Comment by jokull | Hacker News Reader

Comment by jokull | Hacker News Reader

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There's an Icelandic legend that beat all this crap in 1984. His ship sank with all his friends and co-workers. He swam to shore, walked bare feet on razor sharp lava and walked to town. Guðlaugur Friðþórsson.

His descriptions are chilling. "When the ship sank from underneath us and we were submerged for the second time we decided [the three of us] to swim. We decided not to help each other which would have been hopeless. We spotted the lighthouse and started swimming towards it. Soon there was only the two of us left calling between us, but soon enough I stopped hearing any calls."

More amazingness: On his way to shore a ship came within 100m of him. He spoke to "múkki" an imagined sailor's friend on the way, told himself jokes and said some prayers. When he came to shore he had to hold onto a rock wall while waiting for the tide to recede. While walking he spotted a bathtub used for lifestock feeding he punched through a layer of ice to get drinking water.

Apparently he survived because he was fat.

http://books.google.com.au/books?id=rYIJJP7audkC&pg=PA26...

I can't find a citation for this now, but I recall reading somewhere that he had a higher ratio of brown fat than is normal. I.e. just being fat isn't enough, it has to be the right sort of fat.

http://www.vikingrune.com/2009/03/true-viking-grit/

However, a startling fact was discovered by the researchers from the University of Iceland: Guðlaugur’s fat is almost like seal fat. It is more solid and two or three times thicker than human fat.

"cold water is highly viscous and impedes swimming"

This is very size and speed dependent, but increased viscosity delays separation and can actually reduce drag [1], [2]. In any case, the viscosity difference is not huge and water temperature is normally not precisely controlled for swimming events.

"Most people [...] suffer from vasodilation in extreme cold."

Only when the core is doing well [3], the opposite (vasoconstriction) occurs otherwise.

[1] http://jeb.biologists.org/cgi/content/abstract/204/1/81

[2] http://www3.interscience.wiley.com/journal/120798746/abstrac...

[3] http://www.springerlink.com/content/l776704k04017q43/

The Mythbusters checked the increased viscosity myth (opposite presumption, same speed is possible) and found it plausible.

http://mythbustersresults.com/swimming-in-syrup

It has been a long running debate which way viscosity would affect swimming. Higher velocity increases resistance to forward motion but also allows for more propulsive force from the swimmer - which will dominate?

It turns a research group at UMN actually was crazy enough to do the test - it looks like the effects balance for a human swimmer.

http://it.umn.edu/news/inventing/2004_Winter/goingforthegoo....

http://www.cems.umn.edu/research/cussler/pool/

As as a swimmer, I know I'd much rather swim in cold water than warm, at least as far as pools go.

It's easier to maintain momentum and glide in cold water, whereas swimming in warm water feels like you're swimming in molasses.

Also, as my body heats up, cold water feels more cooling, obviously.

"Múkki" isn't an imagined sailor's friend. It's the Northern Fulmar, an abundant sea bird. He was talking to the birds he saw overhead to pass the time.

Thanks for correcting me. Hvernig datt mér þetta í hug?

Guðlaugur was dressed in jeans, shirt and sweater, with nothing on his feet. He did not know that wet clothes draw heat from the body 20 times faster than dry ones. [1]

I'm curious what should I do if I fall into cold water: should I really take my clothes off or not? The first option sounds a bit counter intuitive to me.

By the way, how can people swim in jeans or other clothes? I find it very hard, it's like dragging some weights.

[1] http://www.vikingrune.com/2009/03/true-viking-grit/

Yes you should take your clothes off. They impede your movements and provide you with no insulation.

What about after you're out of the cold water and on land? Take off the wet clothes and dry off naked, or leave them on for protection against wind chill? Or does it just depend on the wind chill and other circumstantial factors?

It depends entirely on what sort of clothes they are. Wool will insulate you even when soaked, but wearing a pair of wet jeans is worse than wearing nothing at all.

They don't provide insulation, and only serve to make you wet and extract heat from you. Just like a wet towel wrapped around a champaign bottle.

Are you sure about this? Surely they keep a layer of warmer water nearer your skin - the same way wet suits work.

Once someone is out the water wet clothing should be removed.

Wetsuits are made of neophrene, they only work because neophrene is completely waterproof. That's not the case with a pair of jeans and a sweater.

New cold water will seep through much faster than your body can warm it. Even if you gained a fraction of a degree from tightly fitting clothes you'd lose much more than that through lack of mobility.

Wetsuits are named wet because their operational concept depends the water they absorb. Maybe you intended to refer to a drysuit?

See: http://en.wikipedia.org/wiki/Wetsuit

". . .a thin layer of trapped water could be tolerated between the suit fabric and the skin, so long as insulation was present in the fabric in the form of trapped bubbles. In this case, the water would quickly reach skin temperature and the air in the fabric would continue to act as the thermal insulation to keep it that way. The suit did not need to be dry to be insulative."

No I meant a wetsuit. Wetsuits are completely waterproof aside from a select few entry points where water is allowed to seep through as you first get in the water.

The idea behind their operation is that you have a thin film of warm water around your body, isolated by a waterproof neophrene layer. So there's: The Sea -> neophrene -> Warm water that doesn't freely mix with the sea -> You.

That doesn't work (as deadmansshoes thought) if you're wearing normal clothes instead of a neophrene layer. In that case the water next to your body is constantly being replaced by new & cold water, faster than you can heat it up to provide you with insulation.

Both wetsuit and drysuits depend on there being a layer next to your body that you heat up. With wetsuits this is a layer of water that doesn't get swapped out, with drysuits it's a layer of air + rubber.

Do you have any links?

The article suggests you won't be able to swim so struggling to take your clothes off seems like very bad advice.

Several layers of clothes, and even a semi-waterproof jacket or anorak will trap water - and air which would help with bouyancy.

A fraction of a degree could be all important - there is a tipping point where a fraction means living or dying.

I live in Michigan's UP, and there was a sailor who fell out of one of the shipping boats... at night. Lake Superior is 40-45 degrees out there, at best. He swam to miles shore and managed to knock on the door of an elderly couple.

I'm impressed. That guy must be so fit.

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