High moisture reading .

[CARL]

Having found the yacht of my dreams and placing an offer, which has been accepted, subject to survey, iam a little concerned when the surveyor reported a high moisture reading for the hull. The yacht has been standing on the hard for about 12mth, so must have dried a little.In 1997 the gell was removed and International Epoxy barrier applied.Now i realise the hull should at some time be restripped again allowed to dry and redone,The surveyor lead me to believe that the yacht was otherwise sound apart from obvious work i.e mast repaint varnish etc,allso the high moisture was ownley probmatic for a resale point and that the boat would certainly not sink because of this.My thinking is ,if i can come to some agreement regarding cost of redoing the hull,i.e meet half way,Icould continue with plans ,set sail, and acouple of years down the route,pull in and have work done.Any views would be appreciated ,regards Carl.

[capt lar]

http://www.daviscoltd.com/nams/Docum...er_Report.html
This link will take you to the URI - USCG report on blisters. Heavy reading. The bottom line for me is to try and understand why the hull has high moisture readings and what effect that may have on the specific boat. I will assume this is an all glass hull - not cored. If cored - run ! If the hull was all glass and built with very poor quality control, there may be more severe problems over time. I would dig into the history. Has she really been on the hard for a year ? When was the bottom last painted ? Were there blisters ? Are you saying she was "peeled" in the past, not just stripped ? I am suggesting you go beyond the moisture reading to see if there is a bigger problem. More info on the specific boat and location would help.

Larry

[CARL]

The yacht is a Cheoy Lee off shore 47, all ways thought were well built,In Nov 97 all gell was removed on removal some areas midships on stabd side showed signes of an osmosis repaire this filler was removed fresh one applied and a complete epoxy coat put on, since then, when the boat has been hauled 5 small blisters on the lower keel below the ster tube have been found. The time on the hard i can not be sure, but it is many mths if not a year.This information is from the present owner.The small pin pricks i described to Larry are very likely due to sand blasting like he suggested ,i will have to find out. regards Carl.

[capt lar]

From what I hear so far, she was not peeled - she was sandblasted - the tiny pinholes are typical when blasted and then only one or two coats of bottom paint applied. They will fill in as you add coats. If done correctly, they would not remove the gelcoat - just the paint and the soft areas where blisters were present. Quality control is important here. Where was the work done ? Can you talk to the yard foreman and get specifics ? If she was blasted, I would feel better. Peeling is a big deal and often not done right.
The big issue is where is the moisture coming from. Was it high everywhere or only in specific areas. How elevated were the levels ? Were there corresponding elevated areas in the decks ? How were the decks ?
I think you need to learn more about the history of the boat before you can make an informed decision. You can also use the search option on this Forum, type in "blisters", and you will find good reading.
My boat had blisters. They were repaired by a quality yard and all is good so far.
I would also tell you that my surveyor says moisture readings in a hull are not reliable. When you sounded the hull, were there any problem areas ?

Larry

[By Invitation]

Carl,

Before you decide on anything, get a second measurement of the "moisture" in the hull. My brother had a survey done on a Peterson 44 and the first surveyor found the same thing except on the decks. He hired another surveryor with a much better and more accurate meter which was calibrated on site and the reality was that there was no problem. The first meter was faulty and was confirmed later to be reading false high measurements.

By the way - Cheoy Lee's are great boats, I have an Offshore 41 and love it.

[CARL]

All usefull information thanks, i will phone tomorrow and ask some questions,by the way the teak decks were removed in 2000 and replaced with fibre glass.

[AnchorageGuy]

Carl, Many surveyors have moisture meters now but few really know how to use them. Even a hull with problems would probably not show up with a high moisture content after being out of the water for 12 months unless maybe it is in Guatemala during the rainy season. I speak from 30 years in the marine industry experience. Get a second opinion from a QUALIFIED surveyor that knows how to use these things. Metal objects such as fasteners, thru-hulls and even steering gear show up as moisture if you don't know what you are looking at. Good luck, I know it can get confusing. Chuck

[GordMay]

As others, like Chuck, have noted, it’s difficult to calibrate a moisture meter intended for wood, to read accurate moisture percentages in fibreglass.
Notwithstanding the inexactitude of any particular percentage reading, you can easily assess the uniformity of numerous readings. Any significant upwards variation, from that particular hull’s readings with that instrument, will point to a problem area, deserving further investigation.

[swagman]

.....that even this surveyor stated the possible osmosis 'will only efffect any resale'.

To my knowledge, no yacht has sunk from it yet - and I suspect almost all 30 year old GRP boats will have osmosis to some limited extent.

Cheers
JOHN

[Richhh]

First of all moisture meters only read the 'surface' moisture'. The internal moisture content is then approximated by correlation to the surface moisture.
Second, unless the instrument is calibrated to a standard, then the measurement is 'doubtful' at best.

That the hull was 'sandblasted' is NOT a good sign and one would expect such a hull to have a goodly amount of 'moisture uptake' as a result of the inevitable fractured glass fibers, etc. Sandblasting breaks the glass fibers and creates 'channel pathways' for water intrusion into the underlying stucture; and, sandblasting can/may enhance the process of hydrolysis to accelerate. Hydrolysis is the destructive process wherein the long chained polymers breakdown (weaken) and is the underlying cause of blisters, etc.
For me, that the boat was sandblasted, would tend to make this a 'deal-breaker' --- unless I had a phycical report/documentation (for legal purposes) of the actual process used to restore the hull. Blisters and hydrolysis are not 'usually' a structural problem; but, so many do-it-yourself and 'shoddy' yard repairs of such have totally ruined otherwise good hulls that I'd be extremely concerned. With such evidence of 'contra-indicated' repair, the only way I'd accept such a boat would be to take a small core sample and send it to a lab for analysis, etc. or make the acceptance of sale of the boat contingent upon a good test report of the laminate core analysis, etc. If this is an expensive boat and the seller is 'motivated', I'd hire a shyster to work out the 'mutually agreeable terms of the sale contract' and to include such analysis of the laminate as a 'contingency' within the agreement.

For some good info on blisters/hysdrolysis, etc. go to www.yachtsurvey.com and find the sidebars for blisters, buying a used boat with blisters/hydrolysis, etc.

Hope this helps.

Do you know if the hull was dried out before the barrier coat was applied? It is pointless to apply a barrier coat until moisture content has dropped to an acceptable level. Applying a barrier coat will not only prevent moisture intrusion, but trap existing moisture. That might account for high moisture reading after being out for 12 months?

Our 28 foot sloop has a case of the pox (very small half moon blisters). We thought of stripping gelcoat, letting her dry out, then applying a barrier coat. Our (reputable) surveyor said not to bother, as long as the moisture is not deep and in the core (which it wasnt) it wouldnt be worth the time and effort.

Also, my wife (who works in a boat yard) has heard many cases of local yards selling gelcoat peel/barrier coat jobs without properly drying them. These jobs make a lot of money for the yards. And if they can get the boat in and out of the yard while giving the owner a feeling of a "proper repair" for their blister problem, all the better (for them of course).

As was stated previously, water intrusion into the laminate has rarely caused catastrophic failure. Use it as a bargaining chip to get the price down .

[ssullivan]

Supporting the fact that the moisture indicators do indeed register moisture that is not caught in the laminate:

I had a surveyor tell me that my deck had a patch of moisture next to a loose stanchion toward the aft. Upon close inspection, I found that water was just seeping between the layers of fiberglass from a leaky port. The moisture was not "inside" the fiberglass, but was just pooling on the surface of it, as it traveled between the two "spaced apart" layers the port sandwiches.

So, I had a moisture reading that the surveyor indicated was a problem, and luckily, it turned out he was wrong. There was no structural issue... just a leak.

I shared this as information pertaining to moisture readings... not to comment on the exact problem in this thread. Just to add to the experience with moisture readings in surveys.

[rsn48]

Below is a link to a short discussion of moisture meters and why they can be hard to understand.

http://www.turbolink.co.uk/jlasurvey....html#Moisture

[GordMay]

David Pascoe on Moisture Meters: http://www.yachtsurvey.com/moisture_meters.htm