I've got the pox

[jimboaw]

I\'ve got the pox

Just hauled for the first time in four years and low and behold blisters. B*gger. My concern is that the yard wants to force dry the hull after stripping but I am more inclined to let it air dry for a longer period, say 4-5 months and then do a final heat dry before re coating. Boat is in N. Carolina so weather is moderate and the relative humidity over the winter months is fairly low. Any advice would be gratefully received.
The yard have given me a rough estimate of $10,000 to do the job. How does that compare to UK prices for a 40 foot boat?

 

[damo]

Re: I\'ve got the pox

Big blisters, lots of blisters??? Many hulls show blistering after being lifted, which disappear as the hull dries. They often show up on the topsides where the prop pads have held moisture against the gelcoat, but go away quickly. The point is - how serious is the blistering, and do you really need the hull stripping??

 

[jimboaw]

Re: I\'ve got the pox

Yes Yes and Yes /forums/images/graemlins/frown.gif

 

[temptress]

Re: I\'ve got the pox

Well at least you won’t sink because of it. But I guess it needs sorting. I would go for the forced drying option in a controlled environment but this adds cost. On the up side it curable and as you are having it professionally done should get a warranty on the work.

As for the cost US$ 10K is about GBP £7K given the current exchange rate. IMO it is probably slightly on the expensive side but maybe not. Can’t you negotiate with them. After all given the dire economic warnings and over here at least boat yards laying off staff or reducing their working week you may be able to get a reduction. Always assuming they quote you a fixed price for the work.

Good luck,

/forums/images/graemlins/smirk.gif

 

[JonJon]

Re: I\'ve got the pox

Seems about par for the course I was quoted initially 9000 euros - after a bit of bargaining now 8100 euros for a 40 footer. But they havent started yet so who knows? Of course, the euro is changing value every week with Gordon's attempt to sure up, with some of my money, the banks profligacy and Cletus' 5 storey mansion in florida and it looks as tho he will continue to do so - what will the final bill be??? /forums/images/graemlins/frown.gif

 

[pandos]

Re: I\'ve got the pox

Again How big, how many. Photos??

Do not panic, there will be plenty of time for that later.

Many boats have a few blisters that can be treated easily without a full strip,

Tony.

 

[absit_omen]

Re: I\'ve got the pox

If that price includes the force dying I would go for it. What are you going to do if, after 4 months air drying she is still too wet?

By letting them do the drying you are going to be back in commission faster.

What have you got to worry about - presumably they will give a warranty?

 

[Bilgediver]

Re: I\'ve got the pox

Suggest you speak to a few locals who have dealt with this problem..

Force drying is a waste of time as you are not dealing with water but the products of osmosis and the only way to so called dry out is to release the trapped fluids.

The usuall yankee method which I support flly is to conterbore the blisters which releases the fluids. You do not force dry but actually wet the hull at least once a day with warm to hot water to wash the released fluids away and stop them drying on the surface and preventing the further release.

Yes you can remove the gelcoat and replace however some operators of gelcoat removal tools are a wee bit gung ho and can do more damage to the hull than caused by the osmosis. I have seen hulls where they have shaved right through and let daylight in!!!

Once the vinegar smell is no longer aparent you cna finish with the washing and allow to dry out. This might take a few months. It is easy to fill over the counterbores with suitably epoxy filler.


I have seen many reports from your side of the pond doing this and in some cases the number of counterbores was in the thousands.

 

[jimboaw]

Re: I\'ve got the pox

I don't need to be "in commission" before next spring and I have the boat up for sale as well. I am just a little worried that forced drying may lead misleading moisture meter readings because it has dried the outer surface whilst the inner layup may still be wet.
I did say in my OP that I would want a final force dry.

 

[pappaecho]

Re: I\'ve got the pox

Are these blisters showing the telltale sign of vinegar/acetic acid smell?

 

[jimboaw]

Re: I\'ve got the pox

Yup. No doubt about it. POX

 

[absit_omen]

Re: I\'ve got the pox

OK, however, I recently visited a large Osmosis Repair Centre on the East Coast where they were busy drying a 35 ft yacht with heated pads. 6 days as opposed to 6 months in terms of inside storage.

This is what they say:

Osmosis

Worried about moisture absorption in you hull? Blistering on your underwater surfaces?
We can check and re-assure you. If there is a problem found, we deal with this quickly and effectively with HOT VAC. This system will not only dry your hull rapidly but also remove, in a controlled process, trapped solvents. We then fill and fair, relaminate, epoxy bottom and antifoul to complete.

With a 5 year warranty you can enjoy peace of mind.




As I said, if you are going to an approved centre and there is a warranty what is the problem?

 

[tangomoon]

Re: I\'ve got the pox

Hot Vac - yes I have heard of that one read about it - sounds b good!

Found it:

http://www.hotvac.com/

Both sides of the water too.

 

[flyingscampi]

Re: I\'ve got the pox

These sites are well worth a read:

http://www.passionforpaint.co.uk/
http://www.yachtsurvey.com/blisters.htm
http://www.daviscoltd.com/nams/Documents/Blister_Report.html

The Hotvac treatment is probably the best solution.

 

[FlyingDutchman]

Re: I\'ve got the pox

I always assume that since my boat is now 14 years old and has no osmosis now, it will never happen in the future. Is this correct thinking? How old is your boat?

 

[Evadne]

Re: I\'ve got the pox

[ QUOTE ]
I always assume that since my boat is now 14 years old and has no osmosis now, it will never happen in the future. Is this correct thinking?

[/ QUOTE ]
My boat "got osmosis" at the ripe old age of 29. It was more a case of bad layup, which only showed up after two consecutive winters afloat, (but that's another story). I wouldn't make any rash assumptions!

 

[FlyingDutchman]

Re: I\'ve got the pox

What do you mean with "bad layup"?

 

[NickiCrutchfield]

Re: I\'ve got the pox

A bad lay up is one where the fibres have not been completely wet out with resin thus leaving voids. Often it is possible, when the gel coat is stripped, to see a surprising amount of soft white strands in the CSM (chopped strand mat). There is much argument about what causes pox, but I am with Hugo du Plessis in his contention that whatever causes it is less relevant than the fact that completely wet out lay ups very very rarely develop the problem and in most cases of it developing there are dry strands in the hull.

 

[rogeriorg]

Re: I\'ve got the pox

Do not panic.
Have a look on http://www.passionforpaint.co.uk/

 

[pip50]

Re: I\'ve got the pox

Here are a few points which might be of help

First Ensure You Do in Fact Have an Osmotic Condition

Because you can bet that the Yard will happily treat your Pox even if it’s a false alarm!

Make a close inspection of any suspect areas identified by initial visual inspection.

Check for any noticeable blisters, cracks, crazing etc. Take photographs!! Digital are great as you can enlarge them on your computer. If not get your spyglass out!

External hammer test for any possible delamination, repairs, voids, hard or soft spots.
Listen for any areas with markedly different sound.

Scrape off a number of patches of antifouling - Inspect for any blisters, cracks, crazing, delamination, fibre ends/ wicking evidence of previous or use of fillers


Check the laminate (if suspect remove small area of gel coat )
Check for poorly bonded laminate, loose bundles of glass matting and any voids.


Investigation of any blisters.

First identify type of blister

Are they dry or osmotic blistering or perhaps delamination.

Check for any fluid
Fluid indicates a problem. (Generally blisters must contain a fluid to be osmotic)
Smell the fluid, pungent or vinegary smell is an indication of presence of acetic acid.

Open up the blisters with a wood chisel, check the laminate

Check pH readings – lower than 7 indicates presence of an acid.

Check fluid for glycol. Rub fluid between finger/thumb for sticky/greasey
residue and sweet smell.

Estimation of Blistering

Measure average diameter of blisters.
Count the number within 100mm by 100mm square if small and numerous
Count the number within 300mm x 300mm if few and large.
Calculate blister area as a percentage of measured area.
Open up several blisters to be able to record depth of larger blisters in particular.

Must also agree with other comments, a wet hull just proves it’s a boat!! Do not just go by moisture metre readings and just drying out a hull does not remove osmosis, it’s the chemical reaction you need to stop and the water though activates this it will not stop just because you dry it out. e.g you dry her out re launch and guess what when you haul her out again the pox is back – no it never went away. Yards make a fortune out of so called osmosis treatments.

You need to get to the core of the problem – dry vacuum is a popular one but you need first to be able to get to the laminate so gel coat peels are usually required.
You can also use steam, it may sound odd adding moisture but remember you are trying to get rid of the glycol so steam and rinse and do it again and again.

I can not comment on costs as it’s a free market and where osmosis is concerned
Buyer most definitely beware.