Thermal blanket replacement

[weustace]

For some time I have carried emergency foil survival blankets (never yet required, thankfully) with a view to warming up crew in the event of a MOB or similar hypothermia-inducing incident. I recently attended a first aid course in which the instructor (who is experienced and very well qualified) advised one should in fact carry survival bags, as the main mechanism of heat loss from a wet casualty is evaporative rather than radiative; I have ordered a couple, but wondered what the experience of the forum would advise?

 

[Motor_Sailor]

Your instructor was quite correct. A cold, wet body radiates almost no heat, so the silver bit is irrelevant. In these circumstances a 'space blanket' is no more effective than any impervious material of the same thickness.

What you need it something you can completely seal around the body with no leaks or draughts and once you've achieved that, then it's thermal insulation in terms of 'loft' or trapped air insulation that will pay dividends. If you also have the capacity to add a heat source (hot water bottle, another dry human, etc), then so much the better.

The combination of easy storage, complete seal and trapped air lofted insulation can be achieved very conveniently by something like the Blizzard Survival bag. Alternatively there are various 'bivi bags out there, but a lot of these 'bags' suffer from the same problem of being difficult to get the casualty into them easily.

Something fully zipped solves this and if it has some fibre pile insulation it's going to be perfect for warming up a wet casualty. The ultimate (and very costly) solution is a 'casualty bag' (https://www.aiguillealpine.co.uk/product/safety-rescue/mr010/), but if you spoke to Adrian there, I think there's a market for a simple pile / pertex, full zip bag made as simply as possible for sailor's use.

 

[JumbleDuck]

Your instructor was quite correct. A cold, wet body radiates almost no heat, so the silver bit is irrelevant. .

As soon as the body warms up a bit, though, radiation kicks in, and matters more than most people think. The silver coating does no harm at all at first, and helps later on.

 

[weustace]

Interesting perspectives; thanks both. I can see the potential issue with getting a wet and potentially unconscious casualty into such a bag; will have to find a volunteer and give it a go... Re the radiation point, I will definitely retain the foil blankets as part of the arsenal--not too much space compared to all the other clutter aboard!
Thanks again.

 

[Motor_Sailor]

. . . the potential issue with getting a wet and potentially unconscious casualty into such a bag; . . . .

The unconscious ones are easy! It's the conscious and injured ones who bitch about being stuffed in a bag.