Originally Posted By: Deathwind
I'd like to see charts for various proposed survival times for different PFD's like float coats and the float coveralls, which I hadn't even heard of before. And what about various, such as wearing a hat, boots or other base clothing. Someone, somewhere must have looked into this? Maybe military.


I am late to the party, but since TeacherRO brought it back ---

It has been looked into extensively. Mostly at the University of Victoria in British Columbia. The most complete testing on human subjects was done in the '70s and led to: Hayward, J.S., Lisson, P.A., Collis, N.L., and Eckerson, J.D. Survival Suits for Accidental Immersion in Cold Water: Design-Concept and their Thermal Protective Performance. Dept. of Biology. Univ. of Victoria, B.C. 1978. I have not found a copy online and don't know if I can find my copy, but testing was done in Victoria Harbor on students wearing several different types of clothing. As you might expect wool was better than cotton (but not as much as you might expect) and the fit of the clothing made a difference but again the activity was more important (see below). Human testing of this sort will probably never be done again, but it was a sea change in our understanding of immersion hypothermia.

This work led Hayward to develop what is now the Mustang ThermoSystem Float Coat. The beavertail (or diaper at is commonly called) changes a moderate increase in survival time to a huge one (the modern coat is even better than the original). I have used one for many years and would not be comfortable offshore in cold water without it. I have had it in the water many times (for practice, my only sinking ship I got off with dry feet). Mustang makes several other coats so fit of one may not control fit in the ThermoSystem.

The following is a bit of information from this work that was printed in a pamphlet by Hayward through the Sea Grant Program at UBC. ir.library.oregonstate.edu/xmlui/handle/1957/24392?show=full

SUMMARY
The following table summarizes how a selection of
different situations can affect predicted survival time
of the average adult* in water of 50OF (100C):
Situation Predicted Survival Time (Hours)
NO FLOTATION
Drownproofing 1.5
Treading Water 2.0
WITH FLOTATION
Swimming 2.0
Holding-still 2.7
H.E.L.P. 4.0
Huddle 4.0
UVic Thermofloat 9.5
*Clothing worn was cotton shirt, pants, and socks, plus
running shoes.

Respectfully,

Jerry