The S. S. Edgar F. Luckenbach lay moored to a dock receiving cargo from a barge positioned alongside. The loading operations were being performed by P and his fellow longshoremen under the direction of their employer. Some of the men were on the ship, operating the port winch and boom at the No. 2 hatch. P and others were on the barge, where their job was to 'break out' the bundles of cargo by securing them to a sling attached to the fall each time it was lowered from the ship's boom by the winch operator. On one occasion the winch operator did not lower the fall far enough. Finding the sling beyond his reach, P motioned to the flagman standing on the deck of the ship to direct the winch operator to lower the fall farther. The winch operator then lowered the fall, but he lowered it too far and too fast. The sling struck P, knocking him to the deck of the barge and causing his injuries. Neither before nor after this occurrence was any difficulty experienced with the winch, boom, fall, sling, or any other equipment or appurtenance of the ship or her cargo. P brought this action against Fd, the owner and the charterer of the ship, in a federal district court, alleging that his injuries had been caused by the ship's unseaworthiness. Ds moved for summary judgment claiming that a single negligent act by a fellow longshoreman could not render the ship unseaworthy. The Court denied the motion and Ds took an interlocutory appeal. The Fifth Circuit allowed the appeal and, reversed. P appealed.