Helmsman and Pilots Worked Against Each Other During Fremantle Allision

An interim factfinding report on the allision involving the boxship Maersk Shekou at Fremantle last year suggests that the vessel's helmsman and pilots were operating with different goals. The helmsman was actively steering to maintain a heading of 083 degrees, his last received helm order. Meanwhile, the pilots were trying to make an emergency turn to port, using full ahead thrust, assist tugs, bow thrusters and the port anchor - unaware that their helmsman was applying starboard rudder to counteract them. The ship hit a historic tall ship and a museum, causing considerable damage.

In the early hours of August 22, 2024, Maersk Shekou began heading inbound into Fremantle's harbor and took aboard two pilots. The primary pilot assigned for the transit was fatigued, so the backup pilot took charge during the master/pilot exchange.

At about 0610, as they entered the narrow entrance channel for the inner harbor, southwesterly winds picked up to about 40 knots on the starboard quarter. The ship began to swing to starboard. The pilot ordered the helmsman to steer 083; the helmsman correctly acknowledged the order at about 0613:45. This was the heading that the helmsman would try to maintain throughout the final minutes of the casualty sequence.

At the time that the order was given, the helmsman had the rudder hard to port to counteract the effects of the strengthening wind. It wasn't enough to do the job, and Maersk Shekou's heading was about four degrees off to starboard (087). The master suggested going to full ahead to increase steering forces, and at about 0614:34, the pilot agreed. There was a pier ahead, and they needed to turn to port fast in order to enter the harbor.

With more power and a series of assist tug movements, Maersk Shekou began to swing back to port. As it swung back from 087 through 086, the helmsman moved to check the swing: he brought the helm to midships, then briefly to 33 degrees starboard. The vessel steadied up squarely on 083, the last ordered heading he had received, which was straight towards the pier.

Courtesy ATSB

The pilot was unsure why the vessel had stopped swinging to port, and at 1615:33 he told the (fatigued) secondary pilot that something was wrong. The secondary pilot had been on a phone conversation at the back of the bridge and had not been involved in the back-and-forth among the bridge team, but he interrupted the call and joined the decisionmaking process.

Together, without checking in with the helmsman, they began working the assist tugs to try to turn Maersk Shekou to port. The rudder was amidships at this point, and the helmsman was maintaining a steady heading of 083.5 towards the moored tall ship STS Leeuwin II - now less than a ship length away, with the boxship full ahead and making seven knots.

At 0615:54, the master put the bow thrusters full to port. At 0616:10, the secondary pilot ordered stop engines, then full astern, and the master ordered the crew to prepare to drop the port anchor.

Beginning at 0616:21, as these emergency measures to turn to port were under way, the helmsman applied more starboard rudder to try to counteract the effort to turn to port. The rudder would be over to starboard as much as 29 degrees over the course of the next minute.

At 0616:49, the engines reached full astern and Maersk Shekou began to slow. The anchor, tugs and bow thruster managed to start a swing to port, but not fast enough to avert an allision. At about 0618, Maersk Shekou hit STS Leeuwin II at about three knots, dismasting the sailing vessel and prompting the two crewmembers aboard to flee onto the pier. They escaped with minor injuries.

Maersk Shekou makes contact with STS Leeuwin II

Maersk Shekou came to a full stop by about 0618:30, but continued to spin in place. The bow thrusters were still on full to port, and the ship was swinging to port at about 13 degrees per minute. At 0619:52, the master noted to the pilots that the bow thrusters were still running with full power to port, and the thrusters were shut down - but not quickly enough to prevent contact in the narrow confines of the harbor.

40 seconds later, a stack of containers on Maersk Shekou's starboard quarter hit the roof of the Western Australia Maritime Museum. The ship's hull scraped along the wharf for a short distance, damaging the quayside and breaching a small section of the hull plating above the waterline.

The ATSB continues its investigation and will release its full report, including its formal conclusions, when it has completed its review.