Sovereign A Moisture Scale

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Tai_Lam

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After many years of dinghy sailing I am looking to purchase a yacht of the "older and needing some work" variety. Last weekend I took a look at an early 70's boat for which the owner had a copy of a recent survey. The report gave hull moisture readings on the Sovereign A Scale of between 12 -15, with readings of 18-25 in the skeg area. Can anyone advise if these reading are good/bad, or indicative of possible osmosis problems.

Thanks In Advance.

John.

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Here's another personal opinion that's also been seen numerous times.

Having bought an early 70s boat last year, I learned lots about the subject.

Just about everyone agrees that osmosis has never caused a boat to sink or become structurally unsound. However, few want to buy a boat with osmosis unless the price is good enough to take account of a treatment. Hence if you get a boat that develops blisters you'll lose quite a bit of money either in treating or resale value.

I bought my boat with reasonable readings for the age and no signs of osmosis. I walked away from a boat that showed signs of shoddy work - various colours of epoxy paint falling off once the anti-fouling was removed. I also walked away from a boat that showed blisters once it was hauled out.

I'm half expecting that the boat will blister during my ownership. If it does then it'll cost me. If it doesn't then great.

I think that's really the only way to look at it. If you want any guarentees then don't buy a boat.

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Like all measuring devices, some form of calibration is essential. Take a reading from a surface that you know to be absolutely dry and record the meter reading. Do it again with something that is totally wet and record the reading, and you are in a position to make some sense from the scale. The numbers are purely relative to the meter & do not indicate percentages of mositure, fibre glass can only take up a maximum of c5% moisture by weight, so we are dealing with small numbers in any event.

Moisture readings are certainly not a good indicator of forthcomimg problems, lots of older boats have high mositure readings and absolutely no trace of visible osmosis, some newer boats develop visible osmosis within months of a survey where mositure contents were very low. Sorry, but the science plays a poor second to a well applied mark one eyeball.


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Readings are pretty good, as someone else has said, probably wintered ashore.
One good thing about early boats is that many were built using wooden technology & as a consequence are a lot more robust than modern GRP boats, which are (mostly) built to minimum cost/no more than adequate strength. I have a 1970 boat & when enquiring about the likelihood of osmosis & treatment for same, was firmly told to B****r off & go sailing! The guy telling me ran an osmosis treatment firm in Chichester & basically said same as others on this forum. If it ain't broke don't worry about it. If it gets osmosis later, it's a pain, but there aren't any guarantees even with brand new boats.
Hope you find something that suits, to get you out on the watter!
Cheers
Mike

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When I had my current boat surveyed, the chap was on the brink of warning me of impending osmosis problems (even though boat was only manufactured in 1991) based upon his meter readings. However, once he'd taken the bung out and drained all the water from the bilges the meter readings were fine!

Check your bilges!

<hr width=100% size=1>Tomsk -

What the hell... it's only money!
 
Thanks for this info. I wasn't aware of the % water uptake of grp. A visual check of the hull showed no signs of blistering so I guess its probably pretty good for its age.



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Thanks, sounds like good advice. From the comments on this tread I think the hull will be the least of my problems. I suspect on a boat of this age the engine will present the most problems.

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The problem is more from :

Not the content 'absorbed' by the strata .... but the amount of wtaer in blisters etc. separating the gel from the underlying lay-up and possible deterioration of lay-up.
So to quote circa 5% is not relevant.

The readings are relative to so many factors that quoting the numbers only is insufficient to give proper answer. EG : What is the above water hull reference reading ? This should give a reference for 'dry-hull' ex builder .......

Is the hull bilstered ? Are the bilges dry ? Has the antifoul been stripped ? Is there antifoul primer ? Has the boat been epoxied before ? All these affect readings substantially .... in some cases making metering useless - regardless of what some 'experts' and meter companys say.

I can honestly say that I have no recollection of a boat lost due to osmosis ...... second that many older boats cary heavy hulls from water absorbed many years with no problem. Third - that wintering ahsore does not remove the problem - only the water that has not had time to increase density etc. stopping it from getting back out ..... (note : pop a blister and you will find a smelly sticky fluid - this is water that has dissolved uncured components of resin / catalyst and has increased density and pressure in that void such that the blister occurs .... it cannot escape via the microscopic hole / capillary it used to get in as its too thick ....)

So maybe you should get someone to look at it properly - stating clearly what you want and not just asking for survey ..... be exact, clear.

<hr width=100% size=1>Nigel ... and of course Yahoo groups :
http://groups.yahoo.com/group/gps-navigator/
 
Re: The problem is more from :

Having a 36 year old seamaster 34' presented the usual heart stopping sight on removal of the years antifoul, Blisters, I opened some up to inspect them only to find that they were voids in the gel coat, according to "Fibre-glass boats- by Hugo du Plessis" I suggest you by the book it has become my bible.

My moisture readings were fair for a boat of it's age and mistreatment, on purchase it had approx 500 liters of water in the bilge, and that was on hardstanding. The best advice I have to give is that if you do have blisters, remove them with a pencil grinder, not an angle grinder(as it rips seven shades of hell out of the rest of the boat also) and fill the new voids with the appropriate filler

Too many surveyors shout about stripping the gelcoat as soon a one tiny blister is sighted, and to strip the Gelcoat means you'll be stripping some of the hull also so you end up with a paper thin hull covered in 6mm of an epoxy gelcoat.

my boat is far from finished but the hull is no longer a major issue, Now then. Will a pair of oars be able to replace a pair of Perkins

<hr width=100% size=1>http:\\mysite.freeserve.com/leisure_marine_prep
 
Re: The problem is more from :

I am Professional Surveyor - owner of a respected and established division across the Baltics and a small unit in UK.

The post about blisters that I made is illustrating those blisters caused by water ingress.

The blisters mentioned by <ollari - are not uncommon in older boats where the lay-up was not rollered out properly onto the gel-coat ...... so no argument there.

I also agree that Osmosis has earnt many people a lot of money ..... its debatable as to its possibility to 'destroy' a good boat .... No-one has lived long enough or for that matter a boat long enough to go the distance needed !

Any defect in structure must be cause for concern and I do not advocate ignoring it, but also I have a boat that has moderate to high moderate moisture - I will not touch her till blisters are evident. The boat is sound, heavy lay-up and built like a battle tank ....

Finally a boat without gel-coat is NOT paper-thin as you suggest .... Gel-coat carries NO structural duty other than cosmetic ..... the structural factor is in the main GRP lay-up. It is documented many times of boats being stripped and then sailing to treatment centre ..... yes you read me right ..... ok I wouldn't advoacte a Circum-navigation in that condition ..... !!

There are many good books available - one of the best is by the Importer of the Tramax Skipper Meter ......


<hr width=100% size=1>Nigel ... and of course Yahoo groups :
http://groups.yahoo.com/group/gps-navigator/
 
Does osmosis cause sinking?

It can happen, even if very unusual. Many years ago I saw a small motor boat at Sandwich, Kent, that had been salvaged after sinking at its moorings as a result of osmosis. It had been neglected for many years. It was completely covered in huge blisters below the waterline, up to nearly a foot across, and which had given way allowing water to run through the thin, dry and very inferior lay (possibly amateur). I've never seen anything remotely like that since.

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OK - anyone else with observations ...

I am REALLY interested ..... straight up ..... in any reports that confirm structural loss or sinkings due to osmosis or water ingress based on poor lay-ups.

I have to say that this is the first instance I have heard of - ok .... I know of many where sheer neglect and other factors as well have caused TCL - (total constructive loss) ......

I would hazard a guess that this example was seriously deficient on initial building / laying-up of structure.


<hr width=100% size=1>Nigel ... and of course Yahoo groups :
http://groups.yahoo.com/group/gps-navigator/
 
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