One of history's most expensive ship salvage jobs is set to get even costlier, with a major new underwater project to be put on the MV Rena's running tab of $300 million.
The owners and insurers of the container ship have announced plans to remove the Rena's submerged four-storey accommodation block from the wreck on the Astrolabe Reef in the Bay of Plenty.
Neither the owners nor the salvors contracted to chop away the structure could reveal estimates of the operation, which adds to what was this year listed as the third most expensive salvage in the world.
The latest project will kick off in October, two years after the ship struck the reef and spilled 350 tonnes of heavy fuel oil into the ocean.
It comes after concerns had been raised that the block, which housed the ship's bridge, crew quarters, offices and galley, could collapse and send more debris towards the shore.
Captain John Owen, of insurers The Swedish Club, said he understood that people did not want the uncertainty of not knowing when such an event might happen.
"Although there is a considerable cost to removing the accommodation section, we recognise the importance of minimising the effects on the community of the Rena grounding as much as we can."
While yet to lodge a resource consent application, the Rena's owners have sounded their preference for leaving part of the wreck on the reef after properly containing the site.
Their initial approach had been to leave the accommodation block after making it safe to use as a diving attraction but changed their minds in light of wave action and currents potentially battering it into a hazard. Removing the block is scheduled to take 80 days. Half of that time allows for bad weather and sea conditions, and will begin once a special crane barge arrives from Singapore.
US salvors Resolve Salvage and Fire will cut away sections and lift them on to a barge to transport to the Port of Tauranga and scrapped.
A team of smaller craft at the site will prevent debris reaching the shore. Minimal damage would occur to the reef.
Salvors are meanwhile whittling down the Rena's bow to 1m below the lowest tide mark, removing container wreckage from damaged holds and clearing hundreds of tonnes of debris from the sea floor.
The entire operation - a logistical nightmare which has involved a race to pump Marmite-like oil from fuel holds and cranes plucking away containers stacked in high leaning towers - has now reached the point where nothing of the Rena is visible from above the water.
Assessments of the wreck's environmental, social and cultural impacts are due to be complete by the end of the year, and until then the owners say any decision to lodge a consent application won't be made.
Several iwi groups have gone to the Waitangi Tribunal in a push for the wreck to be completely removed and appeals have been lodged with the Bay of Plenty Regional Council over a temporary suspension of the reef's recognised environmental status.
Long, slow haul
US salvors Resolve Salvage and Fire will remove the accommodation block in two sections by cutting it away from the deck. Each section will be taken by barge to the Port of Tauranga and dismantled for scrap and recycling.
For a video of the next stage click here