# Boat Owners & Moisture Meters



## Maine Sail (Jan 6, 2003)

For a long time I have been a proponent of boat owners, especially those in the buying process, owning moisture meters. It's been a few years but I finally got around to doing an article on DIY use of a moisture meter.

Moisture meters can be had for well under $200.00 and will pay for themselves ten fold over your boating life. In fact they are free usually after the first use.

Please don't buy the hype and scare tactics used by "surveyors" about how "difficult" using a moisture meter is. It is fairly straight forward and easy for how and why you would want to use one. By owning a meter you are NOT circumventing the need for a real survey but you can use one to "rule out" certain boats or to create a map of the moisture in your current boat and monitor it's worsening or stability or to effect repairs in moist areas.

I know sailors are an overly "cheap" lot of folks but moisture meters, like almost any tool used by a DIY, are FREE! Think about this:

You bring your wife to look at a boat and she and you fall in love. The boat looks good and it has been cosmetically maintained and has new sails and low engine hours. You make an offer subject to survey. On the day of survey you find serious deck core rot and delamination in some critical areas and decide NOT to move forward with the deal.

At the end of the day you still cut a check to the surveyor for $500.00+ dollars and have nothing ot show for it but an empty wallet!!!!

If you owned your own meter you would have saved $300.00+ dollars, a day of your time, plus had a meeter to show for it that you can use on the next "specimen" in your search!

Feel free to read the article. The basic understanding needed to rule out "basket cases" or "money pits" is easy stuff!

P.S. I have zero affiliation to Electrophysics but do find the CT-33 to be the current best value in a DIY moisture meter. I used to own a J.R. Overseas GRP-33 but after I dropped it off a boat onto a tar parking lot I replaced it with the very similar CT-33. The GRP-33 had paid for it's self about 30-40 times over by the time I stupidly dropped it by not zipping my pocket!

*Understanding The Moisture Meter / Electrophysics CT-33* *(LINK)*


----------



## FarCry (Apr 21, 2007)

Great post and a well written article, thanks.


----------



## dgr (Apr 13, 2008)

Halek... Maine Sail,
Thank you for the great article. I just ordered a moisture meter now that you've educated us.


----------



## BarryL (Aug 21, 2003)

*Nice post, but.....*

Hello,

Very nice post. And I think I will buy a meter for use on my own boat. I think it will be very handy to know when and where I need to take action.

Anyway, it's one thing to know (or think you know) there is some moisture in the deck (or hatch or ...), it's an entirely different thing to know if it's important, EXTREMELY important, or just something to be aware of. IMHO, that is what the surveyor is supposed to do.

As you wrote, using the meter is not just a simple matter of seeing 'Oh, the deck is wet in this sport, better pass on this boat.' because you may be passing up a perfectly good boat that just needs a simple repair. I know that I am not qualified to know what is simple and what is complicated. I want to pay a professional for that knowledge.

True, if you find a boat that looks good, and your meter shows wet everywhere, you will have saved the cost of the survey. BUT, in the hands of a novice, I think the meter is just as likely to cause someone to reject a boat that is probably pretty good.

I guess if you plan on buying a boat every 10 or so years, and don't want to learn a lot about boat buying, you are better off just hiring a surveyor. If you plan on buying lots of boats, or are interested in a make that is prone to core damage (certain C&C models) you might want to invest in a moisture meter, and to learn how to interpret the readings, and what to do with high reading values.

Thanks again,
Barry


----------



## sander06 (Sep 18, 2003)

We had our boat surveyed with a moisture meter and the guy found "significant" moisture in the rudder. Interestingly, the rudder was solid fiberglass and it was impossible for it to be saturated. He then noted that bottom paint can give a moisture meter a false positive for moisture. Of course, he also said that the 25-year old cutless bearing was in good shape, too!!


----------



## Maine Sail (Jan 6, 2003)

sander06 said:


> We had our boat surveyed with a moisture meter and the guy found "significant" moisture in the rudder. Interestingly, the rudder was solid fiberglass and it was impossible for it to be saturated. He then noted that bottom paint can give a moisture meter a false positive for moisture. Of course, he also said that the 25-year old cutless bearing was in good shape, too!!


How did you confirm the rudder was solid glass? If I'm not mistaken you sail a Westsail 28? I have seen the insides of a couple of Westsail rudders and they were both foam cored. Both had split from absorbing water and then freezing. The yard removed the skins and re-built these rudders.


----------



## Joesaila (May 19, 2007)

*Now you tell me!*

Kidding on that. Great information. We bought a 77 Morgan a year ago and did so w/o a moisture meter. Now that I've read this I can't believe the surveyor didn't use one. I think he was good and used a mallet for sounding but the meter is obviously superior. I am curious about the picture that showed a high reading near a waste water cover. Would the closenes affect the reading? Thanks again though!


----------



## sailingdog (Mar 19, 2006)

That probably means the deck fill was installed without removing the core or potting the fastener holes properly...so that water is entering the deck at that location.


Joesaila said:


> Kidding on that. Great information. We bought a 77 Morgan a year ago and did so w/o a moisture meter. Now that I've read this I can't believe the surveyor didn't use one. I think he was good and used a mallet for sounding but the meter is obviously superior. *I am curious about the picture that showed a high reading near a waste water cover. *Would the closenes affect the reading? Thanks again though!


----------



## boatpoker (Jul 21, 2008)

Any surveyor that needs a moisture metter to find "wet, rotten" core is not worth his salt whether it be in the hull or deck Percussive soundings of a couple of thousand boats has proven more accurate for me. 

The comment about certain bottom paints affecting the meter readings is correct. Moisture meters do not measure moisture ! 
The GRP33 is a capacitance meter that measures the capacitance (measured in farads) of the substrate with the theory being that a higher moisture content will have higher capacitance. As they measure capacitance rather than moisture many things will affect their readings such as conuctors or metal tanks in contact with the area being measured, certain gelcoats containing titanium dioxide, copper oxide, carbon and several other compounds with high capacitance (the same reason some bottom paints cause high readings.

These meters are a guide only ,they will show the casual user that some areas have higher capacitance than others..... but what does that mean and is it worth the $200.00 for the meter. 
These meters can be of some use to the casual user but to stick one on a surface and say "thats wet" is only about ten percent of what you need to know.

I keep an eye on this forum but rarely post so I don't think I can show a link but I do have an article on my website entitled "Moisture Meter Myths" that goes into some detail on the strengths and weakness's of these meters.
If you put "Port Credit Marine Surveys" into one word and then add dot com that should get you there.

"Dirt People Scare Me"


----------



## sander06 (Sep 18, 2003)

Maine Sail said:


> How did you confirm the rudder was solid glass? If I'm not mistaken you sail a Westsail 28? I have seen the insides of a couple of Westsail rudders and they were both foam cored. Both had split from absorbing water and then freezing. The yard removed the skins and re-built these rudders.


 Actually we have a Liberty 28 Cutter that is very similar shape-wise to a Westsail 28 but without all of the associated problems. The Liberty boys figured out the problems Westsail had with soggy rudders, wet decks, etc. and fixed the issues (I think that's called "back-engineering"), anyways the boat specs say that the rudder is solid. My main comment is concerning surveyors who, rightly or wrongly, I have near universal disdain. Just my opinion and I could be wrong.


----------



## justonemoreproject (Nov 13, 2008)

*good meter*

My surveyor uses a protimeter. If anyone is interested that one is good one to look at.

Cheers,

Larry


----------



## sailingdog (Mar 19, 2006)

Boatpoker-

Just would mention that as a marine industry professional, you need to read the *full disclosure post*.


----------



## Maine Sail (Jan 6, 2003)

sailingdog said:


> Boatpoker-
> 
> Just would mention that as a marine industry professional, you need to read the *full disclosure post*.


He made good points right up to the scare tactics and the 10% of what you need to know comment.



boatpoker said:


> These meters can be of some use to the casual user but to stick one on a surface and say "thats wet" is only about ten percent of what you need to know.


Surveyors like to protect their trade, when they don't actually need to in most instances, due to the vast majority of insurance companies requiring NAMS or SAMS accredited surveyors for insurance coverage. In doing so they often try to portray the moisture meter as a mysterious unreliable beast, which in certain instances it can be, but they usually take the scare tactics over the line.

I wonder how much boatpoker would continue to charge a client after the third or fourth failed survey due to something as simple as wet decks? Would he be willing to come out and just do hull and deck first at a reduced rate?

Having done many deck repairs/re-cores I can assure you that the meter is usually fairly close and very close when combined with spot soundings. When it's pegged you'll likely have "compost" as he refers to balsa as. I've yet to drill into a "pegged" reading and find dry balsa.

Like he said the meter is only part of it and this is why I suggested a full survey, in my original post, and to only use these meters to monitor your own boat or to rule out basket cases when shopping.

Of course boat poker would like to get his hands on your money for each and every boat, fail or pass, when you can easily rule in/out many without a surveyor. Once you've found a candidate boat BRING IN A SURVEYOR!

P.S. Electrophysics, the makers of the GRP-33 & the CT-33, seem to think my article is fairly thorough and concise and have chosen to direct link to it from their web site..


----------



## sailingdog (Mar 19, 2006)

As I said in my *Boat Inspection Trip Tips* thread... *The use of the trip and the use a moisture meter are only to determine if the boat is worthy of spending the money to survey.... They aren't designed to replace a professional survey...just help people figure out which are lemons and which are worth looking at further. * _If the advice Maine Sail and I gave prevents one unnecessary survey for everyone looking to buy a boat, that's some serious boat bucks saved.  _


----------



## boatpoker (Jul 21, 2008)

No scare tactics intended and yes the meters are pretty accurate in finding wet balsa but I have never found wet balsa with a meter that I did not already find with my brass hammer. My major concern with the inexperienced use of meters is when they are used on non-cored substrates and often touted as "osmosis" predictors ..... another myth.

My personal business practices are to provide as much information to a buyer pre-survey to help prevent him paying for multiple surveys. I never accept a survey without advising my clients to first read all the tips on my web site which include much information on this and many other boat buying tips.

Sailing Dog, I appreciate your comment about disclosure but as I have nothing to gain from this I did'nt think it necessary as these posts all seem to be from the US and I am in Canada. If this contravenes the rules of this forum please accept my apologies.


----------



## Maine Sail (Jan 6, 2003)

boatpoker said:


> No scare tactics intended and yes the meters are pretty accurate in finding wet balsa but I have never found wet balsa with a meter that I did not already find with my brass hammer.


Me too! Why do you choose brass over phenolic oher than better sound returns? I have seen surveyors do a number on a painted deck with a metal sounding hammer..? I generally use metal bellow the waterline and phenolic on finish painted surfaces



boatpoker said:


> My major concern with the inexperienced use of meters is when they are used on non-cored substrates and often touted as "osmosis" predictors ..... another myth.


Again I agree 100% but this post was not about ruling out boat due to bellow waterline blisters and was more directed at, bulkhead moisture and deck moisture.



boatpoker said:


> My personal business practices are to provide as much information to a buyer pre-survey to help prevent him paying for multiple surveys. I never accept a survey without advising my clients to first read all the tips on my web site which include much information on this and many other boat buying tips.


I understand your position but reading your site still does not prevent a potential buyer from paying for a survey on a boat that fails due to deck moisture of which sever moisture can be easily identified and ruled out by a potential buyer either via soundings or a meter but preferably both. I don't feel it is necessary for a boater to lay out $600.00 +/- to find out a boat is saturated when with a little common sense and about three hours of reading and some practice will get them to a competency to discern a lemon from a potential good deal..

As dog said this post is intended only to rule out certain boats and to move others to the survey level.


----------



## eherlihy (Jan 2, 2007)

boatpoker said:


> These meters are a guide only ,they will show the casual user that some areas have higher capacitance than others..... but what does that mean and is it worth the $200.00 for the meter.
> These meters can be of some use to the casual user but to stick one on a surface and say "thats wet" is only about ten percent of what you need to know.


I believe that BoatPoker left a grammatical error in the above. The _question_ is wether a meter is worth $200. In my mind, I believe that they are.

Initially, based on readings that I had done at other sites (surveyor sites as I recall), I was skeptical about the value of a moisture meter (comparison's to a doorstop were made). When Maine Sail (formerly Halekai) suggested that I purchase one, I didn't think that I had the knowledge, or experience, to benefit from one. However, shortly after Halekai suggested the purchase of a meter, when looking at a boat, the broker showed up with a meter, and showed me how to use it. Quoting the broker; "Anything over 20% is an area of concern." I quickly decided that it would be a very useful addition to my boating gear. You can read all about my experience here - What do YOU look for.. (the meter is suggested in post #23.)

My primary area of concern for the make and model of boat that I am interested in, has been about moisture in the deck. IMHO the meter is an extremely useful tool for checking this. To date, I have used my meter on 4 boats that I was interested in, and (fortunately/unfortunately) discounted all of them for moisture or other reasons.

The link to BoatPoker's article is here. I found it interesting, _and _it points out some of the limitations of a moisture meter. It is a useful read.

Regarding BP's question; "what does that mean and is it worth the $200.00 for the meter*?*" I suggest that when first looking at a boat, more information is better than less. If you find that moisture is a common issue with a particular make and model boat, I suggest reading BP's article and understanding the limitations of the meter, and then buying a meter.

- Ed


----------



## sailingdog (Mar 19, 2006)

Just to point out... if the use of a $200 meter saves you from doing one $300 survey... it has paid for itself in fact. 

The fact that you can also use a moisture meter diagnostically to see if you've got problems on your existing boat and can use said meter to help track down and fix those problems, preventing possible future problems and problems with selling the boat at some point in the future is a bonus.


----------



## Maine Sail (Jan 6, 2003)

*Ed..*

There is also this article that does not try to scare you off of a meter and instead helps you understand how to physically use one, in a very basic sense, & for exactly the reasons you listed..

*Understanding The Moisture Meter - Electrophysics CT-33 (LINK)*


----------



## justonemoreproject (Nov 13, 2008)

*Nope*

Thanks for the tip. No I am not a marine professional.


----------



## camaraderie (May 22, 2002)

BoatPoker...welcome to the forums and for your contribution to this thread. 
The rules here require everyone with a commercial interest to designate that in their signature so that readers may discern the self-interest and/or perspective of the writer. You were up front about your profession so no problem....but would appreciate you including your info in the signature in the future. Thanks in advance and it is nice to have another surveyor on board. You should "meet" member CardiacPaul if only to assure yourself that you are not as crazy as some surveyors!


----------



## boatpoker (Jul 21, 2008)

*one more try*

Perhaps I have not made myself clear. I am not trying to scare anyone into hiring a surveyor. I simply mean that most of the time on wooden bulkheads, encapsulated frame members and balsa cored structure a small brass hammer (I've never marked a deck) Is just as accurate as a moisture meter. Why spend $200.00 for a meter when a $9.00 brass hammer will give you the same information 95 percent of the time.

Port Credit Marine Surveys


----------



## sailingdog (Mar 19, 2006)

Boatpoker-

A lot of people will resent/resist/dislike a person tapping their boat with a metal hammer... where most will allow you to use a pinless moisture meter.


----------



## boatpoker (Jul 21, 2008)

Sailing dog: I done over 2500 surveys, never damaged a boat and have never had a complaint about the brass hammer which I keep very clean. It takes only a very light tap on cored structure to hear the anomalies.

Port Credit Marine Surveys


----------



## sailingdog (Mar 19, 2006)

*Yes, but letting an accredited surveyor tap away with a hammer and letting just any person coming to see the boat whack away with a hammer are TWO VERY DIFFERENT THINGS.*


boatpoker said:


> Sailing dog: I done over 2500 surveys, never damaged a boat and have never had a complaint about the brass hammer which I keep very clean. It takes only a very light tap on cored structure to hear the anomalies.
> 
> Port Credit Marine Surveys


----------



## brak (Jan 5, 2007)

I'll chime in and fully agree. I bought my Protimeter Aquant about 5 years ago when I realized that surveying every boat that I like would make me quite literally broke. At $20 a foot it's no small feat. 

One thing that I learned is that what meter shows has to be taken in the context of what it is I am looking at. The understanding came to me as I got to take apart, grind, cut and otherwise fix or break cored and non-cored fiberglass on my boats (and occasionally on other boats) that I used moisture meter on. So now with that knowledge the numbers are more meaningful and in recent times there wasn't a survey I paid for that found anything I didn't find on my own before. 

I am still going to be broke because of the boat, but at least not while paying surveyors


----------



## obelisk (May 23, 2008)

i do not own a moisture meter but i may be in the market for one...

i pulled my 1982 Skye 51 out of the water last Monday Nov. 17 to rebuild the skeg and rudder. once i had sanded the bottom paint off the skeg, someone from the (very reputable) yard and i took a hammer to it and it sounded extremely solid--not even the slightest hint of a thud or hollow sound--all crisp pings. after grinding away some visible damage at the bottom of the skeg, i could see a little water in the laminate. however, there were no voids and after grinding some more and tapping again with the hammer on the area, we still got a good sound. 

this is when i decided that i may need a moisture meter. it seems to me that the Electrophysics is the way to go. if i get one, what is an acceptable moisture content in 26 y/o 1" solid fiberglass laminate? i know older boats tend to have some moisture but how worried should i be about getting it all?


----------



## boatpoker (Jul 21, 2008)

Obelisk it is physically not possible for resin to absorb more that 3-4 percent water. Small voids in the laminate may have absorbed a few more drops. 3-4 percent constitutes saturated (so what !) If it sounds good and there is NO core...... go sailing. Before spending your money on a meter read the article on my site. index.htm

I live on my boat in Mississauga (toronto area) I put the shrink wrap on this morning....it sucks


----------



## obelisk (May 23, 2008)

boatpoker, that's just the advice i was looking for...i tend to take the worst-case-scenario on things like this. i am going to repair the areas with some West and 406 filler, put the rudder back on after it's rebuilt, take your advice and go sailing!


----------



## brak (Jan 5, 2007)

moisture meters do not show "percent" saturation (at least the ones I used including my Protimeter). they have a fairly generic scale and, as in the case of mine, also a colored light bar going from green to yellow and then red as things get worse. 
I also found that while good readings generally mean good and very bad means very bad (or metal  ), borderline readings (anywhere from 120 to 200) could vary widely - from total chunky toona looking wet core, to fairly decent laminate with either special paint on top of it (or behind) or good solid wood inside (solid wood, such as teak, will have natural moisture and it seems to be at approximately the same level that means rotten wet balsa core).

So - percents don't matter, you need to know your meter and it is a good idea to try it on variety of surfaces with known conditions to get a feel of what readings mean.

Also, it's good to have a meter that adjusts for ambient moisture (mine does, and I found that NOT doing that prior to testing can result in widely divergent moisture readings)


----------

