Best Marine CO Detector (for Boats in 2024)

Carbon Monoxide Detector, CO Alarm, CO Detector, Low Level CO Detector -

Best Marine CO Detector (for Boats in 2024)

Carbon monoxide (CO) monitoring is important for ensuring safety in boats and houseboats, as these confined spaces can quickly become deadly gas chambers if CO leaks occur in the cabin, sleeping quarters, cockpit, or stern. The primary sources of carbon monoxide are generator and boat motor exhaust. To provide maximum protection, it is highly recommended to use low-level carbon monoxide detectors that alarm occupants at 25 ppm, as opposed to generic CO detectors that only trigger at 70 ppm after 60 minutes. These sensitive gas detectors continuously monitor the air, providing early warning of dangerous CO levels and potentially saving lives. With carbon monoxide poisoning being a serious hazard associated with recreational boating, responsible for approximately 7 deaths per year in the USA, investing in reliable and quick-responding CO detectors is a critical step in prioritizing the safety of boat occupants.



  • A Marine Carbon Monoxide Detector is a perfect early warning systems for boats and marine applications.
  • A Marine CO detector is suitable for boat cockpit and deck areas.
  • Make sure your marine carbon monoxide detector has low trigger alarm thresholds less than 50ppm.
  • A marine carbon monoxide detector costs less than $99.
  • Carbon monoxide gas can infiltrate a boat cabin very quickly.
  • It can be difficult to track down the carbon monoxide pathway into the cabin.
  • Even with experienced boaters, monoxide poisoning awareness is limited.
  • Carbon monoxide is a silent killer.

What Is the Best Carbon Monoxide Detector for My Boat Cabin?

You must have a UL STD 2034 Marine carbon monoxide detector on your boat.

We recommend to also have a low level CO detector for children, elderly, pregnant, and passengers with pre-existing conditions.

There are various low level carbon monoxide detectors on the market that would be an excellent companion to your UL STD 2034 Marine carbon monoxide detector.

The top brands and most popular low level CO detectors are:

CO detector low level

What Is the Best Carbon Monoxide Detector for My Cockpit and Rear Deck?

We recommend waterproof CO detectors where water may spray or flood in the cockpit and rear deck areas. CO analyzers in these areas will monitor station wagon effects, carbon monoxide accumulation due to wind direction changes, and other anomalies.

CO meter waterproof boat

Which Is the Best Marine Carbon Monoxide Detector for Boats?

All boats should have a working UL STD 2034 Marine carbon monoxide detector. For early warning in the cabin, we suggest low level CO detectors. For cockpit and rear deck CO protection, we recommend our waterproof carbon monoxide detectors.

Is Carbon Monoxide Dangerous on Boats? Why?

Carbon monoxide (CO) gas is very poisonous. It is invisible, odorless, and tasteless - a silent killer. Even a few breaths can be fatal. Carbon monoxide can be produced on your boat via the gasoline engines, gas generators, cooking ranges, and heaters.

What Are the Carbon Monoxide Symptoms to Watch for on a Boat?

According to the CDC, carbon monoxide symptoms include:

  • Headache
  • Dizziness
  • Weakness
  • Upset stomach
  • Vomiting
  • Chest pain
  • Confusion.
  • Large amounts of CO can cause unconsciousness or even death.

Can You Get Carbon Monoxide Poisoning From a Boat?

Yes you can.

Based on statistical studies from 2005 - 2018, there were 78 known deaths due to carbon monoxide on boats in the U.S. This data is likely under-reported since some deaths are categorized as drowning instead of CO poisoning. 

In another epidemiology study over 10 years, people on recreational watercraft had an average of 14.5 accidents, 30.9 injuries, and 6.7 deaths per year. Cabin motorboats accounted for a total of 49 accidents, 123 injuries, and 29 deaths.

boat marine carbon monoxide

How Does Carbon Monoxide Poisoning on a Boat Happen?

Gasoline Generators & Carbon Monoxide

Carbon monoxide originates from exhaust coming from your built-in generator, typically residing in the bilge. The ventilation of generator exhaust may be compromised by a defective exhaust system. From there, the exhaust enters your cabin via panel holes, panel seams, cracks, and other entry pathways. CO accumulation may poison boat occupants, especially when sleeping. See an example case here.

    carbon monoxide boat generator

    Gasoline Engine Exhaust and Carbon Monoxide

    Another hazard for boats is exhaust coming from the boat engine. The carbon monoxide can be redirected to where passengers reside. Slow speed or idling causes exhaust gas and carbon monoxide to accumulate in the cabin, cockpit, bridge, or aft even in open areas. Wind direction can increase the speed of carbon monoxide accumulation in your boat.

      carbon monoxide

      Exhaust Gas Redirection

      Another hazard for boats is exhaust being redirected due to physical obstructions, particularly from neighboring boats and slips when docked.

      carbon monoxide boat

      Neighboring Boat Exhaust Gas

      Close proximity exhaust from a neighbor's generator or engine exhaust can make its way onto your boat. With the right conditions or a change in wind direction, this problem may occur without any warning. This is common when docked, beached, or anchored.

        carbon monoxide boat

        The Station Wagon Effect & Carbon Monoxide

        A phenomenon called "station wagon effect" is when the exhaust gas circles back into the cockpit and cabin due to the pressure differential at high speeds. When moving, exhaust gas makes its way to low-level pressure areas of the vessel, eventually accumulating to the cockpit and cabin.

          station wagon effect carbon monoxide

          Avoid Teak Surfing or Residing next to the Exhaust

          Do not teak surf, or hold onto any part of a power-driven vessel's transom while the engine or generator is on. Many children have died from teak surfing. Never let passengers sit or "hang out" on the stern swim step.

            teak carbon monoxide poison

            Propane Appliances and Carbon Monoxide

            Carbon monoxide can be generated from gas heaters, water boilers, gas cooking appliances, portable propane camping stoves, and grills. When cooking, make sure a window or door is open for good ventilation. This ensures carbon monoxide venting and that there is enough oxygen for proper propane combustion to take place.

              boat propane carbon monoxide poisoning 

              Do People Die From Carbon Monoxide in Boats?

              Yes they do. 

              About 7 people per year die from boat carbon monoxide poisoning in the USA.

              How Common Is Carbon Monoxide Poisoning From Boats?

              The CDC estimates that at least 430 people die in the U.S. each year from accidental carbon monoxide poisoning, with some occurring in boats. Some tragic carbon monoxide deaths in boats and houseboats are listed below:

              • Young Boy Dies From Wakeboarding: "He crawled onto the back of the boat and curled up in a ball..."  Although the parents were experienced and competent boat owners, they were unaware of the danger of carbon monoxide poisoning on their boat.
              • Women Dead From CO on Boat: A couple staying overnight on a boat docked along the Erie Canal when they were struck with carbon monoxide poisoning... police are investigating whether the boat’s engine or a portable space heater was the source of the carbon monoxide leak.
              • 4 Die at Lake Erie: A soccer player, two men, and a young boy died on Lake Erie. Nearly three quarters of carbon monoxide poisonings on power boats occur while on or near the swim board at the rear of the boat.

              marine boat carbon monoxide

              What Is the Best Protection Against Carbon Monoxide Poisoning on a Boat?

              Some tips to improve carbon monoxide safety include:

              • Ensure you have working carbon monoxide detectors.
              • Know where exhaust outlets are located on your boat. Make sure you know what "normal" looks like.
              • Operate fuel burning appliances, such as charcoal, propane, LPG, CNG, or alcohol cooking devices, in areas where fresh air can circulate well.
              • Educate all passengers about the symptoms of CO poisoning and where it may accumulate. Show them where the CO detectors are located.
              • Be aware of exhaust emissions from your neighbors' boat(s).
              • Listen for any change in exhaust sound, which could indicate an exhaust component failure.
              • Test each CO detector monthly.
              • Check exhaust clamps are secure monthly.
              • Inspect exhaust for leaks monthly.
              • Have a qualified marine technician check on engine, generator, and all exhaust systems. Do this annually.

              What Should I Do When I Smell Engine Exhaust?

              If you smell engine exhaust, you are also breathing in carbon monoxide. Take immediate corrective action. Seek fresh air and eliminate the exhaust source.

              Should I Have Good Ventilation to Prevent Carbon Monoxide Dangers?

              Yes you should.

              • Proper ventilation must be maintained, even during inclement
                weather, to prevent dangerous levels of carbon monoxide.
              • Always keep fresh air circulating.
              • Open all doors, hatches, curtains, and windows to allow fresh air to circulate and dilute the amount of carbon monoxide in enclosed spaces, especially when the boat is moored or anchored.
              • Ensure there is a working carbon monoxide detector in each sleeping quarter.

              What Do You Do If You Suspect Carbon Monoxide Poisoning?

              • Evacuate enclosed areas immediately.
              • Seek fresh air and medical attention, call 911.
              • If safe, shut OFF any fuel burning equipment or appliances.
              • Open hatches, doors, port lights, etc. to improve ventilation.
              • If making way, head boat into the wind.
              • If the CO source is not apparent, seek mechanical help to determine the source and leakage path.
              • Check with your boat manufacturer for any recall or service bulletins related to carbon monoxide. 

              Where Should I Place the CO Detector in My Boat?

              There is a lot of misinformation about where to place a CO detector. Some sources say to place it high on the ceiling while others say to place it low because carbon monoxide is a heavy gas. Both are incorrect.

              Carbon monoxide gas mixes evenly with air because the two have nearly the same density. This has been scientifically proven in various literature studies. It would be reasonable to place a CO alarm at any height.

              • Cabin and Sleeping Areas: Noting that most deaths from carbon monoxide occur when occupants are sleeping, it is best to keep your CO detector in the main cabin. The actual height installation is only important for practical reasons, such as the potential to be tampered with by kids and pets or inadvertently being bumped. Also think about a convenient height for monitoring and service. Installing a CO detector in each sleeping area of the enclosed accommodation compartment is recommended.
              • Small Craft: Small craft with an open design may only require one CO alarm for adequate protection.
              • Partitioned Sleeping Areas: If any two sleeping areas are partitioned, then a CO alarm should be installed in each sleeping area.
              • Large Craft: Larger craft often have aft and forward cabins with convertible sofas in the saloon. These boats will require three CO alarm monitors. Installation should be at eye-level height for convenient monitoring and service.
              • Cockpit Area & Rear Deck: We recommend waterproof CO detectors where water may spray or flood in the cockpit and deck areas. CO detectors in these areas will monitor station wagon effects, carbon monoxide accumulation due to wind direction changes, and other anomalies.

                Should I Install a CO Detector in My Boat House?

                Yes you should.

                Boat homes are also prone to carbon monoxide accumulation due to the various appliances and fossil fuel burning items. See the low level CO detector article here.

                  Will a Low Level CO Detector Alarm Faster Than a Normal CO detector in My Boat?

                  Yes it will.

                  Your regular boat carbon monoxide detector complies with UL STD 2034 Marine alarming sequences.

                  The Forensics Detectors low level carbon monoxide detector is programmed to alarm much faster than a generic UL2034 Marine CO detector. For example, an ordinary CO detector alarms at 70 ppm after 60 minutes. On the other hand, a low level carbon monoxide detector will alarm at 25 ppm after 60 seconds.

                  The video below shows this difference.

                  What Is the Difference Between a Low Level CO Detector and Ordinary CO Detector?

                  An ordinary marine CO alarm is compliant with UL STD 2034 Marine specifications. This device alarms after 60 minutes of exceeding 70 ppm CO.

                  In comparison, the FORENSICS low level CO detector triggers an audible alarm when carbon monoxide exceeds 25 ppm (for 60 seconds). 

                  What Are Acceptable Carbon Monoxide Concentration Levels in a Boat? 

                  No standards for CO have been agreed upon for your boat or indoor cabin space. It can get confusing since various agencies, departments, and organizations have different recommended exposure levels.

                  We believe any leakage or accumulation of carbon monoxide is problematic within your camper or RV. It is no different than a small water leak in your home. In either case, it is just a matter of time before a pin-hole leak become larger. Address the problem immediately.

                  However, there are some guidelines that can be extrapolated for personal safety. Below is a table that summarizes the carbon monoxide exposure limits:




                  9 ppm average over 8 hours


                  9 ppm average over 8 hours

                  The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)

                  9 ppm average over 8 hours

                  National Institute for Occupational Safety and Health (NIOSH)

                  35 ppm average over 10 hours

                  200 ppm ceiling value

                  Occupational Safety and Health Administration (OSHA)

                  50 ppm average over 8 hours

                  American Conference of Governmental Industrial Hygienists (ACGIH)

                  25 ppm average over 8 hours

                  CO Detector Alarming Protocol
                  UL2034 (USA)

                  > 70 ppm (60 to 240 minutes)

                  > 200 ppm (10 to 50 minutes)

                  > 400 ppm (4 to15 minutes)

                  CO Detector Alarming Protocol
                  EN 50291:2001 (Europe)

                  > 50 ppm (60 to 90 minutes)
                  > 100 ppm (10 to 40 minutes)
                  > 300 ppm (3 minutes)

                  Forensics Low Level Carbon Monoxide Detector

                  > 25 ppm (1 minute)

                  Can I Leave My Carbon Monoxide Detector in My Boat Throughout the Year?

                  • If you are storing your boat in extreme conditions, remove the carbon monoxide detector as it may malfunction when repeatedly exposed to freezing and or scorching temperatures.
                  • Store your low level CO detector at normal room temperature - about 70F with 50%RH (well within operating specifications).
                  • Store it away from electromagnetic or magnetic sources, such as phones.
                  • Store it in a clean environment with no dust or particles.
                  • Store it away from any exhaust gas, concentrated vapors, and harsh chemicals.
                  • Clean the casing of your detector with a damp cloth.

                  How Do I Test My Carbon Monoxide Detector?

                  To test your carbon monoxide detector see: "How do I test my Carbon Monoxide Detector?

                  To summarize, there are three ways:

                  • Spray carbon monoxide test gas, or bump gas, onto your detector
                  • Try the wood stick method. It is easy to try at home with no special equipment. See here.
                  • Press the TEST button on your CO detector following your instruction manual. Pressing the TEST button only helps to verify that the electronics, LED, and buzzer alarms are operating. Exposing the CO detector to actual carbon monoxide is the only way to truly confirm operation.

                  What About CO Detector Nuisance Alarms (False Alarms)?

                  Every piece of technology has its limits. CO detectors and sensors are not 100% perfect. Some are sensitive to other gases, vapors, and chemicals.

                  Treat these “nuisance” alarms as an actual carbon monoxide alarm. Evacuate and ventilate the area. Before, during, and immediately after working with any chemicals, make sure enough fresh air ventilation is available. 

                    Final Words

                    Carbon monoxide detection is vital for ensuring safety in boats and houseboats, as these confined spaces can rapidly become deadly if CO leaks occur. Gas detectors should be installed in the cabin, sleeping quarters, cockpit, and stern, where CO can accumulate from generator and boat motor exhaust. For maximum protection, low-level CO detectors that alarm at 25 ppm are recommended over generic detectors triggering at 70 ppm after 60 minutes. These sensitive detectors provide early warning of dangerous CO levels, potentially saving lives. With CO poisoning being a serious hazard in recreational boating, responsible for about 7 annual deaths in the USA, investing in reliable, quick-responding CO detectors is crucial for prioritizing boat occupants' safety.

                      About The Author

                      Dr. Kos Galatsis ("Dr.Koz") is the President of FORENSICS DETECTORS where the company operates from the scenic Palos Verdes Peninsula in Los Angeles, California. He is a subject matter expert on gas sensor technology, gas detectors, gas meters, and gas analyzers. He has been designing, building, manufacturing, and testing toxic gas detection systems for over 20 years.

                      gas detector expert

                      Every day is a blessing for Dr. Koz. He loves to help customers solve their unique problems. Dr. Koz also loves spending time with his wife and his three children going to the beach, grilling burgers, and enjoying the outdoors.

                      Read more about Forensics Detectors here.

                      Phone: +1 424-341-3886