Picton Harbour, New Zealand

August 2015 Picton Harbour, New Zealand

Project The Outcome Key Learning

Transport of cement for Dryden Bay construction site • Double fatality. • Two concrete trucks lost into the water. • Do not underestimate dual lift complexity. • Multiple contracting parties requires clear ownership of risk management.

In August 2015, two concrete trucks tipped off a barge and into Picton Harbour, killing both truck drivers. The drivers were trapped inside their cabs which sunk approximately 8 metres to the sea floor. The two loaded concrete trucks were scheduled to travel from Picton Harbour by barge (Mac III) to Dryden Bay along with a third vehicle, a pump truck, which was to be used to discharge the cement upon arrival. Firth Industries was contracted to supply the cement, and McManaway was contracted to transport the two trucks. On the day of the incident, the loading plan for the trucks was not adhered to. Instead of the Isuzu and Hino concrete trucks carrying 6 and 7 cubic metres respectively, they carried 5 and 8 cubic metres. The lighter truck was loaded onto the barge first. Once it was in position, the driver of the second truck, the Hino, began to board Mac III. It was reported the deckhand signalled the driver to manoeuvre to the port side to offset the starboard list caused by the Isuzu. However, the truck headed towards the starboard side. When the driver began to correct the position, a juddering noise was said to have come from the barge. The rear end of the Hino immediately started to slide to starboard, towards the low side of the barge. As the Hino continued to slide, the list of the barge and the momentum of the truck increased. The tug skipper reported applying full engine revolutions and placed the tug’s wheel hard to port to provide an opposing force; however, the Hino toppled into the water. Seconds later the Isuzu also toppled over the top of the starboard bulwark into the water. The barge lost stability as weight was transferred from the loading ramp on to the barge deck. The skipper, deckhand, and pump truck driver attempted to assist the drivers of the two concrete trucks, but tragically both drivers drowned.

The drivers were trapped inside their cabs which sunk approximately 8 metres to the sea floor.

Active failures that led to this event included:

1.

2.

The Hino truck’s weight transfer from the ramp to barge caused the barge to lose stability, which in turn caused both trucks to slide to starboard and topple over

Mac III’s reserve static stability during loading did not have sufficient margin for error without proper analysis and McManaway’s other barges gravity carried on the barge. This tragedy is a solemn reminder of the importance of working to an approved load plan, particularly when working on water and barges. The incident highlights the importance of proper planning and the completion of stability calculations for the particular load and load position on the barge. What may seem to be a minor adjustment in load weight, load length (or dimensions), positioning, and/or approach to the vessel, can have a very dramatic

3.

A truck of greater weight (the Hino) than was normally carried on Mac III was loaded on the barge

4.

The Isuzu (6 wheeler) was greater in length than the trucks which were routinely carried on Mac III

5.

The centre of gravity of the loaded concrete trucks was higher than the usual centre of impact on the outcome.