Abstract: An assembly for a boat having an internal combustion engine which uses sea water as its coolant and a bilge which collects sea water. The assembly comprises a Y-shaped pipe whose tail is connected to the water pump of the internal combustion engine, a first manually operable on-off valve for controlling the flow of sea water into the water pump located in one arm of the Y-shaped pipe, a second manually operable on-off valve for controlling the flow of an alternative source of water into the water pump located in the second arm of the Y-shaped pipe, and a length of flexible hose attached to the end of the second arm of the Y-shaped pipe, the free end of said hose being alternatively connectable to a source of fresh water or to the sea water in the bilge. The assembly may include a switch mounted on the Y-shaped pipe whenever the on-off valve between the engine's water pump and the hose leading to the sea is closed.