Bank effect

Bank effect refers to the tendency of the stern of a ship to swing toward the near bank when operating in a river or constricted waterway.

The asymmetric flow around a ship induced by the vicinity of banks causes pressure differences (Bernoulli's principle) between port and starboard sides. As a result, a lateral force will act on the ship, mostly directed towards the closest bank, as well as a yawing moment pushing her bow towards the centre of the waterway. The squat effect increases due to the decreased blockage.