Moisture in hull ?

[BobH260]

A friend may have a moisture problem with his 1999 Hunter 410. It has mostly been hauled in Florida for the past 4 or 5 years. She was in for a couple of short cruises of about 2 months each.

It was surveyed last year for a purchaser and the surveyor's moisture meter showed high levels along the port side bow to stern just above and below the water line. It was rechecked with a second meter with same result.

The boat has balsa only above the waterline. Two core samples were taken of the balsa core from the inside of the cockpit locker. The balsa looked fine, solid, didn't appear wet. It was placed in a sealed zip lock bag for a couple of hours in the sun. Moisture appeared on the inside of the bag. The boat had been out of the water for a year and a half. Prior to that it did a two month cruise to the Bahamas. It does not have any blisters on the bottom.

The masking tape on the boat photograph outlines the area giving a high reading.

Any ideas on what's causing and what the solution might be ?

Is it actually a problem ?

Thanks Bob

[Cheechako]

I had a boat with core "above the waterline". The one in my avatar. It had to have a major repair for several feet on one side similar to those tape lines. Expensive, including hull repainting. The balsa was soggy in mine though.

[Navicula]

really..balsa core from the waterline up on a hunter???....I had no idea...are the water tanks on that side??

[Cheechako]

One wonders how much moisture is absorbed by balsa just sitting on the table for instance. If put in a bag in the sun, will it come out?

[CarlF]

That strikes me as fishy. It's too big and well defined an area. Why didn't it spread higher? Why not on the other side? And except for the anchor well drain, there appear to be no penetrations. (I would pull off that drain and probe).

How humid has it been inside the boat for the last year on the hard? I assume there aren't a lot of interior rain leaks. But could this be humidity from the inside of a closed up boat? Does the port side of the hull get more sun? Or less sun? What's installed against the hull inside at that upper tape line? Could the dark waterline and bottom paint get hotter in the sun and somehow fool the moisture meter on nearby areas?

I also think you might get condensation in the right humidity conditions with a plastic bag filled with just air. Or moisture might have condensed on the balsa sample after you pulled it from the hull before it went in the bag. A cool water glass will show condensation in less than a minute.

When I've seen bad balsa core, there was no doubt it was rotted. It was a gross emulsified mess.

[dakno]

Sounds odd to me also. Go to the Hunterowners.com site and chat with actual owners of these boats. You will get answers to any boat specific question you have.

[rognvald]

There is a similar 410 in our yard that has the entire hull above the waterline saturated. Perhaps there is a problem with that model that the Hunters Owner Association could detail for you. In any respect, I would get a professional "glass man" to inspect your boat. I would not use a surveyor since there is no room for speculation. I hope this helps. Good luck and safe sailing . . . Rognvald

[Dave852]

It's a fairly common problem in any cored boat. The entry point very well could be the anchor locker drain. After getting in it's a simple matter of gravity and all the passages left where the sheets of core material end. Once the sheets of core are placed against the outer skin some filler is placed along the bottom edge so the inner skin will have a tapered edge to lay up against. The water then followed the tiny voids left behind all the way aft. Only way to fix is cut the outer layer of skin away, remove the bottom edge of the core material and grind out all the filler until all moisture is removed then glass back. Need a very good gelcoat person to match the color and voila, your done. On many boats this may be to big of an investment so is never done. Main issue is resale value if you leave it be. I would fix the entry point regardless.