Prevent carbon monoxide poisoning
Odorless, colorless and tasteless, carbon monoxide gas is often called the “silent killer” because it effectively blocks oxygen delivery to the body, causing a startling number of fatalities each year. Carbon monoxide poisoning deaths can also happen aboard your vessel. Learning how to prevent carbon monoxide poisoning will help keep you safe on the water year round.
Boat engines, cabin heaters, generators and galley stoves can all produce carbon monoxide, with engine and generator exhaust being the most prevalent source. CO fumes can also accumulate in areas away from the exhaust source.
In the absence of a breeze, high CO levels can cause unconsciousness in minutes. Without a carbon monoxide detector onboard, CO is often impossible to detect before it overcomes a victim, who is then too weak to escape or summon help.
Early symptoms of carbon monoxide poisoning
The symptoms of mild CO poisoning can mimic seasickness, colds and flu:
- Nausea, weakness, dizziness or headache
- Ringing ears and watering eyes
- Cherry-red coloring to the skin
Moderate carbon monoxide poisoning can cause
- Lightheadedness or headache
- Drowsiness
- Unconsciousness
- Death
Severe CO poisoning can result in damage to the brain or heart followed by death.
How to prevent carbon monoxide poisoning on your boat
Prevent CO buildup by regularly checking for leaks in your engine and generator exhaust systems and in the seals around your hatches and portholes. Take the following precautions:
- Check the ventilation of your alcohol stove.
- Maintain your generators meticulously.
- Run your exhaust blowers while using generators.
- Ensure that airs flows freely from front to back on a moving boat; avoid the station wagon effect.
- Keep passengers clear of the platform over engine or generator exhaust when running unless there’s a strong airflow.
- Be cautious about running engines or generators when anchored, moored, or docked unless there’s a substantial breeze; do not run generators overnight when stopped.
- Don’t allow anyone in the water to approach within 10 to 20 feet of the engines or generator exhaust.
- Don’t tow anyone close to the boat while underway.
- Check stove and other fuel burning device vents for leaks; keep vents clear.
- Beware of nearby boats with engines or generators running; stay clear or move away.
Install CO alarms in your boat’s cockpit, cabin and sleeping areas, and test the alarms regularly. If you already have a CO detector installed, it might be time to update it to a newer model.

Become a better boater
Learn the basics so you can boat with confidence and have more fun on the water. Take America’s Boating Course today.