Join Date: Mar 2010
Location: Baltimore, MD
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Are Moisture Meters for Novices?
A couple of months ago I went to look at a boat for sale. The listing was promising and the pictures looked great. She showed as well in person but then the broker said "wet decks." Not a little bit either, real wet. It turns out this great looking boat had been through survey four times without a sale. That's $3000 spent by buyers with no return other than the knowledge not to buy. That was the moment that I realized that my job was not just to "look" at boats, but to carefully evaluate them for reasons not to go to survey. The first thing I did was read SailingDog's "Boat Inspection Trip Tips" on this forum. If you are a buyer, do yourself a big favor and carefully read this article. The second thing I did was buy a CT-33 moisture meter. I don't want a boat with wet decks, but do I need to pay a surveyor to find out?
Last weekend I went to look at a very desirable boat for sale. It didn't take long know that I wanted her IF she was a sound as she appeared. When it came time to evaluate the deck I started at the bow. The meter read a very consistent (uncalibrated) 9% but then suddenly read higher following a line across the deck. Measuring the location I went below to find I was reading the forward bulkhead. Okay, that is good, at least I can find something I thought. The rest of the large deck and cabin top read consistently 9-10% except the whole surface outboard the cabin on the port side read 12-14%, and a palm sized patch on the starboard side between the forward portlight and the shrouds pegged the meter. I headed below.
This older boat cabin had obviously been kept dry. The cabin smelled dry, the laminantes were all in great shape, there were no obvious streaks and drips, and not a spot of mildew was evident. I suspected the slightly elevated port side readings were nothing and the starboard side would be a plate or something on the deck underside. Opening a locker under the high starboard reading proved me wrong. The locker was dry to a casual inspection with no discoloration or damaged wood, but poking my head in revealed a soaked headliner. Aft of the locker was dry, forward was dry. Just this one small patch of a deck soaked on the underside. I moved to check out the port side.
To port I also found one small area where the headliner was wet but using papertowels and Q-tips I determined that the whole region under the elevated readings was damp behind the headliner. That encouraged me to look more carefully and I noticed that a lot of the wood outboard was quite damp on its back side, something I never would have uncovered otherwise. So what to do with this information?
The caveat always mentioned with moisture meters is that they are only a guide, that it takes a knowledgable expert to interpret the results. In this case I was impressed with the high level of maintenance on the rest of the vessel. I suspect the port side is not a wet deck but probably condensation. On the starboard side I'd guess that part of the problem is water intrusion with the nearby portlight being suspect. Is the core wet? I don't know but tap-tests sounded fine. I think if I'd carefully dried the area on the inside I could have narrowed it down better. In the end it didn't matter bacause the overall good state of the vessel made me confident enough to take her to survey. Specifically, I would be very surprised to find out the rest of the deck had any wet areas. So did the CT-33 actually help?
Yes. I walked away from the inspection feeling pretty good about the decks which would have been a complete mystery otherwise. The meter does find water that is otherwise invisible to routine inspection. Hopefully I won't need to check many more boats that are on the market but I believe I will get pretty good at interpreting the results if I do. Remember, I'm not trying to determine if the boat is a good purchase opportunity-just a good survey opportunity. I think the meter is a big help in that regard.
More importantly I will use the meter to regularly assess whatever boat I end up with. Had the boat this past weekend been mine I would have followed the (damp) bread crumbs to the hidden wet wood. Better to catch water intrusion in the early stages. So I'm sure it will take practice to interpret the CT-33 readings with good fidelity. But can a novice use the meter as very helpful tool-absolutely.
I'm very happy with the $170US spent on this meter.
Last edited by GeorgeDog; 01-15-2011 at 08:40 AM.