Ineffective pilotage and port deficiencies caused the grounding of a bulk carrier last year, the Australian Transport Safety Bureau (ATSB) has determined.
In its final report on the grounding of the World Diana at the Port of Bunbury in April 2023, ATSB contends that ineffective bridge resource management was largely to blame for the incident. The port authority also came in for criticism: at the time, it had not developed adequate procedures for arrival and departure plans for larger ships, ATSB said.
On the morning of April 22, 2023, World Diana was scheduled to depart the Port of Bunbury with the assistance of a harbor pilot. The ship was berthed starboard side to at the number three berth, and needed to be maneuvered into the inner harbor turning basin and then turned to port towards the harbor entrance. It was nearly fully laden with a cargo of grain, destined for the Port of Kosichang in Thailand via the Singapore Strait.
The 81,200 dwt, 229-meter ship had a crew of 19. The pilot had completed about 4,000 pilotage movements at the port of Bunbury, including about 35 vessels of over 200 meters.
Beginning at 0542 local time, the pilot conducted a master-pilot exchange on the bridge. The departure plan called for two tugs to help the ship turn around and sail out of the harbor. At 0632, when all the mooring lines had been cast off, the pilot instructed both tug masters to ‘lift off’ using quarter power and, shortly after, asked them to increase to half power. Four minutes later the ship had developed slight headway with its main engine running dead slow ahead.
As the 2020-build Panamax bulker turned, its headway increased. By 0641, the ship’s bow was closing on the shallow water on the eastern side of the harbor. Two minutes later the bulker’s bow grounded on the bank and its speed rapidly reduced to zero. The pilot then maneuvered the ship astern using its propulsion and the tugs. Once the ship was established in the center of the turning basin, the turn was completed.
“This turn was started earlier than planned, reducing the amount of room available. The ship’s speed was then allowed to increase until there was no room to safely turn, and the bow of the ship grounded on a shallow bank to the east of the harbor entrance,” said Angus Mitchell, ATSB Chief Commissioner.
The investigation established that at the time of the incident, a pilot transfer vessel inspected the shallow area but did not identify any evidence of a grounding therefore it was believed to have been a near miss. There was no inspection of the ship’s hull carried out prior to departing Australia. The pilot and ship’s master continued the departure and the pilot disembarked the ship outside the outer harbor.
But two days later the pilot reported the incident as a near miss with a subsequent review of incident data indicating a grounding. A survey of the seabed in the incident location also identified an indentation in the soft seabed where World Diana’s bow had grounded.
The ship’s managers were made aware of the grounding, with an underwater hull inspection that was conducted on May 1 identifying minor contact damage of the shell plating of the fore peak tank. The ship was cleared to continue trading with the damage to be attended at its next scheduled dry docking in 2025.
In its findings, the ATSB determined that World Diana's turn to port to depart the inner harbor was started earlier than planned, reducing available room to complete the turn. Once the turn began, the ship’s speed was allowed to increase until there was no space left, and the ship ran aground.
Courtesy ATSB
The investigators also determined that the Port of Bunbury had not developed adequate arrival and departure plan procedures for larger ships that were berthed starboard side alongside berth number three. In effect, this increased the risk of grounding.
The Southern Port Authority has since updated its marine pilotage standards and procedures for Bunbury with standard procedures for departing all berths. A maximum rate of turn for turning ships in the harbor has also been specified.
