Rena - the challenge continues
Safe Seas Clean Seas Issue 39, March 2012
The cargo ship’s long-anticipated break-up immediately triggered an intensive response on land and at sea.
Containers and debris toppled into the roiling water as swells of more than 7 metres battered the wreck. Salvage activity was escalated along shorelines and at sea, with response teams for beach clean-up and oiled wildlife reactivated.
Response plans were already well established for Rena’s inevitable break-up. The ship was in a fragile state from damage sustained when it grounded on 5 October, and a crack was yawning open between its forward and aft sections. In the days leading up to the storm, electronic sensors had picked up extra movement in the ship. Transponders were fixed to vulnerable containers and others containing dangerous goods, so they could be tracked if lost overboard.
The container recovery company Braemar Howells set to work to identify, tag, corral and collect containers and other debris spilled from the ship during the storm and break-up. Harbour channels and shipping routes were closely and regularly checked for submerged containers. Meanwhile, MNZ reactivated its full oil spill response capability. The oiled wildlife facility at Te Maunga, which had been scaled down, was scaled up ready for action.
As the sea calmed and visibility improved, it became evident that the forward section of the ship was in its original position on the reef, but the stern section had separated by about 30 metres, pivoting some 13 degrees clockwise. Days later, most of the stern slipped off the reef.
Both sections are now open to the sea and extremely vulnerable to further damage. The continual movements of both sections with tidal flows, and increased movement as containers are removed and the ship grows lighter, are being closely monitored.
The wildlife response was reactivated, in anticipation of a fresh release of oil from the broken ship affecting local populations of little blue penguins and dotterels. Fortunately, no significant release of oil eventuated. Few birds were affected and the facility was progressively demobilised during February. Rough conditions at the reef persisted for several days, keeping the salvage company Svitzer from evaluating the ship’s status so it could resume its work.
For Svitzer’s recovery work at the ship, the break-up brought new risks and challenges. Many containers are damaged and have to be individually extricated in pieces from their secure positions in the holds, where jagged metal and noxious fumes from decayed goods present serious hazards. Cutting and grinding the containers and removing their contents by hand is slow, labour intensive and dangerous.
While it remains impossible to put a timeframe on the container removal work, the crane barge Smit Borneo, delivered from Singapore in December, has meant less disruption and time lost in transferring workers back to port.
A 180 tonne ‘crawler’ crane installed on board Smit Borneo enables salvors to be transferred during recovery operations, and the 150 personnel working at the ship can be accommodated on the barge, meaning they can remain out at the site 24/7.
By the end of February, almost half of the 1,368 containers on board Rena when it grounded had been received ashore by Braemar Howells’ container processing teams. The 637 containers had either been directly removed from the ship or recovered from the water and shoreline.
A number of containers have been located underwater but not yet recovered. Braemar Howells’ teams have also been clearing debris and removing timber from as far away as Hawke’s Bay.
Over 1,300 tonnes of heavy fuel oil is now safely off Rena and most of the approximately 350 tonnes of oil released earlier has been cleaned up from shores. However, the wreck still poses a threat, from an estimated tens of tonnes of oil remaining out of reach in isolated pockets of the ship. Salvors were able to remove a further 10 tonnes in February, and will do so whenever their work gives them access to the oil.
A light sheen of oil has been visible around the ship since it grounded, and is still visible today. While it indicates residual oil in the water, the amounts are not considered serious and the oil naturally disperses with the currents and weather conditions.
Closer to shore, a small amount of residual oil remains in the water and in the sand, and occasionally resurfaces with strong weather or tidal changes. The oil spill response team continues to respond to any reports of this residual oil being exposed.
A volunteer Adopt-a-Beach programme launched in December, in which residents joined forces to keep their local stretch of beach clean, proved hugely successful. A celebration was held in March to acknowledge and thank volunteers for their contribution to the recovery effort.
The oiled wildlife response facility is now closed, but the response capability remains live. Local wildlife experts and the Department of Conservation are responding to any reports of affected animals and members of the National Oiled Wildlife Response Team at Massey University stand ready to treat and rehabilitate any affected wildlife. The team is poised to escalate the response at any time it is needed.
At the height of the response, more than 400 birds were being cared for at the Te Maunga oiled wildlife facility. Affected birds were progressively released back into the wild as wildlife experts signed off their health and habitats. Of 2,299 dead birds collected during the response, 1,443 were oiled.
In recent developments in MNZ’s investigation into the grounding, Rena’s master and second officer (navigation) pleaded guilty at the Tauranga District Court on 29 February to 10 of 11 charges laid by MNZ.
The men were charged under Section 65 of the Maritime Transport Act (MTA) 1994, “for operating a vessel in a manner causing unnecessary danger or risk”, and under Section 338 (1B) and (15B) of the Resource Management Act 1991 (RMA) relating to the “discharge of harmful substances from ships or offshore installations”. The second officer entered no plea to the RMA charge.
They were also charged under Sections 117(e) and 66 of the Crimes Act, that they “wilfully attempted to pervert the course of justice” by altering ship’s documents subsequent to the grounding.
The men, whose names and identities remain suppressed, will be sentenced on the 10 charges on 25 May.