How do I dry out my damp boat interior (Off The Grid)

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Venomgrass

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Hi all,
Looking for tips and the best way to dry my boat out off the grid, I have no mains power in the dock where my boat is moored. I'm going to add a small 12v solar vent and consider an option to dry her out. Will ventillatiob alone do it or do need a parafin heater, tiny 12v dehumidifier driven from the battery, maybe swap 2 batteries charging the other at home and swapping daily?

Any tips? Thanks.
 
Venomgrass said:
Hi all,
Looking for tips and the best way to dry my boat out off the grid, I have no mains power in the dock where my boat is moored. I'm going to add a small 12v solar vent and consider an option to dry her out. Will ventillatiob alone do it or do need a parafin heater, tiny 12v dehumidifier driven from the battery, maybe swap 2 batteries charging the other at home and swapping daily?

Any tips? Thanks.
Click to expand...

How damp, and why is it damp? Any rain getting in? If so you have to fix that first... even a little bit will make a big difference! Normally given a bit of ventilation and good lining it shouldn't really be damp in the interior IME, except when people are aboard and breathing/cooking.
 
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A parafin heater will only add to your woes as it produces a lot of water vapour when burning. I tried using a small greenhouse heater many years ago and the cabin ran with condensation. I don't know whether a solar vent will help, but I suspect you need something a bit more substantial unless you're trying to dry out a silhouette or something similar. A friend with a Seahorse 800 uses Lild/Aldi silica gel packs on his boat ashore and assures me that a couple is all that's required to keep it dry over winter, but I've not tried that myself.

I'm not aware of a 12 volt dehumidifier, but providing you empty the drip tray when you change the battery, that might do the job.
 
Venomgrass said:
Hi all,
Looking for tips and the best way to dry my boat out off the grid, I have no mains power in the dock where my boat is moored. I'm going to add a small 12v solar vent and consider an option to dry her out. Will ventillatiob alone do it or do need a parafin heater, tiny 12v dehumidifier driven from the battery, maybe swap 2 batteries charging the other at home and swapping daily?

Any tips? Thanks.
Click to expand...

Definitely no to the paraffin heater. The amount of water vapour produced will make it counter-productive.

Any humidifier will require the boat to be well sealed or you will simply be trying to dehumidify the hemisphere. For a 12 volt one you will need a couple of fairly large batteries to swap daily, and the means to recharge them overnight.
 
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12v dehumidifier:
http://www.amazon.co.uk/Pro-Breeze®...4106490&sr=8-1-fkmr0&keywords=1v+dehumidifier

It's damp due to bring neglected for 2 years by previous owner, and sourced a leak at the bow where an old Samson post had been poorly capped with some rotten wood thus letting the bow cabin cupboard fill with 1mof water deep!! I'm draining this away tonight. Then I'll need to tackle drying all of the damp boat out.

What ventillatiob methods are there? Solar fans are expensive...
 
Remove any bilge water as that will just be evaporating and condensing on any cold surface. If water is getting in you will never get rid of the damp. Start off as dry as possible. ventilation should dry it out as long as no more water is getting in or you are running any paraffin heaters or using gas for cooking.
 
You can get dehumidifiers that work by using hygroscopic granules instead of powered condensers. They're not as effective but they don't require any power. I'd probably ventilate the boat well until things are mostly dry then maybe try a few of those to remove the last of the damp.
 
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Make a wind scoop for the fore hatch and companionway, funnel shape if possible and weatherproof at the seams. Try and design it so that the rain stays out or drains off before it is carried into the boat. Without any form of power for heaters or blowers you will have to maximise the opportunity for the wind to dry the inside of the boat. I would also consider solar powered extractor fans fitted into custom built housings over any other openings. I would leave the hull exposed to the weather so that any sun can also heat the hull directly. As others have said mop up every ounce of water that you can. You may be surprised how fast it drys out.
 
Ventilation is the key, after stopping the water getting in; I don't think you have a hood over the companionway but you could just rig a small tarpaulin over there and leave the hatch open slightly - that will help a lot. I don't think you need electrical help.
 
Are you close to the boat? If so, you will have more opportunities to throw the hatches open on dry breezy days. As others have said, remove all standing water first and then ventilate, ventilate, ventilate. It sounds as though your boat is a long way from being fully sealed up and hence any sort of dehumidifier will just be a drop in the ocean.

If she is out of the water, you could remove a few hoses and open seacocks, it all helps.
 
You need to decide how you are drying - ventilation or dehumidifying.

Ventilation will let moisture vapour leave. But you can't dehumidify an open boat - you just absorb moisture from the air on damp days. A small low power (non-combustion) heater can help that because it increases the air temp allowing more moisture in the air that the ventilation then takes away. BUT combustion generates water so unless you can harvest the heat separately from the flame you are on a loosing battle. My caravan heater keeps the flame outside the van (so the CO / CO2 and / H20 are too!) and a hot plate inside the van provides the heat. Not seeing an easy way to temporarily rig that though...

Dehumidifying works on sealed boats. Choices are a heating and condensing option which uses sh17 loads of power. That little unit is 20W which is actually very low power. But realistically you'd need at least 100W solar panel and 80Ah battery to run it all day as you will have far less sun this time of year. Suspect you need more than 1 (multiply the battery and the solar panel sizes!) But also think youd need to think of how the 500ml trap is drained... The general principle of these is it warms the air and then cools it causing the moisture to condense into some form of trap to be removed by hand (or maybe bilge pump?) later. Silica Gel systems work but will depend how wet the boat is. I know people who use salt and rice mixed to do similar. Rejuvinate by heating gently in the oven. You may be able to do similar with silica ones. Rice should be large qunatities (but buy cheap low quality stuff - think TescoValue! Make surface area large...

Quick look at some caravan ones 250g sachet will absorb 175ml of water. Much cheaper than your battery unit. BUT its slow. It takes 2 months. If you are trying to keep on top of humidity thats fine but if you are trying to dry it out its not so good. 250g will dehumidify 2.5cubic metres. I generally would take that to mean you need 1 250g bag every 1m along your cabin floor.

I'd fix your leak, protect from other leaks with tarp etc and well ventilate on some windy dry days. Then once you've done the best you can there, use rice to try and keep on top of it with a sealed boat. But if I had decent power source I'd use the 12V unit as well...
 
Is there somewhere you could sail to that does have power, to dry her out? Sounds to me that the sooner you get the water out and her dry, the better. Then she can live off the grid happily.
 
As others have said,
(1) Ventilate, ventilate some more, then add more ventilation. Fit more vents if you have few or none. It's more important to have at least a small through flow of air all/most of the time, than to have all the hatches open once in a while.
(2) Stop water getting in. Solve any leaks as best you can. Avoid adding more moisture than necessary when you're aboard.

The other important thing is (3) to clean the boat interior. Any salt on berth cushions, side linings etc. will absorb and retain moisture. A fine coating of grime will provide an ideal home for mould, which will then look and smell bad, making it all seem much worse than it may actually be. Even though washing down may seem counter-intuitive as it will involve splashing more water about, this will quickly more than pay off.
 
Agree that if you don't have power, lots of ventilation is the only way, and even then a UK winter really isn't the ideal time to be doing it. The suggestion of a thorough clean first is a good one, followed by manual drying (with towels, paper, etc) of every drop of liquid water.

For our previous boat I made a winter washboard (the "door" that slots into the main hatchway) out of cheap stirling board, with a big vent cut in it and a downward-facing cowl over the vent to keep the rain out. There's a boat moored near us whose owner leaves the forehatch open, but with a plastic storage crate upside down over it and bungeed to the deck. Or if you're able to build a tarpaulin tent over the whole deck and leave everything wide open that would be great, but make sure it's good and strong because the loads in winter wind can be very high. Most blue builder's poly-tarps draped casually over boats in the autumn are shredded to bits by the spring.

Pete
 
Venomgrass said:
How about a small wood burning stove!! Would this work??
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Actually stoves work pretty well for drying out - they provide heat, but the chimney means that they don't exhaust moisture into the interior. And the draw of the fire pulls in the damp air. But of course you have to be on board to run it - I assumed this was a boat that was going to be left unoccupied.

The way to pass the chimney through the deck is called a deck iron:

DeckTradMed.jpg


The trough between the outer rim and the inner pipe is kept full of water so that the rim attached to the deck stays cool.

Remind us what type of boat you have? A full-size wood stove isn't really practical on a small boat, but there are smaller charcoal stoves out there.

Pete
 
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