If a vessel has an installed toilet, technically referred to as a marine sanitation device (MSD), it must be equipped with one of three types of MSDs. The MSDs (Type I, Type II, Type III) are designed to meet different needs and effluent level requirements. Since portable toilets can be moved on and off a vessel, they are not considered installed toilets; therefore, vessels that have portable toilets are not subject to MSDs regulations. The Sewage Treatment Device (Standard Vessel Length) Type I, is a flow-through device (maceration and disinfection) for vessels less than 65 feet in length. The effluent…