MO-2008-209 Loss of the rigid inflatable boat Mugwop, off the entrance to Lyttelton Harbour, 28 October 2008

The Mugwop was a 5.8 metre outboard-driven rigid inflatable boat (RIB), a tender for the dredge Machiavelli, which was working on the Christchurch ocean outfall project in Pegasus Bay off Christchurch. The Mugwop was being used to transfer crew twice daily between Christchurch and the various vessels involved in the project.

On 28 October 2008, the dredge and dive support barge were to seek shelter at the nearby port of Lyttelton from the forecast weather, which had already built up a one to 2 metre sea. The Mugwop would have normally been lifted on-board the Machiavelli for the trip, but the sea conditions made it too risky, so the Mugwop with a crew of 2 set off on the trip to Lyttelton on its own, but never arrived. The bodies of the 2 crew were recovered from the sea near the entrance to Lyttelton Harbour, one 7 hours after the event and the other about 15 days later; the Mugwop was never found. Post-mortem results determined that in the absence of any sign of traumatic injury the crew, who were both wearing life jackets, probably became hypothermic and drowned.

The Mugwop is believed to have suffered a rapid and catastrophic event that prevented the crew using any of the equipment on board to raise the alarm. The boat was likely travelling in the same direction as, and faster than, the waves, a circumstance that is known to cause failure of the inflatable pontoons at their weakest point, the bow on that type of craft.

The Mugwop was known to have 3 defects that could have put more pressure on the pontoons at the bow: the hull was leaking and almost certainly contained a significant quantity of water in its void space; the 115 hp outboard motor could not be trimmed to raise the bow; and the securing tag for the pontoons at the bow was not fastened to the hull.

Neither crew member was qualified to drive the Mugwop, nor had they been trained in driving techniques for rigid inflatable craft in heavy seas.

On 29 October 2008, the day after the accident, Survey Nelson Limited submitted an application to Maritime New Zealand for a safe ship management (SSM) certificate for the Mugwop. Included in the information provided was a Fit for Purpose Document for the Mugwop to ply as a non-passenger vessel to within 5 nautical miles of the coastline. The Mugwop was not fit for purpose because it did not comply with all of the requirements of the Maritime Rules with regard to stability, subdivision of the inflatable pontoons and having a water deflector forward.

The report discusses the general lack of maritime knowledge and awareness of safe ship management systems at the appropriate level of management with the principal contractors for the project, and how this probably contributed to a number of serious accidents and incidents, and non-compliances with Maritime Rules throughout the project.

Also discussed is the failure of the safe ship management system, and in particular the failure of the surveying company to ensure the Mugwop complied with all Maritime Rules, before being issued with a Fit for Purpose Document.

Arising out of previous reports, the Transport Accident Commission (Commission) has recommended that the safe ship management system for New Zealand domestic watercraft be reviewed. The Director of Maritime New Zealand has accepted the recommendation and the review has been completed. A draft Maritime Rule to introduce a new safety management system was under consultation at the time this report was published.

The report also discusses the issue of substance impairment and the need for legislation to regulate the maritime industry to prevent the abuse of substances that impair performance. A previous safety recommendation has already been made to the Secretary for Transport to address that issue.

New recommendations are made to educate drivers of rigid inflatable craft in driving techniques and limitations in what that type of craft can reasonably achieve in heavy weather operation.