This specification provides design, construction, and purchasing criteria for docking/drain plug and boss assemblies. Assemblies are intended for installation in shell, rudder, and tank bottom plate. Assemblies shall be installed at the lowest point of a tank or rudder for draining during dry docking. Docking plugs and bosses shall be classified as follows: type I - docking plug and bosses for plating from 8 to 15 mm, and type II - docking plug and bosses for plating greater than 15 to 38 mm. The procedure for installing docking/drain plug and boss assemblies are presented.