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Nope.  The ice cream thing is based on the melting action and the ability of
salt to lower the freezing point of water.  Ice at 32F and ice water at 32F
are both 32F, but it requires heat for the change in state from solid to
liquid.  The heat energy used in melting is drawn from the cream--The
freezing process gives off heat--thus the heat necessary for melting the ice
comes from the freezing of the cream.
     However, the salt in seawater (or ice cream brine) also lowers the
freezing point, creating a situation where liquid saltwater can exist at
below 32F.  Regs would be no more likely to freeze on this basis in
saltwater at 32F than freshwater at 32F.  But, regs would be slightly more
likely to freeze due to moisture in the breathing mixture if the seawater
were 31F versus 32F freshwater simply because of the temp difference.

Anyway, it's something like this.  It's late, and my memory of the laws of
thermodynamics may be a bit sketchy, so if there's an MIT grad out there who
can correct any flaws in my explanation, go for it.

I'm suddenly very hungry for ice cream.

S/F,
Duane

Ergo the query... recalling what us old farts used
>to do to make ice cream at home- mix rock salt and ice to make a slushy
>brine and then use that to surround and "super cool" the cream inside
>the container.  Does the same principle apply in diving- i.e..  a salt
>water solution at 0 C is going to be able to conduct heat away from the
>reg more efficiently than a fresh water solution at 0 C and therefor
>make you more susceptible to freeze up?


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