Battle to get oil off stricken ship appears lost before it starts

by Richard Gladwell on 9 Oct 2011
At the media conference on mid-Sunday afternoon, those involved with the yet to start oil pumping exercise off the Rena, said the exercise would take 40 hours. That would seem to be too late by at least 12 hours to beat the rising winds and seas expected to hit the stricken ship from midnight.

At 2.20am on Wednesday morning, the 236metre container ship, Rena, ploughed into the Astrolabe Reef, 30 minutes away from New Zealand's second busiest port in calm weather.

The bow of the ship, laden with 1300 containers, has stuck fast, while the stern floats free. She has an 11 degree list to port.

The forward sections of her double bottom have been crushed and one of five fuel tanks has cracked open, releasing about 100 tonnes of heavy fuel oil into the bilges of the ship, and about 20 tonnes of this fuel has escaped along with some light oil.

The remaining oil has been pumped into after tanks, and will then be pumped into a specialist oil barge Awanuia, which arrived on Saturday.

For reasons not explained, the rescue team have not deployed the two 100tonne volume inflatable barges from Auckland manufacturer, www.lancer.co.nz!Lancer_Industries which are owned by Maritime New Zealand who are co-ordinating the fuel offload. Lancer are the largest supplier of inflatable barges in the world, and the purpose of the barges is that they can be easily transported, and in this instance would have been available in a few hours.

The two barges are capable of working in a significant sea condition of six feet - meaning that the barge will remain operable on a 10ft wave height.

Instead Maritime NZ have opted for a strategy using a larger vessel the Awanuia, usually used for refuelling vessel in the Port of Auckland, and will transfer to HMNZS Endeavour if required. That strategy has taken five days to implement.

The backup plan has been to cap the other fuel tanks and even if the Rena did break up in the coming storm, it was hoped that the capped tanks would not release fuel. that assumes the tanks would not be ruptured during any break up of the Rena.

Astrolabe Reef is located in a deepening shelf with water depths of approximately 300ft in the immediate are.

At the time of today's media conference, which started just before 4.00pm, it was said that pumping would start in about five hours - or about 9.00pm all going well and as expected.

Winds in the area are expected to start increasing from midnight and the sea state will increase from the two feet experienced since the grounding to 8-10ft within the next two days.

According to www.predictwind.com!Predictwind.com the winds will swing to the north and east (two exposed directions) and will increase to around 30kts and possibly more as a centre of low pressure moves down the east coast of New Zealand.

Those conditions will be challenging for the pumping operation on the ship, and would probably be too dangerous to continue, and it would be difficult to anchor the Awanuia astern, and upwind, of the stern of the Rena.

In the favourable wind and sea conditions that have prevailed to date the offloading exercise would have been a lot simpler compared to the task which is ahead over the coming week, assuming the wind and sea behave as predicted.

Today experts said there has not been any deformation of the plates in the Rena, indicating she was not flexing significantly. Naval architects have been developing models of the Rena, so that her flex characteristics can be predicted for a given sea state and given the impact damage that has occurred. However unless the exact design of the 20year old Rena were available, it may be that the naval architects use approximate values and check for physical signs of deformation and location and compare those with the predictions from the model.

Transport Minister Stephen Joyce said today that the information they now had indicated the situation of the Rena was better than they had anticipated two days ago, however the salvage effort is yet to get underway on the water.

Oil that has already leaked is expected to come ashore south of Tauranga probably in the Papamoa Beach area.

Loss of sea life has been minimal at this stage.

Two inquiries into the incident are underway, one of which , being conducted by Martime NZ, will determine if charges are to be laid.