When a wedge of water builds up between the head of the barge and the bank it is referred to as __________.

Correct Answer: Option C — bank cushion

Bank cushion is the hydrodynamic phenomenon where water displaced by the vessel's bow is trapped between the hull and the bank. This buildup of pressure creates a cushion that pushes the bow away from the bank, significantly affecting the vessel's steering and requiring immediate corrective rudder action.