~^ beancounter ~^ wrote:
my understanding is that a PFD will hold your head above
water....that's where most heat is lost....it may buy you
an extra few hours....or so....

A lot of body heat is lost when one flails arms and legs around trying
to tread water.
A PFD allows a MOB to stay afloat while curled up, knees against the
chest, to minimize the body's exposure to the cold water.

Up here, there is no such thing for most people as a few hours. Some
are unconcious in a matter of minutes, others take 30- minutes to an
hour before the body core cools to the point where vital organs such as
the brain, heart, and lungs shut down.