Moisture meter question- checking below waterline

[Dune]

While the boat is still in the water (via inside hull of course). Is it normal on a fully cored hull (i.e. balsa cored below waterline) for the readings to be elevated below the waterline compared to above same ?

If it matters, the meter is a new Tramex Skipper Plus on the GRP setting.

In other words is the meter so sensitive as to be detecting moisture in the seawater on the other side of the GRP ? Or perhaps it is detecting the bottom paint ?

 

[boatpoker]

Possibly but there are many variables. Perhaps Moisture Meter Mythology will help.

 

[Scary]

It's normal

Fiberglass hulls are not impermeable, it's normal to have a much different reading. You should be able to find the waterline with your moisture meter. Even epoxy barrier coats allow moisture into the hull unless very thick. Often that same moisture is the cause of blisters and delamenation.

 

[bglad]

I think the GRP scale on that meter is a little too sensitive. I had a predecessor to that machine that seemed to make more sense. The newer Skipper works better on glass using the wood scale. I prefer a GE Aquant versus the New Skipper. I keep a Skipper in my bag but rarely use it.

My basis for the preceding is what I have found after the fact using the two meters. The Skipper frequently gives false positives. The Aquant does not. If the Aquant says it is wet then it is unless there is metal or Hydropel material in the hull.

 

[Dune]

I think the GRP scale on that meter is a little too sensitive. I had a predecessor to that machine that seemed to make more sense. The newer Skipper works better on glass using the wood scale. I prefer a GE Aquant versus the New Skipper. I keep a Skipper in my bag but rarely use it.

My basis for the preceding is what I have found after the fact using the two meters. The Skipper frequently gives false positives. The Aquant does not. If the Aquant says it is wet then it is unless there is metal or Hydropel material in the hull.

Now that is interesting. As I bought the Skipper via Amazon just recently, I could return it. Where does one buy the GE Aquant ?

 

[boatpoker]

Now that is interesting. As I bought the Skipper via Amazon just recently, I could return it. Where does one buy the GE Aquant ?

The Aquant is a good meter but they all have their idiosyncrasies. I have photos of a 12% difference in readings on an Aquant just by rotating the meter 90 degrees on the same spot. By far the most consistent meter I have found is the Electrophysics digital version.

 

[bglad]

I bought my GE Aquant on Amazon.