The so-called "cone of protection" onboard a boat that is struck by lightning may be more aptly described as "the cone of pain, injury, and death."

Article after article, and book after book, have told cruisers for years that a sailboat's mast forms the point of a cone that, when you envision it extending geometrically downward to your boat's deck, is a safe place to be when lightning strikes. The idea is that the bolt will target the tip of the mast and travel straight down, instead of out to the sides. Countless sailors thus believe that if they stand a few feet away from the mast, within the "cone of protection," they will be safe even if Mother Nature picks their boat for target practice.

"It's just ludicrous," said Dr. Eric Johnson, a Staff Physician at Teton Valley Hospital, in Driggs, Idaho; past president of the Wilderness Medical Society; a NAUI diving instructor; and a Mount Everest base camp physician. "There is a way they say you can properly ground the mast, but it involves a little wire brush. A teeny-tiny little brush. If you think you can dissipate 200 million"”two hundred million"”volts with a little wire brush, then I have a bridge to sell you."

Of course, it is prudent to do what you can, having a licensed marine electrician ground your boat, its rigging and its systems according to standards set by the American Boat and Yacht Council.

An actual strike was captured on film in Seattle's Elliott Bay.WHAT ARE THE CHANCES?

As natural hazards go, lightning is a nasty one. A single bolt can travel as fast as 100,000 miles per second, over a distance of 10 miles, and produce temperatures up to 50,000 degrees Fahrenheit (that's five times hotter than the sun), Johnson said. The bolts, which can look several feet wide to the naked eye, are actually only about an inch or two in diameter. They're like precision lasers shooting from the sky.

On the other hand, as natural hazards go, lightning is far from being the most consistent killer. About 20,000 people die each year in the United States from natural hazards, but only about 70 of those deaths are attributed to lightning. Yes, that's about four times more than hurricane deaths, but in the grand scheme of U.S. statistics, you have only a 1 in 700,000 chance of losing the lightning lottery during any given year, Johnson said. And your odds go way up if you're in an open field, under a tree, or on a golf course as opposed to on a boat. Of all the people who get struck, only about 10 percent die. Some 70 percent experience long-term effects, but they continue walking and talking in most cases, Johnson said.

Boaters in the southeastern United States, and farther south toward Cuba, should be well aware of these numbers, since those areas tend to be where lightning strikes concentrate in terms of cruising destinations. More than 90 percent of fatal lightning strikes happen between May and September, with a peak every July, Johnson said. About three-quarters occur between noon and 7 p.m."”say, about the time those cooling afternoon thunderstorms tend to roll through the Florida Keys.

WRONG PLACE, WRONG TIME

If you're the unlucky boater who ends up in the wrong place at the wrong time, it's important to know that lightning can strike you five different ways: as a direct hit, by traveling through an object you are touching, by "splashing" into you from its primary strike point, by becoming a traveling ground current after the primary strike, and by sending shock waves so powerful that they cause blunt trauma even without a direct hit, Johnson said.

That is really all the doctors know for sure.

"The problem is that nobody knows exactly what happens to you physically after the strike," says Johnson, who spoke at the week-long "Medicine for Mariners and Safety at Sea" conference at The Bitter End Yacht Club on Virgin Gorda in January. "My Toyota 4Runner once got struck, and when I brought it to the dealer to have the motherboard with all the circuits checked out, they couldn't figure out what had happened. Now, with all the precise tests they have for different parts of a Toyota's motherboard, if they can't figure out how lightning affects my truck, imagine how hard it is for us to determine everything that happens inside a human body."

One documented effect of being struck by lightning is developing an abnormal heart rhythm. However, it's actually respiratory arrest that more often is the fatal factor, Johnson said.

If you are caught in a lightning storm, turn off your electronics and beware of what you touch."The vast majority of time, your heart will reset itself, but your lungs and breathing will not," Johnson says. "If you're on a boat, you need to do immediate CPR and make sure the person is well ventilated, with a clear airway and breath moving in and out of his lungs. A person may look dead, but you can often bring him back from that secondary respiratory arrest."

AVOID THE PROBLEM

The best option, of course, is avoiding the strike in the first place. How do you know if you're in danger? Do what Dad taught you the first time you got stuck in a storm: When you see lightning, count the seconds until you hear thunder. If you count for fewer than 30 seconds, the lighting is less than six miles away. Seek shelter for at least 30 minutes. That's the "30-30 rule" of wilderness survival.

NOAA actually recommends more stringent precautions, suggesting that you seek shelter when you hear thunder, no matter what.

Technology is now available to help, as well. Handheld products such as Sky Scan and Strike Alert typically cost between $100 and $200, and have proven accurate in providing warning of lightning storms. They're especially beneficial if you can't see the nasty black clouds.

If you're on your boat and can't get to shore, turn off and unplug all your electronics. Put handheld VHF radios and other portable electronic equipment into your galley stove. If you must hold the helm, do so while wearing neoprene gloves to provide an insulation barrier between yourself and the wheel. Don't touch anything metal"”your body will complete a circuit that lightning will just love"”and consider hooking yourself into a jack line to prevent being blown off your boat by the sheer force of a strike.

Should someone on your boat get struck, seek immediate medical help and begin CPR to restart the person's respiratory system. That's really all the average person can do.

"Don't be arrogant. Learn the risk factors," Johnson says. "All your lightning-detection equipment may do squat for you. I'm a real skeptic on the true protection that these products provide. I've seen so much weird stuff with lightning, I don't want people to have a false sense of security."