PHOENIX — The occurrence of two boat explosions two days in a row at Lake Havasu is an important reminder of the crucial role of ventilation systems, which work to remove flammable gases. Properly installed ventilation systems greatly reduce the chance of a life-threatening explosion.

A properly functioning ventilation system circulates air through the engine and fuel tank compartments to remove fuel vapors from the bilge. A best practice to follow is to always open an inboard engine compartment and let it air out before starting an engine — this allows you to smell for gasoline fumes.

Before going out on the water, check your ventilation hoses in the engine compartment. In a passive system the fresh air enters higher in the compartment to force gasoline vapor out through the lower hose. In a powered ventilation system the blower should be on the exhaust hose so any gasoline vapors are drawn away from the engine rather than introducing fresh air to the engine compartment if the blower was on the intake side.

“When considering repairs on your boat remember that marine-rated parts like starters, alternators or generators are designed to limit spark exposure, that’s why they are more expensive than standard automotive parts,” said Tim Baumgarten, boating law administrator for the Arizona Game and Fish Department. “Resist the urge to replace engine parts with automotive parts because they are cheaper.”

According to The Boater’s Guide of Arizona:

• All gasoline-powered vessels constructed in a way that would entrap fumes must be properly and efficiently vented to remove the fumes. It is recommended that at least one intake duct extend from a point midway to the bilge or below the level of the carburetor air intake, and at least one exhaust duct extend from the open atmosphere to the lower bilge.
• If your vessel is equipped with a power ventilation system, turn it on for at least four minutes in either of these situations: after fueling and/or before starting the engine.
• If your vessel is not equipped with a power ventilation system (for example, a personal watercraft), open the engine compartment and sniff for gasoline fumes before starting the engine.
• Regularly check the ventilation ducts for obstructions, such as birds’ nests. Make sure you can feel air coming out of the cowl when the ventilation system is turned on.

A great resource for information is the Arizona Game and Fish Department’s Boating Safety Education program. The department’s free courses include instruction on the basic skills required to safely operate a boat or personal watercraft, trailering your vessel, navigational rules, buoys, anchoring, legal requirements and boating emergencies. Upcoming courses and information can be found online at www.azgfd.com/Education/Boating/.