This is my report on using the CT-33 moisture meter and drying out my core
in several places. I think I have something novel to report.
The meter works great. Any time it has read 30 to pinned, upon drilling a hole I found loose water
, so the core
was past the fibre saturation point. Away from the high readings around most of the stanchion bases and other water
ingress places it reads about 5 to 10. There is a nice slope in the readings as I transition between a known wet spot and an (assumed) dry 6-10 reading area. All my hole drilling and inspection
of what comes out tracks very well with what the meter tells me, as do percussion soundings.
Frankly for the $200 some dollars these things cost, every boat owner with a cored boat should own one. The only problem I had was that the meter scale came unglued, buckled up and stopped the meter needle. A bit of super glue and swearing fixed that.
I have about 10 areas each of 2 to 3 square feet that are wet. Many would likely have cut out the areas, dug out the core and put the old piece back in, but I opted for the drill holes on 1 inch centres approach. It is a lower skill but brute force approach, and a good chance it will even take longer for the average person. I did this for a number of reasons. I figure though reattaching skins is not that hi tech, there is enough art to it that I would have trouble getting things back in plane again, for the same reasons that I can't lay floor tile well (BTDT, trip over the high spots). My brain does not do art, I can barely sign my name, and any actual handwriting is illegible, even to me. Plus, my boat is under a frame and clear tarp, so there just isn't adequate room to work with anything much bigger than a syringe filled with epoxy
Now we come to the novel part. How to encourage the core to dry? There are just too many areas and too little electrical
feed to consider electric
heat of any sort. Plus I don't want to pay $10 a day for months to dry things.
The first part is being under a clear tarp, and this does a great job of getting the deck
air temperature 30 degrees F above ambient in full sun (which thus far wasn't often this year
). However, placing hand upon deck
does not feel particularly warm, all white and reflective and all.
Next my thoughts turned to maybe painting the areas black, but I didn't relish the thought of having to remove whatever paint
I used. How about black fibreglass window screen
? Not enough black there, weak contact to the boat, and expensive.
Then it came to me ... black duct tape. Two $8 rolls, a bit of time poking out all the holes so the moisture can escape and bingo. The meat thermometer (Don't report me to my wife for a kitchen utensil infraction) read about 100F inside one of the holes one day (ambient 60 to 70, no actual measurement recorded), and the areas feel very warm to the touch. About 5 in the afternoon one day, I taped a piece of clear plastic to a small area to seal in any escaping moisture, and 2 hours later, I could see a condensation
pattern over the holes on the plastic. Moisture has left the building.
The first area was done about 3 or 4 weeks ago and has probably seen about 10 full sun days, and a few partly sunny. The high reading at the start was over 30, but not pinned, and now reads about 28. Some of the more marginally wet areas that started at 15 to 20 are now in the 10 to 15 range. I take readings about 9AM, after any dew has evaporated, but the sun isn't working its magic yet. Late day readings tend to all be 30 everywhere as I believe the moisture is driven to the surface by the heat of the sun. I only take a reading about every week or so, as the day to day readings just got lost
in experimental error - I could not detect any differences over such a short time interval.
I will report back in another month or so.
I hope someone finds this interesting.