Chilling facts about cold water Peril: However warm the air, the waters of the bay and its tributaries remain dangerously cold well into the spring. Exposure to cold water is frequently a key factor in bay drownings.

On the Bay

March 28, 1997|By Tom Horton | Tom Horton,SUN STAFF

MARCH 12 WAS the kind of day you can get on the bay from late winter, nearly until summer -- pleasant and deadly.

With air temperatures pushing the high 50s and no wind, Charles Lee Cecil may have felt he could easily swim to the nearby Choptank shore from his disabled boat that afternoon.

But water temperatures were another story entirely, say Maryland Natural Resources Police, who found the Easton-area man's shoeless, shirtless corpse a few days later.

The temperature of the Choptank was still less than 50, below which water is defined as "very cold," says the University of Manitoba's Gordon Giesbrecht, an expert on how cold affects human physiology.

Water, he explains, is much more conductive than air, sucking heat from your 98.6-degree body 20 to 30 times as rapidly as air of the same temperature.

In experiments in water below 50 degrees, "I have seen even world-class swimmers fail very quickly," Giesbrecht said in a telephone interview.

Sgt. Dave Thomas of the Natural Resources Police says his agency has a saying, "the rule of 50," which holds: "You've got a 50-50 chance of survival in a 50-yard swim in 50-degree water." Cold water is frequently the key factor in bay drownings, he said.

The experts' definition of "cold" involves higher temperatures than you might think, says Dr. Lorentz Wittmers of the University of Minnesota's medical school, a contributor to two books on human responses to cold.

Any water up to 68 degrees qualifies as "cold."

Consider what that means. It is usually late May or early June before water temperatures at the Bay Bridge get above 68 (coincidentally, about the same temperature that triggers the bay oysters' spawning).

Below that temperature, it is all too easy for a swimmer to get into trouble.

The Choptank drowning was particularly tragic. The 29-year-old boater had been reported as a disabled craft before he apparently removed shoes and shirt to swim ashore.

His boat had no anchor, no oars and no life preserver. Friends told police that the victim had just bought those items at Wal-Mart on layaway, apparently unable to afford them before his trip.

By 8.30 p.m. that evening, a wind had pushed his small boat safely ashore. It underscores Thomas' basic advice: "Stay in the boat."

But what if you can't -- if it's sinking, or you're being blown to rougher water, or you're alone in a canoe or kayak, where re-entry after capsizing may be difficult to impossible?

I am a great advocate of boating in small craft throughout the cold months. The bay and its tributaries are bug-free, untrafficked and filled with a variety of waterfowl.

With proper clothing, you can be eminently comfortable most days. I am on the water most Januarys more than in July.

But you need to respect and understand just how fast cold water can kill you.

Fortunately, this is an area that has gotten extensive research. Much of it was begun as early as World War II for military purposes, to address the survival of pilots shot down and sailors on ships sunk at sea.

In one horrifying case, Nazi Germany sacrificed 85 to 90 prisoners at Dachau to study how long it took to chill people beyond recovery.

"Researchers have referred to their work, but it's obviously very touchy, and in retrospect, the experiments didn't even produce good data," Giesbrecht says.

He and Wittmers say a succession of things can happen when you enter cold water.

First, it is possible to die almost immediately if the shock causes involuntary hyperventilation and you start swallowing water as waves wash across you, or if the shock to the cardiovascular system is severe enough to cause a heart attack.

After 10 to 30 minutes, as the brain diverts blood flow from the body's shell to its vital organs, physical and mental performance steadily decrease.

(In retrospect, this happened to me while running outdoor bay education trips one April. I kept diving to unfoul a rope from the propeller until people on board had to order me back in. I was irritated, thinking I was "just a dive away" from success; but by all accounts I was fooling myself.)

Wittmers says that "paradoxical undressing syndrome" can result; you begin to do irrational things, like taking your clothes off.

After half an hour's immersion, the temperature of the body's core begins to go down rapidly. Even shivering ceases, and you may turn sullen and withdrawn.

It is this drop in the core temperature below 86 to 90 degrees that experts clinically define as hypothermia. (The term hypothermia is one that I and many others misuse to mean all effects of cold on the body.)

Revival from a severe hypothermic state, which can resemble hibernation, is best done in a hospital. People have been brought back after hours with no detectable pulse. (One victim, thought dead, was zipped into a body bag and suffocated on the way to the hospital).

Even in the worst cold, you can vastly improve survival chances with just a good life jacket. Wittmers has had volunteers in a life vest, curled up to minimize heat loss, float in 50-degree water for 45 to 50 minutes with only mild hypothermia (swimming would cause more rapid heat loss).

For $120 to $350, a winter boater can buy an assortment of waterproof, flotation and insulating suits that will keep him alive up to several hours in severely cold water.

For all that, it's best if you can follow Thomas' advice: Stay in the boat.

Pub Date: 3/28/97

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