Sorry, got that wrong!
I may be wrong here & I will stand corrected if I am, then you are not entirely correct. Although i cannot find anything on google to support what I am going to say which makes me more uncertain.
I may be wrong here & I will stand corrected if I am, then you are not entirely correct. Although i cannot find anything on google to support what I am going to say which makes me more uncertain.
However, I seem to recall that the first part of your comment is correct to a point. ie cold air holds less moisture. But only so far. At temperatures falling below 4+ C the air once again starts to hold moisture.
That means that if the temperature outside the boat is, say 1deg C one will actually be pumping moisture laden air into the boat. This is precisely the sort of condition that the Op might meet when he wants to dry his boat . Obviously he would expect the temperature to rise at some point but depending on where his boat is & when the heater runs, will have an effect on his efforts
That being said I would still go for the diesel heater & ventilation if an A/C unit is not available-- with the proviso that the OP is aware that there have been stories of some catching fire when left unattended . Discharge the water into the sink & out via the drain otherwise the water will fill the tank & the operation will become pointless.
I am sure others will comment on my memory about the absorption of moisture in cold air. As I said, It is a very long time since I went to school but I did get an "O" level in chemistry-- for what good that did
I'm afraid you are misremembering. Here's a table from Engineering Toolbox:
That part of my post did relate to A/C units. NOT diesel heaters. (Although I failed to make that clear- apologies)They extract water & some collect the water to a tray which needs emptying & some have a discharge hose. I did read a PBO magazine test of them some years ago ( That is where I got this info) & they suggested the "discharge to a sink" idea. Not my idea. They also cited some cases of fires on board caused by electric heaters & A/C units left un supervised for long periods. Acompanied by a picture of a burning motor cruiser!!!
And to back all that up, Antarctica is extremely dry, because the air simply can't hold much moisture at temperatures that average below that of the lowest in JD's table. . The annual precipitation in the interior of Antarctica is less than 2mm per year in many places - Antarctica is by far the driest place on Earth; the Sahara is positively damp by comparison!I'm afraid you are misremembering. Here's a table from Engineering Toolbox:
It's a bit misleading to think of air "holding" moisture. It's not like dissolving something in water, when there is a temperature-dependent maximum solute density. Water in air is just another gaseous component and the maximum possible amount depends on the physical properties of water, not air. So, for example, at 10C the saturation pressure of water is 0.01227 bar, which means that water can contribute at most 1.227% of atmospheric pressure. At saturation the water has a density of 9.39 g per cubic metre, which you'll see is the value in the table above.
That's completely independent of the other constituents; as long as the temperature is 10C the maximum water density will be 9.39 g per cubic metre whether in a boat, at the top of Everest, surrounded by helium or in the "vacuum" space at the top of a water column barometer.
Of course it can help to think of the atmosphere carrying air, but only in the sense of "what does the current temperature permit"? Cumulus clouds don't form because rising air can't hold water - they form because the temperature drops below the saturation temperature for the local pressure.
Indeed. Below 0C at 1 bar the game changes a bit because it's now solid and gas in equilibrium, not liquid and gas. Water sublimes quite nicely - it's how hailstones disappear on dry days.
It would have built up faster initially; much of the present low temperature is caused by the ice cap itself - it reaches over 4000m high, and is part of the mechanism that causes the polar vortex, which keeps the air dry and the temperatures low. There is a mountain range beneath the ice - the Gamburtsev Mountains - that are though to have formed the nucleus for the initial formation of the ice cap, But basically, it's all about time - the ice cap has been there for a long time; Antarctica has been centred over the pole since the Cretaceous, or even earlier (I forget the exact period) and the ice cap has been in existence since the Eocene, 45 million years ago. Even 2mm a year accumulates a vast thickness over that kind of period - I make it 90km, and the ice only averages 2 km thick! Of course, the discrepancy is because ice is plastic and flows; I think the oldest ice at the bottom of cores like that at Dome C is dated less than a million years ago, but it gets a bit messy at the bottom of the core because the flow regime of the ice is no longer simple.
Rain water qhilemit was sat on its mooring winter spring time.
