In a powered ventilation system, one or more powered blowers does the work of circulating air through the ducts. Which boats are required to have powered ventilation systems? Ventilation will remove gas fumes from the hull and engine compartments, which will help prevent a fire or explosion from occurring. The purpose of a ventilation system is to circulate fresh air on your boat. What does an inboard engine ventilation system do? If your boat is equipped with a power ventilation system (exhaust blower), turn it on for at least four minutes before starting your engine.Open all windows, ports, doors, and other openings.Put the fill cap on tightly to prevent vapors from escaping.How do you ventilate a boat with an inboard engine? The exhaust sucks out the explosive fumes from the lowest part of the engine and fuel compartments. As the boat moves along, an air intake scoops up fresh air and forces it down the air duct into the engine compartment. Powerboats are built to ventilate the engine when underway. What kind of vessel has a ventilation system that is designed to ventilate the engine as the boat moves along? 6 When do you need a bilge blower on a boat?.5 What kind of ventilation system do gasoline boats need?.3 Which of the following is recommended maintenance for an inboard boat?.2 What does an inboard engine ventilation system do?.1 What kind of vessel has a ventilation system that is designed to ventilate the engine as the boat moves along?.