Oil Escapes From Rena’s Duct Keel

in General by Jon C — October 23, 2011 at 3:26 pm | 0 comments

Four vessels have been working since early this afternoon to corral an estimated 5 to 10 tonnes of oil spilled overnight from the cargo vessel Rena.

National On Scene Commander Alex van Wijngaarden said it was probable the oil had escaped from Rena’s duct keel.

The duct keel is the tunnel running the length of the vessel that houses pipework and other service equipment.

“This overnight spillage is a combination of tidal movement – seawater effectively plugs gaps in the duct keel but low tide exposes those gaps – and the reducing buoyancy of the vessel as we remove oil from above the waterline,” he said.

Oil recovery teams on vessels at the scene have been using booms to contain the oil, so that it can then be skimmed off the water.

“These booms are capable of functioning in strong currents and with the calm water out there today, the conditions are good for on-water recovery of the oil.”

Captain van Wijngaarden said even in good conditions, it was not possible to recover all the oil. The potential movement of the spilled oil was being monitored both by aerial observation and by trajectory modelling in the incident command centre.

The indications were currently for the oil to move slowly north.

“Our trajectory modelling – that is, looking at the weather forecast and tides – indicates that it will swirl in several directions offshore, but would not reach any coastline before Wednesday. That would place some of it on track for Mayor Island (Tuhua), if conditions remain as forecast.

“However, it is important to note that this is based on today’s conditions and the trajectory could change. We will be monitoring its progress closely.”

By this afternoon, a total of 337 tonnes of oil had been removed from the port number 5 tank. This tank originally held 772 tonnes. This figure is the amount pumped off in total since pumping operations began.

Oil continues to be pumped from Rena, with options being explored for speeding up removal from the main tank.

It is hoped to have another pump in action this afternoon to remove oil from the two settling tanks, which have about 220 tonnes of oil between them.

A 3km stretch of beach from Mount Maunganui to Tay Street is now open to the public after public health officials confirmed it is safe for swimming.

However, people should be careful and look for any signs of oil contamination.

“If in doubt, use your common sense,” Captain van Wijngaarden said.

Several hundred people – a combination of iwi, Defence Force personnel and volunteers –are out cleaning the beaches today. They are based between Mount Maunganui through to Waihau Bay.

 

 

 

Tags: Oil spill Rena