Osmosis treatment.

Allan

Allan

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I will be buying an old boat in the near future and I have to be realistic about the possibilty of Osmosis. Can anyone give me some idea of the cost of treatment and recommend any good companies in the South? The boat will be upto 33 feet and have bilge keels.
Allan
 
To my mind, the first question is no how much it will cost, but is it worth doing at all? By all means use the odd blister to get a discount on the price, but I'd think your survayor would be able to give a rough estimate on how much to knock off your offer. VERY few boats have bad enough osmosis to warrant urgent treatment. Most of what "experts" say about it seems to be based on one of two things:

1. Surveyors covering their rear end for a worst case scenario and insurance companies doing likewise.

2. Boatyards thinking about how much they can make off you if they can convince you your boat will sink next week if the treatment isn't done. (It won't!)

A load of little blisters are for practical purposes, a cosmetic defect. OTOH, one blister the size of a dinner plate is TROUBLE. That ain't "osmosis", that's delamination, which is a walk away job, cos there's no telling how bad it is until you start the surgery.

Have a look at This site which will tell you all you want to know - and more - on the subject of GRP hull defects
 
I have recently bought a boat with osmotic blistering, I was quoted between £5-£6k at Pedros in Galampton, nr Dartmouth. But the others are right it is not the damaging desease that it was once thought. I have done quite a bit of research and the general consensus is monitor it over a period of time, several years. But the overriding advice is don't do it too quick as most treatments last 3-5 years some longer. A good guide to the overall seriousness of osmotic blistering is that insurance companies are not that interested in it, it's only the value of the boat that they worry about, ie it's not going to sink and cost them money. If you are buying the boat the surveyors maxim is that any expenditure, on a boat to be purchased, that will bring it up to scratch and improve it value, it's only reasonable to ask the seller to meet 50% of the expense. Hope that helps, but there are some good books available on the subject too
 
[ QUOTE ]
I will be buying an old boat in the near future and I have to be realistic about the possibilty of Osmosis. Can anyone give me some idea of the cost of treatment and recommend any good companies in the South? The boat will be upto 33 feet and have bilge keels.
Allan

[/ QUOTE ]

If she is old and has no Osmosis chances are very good she may well never develop it.

If she is old and has Osmosis, the cost of treating her may be more than the boat is worth in as much as you will never recover the cost.

However, you still have a couple of choices left.
You could treat any Osmosis yourself by treating any blisters every time you pull her out for the winter, some owners have been doing just this for years without major problems.

Or, you could treat the underwater area yourself. After all 70% of the cost is labour.

Hope this helps.

Avagoodnewyear......
 
Chat to the guys at Osmotec, as the name suggests they are one of the experts, they did repairs on our boat when we got it, not for osmosis granted but they are really helpfull and very good at repairs.

They are based at Hamble Point Marina
 
My personal experience as a customer of them is that they are very straight talking and don't need to poo poo any osmosis treatment.

Obviously they will be reluctant to price a job without seeing what is involved and remember that untill the hull is stripped back no one can really tell you how bad and how much repairs might be.
 
Couple of comments Alan. Firstly, many older boat will have been treated for osmosis. If the work was done properly, that might solve the problem for good. You'll hear comments about the epoxy coatings only lasting 10 years or whatever, but I've got first-hand experience that says that is nonsense if done professionally in the first place. Secondly, I suspect the cost will depend on what degree of stripping / re-laminating is needed. I considered buying a Sadler last year that had blisters. The owner had got a few quotes and they varied a lot. The best in this area was Ray Harris Marine in Barry from what I recall. Give them a call and have a chat.
 
I would think twice about osmosis treatment if the boat does have it. Get a survey and a quote for treatment then negotiate on price. Use the discount to upgrade running and standing rigging and electronics.

Many or most of the osmosis treatments carried out until recently were ineffective as they did not understand the real cause of blistering and they failed to remove the chemicals in the substrate that attracted water. Some of the more modern processes, such as hotvac, now claim much higher success rate - but if I were you with an older boat I wouldn't bother doing anything about it. If the boat has really severe blistering choose another.
 
I bought a boat with (the pox) after masses of research it becomes less scary.I got it at a good price so if i wanted to sell it i could get the money i paid for it.If you want to get it treated do it just before you sell it , with the repairers five year garantee
 
[ QUOTE ]
If you want to get it treated do it just before you sell it , with the repairers five year garantee

[/ QUOTE ]

I can understand why you say that (and I was of the same opinion when lookng for a boat some years ago)...BUT I believe many boatyards won't now give a guarantee of this length, or if they do it's an insurance scheme that costs around an additional £500!! That's what I came across anyway. Also, as the failure rate is higher in the years immediately after treatment, there is an argument for buying a boat where the work has been done further in the past. The logic here is that if it's survived the first 5 years or so with no problems, it probably won't have any. I'd be interested in other views on this.
 
[ QUOTE ]
I will be buying an old boat in the near future and I have to be realistic about the possibilty of Osmosis. Can anyone give me some idea of the cost of treatment and recommend any good companies in the South? The boat will be upto 33 feet and have bilge keels.
Allan

[/ QUOTE ]
Don,t start with a negative Allan, it may not have the problem, if it has, asses how serious it is then, I bought a boat in Spain knowing it had pox, I had it treated there, only because she was out of the water, and had been for 2yrs. Otherwise I would not have bothered, in 42yrs., I have never heard of a boat sinking as a result of osmo. It has to be treated, but if it is only the gel, not delamination, it,s simply a paint job. My boat did have some delamination, even then, with an old Nic she is so heavily laid up, we took some laminate off, put a bit back, she will still well outlast me, (I hope to be sailing for 20 more yrs), she is 30!
 
I had my gelcoat stripped, dried & epoxied professionaly a couple of years ago. Drying proved the biggest problem, it took ages (several months) before they could get the levels to the point where hotvac was practical. It cost me a season's sailing and several grand, but I am glad I did it.

I didn't have the confidence or time to chip out the hundred or so little blisters and suspected she would always look as if she had the pox with loads of little scars replacing the blisters.

I also had the old, unreliable MD2b replaced with a new yanmar 30hp. Now, I have had the boat for 15 years & will probably keep her for another 15. Before, I was losing confidence in her & unsure whether I would be able to start or run the engine in an emergency, I had begun to not enjoy using her.

OK, so osmosis isn't that big a deal, but I felt a need to look after her so she will look after me when I need it! You makes yer own choices & lives with the consequences, just ask yourself how important is how it looks & how important is the money? The answers to that question will tell you what to do.
 
Different kettle etc.

You've already had 15 years service from her and are fettling her for the next.
The questioner is talking about buying a boat with pox. He may only keep her 2 or 3 years, so has no loyalty to speak of.
Why pay for something that will not repay itself. (and as you say, in your case the engine issue was more pressing)
 
Unfortunately there are vessels that have taken on water because of osmosis/ hydrolosis or suffered damage when appendages have left the hull ie keels! luckily they are few and far between
small blisters are not an immediate problem, thumb size could be and palm size definately, as what this phenomina does is WEAKEN the laminate as the pressure caused by the chemical reactions going on within the hull build up and tears the resin from the mat, expanding and contracting and slowly moving through the structure
Some manufacturers craft can be more troublesome than others and the method of treatment may have to vary accordingly
My own tried and tested repair scheme is to peel, Epoxy Resin prime until there is no more absorbtion apply a layer of glass cloth and seal with Epoxy Resin, fill and fair with Epoxy fillers, rub down and apply epoxy paint scheme and antifoul
The biggest enemy of an Epoxy repair is temperature fluctuations which will induce amine sweat, this fluid works like a release coat and will draw moisture vapours between the layers of epoxy causing further blistering or and paint detachment
Any underwater aluminium based anticorrosive can be used as a good protective coating providing the hull / laminate is dry and application is per the manufacturers instructions
 
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