Is there an affordable moisture meter?

[jarcher]

Is there an affordable moisture meter? By that I mean, one that a boat owner could buy for occasional inspections of his or her own boat? I checked around and it seems that they are generally $300 or more. That's not super expensive when compared to many boat things, but still a good bit of money for an occasionally used tester...

As an aside, this article is interesting, regarding the accuracy and use of such meters:

Moisture Meters on Boat Hulls - Do They Produce Reliable Results?

[Maine Sail]

You might want to read something NOT written by a surveyor for less "scare".

Understanding The Moisture Meter (link)

[sailingdog]

The meter that Maine Sail recommends is a lot less money... about $160 IIRC...and once you own one, you'll probably find a lot of good uses for it... Pascoe and most other marine surveyors like to think that a moisture meter isn't an accurate or useful tool for the amateur, as someone who knows how to use one properly has far fewer reasons to call a surveyor...

Originally Posted by jarcher

Is there an affordable moisture meter? By that I mean, one that a boat owner could buy for occasional inspections of his or her own boat? I checked around and it seems that they are generally $300 or more. That's not super expensive when compared to many boat things, but still a good bit of money for an occasionally used tester...

As an aside, this article is interesting, regarding the accuracy and use of such meters:

Moisture Meters on Boat Hulls - Do They Produce Reliable Results?

[tommays]

Summary

Moisture meters can be used to reliably determine if hull cores are wet, but not, as surveyors expect from the outside of the hull. The only reliable method is from the inside of the hull. The surveyor will need to make certain that the inner skin is dry and has not been recently submerged, areas such as the bilge, and any other area that may trap and hold water, such as outboard of stringers, even if it presently appears dry. The presence of water stains will usually tell the story.

Moisture meters can be used reliably anywhere from about a foot above the water line, including on decks shortly after a rain, so long as the surface is outwardly dry. Care should be taken to be sure that there is not a residue of salt on the surface. If there is, use a slightly damp cloth to clean it.

Our tests also show that the meter can even work on some non skid deck surfaces such as the leveled diamond pattern, although clearly the reliability of such readings is going to be somewhat reduced.

The meter is most reliable in the hands of a person who experiments with it and carefully considers what he’s doing. It is least reliable in the hands of a person who thinks that it always produces infallible results. The reason that it does not is because we subject the instrument to limitless varying conditions for which there are no absolute answers. In other words, it takes part science and part skill.

When reporting meter readings the surveyor should identify the type of meter he is using. He should also avoid reporting numbers as a percent because that is inaccurate. It is OK to say that readings were, for example, 24 points on the Trammex scale, but do not express it as a percent.

From David Pascoe

It seems like he thinks its fine IF you use it correctly

[jarcher]

Originally Posted by tommays

It seems like he thinks its fine IF you use it correctly

As with any good tool...

Thanks MS and SD, I'll check that meter out!

[brak]

Here is the one I use.
| InspectorTools


Protimeter Aquant.

It's a bit more expensive, to be sure - but it has an important advantage - it tends to give more weight to measurements approximately 2-3mm below the sensor head, and also has automatic adjustment for ambient moisture level. As a cool trick - you can measure laminate moisture with this meter when the surface is dry, then pour some water on it and re-measure through the "puddle" - results will be the same

This device long paid for itself in my use.

That said, it is important to try it on may different types of laminates or surfaces and see whats "inside" to understand what those ranges mean. What is "bone dry" for one type of thing can mean a watery mush in the other.

[Maine Sail]

Originally Posted by brak

Here is the one I use.
| InspectorTools


Protimeter Aquant.

It's a bit more expensive, to be sure - but it has an important advantage - it tends to give more weight to measurements approximately 2-3mm below the sensor head, and also has automatic adjustment for ambient moisture level. As a cool trick - you can measure laminate moisture with this meter when the surface is dry, then pour some water on it and re-measure through the "puddle" - results will be the same

This device long paid for itself in my use.

That said, it is important to try it on may different types of laminates or surfaces and see whats "inside" to understand what those ranges mean. What is "bone dry" for one type of thing can mean a watery mush in the other.

But does it come with a scale to translate the meter readings into % of wetness for fiberglass?

This is a very important part of any moisture meter and if you don't have that scale it does not matter whether the meter tells you it is 100% or 10% because you don't know what those numbers translate to in fiberglass.

This is the conversion scale for the Electrophysics.


So a pegged 30% reading on solid fiberglass is not a 30% moisture content but rather 3%, which is about the max solid fiberglass can absorb.

[brak]

Originally Posted by Maine Sail

But does it come with a scale to translate the meter readings into % of wetness for fiberglass?
.

Nope, no scale in documentation. This is why it is very important to use it and know what you are testing.

However, ruling out surface moisture is something I value a lot (and here is someone else that does ) - http://www.clarkemarinesurveyors.com/thermography.html

As far as scale goes - I know from experience that even the same % in different laminate may mean different things. As a case in point, on my old Beneteau a relatively benign (borderline poor) reading was usually indicative of fully saturated core (I would guess this is due to core absorbing all the moisture and laminate being relatively dry around it but that's my conjecture ).

My favorite pastime a few years ago was to go into yards (while I was looking for a next boat) and measure anything I could find. I was particularly interested in old boats where I could see "inside" if something was broken or laminate otherwise visible. My old marina cut up a whole bunch of old sailboats once and I spent a day measuring them and looking at the cut inside, poking with a knife etc.