.

 

[charles_reed]

I heard some sensible advice given in the boatyard to some people who had just brought a big power-boat in from Spain with obvious osmosis.
"Rub it down with coarse sandpaper, wash it off with lots of fresh water, put on one coat of antifouling and do the job properly September '14 - May '15."

Now this was in Greek Macedon where it's rather drier than the UK and is famous for dry winter winds (which is what you need to get the substrate dry)

 

[jwilson]

As previously mentioned our Neptunian ketch was hauled out with the intention of soda blasting and then cooper coating. Since then things have gone from bad to worse. The hull was covered in dozens of small blisters, the largest about the size of a small finger nail say 10mm long. A well respected surveyor was called and his meter showed that the readings were on the high side, but only just in the red scale, as opposed to the orange scale. Apparently we are lucky in so much as Tylers, the builders, used a clear gell coat below the water line, so that we can really see what is going on; I must say that it doesn't feel very lucky to me. There is in addition to the blisters wicking, which apparently shows how the moisture is travelling through the outer layer of fiberglass mat.

The surveyors advice was to get the problem dealt with sooner than later ie some time during 2014. The soda blasting has opened some of the bisters, but by no means all, although it could not go back in the water for the rest of the season without spending some money on filler, primer and anti-fouling. The other suggestion is to employ a professional to strip the gell coat, then let it dry and follow that by epoxying the hull.

Our problem is what to do? Are we just throwing money away by putting the boat back in the water and dealing with it in the autumn? Should we bite the bullet and go ahead and let the professionals deal with it; the down side being the cost and the fact that we will be without the boat for at least six months? Or is there some other cunning plan, that we don't recognise?

Your thoughts are much appreciated

Having owned a similar aged "built like a brick ........" hull with similar blisters I'd do what I did, grind out each blister, fill and smooth, and paint AF on top. If you do the work yourself it will take time but cost very little. Every few years you'll find a few more.

The strip gel coat, dry out and epoxy the hull route - if done by a yard - is like writing a blank cheque - probably for at least 25% of the value of the boat, maybe significantly more.

 

[TonyBuckley]

As previously mentioned our Neptunian ketch was hauled out with the intention of soda blasting and then cooper coating. Since then things have gone from bad to worse. The hull was covered in dozens of small blisters, the largest about the size of a small finger nail say 10mm long. A well respected surveyor was called and his meter showed that the readings were on the high side, but only just in the red scale, as opposed to the orange scale. Apparently we are lucky in so much as Tylers, the builders, used a clear gell coat below the water line, so that we can really see what is going on; I must say that it doesn't feel very lucky to me. There is in addition to the blisters wicking, which apparently shows how the moisture is travelling through the outer layer of fiberglass mat.

The surveyors advice was to get the problem dealt with sooner than later ie some time during 2014. The soda blasting has opened some of the bisters, but by no means all, although it could not go back in the water for the rest of the season without spending some money on filler, primer and anti-fouling. The other suggestion is to employ a professional to strip the gell coat, then let it dry and follow that by epoxying the hull.

Our problem is what to do? Are we just throwing money away by putting the boat back in the water and dealing with it in the autumn? Should we bite the bullet and go ahead and let the professionals deal with it; the down side being the cost and the fact that we will be without the boat for at least six months? Or is there some other cunning plan, that we don't recognise?

Your thoughts are much appreciated

How old is the boat and how much is it worth? What is your type of sailing?

"Although many boats have sunk with osmosis..." - really? I would love to see some proper evidence of this and the extent that resulted in a sinking? Not suggesting not true but not seen any occurrences that have been identified to the pox.

I used to do IT work for an insurance company, and they were quite relaxed about the pox. Much more concerned about seacocks and vented heads.

My last boat had the pox on a similar scale to your description. But I sold her for a good price. One surveyor just said it was normal for her age and to move on for a few years without worrying, another pretty much condemned her. Go figure.

 

[Easticks28]

How old is the boat and how much is it worth? What is your type of sailing?

"Although many boats have sunk with osmosis..." - really? I would love to see some proper evidence of this and the extent that resulted in a sinking? Not suggesting not true but not seen any occurrences that have been identified to the pox.

What I actually volunteered was "Although many boats have sunk with osmosis, there is no evidence of any craft foundering because of it as far as I know.

 

[TonyBuckley]

What I actually volunteered was "Although many boats have sunk with osmosis, there is no evidence of any craft foundering because of it as far as I know.

I was confused between the terms of 'sinking' and 'foundering'. I still remain confused lol.

EDIT: OK so get what you are saying I think. Boats that have the Pox have sunk. But not attributed to same. Maybe I am a bit slow lol.

 

[Easticks28]

http://www.thefreedictionary.com/foundering

 

[TonyBuckley]

http://www.thefreedictionary.com/foundering

of a boat or ship : to fill with water and sink

http://www.merriam-webster.com/dictionary/founder

Therefore same as 'sink'.

But who cares about semantics. I understand what you are saying I think.

 

[Easticks28]

I was confused between the terms of 'sinking' and 'foundering'. I still remain confused lol.

EDIT: OK so get what you are saying I think. Boats that have the Pox have sunk. But not attributed to same. Maybe I am a bit slow lol.

Precisely. Enjoy a virtual pint - (or another real one)

 

[TonyBuckley]

Precisely. Enjoy a virtual pint - (or another real one)

About to have first actually. But even in a sober world it is hard to understand people who use two words that mean the same thing.

 

[Sire]

Sunk with osmosis == sunk at the same time as exhibiting signs of osmosis. Not at all the same as sinking / foundering because of it.

 

[john_morris_uk]

If I can return to answering the OP's question, we were in a similar predicament a few years ago. My very strong advice would be to fill and fair and go sailing. Another few months in the water really isn't going to make any difference.

Then save up and get the boat peeled and treated at a reliable boat yard if you want to apply Coppercoat. The dryness of the winters in Greece is irrelevant as once the boat is peeled it needs to be washed and steam cleaned many times (perhaps weekly at first?) to strip out the styrene and water products in the laminate. Against my instincts, the boat yard that treated out boat dried her out in the Scottish west Coast winter OUTSIDE for the most part. In torrential rain and ice and snow, the moisture readings gradually declined.

We waited several years before be got ours treated. (We carried the bags of copper powder round as extra ballast for ages!

Hope that helps.

 

[Easticks28]

About to have first actually. But even in a sober world it is hard to understand people who use two words that mean the same thing.

I can't imagine how language would be if we always used the same words when speaking, reading and writing? If everything (person, place, object…) in the world had only one word to refer to it, the world would be a very boring place.

Well, in order to make language a lot more expressive and interesting I believe we should try to vary the words we use as often as we can (but not too often).

 

[oldsaltoz]

Hi Calico Jack,

All you need is a 40 grit disk on an angle grinder, grind out the effected areas, fill with more glass if more than 6 mm deep and top coat with Micro-Balloons (Resin bubbles) or Micro-Spheres (Glass bubbles) the better of the two but a little harder to sand off. and apply 5 layers of Epoxy resin, then an epoxy primer and paint.

Go get some sailing and treat only what you can see next time you haul out.

Good luck and fair winds.

 

[savageseadog]

If you have her blasted it will only open blisters that are already there or forming just below the surface, there will be blister cells that are deeper or about to form that won't be touched. If you epoxy coat the hull after one blasting you may well find new blisters after a few years. I think the best approach is to open all the blisters you can either by hand in the case of smaller boats and/or minor osmosis or with a blast. fill the holes and repeat each year or two till the problem dies away. In my opinion osmosis isn't an issue structurally and isn't anything to worry about.

 

[Colvic Watson]

Gel coat strip is a very severe solution to a tiny problem, a bit like replacing a roof because there's a lot of moss on it. Osmosis causes no changes to your sailing, your safety or your summer. A peel etc will wreck all three and empty your bank balance. Think of it as a cosmetic issue, deal with it accordingly and enjoy the summer; you just have to add grinding, filling and fairing to your list of winter jobs from no on.

 

[Deleted member 36384]

The web page link below shows bad and not so bad osmosis damage. Anyone who states that Osmosis is cosmetic and implies that it is not serious is wrong. I agree that there are degrees of damage of which some will only weaken GRP structure to a minimum, I also agree that there are environmental conditions, usually not found in colder UK like climes, which can make the problem worse (NZ web site below). Nevertheless, osmosis is serious and should be treated as such, never glibly dismiss it.

The link http://marinesurveys.co.nz/Osmosis-Buying-Advice.html

 

[JumbleDuck]

http://www.thefreedictionary.com/foundering

"An abandoned Japanese child".