The Martha Anne, owned by P, and the steamship Ceara, owned by D collided. On the night of the collision, the Martha Anne was sailing light with a deepest draft of eight feet, eight inches in her stern. She was equipped with one white top lantern and the customary green port and red starboard side running lights, all of which were burning properly; she had no range lights. The Ceara was proceeding up the ship channel to Mobile. The Master, the bar pilot, the chief mate, and a helmsman were on the bridge, but no lookout was stationed on the bow. She was equipped with radar and range and side lights, all of which were functioning properly at the time. She was running light, drawing eight feet, ten inches forward, and thirteen feet even aft. The Mobile ship channel is thirty to thirty-five feet deep and about four hundred feet wide. Both ships, under the command of harbor pilots, were proceeding down the center of the channel. Night had just fallen but the weather was clear and visibility was good. The wind was light and a light tide was running out. Each ship was sighted visually when they were several miles apart, although the Ceara had previously spotted the Martha Anne on its radar. They commenced to maneuver for passing at a distance of three-quarters of a mile. They exchanged single whistle blasts and each ship moved slightly to its starboard for a standard port-to-port passing. The Ceara reduced its normal cruising speed of fifteen and one-half knots to a half-ahead speed of eleven knots; the Martha Anne maintained her cruising speed of eleven knots. When the ships were some three hundred feet apart, it appeared that the passing would be perfect. where they would have passed each other at a distance of from seventy-five to one hundred feet. The Martha Anne took a heavy sheer to port onto a collision course with the Ceara. The attempts by The Martha Anne to break the sheer and the evasive maneuvers by the Ceara were to no avail. The stem of the Martha Anne struck the Ceara and raked her port side for one hundred and twenty feet. Her port anchor cut a gash in the side of the Ceara for this entire length. The initial angle of collision was about thirty to forty-five degrees. Immediately before or at the very time of the collision, the Ceara ran aground on the east bank of the channel. The Ceara extricated herself and both ships returned to port in Mobile, each under its own power, the Martha Anne experiencing no further difficulty in steering. P has raised the defenses of the inscrutable fault and unavoidable accident.