Every time I see a post like this I have to jump in and offer the other side of "Moisture Meter Myths". And no, just be cause I am a surveyor I am not encouraging you to hire in surveyor instead. One of the points of my article is that you do not need to spend the money on a surveyor or a moisture meter. 98% of the time you can find wet decks with a small hammer, dental pick and screw driver. There is a lot of stuff I disagree with Pascoe on, but he got this one right. Check out my article which gives a lot more detail than the one noted above. moisture meter mythology
Sorry, I have to disgree. Maybe I've got more knowledge/experience of boats than most and that colors my view, but just tapping on a deck w/ a phenolic hammer is NOT going to find all wet decks. A moisture meter will find areas of moisture that you might not find otherwise. And as GD pointed out, there *MAY* be very good reasons the meter registered high besides saturated coring.
I worked in a boatyard many years ago when I knew nothing, I've restored a few small wooden boats, built a few and fixed enough things on different boats I should be in business!
I will agree that a complete novice w/ NO knowledge of boats/construction would be ill served to think slapping a meter on the deck and buying a boat based solely on the reading is a bad idea. But someone w/ a little knowledge and some understanding of boats in general can benefit hugely from judicious use of a MM.
A boat I sail on has decks that are somewhat wet. BUT, they have not delaminated and *sound* solid when the tapping test is applied. I know this b/c we had some work done and the core was wet but still firmly attached to the skins. We would not have known about the wetness w/o putting a meter on the deck. Period.
I am a big advocate and will use one on any boat I look at for purchase as well as monitoring the decks of any boat I may own in the future. (currently co-own through my small club)