35 with some lucky guesses and tripping on the spring line (probably got it backwards). The answer for Question 21 with the tugboat needed a much better picture to make it a fair question.
And what answer did the quiz want for Q. 36, which part of the body loses most heat? I guessed trunk but it probably should have been legs and I for sure hope they weren't headhunting:
The US Sailing Study guide (Sailing Emergencies
) under the Hypothermia heading claims, "Most of the heat loss occurs through the head".
The course designer
seems to have bought into a * myth
* based on a misleading US Army study from more than half a century ago. Yes, the scalp has lots of blood vessels that are good at exchanging heat, and with lots of sensitive nerves on the head
and face, covering the head
makes a huge difference in how warm you feel. But the head, with maybe 10% of the body's surface, would generally lose only something more like 25% or 30% of body heat according to the best sources I've seen so far. And if the head is being held up out of the water
by a PFD
(lifejacket) while the rest of the body is wet and a person is shivering, the percentage loss from the head would be even smaller.
Sure, I could probably replicate the mis-leading result--just dress someone up in a survival suit minus a hood
, hang the person upside down, and dunk his or her head in frigid water! NOT a good idea with an (until-then) live person!
This would be a good opportunity for the course designer
to update the class with current
information on the effects of cold water
immersion, including cold water shock, gasp reflex, and swimming failure, which can kill someone before hypothermia or post-immersion collapse get their turn at bat.
Jolie Bookspan, M.Ed, PhD, FAWM: "Losing most of your heat through your head is a popular myth. Head heat loss is not the majority of body heat lost
. Not even close" Do You Lose Most Of Your Heat Through Your Head?
"Scientists debunk the myth that you lose most heat through your head"... Scientists debunk myth that most heat is lost through head | Science | The Guardian
"False claim: Most of body heat is lost
through head" False claim: Most of body heat is lost through head - Science - Home - The Times of India
Also, the Cold Water Boot Camp (Cold Water Boot Camp
) web site and some of the Sea Kayaking groups (Sea Kayaker, Seakayaker Magazine - The latest seakayaking news and information
) have great information on cold water hazards.