CARBON MONOXIDE (CO)

CO is a gas, which is tasteless, odourless and colourless making it extremely difficult to detect.  As it weighs about the same as air it will not rise or fall like other gases, so the danger of it accumulating is very high.

CO is a by-product of incomplete burning of fossil fuels (petrol, LPG, propane and oil) in engines, cooking appliances, generators and heaters. Remember that the source of the CO may not be on your vessel, but on one alongside for instance.  CO can be present in dangerous levels on, or near, an anchored, idling or slow-moving vessel.

Exposure to Carbon Monoxide at either high or cumulative low levels of emission can cause brain damage and death.  It is absorbed into the airways and lungs, and significantly reduces the amount of oxygen in the blood, which then leads to oxygen starvation and its lethal results. Symptoms of Carbon Monoxide poisoning can include any, or all, of the following:

• Collapse
• Nausea and/or Vomiting
• Convulsions
• Fatigue and/or Drowsiness
• Dizziness and/or lack of co-ordination
• Itchy and/or runny eyes
• Headache and/or throbbing at the temples
• Slurred speech and/or incoherence
• Inability to concentrate
• Chest tightness

Prevention is obviously the preference for all boat owners, so educate all passengers on the dangers of CO poisoning.  Do not allow them to swim at the rear of the boat when either engines or generators are operating. CO can enter the cockpit/cabin areas via drains, so ensure plugs are left in sinks at all times.

TREATMENT FOR CARBON MONOXIDE POISONING

If you suspect that a person has CO Poisoning you must act immediately, but carefully, as there is the obvious danger of high CO levels in the vicinity of the victim.

1. Ventilate the area if you can to reduce the danger of more poisoning or explosion.
2. Move the victim to a well-ventilated area and administer oxygen if available.
3. If the victim is not breathing perform CPR until medical help arrives.
4. CONTACT EMERGENCY SERVICES and follow their instructions.
5. Locate the source of the CO, only if it is safe to do so, and wear protective equipment where necessary.

SAFETY STEPS FOR GAS EQUIPMENT

The safety instructions issued by the supplier of any gas-fuelled (LPG, Propane, Butane and CNG) equipment on board your vessel should be strictly adhered to.

In addition, please remember that:

• Gas cylinders should not be stored inside a boat or any area that has not been designed for the storage of cylinders, and which is not aired or vented to the outside, and in which an accumulation of gas can build up.
• Portable equipment (BBQ etc) should not be used in the boat and only when it is securely mounted in a well-ventilated area.
• Close all gas valves on equipment when they are not in use.
• Close all gas valves before re-fuelling.
• Ensure valves on the appliances attached to cylinders are closed BEFORE turning cylinder valves on.
• Replace all protective caps and covers on equipment valves when not in use.
• Do not use cooking appliances when high angles of rolling or extended periods of angles heel are occurring.
• Have all appliances inspected annually by a licensed technician.

THE STATION WAGON EFFECT

In certain circumstances, Carbon Monoxide can enter the boat through the aft of the cockpit, in what is known as the ‘Station Wagon Effect’. The shape of the hardtop and the set up of the clears can lead to an area of low air pressure directly behind the boat and in the cockpit. This area of low air pressure will naturally draw in air from areas of higher pressure. Exhaust gases from the swim platform and surrounding areas will be drawn into the cabin or cockpit area (see diagram below). This effect can be reduced by increasing the airflow through the cockpit; opening the clears, the companionway and the deck hatches will do this.

This situation may occur in various wind conditions, boat speeds and trim angles. Inefficient trim angles can increase the station wagon effect. Having the bow too high increases the boats angle of attack, therefore increasing the amount of CO produced by excessive engine loads. To avoid this, make sure the running angle is as efficient as it can be at all times.

Other Effects
Carbon Monoxide can also enter the boat when the wind is blowing onto the stern (see diagram below). This situation is unavoidable in certain circumstances. Should this situation be experienced, care must also be taken to regularly ventilate the cockpit thoroughly and, if possible, a different route should be taken.