When anchoring the boat, you MUST turn OFF the engine. In most models, exhaust fumes containing carbon monoxide are emitted from the exhaust flap area of the transom immediately below the swim platform. No one should ever be on the swim platform or transom while the engine is operating.
Carbon monoxide is a colorless, tasteless, odorless and poisonous gas that accumulates rapidly and can cause serious injury or death. Exposure to carbon monoxide can be fatal in a matter of minutes. Exposure to even low concentrations of carbon monoxide must not be ignored because the effects of long term carbon monoxide exposure can build up and be just as lethal as high concentrations. Carbon monoxide from exhaust pipes of inboard or outboard engines may build up inside and outside the boat in areas near exhaust vents, particularly during slow-speed operations. STAY AWAY from these exhaust vent areas, which are located at the stern of the boat, and DO NOT swim or engage in any water sports or other activities in or near the stern area of the boat, including, without limitation, the swim platform, the rear sun deck, and aft facing lounge seats when the engine is in operation. Under no circumstances should the owner and/or operator allow persons to hold onto the swim platform while the engine is operating and the boat is in motion. These activities (sometimes known as teak surfing or platform dragging, where the participant holds onto the swim platform and is pulled through the water, and/or body surfs immediately behind the boat) are extremely dangerous, highly likely to result in death or serious bodily injury, and are a misuse of this product.
Carbon monoxide (CO) enters your bloodstream through the lungs, blocking the oxygen your body needs. Prolonged exposure to low concentrations or very quick exposure to high concentrations can be deadly to all on board.
Early symptoms of CO poisoning include irritated eyes, headache, nausea, weakness and dizziness. These can be confused with seasickness or intoxication. Altitude, certain health-related problems, and age will increase the effects of CO. Persons who smoke or are exposed to high concentrations of cigarette smoke, consume alcohol, or have lung disorders or heart problems are particularly susceptible to an increase in the effects of CO. However, anyone can be a affected. Another factor to consider is that physical exertion accelerates the rate at which the blood absorbs CO.