Ventilation systems are crucial. Their purpose is to avoid explosions by removing flammable gases. Properly installed ventilation systems greatly reduce the chance of a life-threatening explosion.
Powerboats are built to ventilate the engine when underway. As the boat moves along, an air intake scoops up fresh air and forces it down the air duct into the engine compartment. The exhaust sucks out the explosive fumes from the lowest part of the engine and fuel compartments.