Hazards: Cold. Of wind double-dipping, clothes into water single-dipping et al.

[vicky_molokh]

Originally Posted by Anthony

What GURPS Low-Tech calls 'waterproof' is what we would call 'water-resistant'; it's designed to protect against rain, not immersion (boot wax is the same technology being described in low tech. Waxing your boots does not turn them into waders). Clothing suitable for surviving a dive into arctic water is TL 7 (a neoprene wetsuit, for example).

It's a piece of clothing used for arctic kayaking; mere water-resistance of the sort as waxed but permeable boots seems to be insufficient for that.

http://en.wikipedia.org/wiki/Kayak_roll#History

[Flyndaran]

Originally Posted by Anthony

What GURPS Low-Tech calls 'waterproof' is what we would call 'water-resistant'; it's designed to protect against rain, not immersion (boot wax is the same technology being described in low tech. Waxing your boots does not turn them into waders). Clothing suitable for surviving a dive into arctic water is TL 7 (a neoprene wetsuit, for example).

A wetsuit, by definition, won't keep you dry. You need arctic clothing underneath a drysuit to avoid freezing when under water.

[Anthony]

Originally Posted by vicky_molokh

It's a piece of clothing used for arctic kayaking; mere water-resistance of the sort as waxed but permeable boots seems to be insufficient for that.

I was referring to Low-Tech, not kayaking, but what makes you think that rolling your kayak doesn't get you wet?

[Anthony]

Originally Posted by Flyndaran

A wetsuit, by definition, won't keep you dry. You need arctic clothing underneath a drysuit to avoid freezing when under water.

It's not actually necessary to stay dry, as long as you don't have water continually moving in and out and you have sufficient insulation -- you just wind up with a layer of warm water next to the skin. Arctic waters require more padding than is generally practical with a wetsuit, but in the end what matters is rate of heat transfer, not being dry, so an impermeable layer of insulation can do the job.

[vicky_molokh]

Originally Posted by Anthony

I was referring to Low-Tech, not kayaking, but what makes you think that rolling your kayak doesn't get you wet?

The fact that getting more than a little wet and sailing on, without an opportunity to get to a shelter and change clothes, will tend to get you dead, not just wet. So those rollers had to have a way to safely continue paddling after the roll. (Wiki also claims that the anorak is waterproof, while the fishtail parka isn't. So that seems to support Low-Tech's claim of waterproofness. Though depth of waterproofing might as well be less than 1 yard deep, sure. And I do realise WP isn't 100% reliable, to say the least; still, the two sources seem to agree.)

[Anthony]

Originally Posted by vicky_molokh

The fact that getting more than a little wet and sailing on, without an opportunity to get to a shelter and change clothes, will tend to get you dead, not just wet. So those rollers had to have a way to safely continue paddling after the roll.

Water resistant clothing will handle a brief immersion, by virtue of having multiple layers that will soak up the moisture; handling sustained immersion requires sealed joins that are beyond the capabilities of low tech levels. In any case, the tech described in Low-Tech is quite clearly oil, grease, and wax.

[BraselC5048]

And I've got a character who was once dumped into Lake Superior in February in his underwear. High levels of escape got problem one out of the way. Very Fit and HT 14 with 18 FP came in handy next. I found a document online listing survival times in water at various temperatures, and determined at that temp you would need to make RAW "freezing water" rules every 4 minutes. So an hour of swimming to shore, then a 4 hour or so hike to the nearest town. He wound up at 6 FP left (12 "virtual FP") when he reached town, all due to cold at that point. Using the stock rules, I determined the temp as +15 F and the windspeed as 40 MPH, for a windchill of -8 F.

One thing I never did figure out is how long it would take for him to fully warm up, now that he's got warm clothes and a warm building. Assuming breath Control and Very Fit didn't apply, it would take 15 minutes per full FP?, for 3 hours? That sound about right?

Anyway, he had some rather "unfinished business" back in Duluth, as you can rather imagine, and had to catch the next train back there. (It was the 1940's. That was how you did it back then. Also: Asking for money for a ticket in coach on the morning local.)

On the plus side, apparently the parish church there (Catholic, since that was his friend's religion, more or less, and they had never talked about religion anyway, so it seemed right) has some rather wide rafters, enough to hide a skinny person there to watch his own funeral. Oh well, if he ever needs to become legally dead, the priest and the tombstone there should come in handy.

[Flyndaran]

Originally Posted by Anthony

It's not actually necessary to stay dry, as long as you don't have water continually moving in and out and you have sufficient insulation -- you just wind up with a layer of warm water next to the skin. Arctic waters require more padding than is generally practical with a wetsuit, but in the end what matters is rate of heat transfer, not being dry, so an impermeable layer of insulation can do the job.

People in wetsuits can handle cool water, but not cold. Water is simply too good of a heat conductor for average wet humans to survive for long immersed in it cold.
If the water can get to your skin, then obviously insulation doesn't exist.

[Anthony]

Originally Posted by Flyndaran

If the water can get to your skin, then obviously insulation doesn't exist.

The rate at which heat can escape from a wetsuit is determined by heat transfer through the suit (i.e. insulation) plus the rate at which the water under the suit is replaced, plus any heat flow through gaps. Insulation most certainly does exist -- though a drysuit provides more insulation at a given thickness and doesn't have any losses to fluid flow at all, and thus handles freezing water better.

[vicky_molokh]

Originally Posted by BraselC5048

One thing I never did figure out is how long it would take for him to fully warm up, now that he's got warm clothes and a warm building. Assuming breath Control and Very Fit didn't apply, it would take 15 minutes per full FP?, for 3 hours? That sound about right?

Why Very Fit wouldn't apply? Fitness modifiers affect everything except supernatural FP expenditure/regain, and very explicitly mentions FP lost to temperature. Kromm also mentioned Very Fit being useful, among other things, for commandos who get little to no sleep during high-intensity operations.

It's more complicated with Breath Control, which isn't as explicit.