Moisture tester woes - Page 2 - SailNet Community
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post #11 of 16 Old 09-12-2010
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A calibrated Electrophysics CT-33 detects the level of capacitance that can be established between the 2" plate at the back of the meter and the surface under examination. Among the things that can cause an increase in capacitance reading are proximity to metal (backing plates, copper in bottom paint, aluminum embedded in the core, chain rode in the anchor compartment), surface moisture, as well as moisture in the core.

Tapping with a hammer (phenolic hammer) is used to detect delamination, through a change in the sound of the tap. Without delamination there is a solid "tap" sound, and where there is delamination, there will be more of a "clack."

Moisture in the core can eventually lead to delamination in two ways. First, as the core turns to mush from constant exposure to water (this can take years). And second, in climates that drop below the freezing temperature of the water in the core, as the freeze-thaw expansion and contraction of the water separating the core from the GRP laminate.

Let me try to net this out for you; High readings on the CT-33 meter do not necessarily lead to delamination.

Also, when was the last time that you calibrated the meter?


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post #12 of 16 Old 09-12-2010 Thread Starter
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I calibrate the meter every time I use it.
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post #13 of 16 Old 09-12-2010 Thread Starter
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It just occurred to me that the boat is probably a few hundred lbs heavier that it should be also.
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post #14 of 16 Old 09-12-2010 Thread Starter
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Quote:
Originally Posted by eherlihy View Post
A calibrated Electrophysics CT-33 detects the level of capacitance that can be established between the 2" plate at the back of the meter and the surface under examination. Among the things that can cause an increase in capacitance reading are proximity to metal (backing plates, copper in bottom paint, aluminum embedded in the core, chain rode in the anchor compartment), surface moisture, as well as moisture in the core.
Thanks for that detailed response for people reading this thread that are not familiar with the meter. In my case however:
1. Metal: Could have been an issue in a couple of places but not the whole boat.
2. Copper: I only tested the topsides
3. Aluminum in the core: Again not likely in the whole boat
4. Chain Road: Not at the chain plates.
5. Surface moisture: I checked for that

So the lack of sponginess is, from the comments above, due to either a very solid laminate or the fact that the sinking was only a few months ago so the core is still adhered though wet.
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post #15 of 16 Old 09-12-2010 Thread Starter
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They paid 8,500 for the boat and put at least 4,000 into it already. They have ambitions of sailing to Florida from NY and then the Caribbean and ports beyond possibly. It has original standing rigging with at least one bent turnbuckle and shot running rigging and a hank-on jib. It has an original, Yamnar and no built-in shore charging system. They are a very hearty minimalist couple and with the right boat can make what they want to do happen. One is 74 one is 50 and both can move about the deck ok.
They are looking to me for advice.
Before learning of the wet deck problem I recommend new running rigging, a no-brainer.
New standing rigging as spending a few years on a boat with 30 year old rigging seems like a bad idea.
There are lots of systems they have never looked at like the stuffing box which leaks too much and the cutlass bearing.
In short where do they stop? They can't do much themselves.
Just basic stuff and we are looking at another 5,000 at least and they still have a wet deck boat.

I'm thinking of telling them to sail a year or two locally, get some experience then get the trip boat and try not to spend too much money on this boat in the interim. He tied a three strand line to the wire main halyard with a bowline. I expect it will cut through in about 10 hours of sailing.

Given the condition of the deck can I condone the
Caribbean? If he sails in the Hudson river and maybe motors on down to Annapolis how long will the deck survive freeze cycles before it becomes unsafe?












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post #16 of 16 Old 09-12-2010
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I'm trying to send you a private message and the system says your all filled up.

Sorry, apparently I get a lot of PM's. Cleaned a few out should be good now...

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