MO-2007-207

At about 1330 on 21 June 2007, the specialised bulk iron sand carrier Taharoa Express left its single buoy mooring in Port Taharoa to seek refuge in Tasman Bay from forecast severe weather. The ship had been scheduled to have a slurry of about 116 000 dry tonnes of iron sand mixed with water pumped aboard. Earlier during the loading process the ship’s duct keel had flooded with water from the slurry-loading process, disabling the ship's ballast and cargo de-watering systems. The water had gravitated from the cargo overflow recesses into the duct keel through welding access holes left unsealed after steel renewal in dry dock prior to the loading voyage. When the Taharoa Express departed Port Taharoa it had an estimated 17 800 cubic metres (m3) of water on top of the iron sand that had settled in 5 of its cargo holds, as well as number 6 water ballast hold and several ballast tanks being partially full.
The ship initially had a 1.5 degree starboard list when it sailed.
During the voyage to Tasman Bay, the starboard list progressively increased, unnoticed by key personnel on board until about 0150 on 22 June when the ship took a larger roll that woke key personnel, who found that the ship had a 17 degree starboard list. The Taharoa Express was manoeuvred for the remainder of the trip to Tasman Bay to minimise the motion of the ship in the heavy seas, but the list reached 22 degrees before the ship reached the shelter of Tasman Bay. The cause of the list was the progressive shift of iron sand in all loaded holds owing to wash action
caused by sloshing free water, and possibly contributed to by an en masse shift of iron sand in one or more cargo holds.
Before the Taharoa Express reached the shelter of Tasman Bay it was losing stability reserves and at significant risk of capsize owing to the shifting cargo and the free water in the cargo holds. The ship was also at growing risk of suffering structural failure owing to a combination of the increasing list, the distribution of cargo against the side shell plating, and the sloshing forces against the structure.
Mandatory safety management systems for the ship operator and for aboard the ship, and a voluntary safety management system for the management of loading and for the operation of the port were all partially or poorly developed and applied by the 3 different organisations responsible, and they did not integrate with each other sufficiently. This meant that the potential for the incident circumstances to arise and be managed had not been realised or planned for. A hierarchal, rigid and compartmentalised culture within the ship’s crew and its management company resulted in communication difficulties that meant that early warnings of the failing systems were misdiagnosed or ignored.
None of the organisations responsible had a clear understanding of the cargo sand’s properties generally.
The onboard stability computer could not adequately analyse the ship’s stability characteristics for a specific load. International and New Zealand standards for carrying bulk cargoes and general regulatory requirements for safety management and oversight were unmet.
A range of safety recommendations to the Director of Maritime Safety and the ship’s Flag State of Panama ask for the deficiencies identified in the report to be addressed.
(Note: this executive summary condenses content to highlight key points to readers and does so in simpler English and with less technical precision than the remainder of the report to ensure its accessibility to a non-expert reader. Expert readers should refer to and rely on the body of the full report.)