Design a logic circuit to control electrical power to the engine ignition of a speed boat. Logic output II is to become high if ignition power is to be applied and is to remain low otherwise. Gasoline fumes in the engine compartment present a serious hazard of explosion. A sensor provides a logic input FF that is high if fumes are present. Ignition power should not be applied if fumes are present. To help prevent accidents, ignition power should not be applied while the outdrive is in gear. Logic signal GG is high if the outdrive is in gear and is low otherwise. A blower is provided to clear fumes from the engine compartment and is to be operated for five minutes before applying ignition power. Logic signal BB becomes high after the blower has been in operation for five minutes. Finally, an emergency override signal EE is provided so that the operator can choose to apply ignition power even if the blower has not operated for five minutes and if the outdrive is in gear, but not if gasoline fumes are present.