PURPOSE: To increase damping effect of the up and down motion of a ship's ends in order to improve propulsion efficiency of the ship in waves by providing the immerged bow, stern, or both portions of the ship with a projection which resists the up and down motion of the end portion of the ship.

CONSTITUTION: A projected portion 9 is installed to an immerged ship's bow, stern, or both portions, which are usually under the water line 5. It is located just above the base line 7 of the ship, and is formed into a flat shape facing breadthwise, port and starboard side, from the ship's center line 8. The constitution like this gives resistance to the up and down motion at the fore and aft ends of the ship. It reduces remarkably the ship's up and down motion including pitching, and results in improvement of propulsion efficiency of the ship in waves.