By William C. Winslow
Carbon monoxide (CO) isn’t called “the silent killer” for no reason. You can’t smell it, you can’t see it, you can’t taste it, but it can kill you after a couple of whiffs.
Incomplete burning of any fossil based fuel creates CO. On boats, the main culprit is a gasoline engine, but other sources can be generators, outboards, heaters, and alcohol or propane stoves.
The CO kills by attaching to hemoglobin, a substance in the human body that facilitates the flow of oxygen. That process stops when CO enters the lungs.
What’s a severe carbon monoxide attack like? Horrible. BoatUS reports a case where a woman went to bed in a closed up cabin while her husband opted to sleep on deck. In the middle of the night, she woke up with a splitting headache. Worse, her entire body was paralyzed — she couldn’t focus and could barely croak out a plea for help. Thankfully, a sudden swell rolled her to the cabin floor, and the crash woke up her husband. He made a May Day call on the radio, a U.S. Coast Guard chopper flew her to the nearest hospital, and it took two weeks there to recover.
CO is heavier than air, so it collects in enclosures below deck and other sheltered areas in a boat, such as a swim platform or under canvas covers. A windy day can also bring back toxic fumes that would normally be dispersed, so no part of a vessel is totally safe.
Mild poisoning usually brings on a headache. If the gas is not flushed, the victim faces greater danger as the headache goes frontal with sharply escalated pain that can lead to dizziness, staggering, nausea, shortness of breath, and unconsciousness.
If someone aboard is experiencing any symptoms of CO poisoning, rush them onto the deck for gulps of fresh air. Shut off the engine and call for help.
What can you do to assure a safe boat?
The skipper should make sure everyone aboard understands the risks of CO poisoning before the boat leaves the dock. Share how it’s better to toss on a sweatshirt rather than go below for warmth.
Ensure you have a fully working marine grade carbon monoxide detector aboard (now required by the Coast Guard) and let everyone know what to do if they hear the alarm, including opening the windows and alerting the captain.
To further reduce the risks of CO poisoning, keep all equipment that runs on carbon fuel maintained in tiptop condition. If you have a gas engine, particularly one enclosed in a sealed compartment, run the fan for five minutes (Coast Guard rule) before pushing the start button. And then make sure water is flowing out of the exhaust.
Double up on ventilation. Let the fresh air flow with large companionway doors, fans, multiple hatches, opening portholes and vents.
Always monitor your vessel’s performance while underway. CO can escape when a boat is running at slow speed or you’re idling at a dock. Make sure no one hangs off the swim platform while underway, as the forward motion of the boat creates an exhaust trapping suction.
If you’re spending the night aboard or napping in a raft up, make sure you aren’t downwind of your neighbor’s exhaust.
The author is the Division 5 – Staff Officer Public Affairs, First District Southern Region, for the U.S. Coast Guard Auxiliary, the all-volunteer, non-military arm of the Coast Guard, teaching boating safety education and conducting search and rescue operations. Visit http://cgaux.org/ to join the Auxiliary or for class information.
