On the evening of 14 October 1918, as New York led a group of battleships into the Pentland Firth, she was rocked by a violent underwater collision on her starboard side, followed shortly after by another to the stern that broke off two blades on one of her propellers, reducing the ship to one engine and a speed of 12 kn (14 mph; 22 km/h). It was immediately clear to the men on board that she had struck an underwater object, but the depth of the channel meant it could not have been a shipwreck. Commanders concluded that New York must have accidentally collided with a submerged U-boat. They agreed that the submarine had rammed its bow into the ship's side, then been struck moments later by the ship's propeller. In their opinion, the damage would have been fatal to the German craft. Postwar examination of German records revealed that the submarine lost may have been UB-113 or UB-123. This strange—and accidental—encounter marked the only time in all of Battleship Division Nine's service with the Grand Fleet that one of its ships sank a German vessel.