Lack of stability book knowledge led to landing barge capsize

Landing barge capsized due to lack of stability book knowledge
Landing barge capsized due to lack of stability book knowledge

On 21 August 2019, a landing barge (operated as a Class 1E and 2D) capsized while transiting from Great Mackerel Beach to Pittwater north of Sydney. AMSA has provided the lessons learnt from this event.

Leading up to the incident the landing barge loaded a vacuum suction truck and secured it to the starboard side of the deck so that the master could maintain forward visibility from the wheelhouse while navigating the vessel. Following, the vessel listed to starboard and subsequently capsized shortly after leaving Great Mackerel Beach. The investigation found at the time of the incident no wind or wave action was present.

It was later estimated that the vessel’s centre of gravity was approximately 0.25m to starboard due to its asymmetrical load. At the time of the incident, the vessel was determined to have been loaded with a deadweight of 38 tonnes which exceeded the maximum deadweight of 35 tonnes permitted in the “Trim & Stability Book”. In addition, the down flooding point identified in the stability book was the starboard wheelhouse door, however the deck hatch in the starboard aft part of the main deck was not weathertight and hence should have been considered the down flooding point.

Probable cause

The investigation identified the following contributory factors:
– The vessel load exceeded the maximum weight limit as identified in the vessel stability book.
– There were inconsistencies between the approved stability book and the physical state of the vessel – due to the down flooding caused by the starboard deck hatch on the main deck not being weathertight.
– The vacuum truck was secured into the landing barge asymmetrically, which generated a list to starboard. This in turn contributed to an initial decrease in the range of positive stability.

Safety message

This incident highlights the importance of operating within the approved limits of a landing barge’s stability book.

Another factor that led to the vessel capsizing was that the down flooding point on the landing barge was incorrectly identified in the stability book as the wheelhouse door, due to the starboard main deck hatch not being weathertight. As a result, the hatch became the flooding point once the vessel lost stability. Landing barge operators and masters need to ensure their vessel loads comply with the limits as laid out in their vessel’s stability book and ensure the safety of all crew onboard.

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