Abstract: A combination valve and pump assembly for use as ballasting apparatus in ships includes a cylindrical valve element disposed within an opening in a ballast chamber. The valve element communicates with ambient sea water and is movable toward and away from the ship's outer surface to block and unblock the opening. The valve and pump assembly also comprises pump apparatus, operable with the valve element, and including an impeller rotatably positioned concentrically within the valve element. The invention contemplates simultaneous reciprocatory translation of the valve element and the pump assembly by hydraulic motor apparatus such that opening and closing of the opening by the valve element is effected by the hydraulic apparatus, while a pump motor causes rotation of the impeller when the valve element is displaced from a position where the opening is blocked.