High Moisture Readings

Hi All,

When I bought Vagrant last year, the survey stated that the moisture readings in the hull were very high. The moisture readings showed "full deflection", i.e. maximum moisture readings at all tested points below the water line. This was perhaps not surprising as the boat had just been hauled out of the water for the first time in, I believe, three years and was covered in a huge amount of weed.

My inusurance company asked me to have another moisture reading done when the hull had had more time to dry out. I have just done this. My local surveyor said that three days out of the water would suffice before taking the reading. He has reported that the moisture readings again showed full deflection. This time the hull had been fully scraped back, prior to antifouling it.

The hull has a some unknown time in the past been epoxy treated. I was not present when the present survey was carried out, but the surveyor said that the epoxy coating (if that's what it was) was pink in colour. The surveyor was familiar with the colours of the different proprietary brands of epoxy coating available in the UK, but didn't recognise this one. He said that the hull was fine, with no signs anywhere of osmosis blistering, but could not explain the very high readings. Does anyone have any suggestions? Mike, the surveyor, who is very experienced, and whose opinion I trust, was wondering if it could be the epoxy coating itself. He says that, odd though it may seem, some epoxy coatings do themselves retain moisture. Mike used a Sovereign moisture meter and on a scale of 1 to 25, the readings reached 25. Above the waterline, the readings were 10 to 12.

All views gratefully accepted!

Fair winds,

John Booth

V1718 Vagrant.[Non-text portions of this message have been removed]
 
Dec 15, 2006
139
Hey John,

I'm not an expert on moisture in sailboat fiberglass, but I am a
woodshop and autobody teacher. The moisture meter I use in the
woodshop uses an electrical current and passes it between two
probes. The principle is that moisture will lower the resistance,
and thus cause the meter to "deflect" as you put it. So your boat
may really have moisture in the fiberglass. A second option could
be the paint. Conductive paint could cause a similar effect. Many
bottom paints contain copper additives, which maybe could have a
conductive effect. Many epoxy paints also are conductive, depending
on the additives. It is my understanding that fiberglass can hold
moisture for months -- even after a haulout. Seems like 3 days is a
little on the shy side of drying out???? Just a few random
thoughts -- I'm just speculating. Good luck.

Larry Bissell
albinvega1493@...
 
Oct 30, 2019
58
John,



I'd get it hauled out over winter for a good six month dry out, then get
your surveyor to scrap patches back to the gel coat before taking any
readings.



Ray (Tortuga)



Ray Wilton

Ship and Field Support Manager

School of Ocean Science

University of Wales (Bangor)

Menai Bridge

Angelsey

LL59 5AB



Tel 01248 382614

Fax 01248 716367
 
Oct 31, 2019
10
Hi Larry,

Thanks for your response. I'm sure you're right that hauling her out for a few months over the winter is the answer.Watch this space next Spring!

Regards,

John

V1718 Vagrant

Larry Bissell albinvega1493@... wrote:
Hey John,

I'm not an expert on moisture in sailboat fiberglass, but I am a
woodshop and autobody teacher. The moisture meter I use in the
woodshop uses an electrical current and passes it between two
probes. The principle is that moisture will lower the resistance,
and thus cause the meter to "deflect" as you put it. So your boat
may really have moisture in the fiberglass. A second option could
be the paint. Conductive paint could cause a similar effect. Many
bottom paints contain copper additives, which maybe could have a
conductive effect. Many epoxy paints also are conductive, depending
on the additives. It is my understanding that fiberglass can hold
moisture for months -- even after a haulout. Seems like 3 days is a
little on the shy side of drying out???? Just a few random
thoughts -- I'm just speculating. Good luck.

Larry Bissell
albinvega1493@...