Swiss Cheese

The investigation into the grounding of the Rena will primarily concentrate on the decisions made on the bridge in the last hours before her grounding on Astrolabe Reef.

However, the Antipodean Mariner expects that the investigation will cast the net wider than just the bridge team and ask what commercial pressures were being placed on the Master and crew.

Every company’s safety management system will contain the motherhood statement that safety is never to be compromised by commercial considerations, but in the real world a Master always has the commercial considerations front and centre in his decision-making process. Container ships like the Rena are always under pressure to maintain schedule for the onward feeder connections at the global container hub ports.

The Antipodean Mariner won’t speculate on schedule pressure at this point, but puts forward the ‘Swiss Cheese’ safety model familiar to most seafarers.



The Swiss Cheese model is applicable to all structured safety management systems and assumes that no accident occurs due to a single, isolated system failure. Accidents occur due when ‘holes’ in the multiple lines of systems, equipment and procedural defences line up.

For an investigation of the Rena casualty to be meaningful, all the factors leading to the decision to turn the auto-pilot dial to 'Port' have to be considered. Did the Rena sail from Napier, leaving cargo behind, to make the tide and berthing slot in Tauranga? What did the Harbour Control advise the ship in respect to her prospects for making the tidal window to enter Tauranga? What would have been the impact of missing the tide on Rena’s onward schedule?

Irrespective of the decision taken on the bridge, the Antipodean Mariner hopes that the decisions of others not aboard the Rena on the morning of October 5th are determined and appropriately weighted to avoid the simple ‘scapegoating’ of a the individuals presently bailed in Tauranga.

The Antipodean Mariner