Moisture meter

TIC

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Joined
Apr 13, 2008
RO Number
29813
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295
Can a layman use a moisture meter to see if a balsa cored hull is saturated?.. I see some meters advertised for less than $200.00.. Are these worth anything or do you need a very expensive meter and expertise in how to use it
 
Before you spend the money you should know that they don't always work. I just had a balsa cored boat surveyed and the surveyor first used a hammer and was happy with the bounce back throughout. He then used a thermal camera to look for water in the hull. When he cracked out the moisture meter, it was useless. He went from above the bottom paint and it showed 0% and then he hit the paint and anywhere it hit the paint it went nuts showing high moisture. Unless the bottom is clean, it will be unreliable.

MJK
 
Just like Mike stated, If the vessel has an ester base either in the bottom paint or bellow the gel-coat, the moisture meter will show false readings. Thermal imaging is the best way to detect a wet area.
356484314.jpg
 
I have a related question which has been confusing me concerning so called moisture. I've heard that as a boat sits in the water for a long period of time it will eventually give off higher readings of moisture, and a boat that has been on the hard will dry out True? If so, how high a reading is normal for a boat that has been sitting in the water? and when should a moisture reading be done? It would seem to me that if I were looking at a boat that has been on the hard for a year vs. a similar boat which as been used and kept in the water, the numbers would be skewed and an unfair comparison.
 
Can a solid fiberglass bottom absorb water?
I have a 1967 Hatteras that I think is all fiberglass (3/4") that was kept in the water (LI,NY) since 2001. I have taken it out for the winter to do some cosmetics and my friend has been urging me to take it out to dry. Is this correct?
 
quote:

Originally posted by captcraig

Can a solid fiberglass bottom absorb water?
I have a 1967 Hatteras that I think is all fiberglass (3/4") that was kept in the water (LI,NY) since 2001. I have taken it out for the winter to do some cosmetics and my friend has been urging me to take it out to dry. Is this correct?






Don't know if it is "correct" but IIRC, gelcoat is porous, hence the barrier coats.

This is an actual picture on another site of water eradication from a 460 Sea Ray.

core460-300x225.jpg
 
David,From the picture your showing, it would be fair to say the moisture leaking from that hull was coming from a very wet free board. Sea Ray had a lot of issues with moisture in there core materials in the larger boats. Moisture will work its way under the gel-coat if not protected. Blister's will start to form after a period of time.

When inspecting the bottom of a vessel thats been in the water for some time. 1st thing to look for are blister's. If there are any, they can tell a story of how bad the hull has been affected by moisture. When a blister is popped it will tell you if the damage is just below the bottom paint or into the gel-coat. If when popped theres a fowl smell and a dark colored fluid from them, this could indercate problems with a core material.
 
As I recall that Sea Ray pic. is one regarding "fixing" a "wet" cored hull. I'll stay away from cored hulls, thank you.

As to the answer about fiberglass "absorbing" water, my recolection is that it typically doesn't absorb water like wood/coreing. But it can blister the gel coat. Smarter people will know more than I. Good luck.
 
i've been told that even solid fiberglass will eventually absorb water, which is why boats kept in slips and moorings have a barrier coat under the antifouling paint.
 
Will a fiberglass boat absorb water? Oh you bet it will. Lots of it. I love the pic of that Sea Ray.
 
Great pic of the searay, but has nothing to do with the question. That's not fiberglass absorbing water. That's a core issue, something completely different.

While fiberglass can "absorb" or wick moisture, its not exactly a sponge. I'm not sure the point of "somebody said to pull the boat to dry'. What and then just put it back in later? makes no sense.

Need to up the game on the discussion. A boat that may wind up with a blister problem is a good candidate to barier coat. Gel coat is porous after all.

Moisture meter readings are often misunderstood, including "professionals" one would think would know better. You are lucky to have some of the folks we do here, don't assume you will find same in the real world. Using a moisture meter is often not one of absolutes, you are looking for relative increases in the readings with a baseline for the particular boat established. Normal on boat A may not be normal on boat B, but both boats are "dry".
 
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