One minute, the two boys were swimming beside their family's anchored boat. The next minute, they were dead, poisoned by an accumulation of carbon monoxide that had built up beneath the swim platform. This tragedy happened last fall on Lake Powell in Utah. And it can happen to you wherever you boat. Coast Guard studies reveal that at least five boaters die every year as a result of carbon monoxide (CO) poisoning.
Thousands more receive medical attention due to the deadly gas, which is odorless, tasteless, and mixes well with air. The deadly vapor is produced any time your engine or generator is running and can affect those both in and out of the boat. Effects run the gamut from simple nausea to brain damage, coma, or death.
How much CO does a boat produce? How does CO kill? Is your boat safe? We took a handheld Gas Baron CO detector ($495; CEA Instruments, 201/967-5660, www.ceainstr.com) on the water to find out. Then we asked the experts what you can do to prevent CO poisoning aboard your boat.
IT'S NO CHOKE. CO attaches itself to hemoglobin-red blood cells-preventing your body from absorbing oxygen. Breathing is unaffected while you're being poisoned, so there usually aren't any telltale warning signs.
THE CHAMELEON. The nausea, headache, drowsiness, and dizziness associated with CO poisoning may be confused with seasickness. Move the person from the immediate area, provide him or her with fresh air, and check for a source of CO. Remember: Evacuate. Ventilate. Investigate.
THE TIME FACTOR. Lengthy exposure to small quantities of CO is as deadly as brief exposure to large concentrations. At 400 parts per million (ppm), it takes an hour for a slight headache to occur. At two hours, brain damage and coma are likely.
GAS VS. DIESEL. When burned, gasoline produces 10 times more CO than diesel. We measured 186 ppm at the exhaust outlet of a 480-bhp diesel-powered boat. A 500-hp gas-powered boat's exhaust registered 1,743 ppm.
RUN FOR SAFETY. Excessive bowrise exacerbates the "station wagon effect," causing more exhaust to backdraft into the boat, particularly when full canvas is erected. Maintaining a flatter running angle is more fuel efficient and safer. Keep companionway hatches closed underway. Windshields with opening vents minimize backdrafting.
DUCK DOCKSIDE DISASTERS. Engine or genset exhaust can concentrate between your boat and a sea wall, bulkhead, or even another boat's hull, where it can be sucked in through open ports or hatches. Position yourself accordingly, and be aware of your neighbor's exhaust location.