Regular readers will know we (the 2½ of us) live on a narrow boat.
That’s just a long skinny boat made out of metal.
Anything made out of metal that gets cold is a condensation magnet and that moisture is mainly caused by us doing silly things like breathing let alone living.
Now you’re probably thinking what’s this got to do with prepping and survival?
Your moisture laden warm breath landing on something cold will cause condensation aka damp. What does that make for? Damp clothing and worse of all DAMP BEDDING.
So what would you do to help alleviate damp in austere conditions?
Regarding bedding. Get off the floor.
Hot air rises, cold air falls, so putting a minimum if a foot (12″) beneath you and the cold floor can make your life a lot more pleasant. Only there is a point to watch. I’ve seen folk pile up bedding (foliage for instance) and either cover it with a tarpaulin and think “I’ve sussed that”. Only in the morning their bag is wet on the bottom. Heat and moisture from the body leaks not only up but DOWN and although you are on a bed of foliage, that moisture has to go somewhere. ONLY IT CAN’T. If they just lay the bag on top of the foliage, they may have forgotten that foliage is laden with moisture. Add a bit of heat and it readily gives it up.
Incidently deciduous (fat leafed) foliage is a source of safe water (CBRN contingent).
Provided nothing bad falls into the collected water.
You could slap a “goretex” breathable type cloth or the tyvek fabric used for clothing NOT the building version onto the bedding then your sleeping bag on top.
Both sheets are breathable so damp ‘should’ just pass into the foliage.
Well it does, sort of.
Except the underneath of a sleeping bag will ALWAYS get a bit damp.
That’s sleeping bags for you.
There are those of us who prefer hammocks.
They put you WAY ABOVE the cold zone if are smart.
Except for you who haven’t used a hammock before, lying in a sleeping bag in a hammock curiously flattens the material UNDERNEATH you. Thus your back gets colder than your front. (I’ve never met anyone who sleeps on their front in a hammock).
Thus it’s a good idea to put good insulation under AND up the sides.
Only what? I like synthetic material pad filled with the same polyester filling in modern duvets and INSIDE a breathable material sac or bag.
Yet think about it for a moment, it’s not infallible.
You will be expiring water through your skin.
That passes through the breathable material, the polyester, then it hits the outside cold. IT WILL CONDENSATE. Your bag may be OK (ish) but NOW the hammock wrap contains water aka damp. Add wind and it will ‘help’ to chill you.
What causes condensation in shelters?
For the most part it is a lack of ventilation.
Hot air rises, gently cools down and condenses on colder surfaces making damp.
So it makes sense to control it by venting out the wet air.
It’s a balancing act though. Let too much out and your heat will vent out too.
Not enough and damp starts.
By in far the nicest way of doing things if you are in the field under canvas, is to set up a fire under a ‘chimney’ or smoke-hole. The fire burning, the up rush of hot air dragging the warm ‘damp laden’ air out of the top pf your shelter.
CAUTION DANGEROUS ADVICE.
Fire needs three things to survive, fuel, heat and oxygen.
Curiously so do you BUT without ensuring you have a good enough supply of fresh air to feed the fire and you, a fire will eat all the oxygen AND YOU WILL DIE.
Fire also produces carbon monoxide.
A clear, tasteless, heavier than air gas WHICH AGAIN CAN KILL YOU.
The clue there is heavier than air.
Thus a sleeping platform is essential for safety when using a fire. i.e.
Note the cold air getting in (in blue).
Those lower vent holes are absolutely essential as is the smoke hole / vent at the top of the shelter.
Some will be thinking “it never snows here”. OK but that’s not the point.
It’s the principle of getting air into and fumes out of the shelter.
Other locations may be more suited for a multi-fuel stove (coal, wood, peat, charcoal).
They need air too and apart from radiating heat, the water rich air usually gets vented through and out the chimney.
So what do you do with damp bedding or clothing?
Bottom line? You need to air your bedding everyday to get the damp out of your kit.
Only how to do that when it’s:-
You can’t even with a roaring fire!
Good question eh?
Airing clothes (or anything else) is all about putting them into somewhere drier than what they are and into warm, moving air, until they are completely dry.
The clue to success being they stop smelling of you (or whatever) and smell clean.
Only when the air is full of water (100% relative humidity) you’re not going to get any moisture out of them as there is no where for it to go to!
There are times when you stand a slightly better chance.
Ever heard of dew point?
That’s when the ambient temperature drops too low for the air to hold the amount of water vapour it contains. Then the water vapour condenses into liquid aka dew. The nice bit about this is it happens twice. Once in the morning and as the land cools down at night.
So if you wait till AFTER the dew has fallen the air will contain less ‘suspended water vapour’ in it, especially if it is windy.
Apart from that, it’s a clothes airer in front of a fire or stove.
Only remember, dry clothes means that moisture has gone into the air so ventilate well!