Safe at Sea: Hypothermia — the cold killer
December always brings a dramatic change in temperature in southern Florida. Certainly, the low 50s we have just experienced are a reminder that winter has set in here. What surprises most every visitor is how quickly that water temperature drops in the Gulf of Mexico (and in the bays, rivers and estuaries, by extension).
The Florida Boating Safety Course booklet reminds its readers: “Don’t ever think that boating activities won’t expose you to the risk of hypothermia Hypothermia can occur on what begins as a warm, sunny day.”
In fact, the initial reaction of cold-water immersion can occur in waters as warm as 77 degrees Fahrenheit. Certainly, our waters are approaching such temperatures already. Cold water can conduct heat away from your body 25 times faster than air of the same temperature. Within minutes, your body’s core temperature – the brain, heart, lungs and other vital organs – begins to cool, and your body responds by trying to keep as much heat as possible in the core.
Cold water immersion kills in a number of ways. Being knowledgeable about how your body reacts to cold water can prepare you to be better able to respond appropriately and, thus, increase your chance of survival should your boat capsize or someone falls overboard.
There are four stages of cold-water immersion:
– Stage 1: Initial “cold shock”
Within three minutes of immersion, involuntary “gasping” for air, hyperventilation and panic can set in. Other bodily changes may occur: heart rate, blood pressure and heart rhythm.
– Stage 2: Short-term “swim failure”
Swim failure may begin as soon as three to 30 minutes after immersion. Manual dexterity may drop by 80 percent. What we know is that normally strong people find themselves unable to even keep their head above water.
– Stage 3: Long-term hypothermia
Cold water robs one’s body temperature between 60 percent and 80 percent faster than cold air. At this stage, one may lose consciousness and die, even without drowning.
– Stage 4: Post immersion collapse
This stage occurs following rescue: the body is still in danger of collapse of arterial blood pressure leading to cardiac arrest.
The following are prevention tips for boaters:
– Everyone’s chance for survival of cold-water immersion is really dependent on wearing a P.F.D. with the capacity to keep one’s head above the water.
– Boating in cold waters requires layered clothing (insulation) and having a windbreaker-like jacket as the outer shell.
– Don’t panic! Control breathing rate, and focus on keeping your head above water.
Symptoms of hypothermia include:
– Shivering accompanied by slurred speech and blurred vision
– Bluish lips and fingernails
– Loss of feeling in extremities
– Cold, bluish skin
– Rigidity of extremities
As the captain of your vessel, you should carry on board extra warm clothing, even blankets. As a responsible operator, you should inform your passengers ahead of time as to what they need to bring to remain safe and comfortable.
Pat Schmidt is a member of America’s Boating Club of Sanibel-Captiva. For more about the chapter and the courses it offers, visit www.sancapboating.club or contact firstname.lastname@example.org or 612-987-2125.