Senior Slacker , I'm with you on this one. Anybody who claims he can tell you moisture content of a hull without burning a coupon in a lab test is absolutely full of it ... No matter how fancy his meter his. My article Moisture Meter Mythology
gives a complete explanation of why this is impossible.
Well, I am not so sure. In fact I was saved from buying a boat with a problem by a moisture meter and I can tell you that not only the boat was relatively new (5 years) as visually and hammering on the hull it would give no sign at all of any problem. Everything seemed perfect.
The meter measured 30% in some areas and I give up on the boat. I know that later the owner, that ignored that the boat had a problem, just to be sure opened a small hole in the hull in the area the meter indicated as more humid….and water just pour out from the core.
A month later with the same meter on a similar boat, the biggest measure we could take was 12% and just in some spots like behind the bilge. Most of the hull read below 10% and as low as 3%. I bought that one.
Of course it was not me that was doing the readings it was a surveyor. You have to know what you are doing and have experience but I can tell you that after that I will never buy a boat without a proper hull humidity reading made by a competent surveyor with a top of the rage equipment.