Tuesday, October 22, 2013

Cold Water Survival – Preventing Heat Loss

This writing is in response to Captain Rande and the comment he made in an earlier blog I wrote on Cold Weather Precautions:

“Unfortunately, you forgot to mention the most important thing. Wearing a life jacket. In cold water, you will never die from hypothermia, unless you are wearing a life jacket. You will assuredly drown first.”

Get the cold facts here:

Although that blog was about how to prevent hypothermia and the proper treatment of a hypothermic victim, Captain Rande raises a valid point, one that we will now explore.  Few will disagree that the first rule of survival when operating in a cold-water environment is to stay dry. Water robs body heat up to 25 times faster in water than air of the same temperature. So when we speak of heat loss, there is no circumstance or condition in which you are better off in cold water than in air, even if you are exposed to wind and sea spray. If you fall overboard into cold water, your body’s natural cold shock response will be for you to loose control of your breathing as you gasp for air and begin to thrash about in an effort to stay afloat.

An important key to cold water survival is very much dependent on your ability to resist this natural reaction. Admittedly, remaining calm under these circumstances may be impossible. However, if you are aware of your body’s natural response to cold-water immersion you can learn to control your breathing and minimize your state of alarm. If you do panic, struggle, or begin to swim, the flushing action of cold water against your body’s critical heat-loss areas will speed the loss of muscle control, ultimately leaving you incapacitated. In the event that there are two or more people in the water, huddle together. There will be less heat loss and you will be easier to find. If you are by yourself assume the Heat Escape Lessening Posture, or HELP position. This posture can increase the chances of survival by reducing the amount of body surface area that is directly exposed to cold water. In this position, the chest and knees are in contact with each other rather than being in contact with cold water. If you are not wearing a life jacket, this is a difficult position to maintain. There is one rule that guarantees your chances of surviving a man overboard accident – don’t be the person in the water! However, if you do fall overboard your chances of survival will primarily depend on two factors:

1. If and how fast your crewmates can turn the boat around and recover you.
2. Whether or not you are wearing a flotation device when the accident occurs.

If the sun, moon, and stars are in alignment and you’re about to be recovered, do not swim towards the boat. In cold water you will not be able to swim far enough to make a difference in how fast they recover you and the resulting heat loss could be disabling. Without wearing some type of flotation device in cold water, your ability to tread water or swim will most likely be measured in minutes. If you are hurt or unconscious and unable to help yourself, your survival time will be greatly reduced. Unfortunately, most people rarely wear Personal Flotation Devises or PFD’s – The only way to be sure you’ll have the proper flotation and insulation is if you wear it all the time.

In a few weeks we'll discuss Cold Water Survival further, looking at how to best dress for cold water. 



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