Surveyors practice of hull scraping!

Zagato

Zagato

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My Crabber is being surveyed next week, I have no concerns over this as she is in very good condition all round supported also by the buyers thorough check and sail. I am concerned however about how a surveyor will check the hull with a moisture meter. For my last boat the hull was scraped back to GRP in about 10 small areas to get a moisture reading but mine has been painstakingly coated with 5 layers of Gelsheild, it would be a crying shame to make holes in the gelshield on either side of the hull as there will be little time to repair the damage due to the tide and only being hauled out on slings temporarily before being dunked again.

I am very confident the deal will go through and I may not need to worry as it won't be my boat anymore - but still, I wouldn't want to see the gelshield being compromised as the boat is such a lovely, hardly used example.
 
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The surveyor should not scrape off any epoxy coating unless it is already peeling off and brakes away. I have read this in books from Ian Nicolson and Paul Stevens, both Surveyors of repute. I would advise the surveyor that the hull is epoxy coated and instruct the surveyor to take care and not scrape through it e.g. if he is using a sharp carbide type scraper.
 
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BlowingOldBoots said:
The surveyor should not scrape off any epoxy coating unless it is already peeling off and brakes away. I have read this in books from Ian Nicolson and Paul Stevens, both Surveyors of repute. I would advise the surveyor that the hull is epoxy coated and instruct the surveyor to take care and not scrape through it e.g. if he is using a sharp carbide type scraper.
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+1 - Surveyors normally try not to go though the epoxy (it's pretty hard) unless there is evidence that it is failing or that gelcoat problem lie underneath.
 
Had a survey last winter and discussed this with the surveyor beforehand. His story was that it depends on the meter, the software and, the person using it. Modern meters will work through antifouling and epoxy with no need to scrape off but, some surface work needed to get a smooth surface.

You could always stipulate that any potential buyer is responsible for the cost of making good if his surveyor "damages" the coatings.
 
I had this same concern when I sold my Gelshielded boat, 2 boats ago.
The surveyor was happy to let me prepare the patches for testing with his damp meter.
He just marked where he wanted to test and I went around ahead of him and carefully sanded down through the a/f to the Gelshield.

Only works if you can be there for the survey of course.
 
Generally, speaking for myself, no epoxy coating is deliberately damaged in removing the antifoul coating, of course if the epoxy is loose & flaking then it will just fall off but that should be obvious immediately on close inspection anyway. Epoxy should not affect the moisture meter readings unless it is flaking off & water is present beneath the coating, again easily detected visually, or the epoxy coating is soft & failing causing high moisture meter readings because of its own developing chemical deterioration.

This also causes blistering but epoxy based blistering as opposed to laminate blistering (less serious). Chemical deterioration of both laminate & epoxy which gives rise to blistering emulates water moisture content on moisture meters, moisture (water) in itself is of no consequence ultimately, it is the degree of chemical activity present & the new chemicals present within the laminate & epoxy coatings that a surveyor is trying to identify. Hence the reason for allowing a vessel to stand for a few days before checking to allow any water to evaporate leaving behind the damaging non volatile chemicals.

Often a vessel that has been epoxy coated will have high readings if the coating was applied without initially checking & it is impossible to be precise on what is causing the high readings unless the epoxy is removed, so in these cases failing visual evidence of blistering the only acceptable course of action is to tell the buyer about high readings & the possibilities based on surveyor experience without any removal or damage to the existing epoxy. If the buyer later wants to remove epoxy then that is their prerogative. There is always a limited degree of risk to a buyer if a vessel is epoxy coated & has high readings.#

Occasionally it has been known that some coppercoat coverings will give a high reading merely because of the conductivity of the copper granules if they are all in contact with one another (no resin insulation).

Other surveyors are bound to have differing opinions so get ready to choose the one you like the most!

John Lilley
 
In the good old days of wooden boats surveyors would stab them with a penknife.

On my first boat, bought when I had no experience and couldn't afford a survey, I found out too late that I could stab my fingers into it. :(
 
Zagato said:
My Crabber is being surveyed next week, I have no concerns over this as she is in very good condition all round supported also by the buyers thorough check and sail. I am concerned however about how a surveyor will check the hull with a moisture meter. For my last boat the hull was scraped back to GRP in about 10 small areas to get a moisture reading but mine has been painstakingly coated with 5 layers of Gelsheild, it would be a crying shame to make holes in the gelshield on either side of the hull as there will be little time to repair the damage due to the tide and only being hauled out on slings temporarily before being dunked again.

I am very confident the deal will go through and I may not need to worry as it won't be my boat anymore - but still, I wouldn't want to see the gelshield being compromised as the boat is such a lovely, hardly used example.
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The moisture meter reads perfectly through antifoul. The patches they scrape are much smaller than the contact patch of the meter anyway.

The scrapes allow a visual inspection of the gelcoat or epoxy, to look for cracking or bubbling. But more to the point it looks like he's done something.

If they scrape through sound epoxy you need a new surveyor.
 
I re-epoxied my boat two seasons ago.
I used a soveriegn meter before during and after.
I surveyed the entire hull with readings at 1 foot centres. There were big variations throughout the hull corresponding to internal fittings tanks/bulkheads and the like. It made me think that the odd random readings commonly used could be misleading.

The test readings before epoxying, after epoxy and after primer and then after 2 coats of antfoul showed no differences
 
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parsifal said:
In the good old days of wooden boats surveyors would stab them with a penknife.

On my first boat, bought when I had no experience and couldn't afford a survey, I found out too late that I could stab my fingers into it. :(
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Still the case now, I think.

I remember Paul Stevens - who taught me all I know about surveying - gouging into a piece of suspect timber.

'Rotten as a pear' he would say.

I cringed. But he was right
 
The moisture meter will work through the antifoul with no problem, some surveyors just like to be a royal pain.
There is no reason to scrape the hull unless there is visible damage or obvious blistering to the hull, and in all honesty one place will do.
Anyway you're paying, what, 3 hours work, @ £200 ph, he will do what he's bl**dy told.
 
ukmctc said:
The moisture meter will work through the antifoul with no problem, some surveyors just like to be a royal pain.
There is no reason to scrape the hull unless there is visible damage or obvious blistering to the hull, and in all honesty one place will do.
Anyway you're paying, what, 3 hours work, @ £200 ph, he will do what he's bl**dy told.
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Most antifouling makes no difference to moisture meter readings, but some - particularly black ones and some coppercoat type ones - definitely do. I assume it is the conductive materials inside (carbon black or copper powder) affecting the reading - moisture meters detect conductivity not water. Equally however some coppercoat types and black AF's don't significantly alter the readings.
 
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