motion. This motion is generated directly either by the water and wind motion, particularly lateral wave motion, exerting forces against the hull or by the ship's own propulsion; or indirectly by the inertia of the ship while turning. This movement can be compared to the vessel's lateral drift from its course. Heave The linear vertical (up/down) motion; excessive downward heave can swamp a ship. Stabilization There are methods for both passive and active motion stabilization used in some designs. They include static hull features such as skegs and bilge keels, or active mechanical devices like counterweights, antiroll tanks and stabilizers. See also References Society of Naval Architects and Marine Engineers (SNAME), "Principles of Naval Architecture", 1989, Vol. III, Pg.41, Section 3 - Ship Responses to Regular Waves Sukas, Omer Faruk; Kinaci, Omer Kemal; Bal, Sakir (2019). Theoretical background and application of MANSIM for ship maneuvering simulations MANSIM Lab. Ocean Engineering, 192, 106239. Nautical terminology