Cold water is the most misunderstood and the most deadly element when considering our safety at sea.

Question – If you fall into 34 degree water, how long does it take to become hypothermic?

With clothes and a life jacket on, one half to one hour to become mildly hypothermic.  If you are not wearing a life jacket, hypothermia will not be the cause of the cold water immersion fatality.

Here are 3 conditions that occur from cold water exposure that cause fatalities:

Cold Water Shock, respiratory gasping, elevated heart rate, inability to control movements. This occurs first when we are immersed in cold water. Cold water shock is responsible for 15-20 percent of cold water fatalities

Cold Incapacitation – vasoconscriction is the narrowing of the blood vessels resulting from contraction of the muscular walls of the vessels, in particular the large arteries and the small arterioles.  Have you ever poked your arm into a cooler of drinks looking for just the right one, to then find how achy and unresponsive your grip has become? The blood of the body is drawn away from the cold exterior muscles and moves inward to the core of the body for survival.  The outer muscles no longer work. It is no longer possible to swim.  50 percent of fatalities occur from drowning as a result of cold incapacitation.  A life jacket will save you. 

Circumrescue collapse – After hypothermia sets in, the blood in shunted to the core of the body and the nature of being in the water, (less gravity), relieves the heart of having to pump the blood aggressively.  Once pulled from the water the heart is forced to more actively pump the blood because of gravity and the cold, but the heart is cold and can no keep up.  Ventricular Fibrillation occurs and then possible heart attack.  Circumrescue collapse is responsible for 15-20 percent of cold water fatalities

These conditions are not so much to create fear of cold water, but to add to your preparation if you anticipate the risk of exposure. Carrying an EPIR or radio with DSC

Nearly all rescues at sea are the result of a captain making a bad decision before leaving the dock.  Those decisions are rooted in the failure to estimate the encountered peril.  The captain does not perceive the destination, whether it is the weather, the water, or the condition of the vessel in use.  When you are at sea, you are surround by an element that can kill you. 

Proper assessment of the peril include knowing the water, knowing the effects of cold water, knowing the effects of the weather and knowing the capabilities of your vessel. 

Whether the captain is right or wrong, the captain is always responsible:

Some of these responsibilities include: Mechanical soundness,  emergency equipment, passenger knowledge

Professional Operations – What makes the safe guys safe?

          Success modeling – checklists, scenario replay, preparation

          Risk assessment – Evaluate risks based on the SPE model.

• Severity –   How severe is the risk?
           (the severity of someone falling overboard at night – very high)
• Probability – What is the probability of the risk occuring.
           (if crew is on deck at night there is a likely probability)
• Exposure – how often and to how many people would this risk occur?
           (not often, but crew can slip)

          Rephrasing the question – “Do I have to wear a lifejacket?”

                   = should you have to wear a lifejacket as the weather is turning bad and the water temp is 39 degrees and being in the water without one could be fatal?