Moisture meters & used boats

[SavinRaven]

So I wanted to get peoples opinions on performing a moisture meter test on a used boat. I am going to look at a boat on Saturday and want to pick up a meter at lowes. They have the general tools MMD7NP version of this. How well will a meter Ike this do through fiberglass to detect transom and hull rot? The weather in Michigan will be cold but shouldn't be wet maybe a little residual snow. Any pointers on performing such tests. YouTube wasn't much help it seems pretty point and click simple but wanted to make sure my instincts are right. The boat isn't quiet enough money where I want to pay to have it professionally surveyed so I thought I'd do as much myself as possible. Has anyone performed such a test with similar equipment.

 

[roffey]

Good question, I have always just checked for soft spots. I will sit back and read the comments.

Full disclosure here, I have owned three boats in the last 20 years. The first two were POS and the last I bought off the show room floor.

 

[JimS123]

I have been using moisture meters for 45 years. Not the model you cited, but a professional grade. If the surface is at all wet or even moist, you won't get an accurate reading.

The last time I bought a meter it cost $850.00. For 44 bucks you'll be taking your chances. Maybe contact a Marine Surveyor and ask what meter he recommends.

 

[SavinRaven]

Good question, I have always just checked for soft spots. I will sit back and read the comments.

Full disclosure here, I have owned three boats in the last 20 years. The first two were POS and the last I bought off the show room floor.

In normal weather I can but the boat has been winterized and ya the current boat I have I just replaced stringers and transom... so not trying to get back into that less but don't have the bank to shop the showroom floor this year sadly.

 

[SavinRaven]

I have been using moisture meters for 45 years. Not the model you cited, but a professional grade. If the surface is at all wet or even moist, you won't get an accurate reading.

The last time I bought a meter it cost $850.00. For 44 bucks you'll be taking your chances. Maybe contact a Marine Surveyor and ask what meter he recommends.

Would simply drying the surface of the glass off with a towel give more accurate results of what's underneath the glass? Not particularly worried about the glass being rotted just the wood under it.

 

[tpenfield]

Most surveyors use the Tramex Skipper Plus to detect moisture in/thru fiberglass. ($500 ish)

The meter you mentioned is for building materials and may not give the right sort of results as the Tramex.

If you can get some direct contact to wood (which is possible on some boats with only a light coating of glass/gelcoat on some of the wood surfaces). . . . you could get some readings. Typical 'dry' wood encapsulated in glass is going to read about 15% moisture. 'Wet' wood is going to be 35+%. Most of those meters 'peg' at 50% moisture.

 

[Scott Danforth]

Moisture meters from lowes are for testing wood in a house. They use direct contact

Different technology is used to test moisture on the other side of a layer of fiberglass

A good marine moisture meter will cost you over 700

 

[dingbat]

While I have the measurement sensor “experts” attention….lol

I saw an ad the other day for touch less (non-contact) digital calipers. Said to accurate to within 0.01% of measured thickness.

How is this physically possible let alone be accurate to the 6th decimal point?

 

[SavinRaven]

After Cross posting this on THT to I found this
Moisture meters Analysis by Surveyor

Very good resource. Also note the end of this surveyors experience using the "cheap" Ryobi for cored hulls. (Which is what I am looking at) I am mainly worried about transom and motor mounts. I will put a reading on the outside hull near the stringers but they are foam filled with some wood/Fiberglass coverings just like many of the bowriders from this time period. The MFG I am looking at "Mariah" from this time period were very solid made boats with very little wood in the construction they also fully encapsulated all of the wood in glass. I believe my findings will be negative but just for my piece of mind I want to take a meter to some of the key areas this weekend I think.

From my research when you are trying to find out moisture in the foam sections its very hard with these meters however on just a cored piece overlaid in fiberglass like a wood cored transom or wood cored motor brackets less then 1/2" thick then these give you a pretty good idea. Need to know what you are testing and the materials going into it. Let me know if anyone got anything else from that article.

 

[Scott Danforth]

How is this physically possible let alone be accurate to the 6th decimal point?

Marketing...... Just like EV's are good for the environment

 

[mr 88]

Hammer and if necessary a drill will tell you more than a meter in the hands of someone that has never used one . Bottom paint , how long it's been out of water and a few other variables will affect your readings. www.yachtsurvey.com. has a write up on them. Punch in Moisture Meter in the search icon.

 

[JimS123]

Would simply drying the surface of the glass off with a towel give more accurate results of what's underneath the glass? Not particularly worried about the glass being rotted just the wood under it.

I dunno. It all depends how dry bone dry is.

Regardless, if its a budget boat and the cost doesn't command a survey, and it's more than 10 years old and was built with a wood core, you can expect it to be rotten unless the owner kept it garage kept and dry.

I am reminded by a boat down the street from me. It sat beside the house uncovered for years. I never saw it move and I was surprised when he put it in the driveway and started working on it. Polished the hull, touched up the rust on the trailer and polished all the upholstery. Then I saw the ad in Craigslist. "One owner, always garage kept, pristine condition". I pity the guy that bought it...

 

[Scott Danforth]

Regardless, if its a budget boat and the cost doesn't command a survey, and it's more than 10 years old and was built with a wood core, you can expect it to be rotten unless the owner kept it garage kept and dry.

True

 

[Grub54891]

If you are in Michigan, I'd say the hull is frozen. I'm not so sure the meter would read correctly.

 

[mr 88]

Meter does not read frozen water. You can put it on a piece of ice and it won't show any moisture.

 

[dingbat]

Marketing...... Just like EV's are good for the environment

Marketing........lol?

Have personally been involved in the installed over 2000 of these systems world wide since I started in the business in the late 1970’s.

With every major Steel, Aluminum, Paper and Plastic producer in the world using either ours or a competitor's measurement system, surely someone would have complained if we don’t meet our advertised specification by now

Also worked in the development and support of radiation and eddy current based sensors for paint and coating thickness, moisture, basis weight (web products), glass and a number of other applications, products and customers I can't disclose under NDAs.

Moistures meters are not rocket science.
Pretty common for a cheap electro-magnetic device to provide an accuracy of plus or minus 4%

What accuracy is required to determine if the wood is wet or not?