Zigzag Maneuver

A zigzag maneuver is a planned series of regular course alterations about a base (mean) heading, used by a ship or convoy to make its future position hard to predict for an attacking submarine and to throw off a torpedo firing solution. Each leg ran a set time and angle off the base course following a numbered zigzag diagram; the mean of advance still made good the intended track. Widely used in both world wars for merchant convoys and warships. The separate IMO zig-zag test (Kempf maneuver) measures a ship’s course-changing and yaw-checking ability and is unrelated to the evasive tactic.