Boating Safety Information

Carbon Monoxide Poisoning—Warning Fact Sheet

Each year, boaters are injured or killed by carbon monoxide. Most occur on older boats, and within the cabin or other enclosed areas. Virtually all of the poisonings are preventable.

Carbon monoxide is a potentially deadly gas produced any time a carbon-based fuel, such as gasoline, propane, charcoal or oil burns. Sources on your boat include gasoline engines and generators, cooking ranges, space heaters and water heaters. Cold and poorly tuned engines produce more carbon monoxide than warm, properly tuned engines.

Carbon monoxide is colorless, odorless and tasteless, and mixes evenly with the air. It enters your blood stream through the lungs and displaces the oxygen your body needs. Early symptoms of carbon monoxide poisoning—irritated eyes, headache, nausea, weakness and dizziness—are often confused with seasickness. Prolonged exposure can lead to death.

Carbon monoxide can collect within a boat in a variety of ways. Exhaust leaks, the leading cause of death by carbon monoxide, can allow carbon monoxide to migrate throughout the boat and into enclosed areas. Even properly vented exhaust can re-enter a boat if it’s moored too close to a dock or another boat, or if the exhaust is pushed back by prevailing winds. Exhaust can also re-enter boats when cruising under certain conditions—the station wagon effect—especially with canvas in place.

Regular maintenance and proper operation of the boat are the best defenses against injury from carbon monoxide.

Checklist for boating regarding carbon monoxide:

  • Make sure all exhaust clamps are in place and secure.
  • Look for exhaust leaking from the exhaust system components evidenced by rust and/or black streaking • water leaks • corroded or cracked fittings.
  • Inspect rubber exhaust hoses for burned or cracked sections. All rubber hoses should be pliable and free of kinks.
  • Confirm that water flows from the exhaust outlet when the engines and generator are started.
  • Listen for any change in exhaust sound which could indicate a failure of an exhaust component.
  • Listen for any change in exhaust sound which could indicate a failure of an exhaust component.
  • Test the operation of each carbon monoxide detector by pressing the test button.


(performed by a qualified mechanic)

  • Replace exhaust hoses if any evidence of cracking or charring or deterioration is found.
  • Replace each water pump impeller and inspect the condition of the water pump housing. Replace if worn. (Refer to the engine and generator manuals for further information.)
  • Inspect each of the metallic exhaust components for cracking or rusting or leaking or looseness. Pay particular attention to the • cylinder head •exhaust manifold •water injection elbow •threaded adapter nipple between the manifold and the elbow.
  • Clean + inspect + confirm the proper operation of the generator cooling water anti-siphon valve (if equipped).

Electrical Shock Hazards—Warning Fact Sheet

Each year swimmers, boaters and people in marinas are injured or killed by electrical accidents. These occur because of wiring problems, component failures or the use of improper equipment when bringing 120 volt or 120.240 volt AC shorepower on board boats. Virtually all of these accidents are avoidable.

While AC electrical power is potentially deadly in any location, it is especially dangerous in and around the water. If there is a problem with the marina wiring, your boat’s wiring or its shorepower cord, contacting concrete or metal docks or the water itself can cause electrical shock. Handling shorepower cords when you are barefoot increases the chance of being electrocuted.

Electricity cannot be detected without the use of specialized test equipment. It may be present on metallic objects such as marina electrical equipment and shorepower connectors or even in the water itself. Contact with electrically energized equipment may result in painful shock, burns, muscle contraction or paralysis, loss of breathing and even stopping of the heart.

Electricity may be present in the water in places where boats are connected to shorepower or where marina wiring is defective. Electricity in the water will generally paralyze swimmers to the point where they lose muscle control, cannot swim and then drown. In a few cases the electrical “field” has been strong enough to cause electrocution from cardiac arrest. The possibility of either of these occurring is greater in fresh than in salt water.

Checklist for boating re: electrical safety:

  • Shorepower cords and adapters must be clean and dry before use. If they are dropped overboard do not use until allowed to dry and then checked by a qualified marine electrician. Keep shorepower inlet covers tightly closed when not in us
  • Get permission from the marina before connecting to a dock receptacle and ask if the “polarity” and ground are correct and when they were last checked.
  • Make certain there are no swimmers in the water around your slip.
  • Before connecting the shorepower cord – turn off both the boat’s main AC circuit breaker and the dock breaker.
  • Connect the shorepower cord at the boat first then connect the cord to the dock receptacle and turn on the dock breaker.
  • Check the boat’s “polarity” alarm or light (if it has one) on the AC panel as soon as the dock breaker is turned on. If the polarity is incorrect shut the dock breaker off and disconnect the dock end of the shorepower cord immediately. Report the problem to the marina. The marina should contact a qualified electrician to make correction.

When disconnecting from shorepower:

  • Shut off the boat’s main AC circuit breaker – then turn off the dock breaker. Disconnect the dock end of the shorepower cord first.
  • Disconnect the shorepower cord at the boat receptacle.
  • Clean and dry the shorepower cord. Store in a dry location on board the boat.

Once a year, have a qualified marina electrician perform the following:

  • Clean and dry the shorepower cord. Store in a dry location on board the boat.
  • Verify that any galvanic isolators (if installed in your boat) meet current American Boat & Yacht Council (ABYC) standards and are fully functional.
  • Inspect shorepower •cords •adapters •boat receptacles for any signs of deterioration including •cord wear •loose connections •signs of sparking •overheating •bent or pitted blades. If there are any such signs examine + correct + test the equipment or replace it.
  • Operate the boat’s electrical system at full load (everything on) and check for AC system leakage or voltage between the boat’s underwater fittings (bonding system if equipped) and the shoreside AC system ground.

What to do to avoid carbon monoxide poisoning

  • Schedule regular engine and exhaust system maintenance inspections by experienced and trained mechanics.
  • Be aware that dangerous concentrations of carbon monoxide can accumulate when a boat or generator or other fueled device is operated while the boat is at a dock seawall or alongside another boat. Do not run the boat or equipment for extended periods of time under these conditions or without continuous monitoring.
  • Keep forward facing hatches open to allow fresh air circulation in accommodation spaces even in inclement weather. When possible run the boat so that the prevailing winds will help dissipate the exhaust.
  • Do not confuse carbon monoxide poisoning with seasickness or intoxication. If someone on-board complains of • irritated eyes • headache • nausea • weakness • dizziness – immediately move the person to fresh air – investigate the cause – take corrective action. Seek medical attention if necessary.
  • Install a carbon monoxide detector in each accommodation space on your boat. Check the detectors periodically to be sure that are functioning properly.

Warning - water and electricity do not mix
Do not:

  • Swim in marinas
  • Alter shorepower connectors
  • Use “homemade” adapters or cordsets
  • Connect to a receptacle with a different configuration than the plug

In the event of an in-water or onboard electrical accident:

  • Turn off (or unplug) the power to all boats in the area immediately (only then is it safe for others to effect rescue)
  • Remove the victim from the water
  • Summon help
  • If needed, begin rescue breathing or CPR (as appropriate)

To find out more information about how to avoid electrical shock hazards on recreational boats and how to make boating safer, contact:

National Fire Protection Association

1 Batterymarch Park
Quincy, MA 02169-7471


NFPA 70 (National Electrical Code);
Article 555 (Marinas and Boatyards)
NFPA 302 (Motorcraft)
NFPA 303 (Marinas and Boatyards)

US Coast Guard

National Marine Manufacturers Association

American Boat & Yacht Council, Inc.

Boating Safety Awareness Series

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