# Humidity smell



## girlgoessailing (Mar 19, 2014)

Hey all!

My boyfriend and I are currently living on our boat part-time as we save up for our circumnavigation (visit us at couchsailors.com if you'd like!) next year. We're based in San Francisco and though we don't have a humid climate, we're battling a lot of humidity inside. We're pretty consistent about wiping everything down, especially when we wake up in the morning, but the smell of humidity is still a constant. I'd love some advice on what we might be able to do to mitigate the odor!

Thanks!


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## mtitus (Jul 10, 2001)

Ventilation and eucalyptus oil should rid your cabin of that musty humid smell.

My first mate, she uses a couple of drops of eucalyptus oil mixed with a little water and leaves it in an open or ventilated jar. On our 27 ft boat she places a jar in the salon, one more in the "wet" hanging locker, one forward in the V berth and another in the storage locker under the salon seats. I was a doubter when she first did this, but damned if it didn't work. She changes the jars out every couple of weeks or so.

I also keep a fan running circulating airflow when ever I'm not at the boat and do my best to keep a dry bilge. 

Hope that helps. 
Murman


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## T37Chef (Oct 9, 2006)

Marine Solar Powered Vents on Sale

Easy to install and move some air, get at least two. One intake one exhaust. Haven't tried Eucalyptus mentioned about, but have found Kanberra Gel (although expensive) to work well on our boat. Kanberra Gel - Home


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## miatapaul (Dec 15, 2006)

Well there is really only one solution is to find the source of the moisture. If it is just from normal living on board, then you need to set up some solar vents to get the air moving and fresh air into the boat. But you sound like you are describing more than just that so there are likely some leaks. With a boat like your Beneteau 423, there is a full liner so you may not see water from a leak and it may be finding it's way behind the liner and causing mold or you may see the water but can't tell where it is coming from. I would start with the usual suspects, with an 11 year old boat. First re-bed all stanchions and other other deck hardware with Butyl tape, a la Mainsail:

Re-Bedding Deck Hardware With Bed-It Butyl Tape Photo Gallery by Compass Marine How To at pbase.com

And do any hatches as well, though leaks from them are normally fairly obvious because they drip directly down. Keep in mind humidity does not really have an odor, so it may well be mold you are smelling and that is not healthy. Cleaning up with a caustic cleaner like Borax, and not rinsing on hard surfaces, can help a lot as well.

That should be a good start. For general odor you might try the Kanaberra jell it has good reviews here and elsewhere. Seems to be mostly natural and gets rid of the musty smell. It is based on Tea Tree oil, so you have to like that scent. They kind of make claims that it kills mold but I do not believe that. But I do like Tea Tree oil in general so I would not be afraid to use it.

edit:

Seems T37Cheif and I think a lot alike!


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## krazzz (Jul 17, 2013)

+1 on ventilation
+1 on Kanberra Gel


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## Brent Swain (Jan 16, 2012)

In the tropics, my boat is painted white. If I leave it white in colder latitudes, the lockers get musty. When I paint her dark green, the hull is warm to the touch ,on sunny days ,even in minus 12 degree temperatures, when the sun shines on her, and the lockers stay dry and must free.
She is very well insulated.


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## jwing (Jun 20, 2013)

Actually, you live in a fairly high relative humidity area. When air with high humidity is cooled, like at night, the relative humidity (RH) goes up. Combine that with your hull sitting in cool water and you have a recipe for condensation. That is why you need to wipe things down in the morning. 

You can't change the RH of the air outside or the water temperature. But you can do things to control the air inside the boat. Essentially, you want to keep the air inside your boat higher than the dewpoint. You can do this by raising the air temperature and/or lowering the dewpoint. Removing moisture from the air (dehumidification) will lower the dewpoint. Heating the air will reduce the RH and lower the dewpoint.

So, figure out how you want to do it. A dehumidifier will work. Simply adding heat will work, but not if your heater works by combustion. An unvented cumbustion heater will add moisture to the air and a vented cumbustion heater will draw outdoor air and it's moisture into the boat. You could try some kind of dessicant, but then you would have to figure out how to recharge it.

The use of vent fans works only if the outdoor air is warm/dry enough to absorb the water vapor from the inside of your boat. I doubt that's a reliable occurance in SF Bay.


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## Multihullgirl (Dec 2, 2010)

Wash all your cushion covers and boat linens, and wash and air out the foam inside the cushions.

For foam, I make a bleach solution, spray it on the foam, and then leave the foam out in the sun to dry.

Rather than spending a fortune on Kanberra, which is a tea-tree oil formulation, just make up your own: 1-2 tsp tea-tree oil in a spray bottle, fill the rest with water. Shake and spray around.


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## christian.hess (Sep 18, 2013)

I was about to say san fran has one of the most humid climates ever...

when I was in berkely a dehumidifier was mandatory...and good or bad lots of people left them on for many hours days unattended...a fire or 2 here and there was common.

to combat the physical mold and stuff bleach water all the surfaces...

but I like all the recomendations being mentioned

although I havent used any of those except for the dehumidifier and or a wood stove heater...which did the trick in winter but then you have to deal with soot.


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## girlgoessailing (Mar 19, 2014)

mtitus said:


> Ventilation and eucalyptus oil should rid your cabin of that musty humid smell.
> 
> My first mate, she uses a couple of drops of eucalyptus oil mixed with a little water and leaves it in an open or ventilated jar. On our 27 ft boat she places a jar in the salon, one more in the "wet" hanging locker, one forward in the V berth and another in the storage locker under the salon seats. I was a doubter when she first did this, but damned if it didn't work. She changes the jars out every couple of weeks or so.
> 
> ...


Ooh that's a great idea! Eucalyptus is quite strong so I bet that even diluted it would cut through the odor. Does it just mask it though? We just cleaned out the blige (we were having a leak from our water tank and went ahead and dried everything out...I hope that helps). Thanks for your input!


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## girlgoessailing (Mar 19, 2014)

We bought a dehumidifier and are testing that out as well as these moisture absorbers (I had never seen them but my boyfriend was recommended to them through the forums). We've had endless electrical issues (that's a whole other problem) so we haven't been able to test out the dehumidifier consistently. 

Mold is definitely an issue and it seems like we're battling it constantly. It's especially present along the sides of the "ceiling" of the v berth (is this what you'd call the liner? I'm sorry, still new and learning the right vocabulary!). When we bought the boat it was already full of things from the last owner so it's been quite a work in progress trying to clean everything out. I hadn't realized that SF was actually humid...when I think of humidity I image Hawaii or Mississippi! Haha. 

Thank you all for your input! I'm going to give these a try.


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## Stumble (Feb 2, 2012)

The desiccating chemicals frankly aren't worth the trouble. In small confined places they work fine, but for an area the size of a boat they are pretty ineffective. Ideally these chemicals need good airflow, and again a lot of them. The manufacturers recommend 25 grams/cubic foot. Assuming a 35'x12'x8' boat (of course this is a weird shapped boat) would require 85kg of stuff.

The best option is an air conditioner or dehumidifier, but an AC is probably cheaper. If electrical problems are the issue, then just run a power cord from the dock to a window unit in the companionway. This will cost about $100 and will both freeze you out and drop the humidity to nothing.


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## Multihullgirl (Dec 2, 2010)

My solution to "funky boat" has been thus, and my boat was certainly funky when i bought her:

1. Ventilation. I installed PortVisors over the portlights in the heads, so now those can stay open 24/7. There are portlights forward, which are at an angle such that it doesn't rain in on those, so they stay open 24/7 (unless underway  Let your boat BREATHE....

2. I do canvas, so I replaced all coverings of all cushions, and as much foam as I could afford to (foam is expensive). The foam I didn't replace I treated as I mention above, with bleach (Clo cleanup and sunlight). I do regularly wash my cushion/mattress covers a few times a year. Sunbrella can be washed in cold water, and other cushion coverings can be washed cold as well; just don't put 'em in the dryer. All cushions and mattresses are backed with Phifertex mesh btw

3. For the walls, I initially cleaned with Clorox Cleanup, and then spray with, depending on what I have to hand or feel like using, either Concrobium Mold Control (little to no scent) or the tea-tree oil mix (very piney scent) I mention above. Every here-and-there (several months?) a bit of mildew reappears and I just wipe down with Concrobe or tea tree mix and the problem goes for several more months.

4. Bilges. Don't let them be wet if you can help it. My catamaran has shallow bilges and I don't let water stand in them. Reefer drains overboard, and I mop the bilge after showering. Monohulls have deeper less accessible bilge space, but just try to keep 'em empty and clean. The Boat Galley has tips on bilge cleaning for monos IIRC


You have to realize that since you're on a boat, and the boat is in water, you will be experiencing humidity  and it will be an ongoing maintenance issue. I don't, nor will I, have A/C on the boat and I don't like to be plugged in 'cause I'm scared of fire. YMMV


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## Group9 (Oct 3, 2010)

I live in a high humidity area and my boat always had that mildew smell and we fought mold and mildew constantly. One day, we said we had had enough, went to Lowes and bought a de-humidfier. We leave it running in the boat with the drain hose going into the bilge. 
a. No more smell
b. No more mold and mildew.

It's great. The only down side is that it does generate some heat. Not burn the boat down heat, but enough that it might be uncomfortable to live on it.

What about AC? It works just as well and keeps the boat cool, too. I just don't like running my AC because of fear of a hose bursting and flooding the boat when it is unattended.


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## jwing (Jun 20, 2013)

Using an air conditioner presents two problems to a boat in San Francisco:

1) The weather in SF is usually cool enough to not want to chill the boat interior even further. The heat from a dehumidifier might be a advantage.

2) A sailboat has a small air volume so a small A/C unit is required. Remember, A/C is controlled by air temperature, not relative humidity. If the A/C is oversized compared to the heat gain, it will quickly get the space cooled down, then shut off. The amount of dehumidification will be insufficient. Additionally, by cooling down the air temperature but not taking an appreciable amount of moisture out, the relative humidity will actually go up.

A/C works well in areas that have hot, sunny days and warm water; the heat gain inside the boat is high enough to keep the A/C unit running. But in those areas, the ventilation strategy becomes viable. My boat is in Alabama, where the nightime RH goes up to greater than 90%, but the days are so hot that the RH drops back into the 50's or lower. I can keep my hatchboards off and hatches slightly open and that's enough to keep the boat mildew free.


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## pdqaltair (Nov 14, 2008)

I've done a bunch of side-by-side testing on this. Solutions that work for storage and weekend warriors don't always have much in common with live-aboard use, and cruising is different from that, so there will not be one answer.

* Forget descants and adsorbents. While they can work in a well-sealed boat, removing the few gallons of water that sneak in through the cracks and out gas from the hull, they have very limited capacity in and open system (opening the door a few dozen times each day or opening a window) they are about like burning dollar bills; not effect and expensive. They are useful for camera bags and lap top bags; the bag must be reasonably air tight and they must be regenerated in the oven every so often.

* Eucalyptus oil / tea tree oil. There is some proven effectiveness at VERY high concentrations. They do demonstrations with a bit of fruit in a tupperware container, but they don't hint that the concentration in the container would be lethal or harmful. In a sealed boa, used at the recommended concentration, these products can approach the minimum inhibitory concentration, but not in a boat that is ventilated. Basically they mask the odors and good housekeeping does the rest. I would also be asking myself if continuously breathing the high concentration required to kill mold is good for me; there are clinical cases where these oils have done harm. Google EPA, NIH and CDC. In the testing I did these products did not approach the effectiveness of of other products and approaches (several orders of magnitude). Basically perfume if the boat is not well sealed. IF well sealed, they could be used in combination with desiccants.

* Dehumidifiers. They work, period. Don't get one that is over size (noise and heat). I've been using a small thermo-electric unit (can run off the solar) for several years and it works great, but a larger compressor unit would be needed for a live-aboard (or perhaps 2 of the small ones). They remove about 1 quart per day.

* Ventilation. Works when the water is near air temperature. Fails when the water is cold (humidity condenses against the hull no matter how much you vent--venting can even make it worse). This explains why some are happy with ventilation and some are not.

* Cleaning. No food, no mold. The most effective mold preventatives are slightly alkaline (mold likes weak acid conditions) and are same for fabrics, which are probably the major sources. They can also be used on all pourus surfaces.

One Penny Mildew Spray - Inside Practical Sailor Blog Article

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Thus, there are multiple answers. For a live-aboard, I would go with ventilation some days, and a good drying with dehumidifiers every few weeks, where I keep her shut up for a few days. Much would depend on the weather (not much point in ventilating while there is fog or rain).


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## miatapaul (Dec 15, 2006)

pdqaltair said:


> I've done a bunch of side-by-side testing on this. Solutions that work for storage and weekend warriors don't always have much in common with live-aboard use, and cruising is different from that, so there will not be one answer.
> 
> * Forget descants and adsorbents. While they can work in a well-sealed boat, removing the few gallons of water that sneak in through the cracks and out gas from the hull, they have very limited capacity in and open system (opening the door a few dozen times each day or opening a window) they are about like burning dollar bills; not effect and expensive. They are useful for camera bags and lap top bags; the bag must be reasonably air tight and they must be regenerated in the oven every so often.
> 
> ...


Good run down. I have a question about the one penny spray do you use real TSP or is the TSP commonly sold as phosphate free TSP as good? I know some places the real stuff can be very hard to find, sometimes having to go to a commercial paint supplier.

I have had good luck with using just a strong solution of Borax, wiping with a wet cloth once then reapplying and leaving to dry without rinsing or wiping. Bleach seems to remove the black color, but does not prevent it from coming back.


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