Does heating hull with heat lamp really get rid of moisture?

[Buddha21]

Just had a survey done that detected moisture in the deck around the bow window hatches (8-10%), and in the hull around the anchor locker drain (18%). The boat is a 2006 Cruisers 300. The surveyor recommended removing hardware around affected areas (during heated winter storage) and hitting area with heat lamp several hours a day until moisture level decreases.

Will this work? The heat will allow the water to migrate/evaporate out of the small openings you provide it with removing the anchor locker and windows? I've been searching various boating forums and got a few hits which discussed this, but nothing that reported its effectiveness.

[GordMay]

Greetings and welcome aboard the CF, Budhha.

[Van Der Beek]

Originally Posted by Buddha21

Just had a survey done that detected moisture in the deck around the bow window hatches (8-10%), and in the hull around the anchor locker drain (18%). The boat is a 2006 Cruisers 300. The surveyor recommended removing hardware around affected areas (during heated winter storage) and hitting area with heat lamp several hours a day until moisture level decreases.

Will this work? The heat will allow the water to migrate/evaporate out of the small openings you provide it with removing the anchor locker and windows? I've been searching various boating forums and got a few hits which discussed this, but nothing that reported its effectiveness.

That all depends on the amount of moisture. If it's enough of it the result will be that a heat lamp will push the moister further into the hull, only making the surface dry, then when you no longer use the heat lamp, the moisture will simply move forward again. Best way I think would be to find a way to setup and use a dehumidifier, a dehumidifier will draw the moister out of the hull, not push it further into the hull.

I have never tried this out on a sailboat though, but I have in a basement with a wet concrete walls and it worked. Took well over a month, and of course, after first having made sure that no NEW moister could get into the wall.

Good luck.

[Buddha21]

Originally Posted by GordMay

Greetings and welcome aboard the CF, Budhha.

thank you!

[Cheechako]

I think the heat just makes the moisture inside the layup condense but not go away. JMO. Your situation doesnt sound too bad yet. Do you winter store? If inside or tarped maybe remove everything possible, add an incandescent lamp near the area that doesnt get real hot and leave it for winter.... and see. then rebed it all. Supposedly air conditioning that dries the air is best...
Not sure a bit of moisture in small areas is worth a major repair for. If you rebed and get much of the moisture baked out, it shouldn't migrate as there's not enough moisture left to do so. Another option, depending on the situation, is to drill some holes underside and leave them open for winter. Sometimes water will actually drip out there's so much in there. Other times the core is just a bit moist.

[rwidman]

If you heat strips of beef for long enough at a low temperature, the moisture will be driven off and the result will be jerky.

Stacks of lumber are heated in kilns to drive off the moisture. The result is "kiln dried lumber".

I doubt a heat lamp directed at part of your hull for a few hours per day is going to make a difference but it is possible to use heat, dehumidifiers and a tent to dry out a hull. This is usually done over a period of several months and it is best done by someone who specializes in this field.

[Cheechako]

If you steam vegetables in a closed enclosure they steam, not dry. The key is opening up well so the moisture gets out, not drips from the cover. Otherwise you are just cooking in moisture.

[Buddha21]

Thanks for the responses. Seeing how its an 11 year old boat, is it normal to have some parts of it test positive for moisture?

I'm thinking during winter storage (heated), I'll have the portlight windows and anchor locker removed, let sit for a few months to air out, and then re-bed the equipment.

[Cheechako]

There are more people here familiar with moisture meters than me, but from what I've seen, it's not positive there is much going on. I would drill an interior hole into the core, take the sawdust from the drill spiral and squeeze it between your thumb and finger and see if any water comes out ....before doing anything.

[Buddha21]

Originally Posted by Cheechako

There are more people here familiar with moisture meters than me, but from what I've seen, it's not positive there is much going on. I would drill an interior hole into the core, take the sawdust from the drill spiral and squeeze it between your thumb and finger and see if any water comes out ....before doing anything.

The hull is fiberglass, how deep of a hole can you drill? Sorry if that's a dumb question, newbie here. Quite frankly, I didn't even know "moisture in hull" was a thing, especially above the waterline. I mean, where does the water have to go? The hull can't be that thick.

[Suijin]

1) What do you mean by "bow window hatches"? Are they bow port lights, at the front of the cabin, or deck hatches? Or maybe port lights in the hull?

2) 8-10% is pretty dry on the scale of most moisture meters. It's pretty much what the core went into the boat with.

3) 18% in the hull around the anchor locker...higher moisture, but still not critical depending on the construction and where the reading was taken...was the chain removed when this reading was taken? I'm asking because moisture meters will give varying readings around metal, hardware, etc. How far up from the waterline was this reading? Is the bottom barrier coated? More information would be helpful

Based on those readings I would not be concerned. I might consider rebedding hardware, but without pictures and a better description of what specifically is going on would not immediately jump to it. The boat is only 11 years old. I just rebedded my deck hardware, after 31 years, and there were no leaks or failures of the bedding when I pulled everything up. But every boat is different.

As for pulling the hardware and putting a heat lamp on those areas during dry storage in winter, that's nonsense. I'm starting to think your problem is not moisture intrusion but rather a bad surveyor.

[Buddha21]

Originally Posted by Suijin

1) What do you mean by "bow window hatches"? Are they bow port lights, at the front of the cabin, or deck hatches? Or maybe port lights in the hull?

2) 8-10% is pretty dry on the scale of most moisture meters. It's pretty much what the core went into the boat with.

3) 18% in the hull around the anchor locker...still not critical...was the chain removed when this reading was taken? I'm asking because moisture meters will give varying readings around metal, hardware, etc.

Based on those readings I would not be concerned. I might consider rebedding hardware, but without pictures and a better description of what specifically is going on would not immediately jump to it. The boat is only 11 years old. I just rebedded my deck hardware, after 31 years, and there were no leaks or failures of the bedding when I pulled everything up. But every boat is different.

Bow port lights. I saw the surveyor take the readings- was about 8% directly in front of each port light going up about a foot. Then he showed me another reading beyond that, and it was zero.

He took the anchor locker readings during the haul-out, so I'm fairly certain the anchor and chain were still in there.

[Suijin]

Originally Posted by Buddha21

Bow port lights. I saw the surveyor take the readings- was about 8% directly in front of each port light going up about a foot. Then he showed me another reading beyond that, and it was zero.

He took the anchor locker readings during the haul-out, so I'm fairly certain the anchor and chain were still in there.

Clearly he's using a different meter than I'm familiar with. I've always used one with a meter similar to this:



I've never seen a reading of absolute zero. Wood has moisture in it, period. On the above meter, anything in the green is normal, and that's up to 8-10% I believe. Here's a picture of the same meter over a dry part of my deck during my recent refit:



Not sure why you'd have moisture in front of each port light and going up. If the port light is leaking, it would be wet below. Makes no sense that it would be in front and above, unless a fixture above that is leaking.

[Cheechako]

Originally Posted by Buddha21

The hull is fiberglass, how deep of a hole can you drill? Sorry if that's a dumb question, newbie here. Quite frankly, I didn't even know "moisture in hull" was a thing, especially above the waterline. I mean, where does the water have to go? The hull can't be that thick.

I'm confused about where the problem is. I thought around a hatch. Most decks are an inner layer of glass, 1/2" balsa core, then the outer glass. You just drill thru the inner into the balsa ... no further. The drill will plunge into the balsa fast and you'll know. If you are talking portlites on the side of the cabin or possibly hull.... it may not be cored... DONT drill there!

[Buddha21]

Originally Posted by Suijin

Clearly he's using a different meter than I'm familiar with. I've always used one with a meter similar to this:



I've never seen a reading of absolute zero. Wood has moisture in it, period. On the above meter, anything in the green is normal, and that's up to 8-10% I believe. Here's a picture of the same meter over a dry part of my deck during my recent refit:



Not sure why you'd have moisture in front of each port light and going up. If the port light is leaking, it would be wet below. Makes no sense that it would be in front and above, unless a fixture above that is leaking.

Actually that's exactly the meter he's using. This is the survey pic with the reading from the anchor locker drain.