Ohio Revised Code Title XV. Conservation of Natural Resources § 1547.29

(A) At least two ventilators fitted with cowls or their equivalent for the purpose of properly and efficiently ventilating the bilges of every engine and fuel tank compartment in order to remove any inflammable or explosive gases;

(B) Any type of ventilating system approved for use by the United States coast guard;

(C) The ventilation of the boat is not required where the greater portion of the bilges of the engine and fuel tank compartment is open to the natural atmosphere.