# 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

*Yes!!!*

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... 



jarcher said:


> 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

tommays said:


> 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

brak said:


> 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

Maine Sail said:


> 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.


----------



## Dr.Faustus

Maine Sail said:


> 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.


I think it's not important the brand of the meter, but the scale itself,on condition that on your gauge has the same ragulation for wood density, so you can set 0,5 in order to use the scale for fibreglass, isn't it?


----------



## boatpoker

Sorry Mainesail, I can't pass this one up, especially the point of the scale being useful 
Check out Moisture Meter Mythology for many examples of meters being wrong.


----------



## Maine Sail

boatpoker said:


> Sorry Mainesail, I can't pass this one up, especially the point of the scale being useful
> Check out Moisture Meter Mythology for many examples of meters being wrong.


Perhaps you can enlighten us on why most all surveyors don't start with decks, or cored hull, present the findings, and then let the purchaser decide to continue or walk away from the _rest of the survey_. Perhaps if they did it this way, less owners buying boats would be looking for a moisture meter.

I can't even begin to tell you how many of my customers have paid for two or three full surveys when purchasing a boat only to walk away due to deck or hull issues, which could have been caught in an hours time vs. 6-10 for a full survey which was USELESS to continue with beyond the decks or hull.

Yes used INCORRECTLY they can be VERY, VERY misleading and yet piles and piles of surveyors USE THEM INCORRECTLY too. I have far too many examples of this to even count them, all from SAMS and NAMS surveyors. You have many examples of bad surveyors right on your own site. How do you suppose those guys use a moisture meter. Probably not much worse than Joe DIY, I've read those sample surveys and they are a JOKE......

There are many bad eggs out there including bad electricians and bad surveyors. Two weeks ago I set foot on a boat that just underwent an insurance survey. It had a Paloma water heater (non-compliant), an LPG Cozy Cabin Heater, (also non compliant) three LPG tees (stove, Paloma and heater plus a "spliced" LPG hose outside the LPG locker. She also had clear fish-tank hose for the fuel fill, a plastic fuel filter bowl just millimeters from the exhaust manifold and these were only the high points I noticed. The deck was also dripping "coffee", as in rotted core, from the chain plate areas and when you walked on the deck near the chain plates water squished out. This was a SAMS surveyor who conducted this..... The boat _passed_ with flying colors so the insurance company is happy, as is the owner, until he fails to wake up one morning.....

Like you I have dug into piles of decks, I actually work on boats for a living, and compared the results to my moisture meters far too many times to count, so I am not shooting from the hip on this. Are they perfect ABSOLUTELY NOT, and far from it but every tool we have is another data point to help us make decisions..

Bad data is bad data but I still argue that a moisture meter can be a useful tool for a boat owner _if_ they understand some basic principals and also _when_ to call in the real surveyor...

Lets not forget that I DO NOT and have NEVER SUGGESTED that a DIY owning a moisture meter is a substitute for a SAMS or NAMS surveyor.


----------



## boatpoker

Maine Sail said:


> Perhaps you can enlighten us on why most all surveyors don't start with decks, or cored hull, present the findings, and then let the purchaser decide to continue or walk away from the _rest of the survey_. Perhaps if they did it this way, less owners buying boats would be looking for a moisture meter.


I hope you are not referring to my sample surveys as a joke, I know I am not perfect and not even the best but I do make an honest effort.

I really can't speak for "other surveyors" but my practice is to look for the big issues first (you know what they are) and advise the client.

I then give my client the choice of stopping the survey and paying half rate or continuing with the survey. Half rate gets them a one page letter with photos showing the significant issue. This is usually enough to get their deposit back from the broker. I do this 7 - 10 times per year. If the client is not present (happens more than I can understand) then I proceed and charge full rate. I used to call non-attending clients and inform them of major issues but then they expected me to sit and wait for them to arrive or for me to came back another day at their convenience ..... there are limits to customer service.


----------



## Maine Sail

boatpoker said:


> I hope you are not referring to my sample surveys as a joke, I know I am not perfect and not even the best but I do make an honest effort.


Not at all yours are an excellent example of how it SHOULD BE DONE! I was referring to the samples you have from *other surveyors* that are 1-2 page complete jokes...



boatpoker said:


> I really can't speak for "other surveyors" but my practice is to look for the big issues first (you know what they are) and advise the client.


If more did it this way I suspect the industry would have a better reputation.



boatpoker said:


> I then give my client the choice of stopping the survey and paying half rate or continuing with the survey. Half rate gets them a one page letter with photos showing the significant issue. This is usually enough to get their deposit back from the broker. I do this 7 - 10 times per year.


And this is exactly how it should be and exactly how I do it when called by a surveyor to investigate an electrical system that is beyond their capabilities.



boatpoker said:


> If the client is not present (happens more than I can understand) then I proceed and charge full rate.


Any client who can't be present for the survey deserves what they get. This is just plain odd but I see it too....



boatpoker said:


> I used to call non-attending clients and inform them of major issues but then they expected me to sit and wait for them to arrive or for me to came back another day at their convenience ..... there are limits to customer service.


Yeah not going to happen on my watch either...:wink Heck I charge customers for being late.... If we are to meet at 9:00, we've both agreed, and I am there at 9:00, as I should be, the clock starts at 9:00. I do get paid to wait an hour, easy money, when the customer is too rude to respect my time. I had one super self important guy who paid me over 6 hours of "waiting labor" in one season. He didn't care either way cause he was "super wealthy" and that made him super entitled to be late. I finally cut him loose, after he gave me guff when I left after 1.5 hours and went to another appointment. I don't like to sit nor be late.......:wink


----------



## boatpoker

I like your style 

I am convinced that the insurance companies could put the lousy surveyors out of business overnight if they stopped accepting their crap.


----------



## miatapaul

recently there was a post about a ryobi mositure meter, and that seems perfect for the OP. I think they were like $60 or so. Not going to be as accurate, but once you have a base line you can monitor spots you may have concerns about to see if they get worse, or if remediation was successful.


----------



## Nikita Nik

Here announcement about a new Humidity Sensor for NMEA 2000 (has already passed National Marine Electronics Association certification)


----------



## JimsCAL

Nikita Nik said:


> Here announcement about a new Humidity Sensor for NMEA 2000 (has already passed National Marine Electronics Association certification)


That is for measuring the humidity in the air, not for measuring the water content in a cored deck or hull.


----------



## Barquito

So, does a moisture meter just take a reading of the electrical resistance of the material? I'm guessing it is more complicated than that. If it is just a measure of resistance, you could do that with a multi-meter. You would not get absolute readings of moisture, but, could get an idea if your deck is getting more wet than it was in the past (by taking readings every year).


----------



## SHNOOL

I bought a General tools (General Tools MMD7NP) household quality moisture meter... and NO I would NOT ever suggest its a GREAT tool for a self survey... BUT, in a pinch it'll give you an idea of "relative" moisture compared to other parts of the boat. 

I tested my moisture meter on just 2 boats (my own), both boats I knew where there were problems. This meter helps you tell just when there is a moisture difference. It did identify problem areas on my own 2 boats that I knew about, but it also improperly pegged the meter in 2 locations that I knew had metal directly behind the gelcoat/fiberglass, and one place was an extraordinarily thick layup (no core behind it)... so one should take what the meter "says" with a grain of salt and consider other reasons the meter might be giving a false "positive."

But for the price, $40, I had a tool I could use to find moisture problems on the boats I was looking at that were under $10k. Its not a substitute for a qualified surveyor, but then I was looking at trailerable boats that were already 30+ years old and pretty much guaranteed to have moisture problems, my thing was where were the problems and how much of it was I going to have to address. 

I'll note that I looked at a half-dozen trailerable race boats, and brought the meter along (more for my own info than a deciding factor), and found issues with boats that the owners already knew about. One had a full survey on their boat (the surveyor found 3 more places with high moisture readings than I did) from when he had purchased 3 years prior. Interestingly enough the owner opted to do NOTHING to fix those moisture problems, it wasn't until after I found the areas I did that he provided the survey from when he purchased the boat. The problems noted in the survey were just "high moisture" readings at the time... but had actually turned into full on weeping chainplates and soft deck now.


----------



## travlin-easy

I purchased a refurbished Ryobi moisture meter for $50 from Home Depot - works great.

Good luck,

Gary


----------



## Brendan Mushet

Hi all, 

I recently finished testing a General Tools MMD7NP against a Protimiter Aquant BLD5765. Both meters have a 3/4" sensing depth, and a digital readout coupled with a moisture bar graph going from "dry" to "wet". The Protimeter although used for many materials, it does prove useful in marine applications, and runs around $300-$400. The boat tested was a C&C 30 with balsa cored decks. Testing was on the port side deck, forward of the chainplates. I used the MMD7NP on "Wall" mode as a previous poster mentioned. Although the numeric readouts are different, the LED bar graphs on both indicated the same degree of moisture. In known dry areas, the Protimeter ranged from 80 to 93, and the General measured 4 to 9. As we worked towards the known wet areas, the Protimeter climbed up to 238, and the General up to 80 in the area with the highest moisture. Both meters were indicating "wet" on their bar graphs at this point. Erratic readings occured on both meters if they were in close proximity to any metal. Take this information as you wish, but my conclusion is that the $48 General can accurately detect moisture in balsa cored decks, and if the top skin of glass does not exceed the sensing depth. If I was a surveyor, I would spend the extra on a higher quality tool such as the Protimeter, but for a DIYer such as myself, the General MMD7NP is a useful piece of kit IMO.

Sent from my XT1032 using Tapatalk


----------



## boatpoker

Brendan Mushet said:


> Hi all,
> 
> I recently finished testing a General Tools MMD7NP against a Protimiter Aquant BLD5765. Both meters have a 3/4" sensing depth


Having worked with most brands of meters over the last 25yrs, I can state that manufacturers claims are at best, optimistic. I have yet to see a meter that can reliably/consistently read to much more than a 3/8" depth and often less.


----------



## Ilenart

The most affordable moisture I have come across is to sticky tape clear plastic over the area you are concerned about, wait 24 to 48 hours and if the plastic is wet on the inside you have moisture. If it is dry then you a fine. 

When I did it I grinded out the problem areas, high pressure cleaned the areas and then left the hull to dry out fo 3-4 months. For the first. 1-2 months I was getting wet plastic, but after 3-4 months it was dry. Every week or two I high pressure cleaned the whole hull to assist the drying process.

Ilenart


----------



## boatpoker

This only works if you put the plastic over a spot you have already ground out or over a fracture. The pressure washing does nothing to aid grying. Pressure washing only helps if you have hydrolytic fluid weeping from fractures or grinding areas and then all it does is wash away any soluble hydrolytic fluid which will prevent paint or repair materials from adhering.


----------



## SHNOOL

I threw a ziplock bag over my moisture meter, and used it like that, then did same without it... including wet (outside to touch) and it made little difference in the readings. Only when I put the meter in a puddle did it read differently than while in the ziplock. Imagine this, both read "wet."


----------



## boatpoker

There are those who disagree however I have spent years testing different meters and have found while useful they are by no means infallible. To see some of my tests I suggest again that you look at my Moisture Meter Mythology.


----------



## jppp

I used the meter I bought half a dozen times when boat shopping and now all the time to check moisture on wood blanks that I cut for bowl turning and to check readiness of split fire wood. Gettin' my money's worth.
j


----------



## Bleemus

This one has served me well. No moisture meter is perfect but with proper calibration they can provide some indication of issues. I dont rely on the percentages as much as I do the relative differences between areas that I am scanning.

http://www.electrophysics.on.ca/fiber_mobile.htm#CT33


----------



## boatpoker

Bleemus said:


> This one has served me well. No moisture meter is perfect but with proper calibration they can provide some indication of issues. I dont rely on the percentages as much as I do the relative differences between areas that I am scanning.


Percentages and calibration are only relevant if you know the density of the material you are metering. None of us know the densities of the various laminate schedules and resins in our boats.


----------



## Ilenart

boatpoker said:


> This only works if you put the plastic over a spot you have already ground out or over a fracture. The pressure washing does nothing to aid grying. Pressure washing only helps if you have hydrolytic fluid weeping from fractures or grinding areas and then all it does is wash away any soluble hydrolytic fluid which will prevent paint or repair materials from adhering.


Regular pressure cleaning helps to clean off the muck that comes out of the grind off fibreglass. Otherwise the chemicals and crap builds up and slows down the drying process. Note that this is drying out a hull / fixing osmosis, not associated with fixing a fracture from an impact.

Ilenart


----------



## boatpoker

Ilenart said:


> Regular pressure cleaning helps to clean off the muck that comes out of the grind off fibreglass. Otherwise the chemicals and crap builds up and slows down the drying process. Note that this is drying out a hull / fixing osmosis, not associated with fixing a fracture from an impact.
> 
> Ilenart


I never know what people mean by "osmosis" as it is applied to too many aspects of FRP issues. Please define what you mean by "osmosis" and the mechanics of how regular pressure washing helps the issue.


----------



## Pitt

Moisture analyzer combines state-of-the-art heating with highly accurate weighing technology to deliver a faster, more precise method of moisture analysis.


----------



## boatpoker

Pitt said:


> Moisture analyzer combines state-of-the-art heating with highly accurate weighing technology to deliver a faster, more precise method of moisture analysis.


So you cut a chunk of laminate out of the hull and put it in the machine to analyze. If you cut a hole every foot or so, within a couple of hundred holes you'll know the precise condition of your hull :hammer:hammer


----------

