Moisture reading

jssailem · Mar 21, 2019

captnkw said:
what would be the cause and what is the solution.

Well that is an easy answer... Water...
The second one is a bit more challenging. It generally starts with draining, and drying it, and then finding where the leak may or may not be.

But before all that, you might want to do a little more inspection and try to isolate the location that shows a moisture reading of 22%. And when doing the reading is there any water draining off the hull the could be influencing the measurements.

Who did the reading and what are they recommending?

LeslieTroyer · Mar 21, 2019

Stanchions, cleats, windlass, in my case it’s the U bolt for jack lines or pole fore guy.

Dry it out and poor some penitrating epoxy in there.

Les

jssailem · Mar 21, 2019

The problem stated is the "Hull" not the deck. Hull would have to be a cored design. Or there is an osmosis problem. A bit unusual but possible.

What year of boat?

jssailem · Mar 21, 2019

Seems a bit young to be having water in the fiberglass hull.

Here is a pretty good sight to help identify hull and deck issues. The writer is a Marine Surveyor and does not pull any punches. He tells it like it is.
https://www.yachtsurvey.com/HullFailP2.htm

jssailem · Mar 21, 2019

Here is another one of David's articles.
https://www.yachtsurvey.com/moisture_meters.htm

jssailem · Mar 21, 2019

Not sure if you have had a chance to read about the meters and their reliability.

Here is a key statement after testing.

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.

dlochner · Mar 21, 2019

captnkw said:
I had my Hunter 49 hull inspection and was told I have a higher than usual moisture level reading on my starboard bow hull area with a reading of 22%. Just wondering what would be the cause and what is the solution. Boat is 2008Tall rig
Thanks
Kirk

captnkw said:
Boat inspector routinely checking prior to spring launch. They are saying could be $25,000 fix. Taking core samples and further closer inspections.
Thanks

My first question is what is the relationship between the inspector and the boat yard? My second question is what qualifications does the inspector have? My third question is under what circumstances were the readings taken? My fourth question, and for the moment last, how large an area are we talking about and where is it?

dlochner · Mar 21, 2019

captnkw said:
Questions 1&2 don’t know
Boat is on the hard and shrink wrapped
Inspector shows video of himself doing moisture reading states 10 feet back from bow and 1 foot above water line

Did you hire the inspector? If so for what reason? Usually the folks that do this kind of work refer to themselves as surveyors and have SAMS or NAMS certification.

Weather conditions can have an effect on moisture readings, obviously it is not a good idea to do moisture readings in the rain.

What's behind the area with the high moisture readings?

How did he calibrate his moisture reader? Decent quality moisture readers are good at reporting relative moisture readings but not always as accurate to actual percentage moisture. The can say "This area has higher moisture readings than this other area."

Is there any obvious damage to the hull in that area? Check the inside to look for evidence of a repair. Did he sound the hull with a hammer to confirm the moisture reading? Is your hull cored or solid?

Don S/V ILLusion · Mar 21, 2019

Hull coring doesn’t begin until above the WL so it may or may not be cored there.

BEFORE DOING ANYTHING ELSE - get your own surveyor rather than rely on the prospective buyer’s surveyor to verify the existence of moisture in that area.

JamesG161 · Mar 21, 2019

A typical moisture meter just reads the conductivity between two points.
Since fiberglass is not conductive, the tester had to penetrate your fiberglass from the inside.
1) Why would he do that?
2) Why would he do that above the water line?
3) Did you ever have a collision, that you disclosed?
4) Was there obvious damage to the bow?

If I found that done to my boat, without permission, I would be totally hacked off, and insist on a hull repair.
Jim...

dlochner · Mar 22, 2019

captnkw said:
I did not hire him. I am in process of selling my boat and the buyer hired him.
No damage to boat. I bought boat new so I know this for sure. And sound test was performed. Hull I believe is cored. I will have to check what is behind that area.
Thanks for the info!

At this point the buyer will either walk away or attempt to negotiate a lower price. If the buyer walks, get your own surveyor to take at look at that area. If he walks, demand that he provide the evidence that he received an unsuitable survey, i.e, get a copy of the survey.

Moisture meters were originally designed to measure moisture in wood. They have little spikes that stick in the wood and current is passed through as @JamesG161 notes. When they penetrate the wood they can be very accurate, not as much on fiberglass because the spikes don't penetrate the fiberglass.

Here's a great article on moisture meters: https://marinehowto.com/understanding-the-moisture-meter/

Ward H · Mar 22, 2019

dlochner said:
Here's a great article on moisture meters: https://marinehowto.com/understanding-the-moisture-meter/

What Dave said. That's a great article for a DIY'er on how to use a moisture meter. The article covers many reasons for getting a false reading.

captnkw said:
Boat inspector routinely checking prior to spring launch.

Is this something the yard does or something you have requested? Either way you should be able to get his credentials.
.
If it was my boat I'd pay for my own survey by a certified surveyor before I allowed anyone to put a hole in my boat.

Good Luck!

JamesG161 · Mar 22, 2019

dlochner said:
When they penetrate the wood

There is a SBO thread on Wood in boats using the "typical moisture" meter. I, perhaps, jumped to that conclusion after noting the OP's 49' Hunter.
I have read the links and was a bit surprised by the surveyors 'Typical meter".
If...

Don S/V ILLusion said:
Hull coring doesn’t begin until above the WL so it may or may not be cored there

is true. Then the surveyor must have known that is True for the OP's boat or he is not a good surveyor.
___
I did find out how my H430 hull was done. There is structural wood on my boat, but not in the bow.
____
After seeing "core" materials available in those links, I am still surprise anyone could interpret a reading. This is the second tread by OP. Don noted it was a "capacitance" meter and not my "conductivity" meter.
I my opinion, a capacitance meter makes a big leap to detect moisture , without knowledge of the materials used in the hull, meter calibration block or not.
_____
If I think of a "stretch wrapped" boat on the hard during this years "Lake Erie" area "freezing/thaw" cycle...
It could be just a simple condensation issue, not a hull integrity issue.
Since the boat is on the hard, the hull can be inspected completely.
No Hull issue, then...

LeslieTroyer said:
Stanchions, cleats, windlass, in my case it’s the U bolt for jack lines or pole fore guy.

Then Les has the key point.
Remember to have moisture, water in and water out. Thus a deck source seems most likely, if no hull damage.

Jim...