Pivot point

The pivot point is the apparent center of rotation of a turning ship, the point on the centerline about which the hull seems to swing and where the drift angle is momentarily zero. In a steady turn it lies forward of midships, commonly about one-quarter to one-third of the length from the bow, because the lateral hydrodynamic resistance concentrates forward of the center of gravity. Its position is not fixed: it shifts with speed, rudder, and whether the ship is accelerating into or settling within the turn, and it moves aft when going astern. Pilots use it to judge how bow and stern will swing relative to the track.