Re: [Paddlewise] Cliff Notes

Larry Bliven wrote:
> 
> It's the mid 1930's, along a section of coastal Norway with straight cliffs.
snip
> The teens are concerned that the
> confused waves will capsize their rowboat. Mom tells them to row a quarter
> wavelength from the cliffs. Although waves break around them everywhere,
> they pass through the dreaded area on relatively calm water.

Assuming a perfectly shear cliff, acting as mirror, 1/4 wavelength
into the wall, plus 1/4 wavelength coming back to you, adds up to
1/2 wavelength.  So right at that spot, the reflected wave will be cancelling
the next incoming wave.    Go out to 1/2 wavelength from the cliff,
and now the 1/2 plus 1/2 add up to a whole wavelength, and the waves
will be twice as big.

> Another story was about a fellow who entered an unheated Norwegian cabin in
> winter. He took a sip of brandy and died immediately from a frozen gullet.

The brandy is at ambient temperature, below freezing point of water, 
but not below the freezing point of alcohol.  Not sure a sip would do it,
but maybe a good swallow. The body, trying to heat up the alcohol
loses enought heat that the moisture in the throat freezes. Sort of
like cold throat from eating ice cream too fast, only worse.
Hmm, also, as the brandy is diluted (slight evaporation of alcohol
as the brandy is poured, plus dilution with saliva, may allow the brandy
(going from about 40 percent water to maybe 30) to freeze (less concentration
of antifreeze).  Ice crystals tearing up the throat?
I also recently read about needing to very carefull of spilling stove
fuel one yourself in cold conditions, the cold fuel is still evaporating,
and thus cooling the remaining liquid fuel, good way to get spot frostbite
where the fuel spills on you.

> The quarter wavelength idea seems interesting. Any comments?

Its an interesting idea, assuming waves are coming in at a consistent
size and interval, and that the cliff is acting as a perfect reflector.

I prefer to stay farther away from reflecting surfaces when possible.

dave

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