The ATSB has found that a lack of passage monitoring resulted in the Vanuatu registered offshore tug/supply ship Massive Tide grounding on Rosemary Island, off Dampier Western Australia, at 0445 on 29 August 2006.
The Australian Transport Safety Bureau investigation found that fatigue probably impaired the performance of both the master and the officer of the watch and that the officer of the watch did not adequately monitor the ships progress during the voyage from the jack-up drill rig Ensco 106 to Dampier on the morning of 29 August.
At 0100 on 29 August, Massive Tide departed the drill rig Ensco 106 at a speed of 9.8 knots and on a heading of 129 degrees, a heading that would take it directly to Rosemary Island, rather than the Dampier Sea Buoy as intended.
At 0200 and 0400, the officer of the watch recorded the ship's GPS position in the deck logbook, but did not plot either position on the navigational chart.
At 0445, Massive Tide grounded on the shoals approaching the western shore of Rosemary Island. The rest of the crew were called out and checks of the ship, its machinery and the surrounding area revealed that no damage or pollution had occurred.
Immediate attempts to refloat the ship were unsuccessful and plans were put in place to try again on the next high tide. At 1035, the ship floated free without assistance.
The ATSB report further concludes that the ship's master did not ensure that the bridge watchkeepers routinely followed his instructions and company procedures; and that the procedures and practices in place on board Massive Tide did not ensure that the levels of watchkeeper fatigue were effectively managed.
The ATSB has made two safety recommendations with the aim of preventing further incidents of this type.