Boating and Carbon Monoxide Poisoning

Every year, thousands of people seek emergency care for poisoning from carbon monoxide — an odorless, colorless gas produced when fuel is burned. It can be deadly for humans and animals who breathe in the fumes.

Most people think of carbon monoxide as building up indoors, but it can also be a lethal danger out on the open water — one of the top five causes of boating-related deaths each year, according to the U.S. Coast Guard.

When you have fun on the water, including fishing, boating and water sports. Sometimes, those activities carry the risk of carbon monoxide poisoning.

What is carbon monoxide?

Carbon monoxide, or CO, is a gas that is formed when fuel is burned. CO in boat and generator exhaust can be found on deck, in the cabin, and on surrounding water – sometimes causing illness or even death. You cannot taste, smell, or see CO which is why it is known as the “silent killer”.

Causes of CO Buildup

There are many ways carbon monoxide can build up in your boat. Listed below are five major causes of CO accumulation:

Many large boats are equipped with generators that emit carbon monoxide gas toward the stern of the watercraft. More specifically, this CO emission builds up near the swim or stern deck or water platform of the watercraft. The carbon monoxide that fills up the capacity of this area is capable of killing someone in the matter of seconds.
Idling or traveling at slow speeds can cause CO to accumulate on the boat’s cabin, cockpit or stern deck. In fact, wind blowing from the aft of your watercraft can expedite this buildup of carbon monoxide.
Boats that cruise at a certain speed or direction can rapidly raise carbon monoxide concentrations in certain areas of the watercraft. This is known as the “Station Wagon Effect” or back drafting. Back drafting is accelerated if a boat is heavily loaded and operated at a high bow angle. Also, if there is an opening near the exhaust, the emissions will funnel quickly through the opening.
Anchoring or mooring too close to watercrafts with running gas engines or onboard generators can pose a CO threat. Dangerous levels of CO emitted from these boats can funnel into your boat.
A clogged exhaust, blocked exhaust outlets or improperly ventilated enclosures are extremely threatening causes of CO buildup. A blocked or clogged exhaust can cause life threatening levels of carbon monoxide to accumulate in the cabin of your vessel.

Symptoms of Carbon Monoxide Posioning

If anyone on the boat starts feeling sleepy, nauseated or dizzy, move to the front of the vessel to get fresh air. Keep a life vest on just in case. Kids are more sensitive to the fumes because of their smaller bodies so monitor their breathing and if it stops, perform CPR and call 911.

If you’re in the water and start feeling unwell, get out and return to solid ground. If the symptoms are severe, Benda advised going to the emergency room and telling doctors you suspect you may have carbon monoxide poisoning — they may treat you with oxygen.

What can you do to prevent carbon monoxide poisoning?

Install a CO detector on your boat.

Install a CO detector approved for marine use. This device will alert all boaters if there is a life threatening level of carbon monoxide in your boat. Test the detector on a regular basis to be sure it’s working.

Stay safe while playing in the water.

Stay away from the exhaust outlets while the boat is running. Swimmers can be harmed by CO that is at the back of the boat or has built up on the water.

Don’t sit on, swim under, or surf from the swim platform while the boat is running. Dangerous levels of CO can be found near the swim platform.

Check the exhaust from the engine and the generator.

Check to be sure water flows from the exhaust outlet when the engine or generator is running.

Check your engine’s exhaust hoses for burns, cracks, or deterioration. Look for leaks in the exhaust system. Signs of leakage include rust and/or black streaks, water leaks, and corroded or cracked fittings. Be sure all of the exhaust clamps are in place and secure.

Be aware of changes in the exhaust’s sound. This can indicate a problem with the boat’s exhaust system.

If you have a generator on board, install and maintain a CO detector in the cabin. Be sure there are no leaks in the generator’s exhaust and that the exhaust flows away from the boat and not into the cabin.

Never block exhaust outlets! Be sure that canopies or other equipment are not blocking the engine’s or generator’s exhaust and sending it back into the boat.