What type of ventilation system is required on inboard gasoline boats?

Inboard gasoline boats require a ventilation system that effectively removes flammable vapors from the engine compartment to prevent explosions. This typically involves a combination of natural ventilation, such as openings that allow air flow, and mechanical ventilation, using blowers to expel vapors. The system must operate effectively when the engine is running and be capable of clearing the compartment before starting the engine. Additionally, the system should comply with Coast Guard regulations to ensure safety.