The ATSB has found that the submarine ethane gas pipeline rupture in Port Phillip on 13 December 2008 was the result of attempting to clear the container ship APL Sydney's anchor, which had snagged the pipeline.
The Australian Transport Safety Bureau investigation found the ship's anchor had been let go too close to the pipeline in the gale force winds and insufficient anchor cable was deployed. The anchor dragged towards the pipeline and snagged it because appropriate avoiding action was not taken.
At 1428 on 13 December, APL Sydney's anchor was let go in Melbourne's Outer Anchorage, about 1 km upwind of the pipeline and shortly afterwards, the pilot left the ship. By 1501, the ship had dragged its anchor and was located outside the anchorage, about 350 m from the pipeline. The master advised Melbourne harbour control of his intention to weigh anchor and shift the ship but was instructed to maintain position and wait for a pilot.
By 1525, the pilot had not boarded and the ship, after continuing to drag its anchor, was about 50 m from the pipeline. Harbour control then gave the master permission to shift the ship. Weighing anchor was started but after a few minutes, control of the ship was effectively lost. At about 1544, the anchor snagged the pipeline and a little later, the anchor windlass also failed.
The pilot re-boarded APL Sydney at 1603 and after first considering releasing the anchor cable, discussed the situation with harbour control. At 1615, he concluded the anchor was south of the pipeline and decided to drag it clear. The master accepted his plan and at 1620, the ship's main engine was started. At 1621, the gas pipeline ruptured. There were no injuries and the pipeline was isolated.
The investigation identified safety issues in relation to: the port's risk management with respect to the pipeline and anchorage boundaries and its shipping control procedures; the ship's safety management system; the pilotage company's safety management system; and the windlass failure.
The ATSB is pleased to report that safety actions to address all the safety issues have been taken or been proposed by the relevant parties to prevent similar incidents in the future. The risk assessment of the anchorage conducted by the Port of Melbourne Corporation and the implementation of measures, including revised anchorages with individual ship berths, is one of the significant actions taken.