Seaworks to recover propeller

18:32, Dec 05 2013

Interisland ferries could have to take a different route into Tory Channel next week with work scheduled to recover Aratere's propeller from the Cook Strait seabed.

Seaworks chief executive Steve MacIntyre said two Seaworks ships would work next week to recover the six tonne, 4.5 metre high propeller from 123 metres underwater.

The propeller had been attached to the starboard driveshaft of the Interislander ferry Aratere, when the driveshaft snapped and the propeller fell off about two nautical miles outside Tory Channel during an evening sailing from Picton to Wellington on November 5. Aratere has been out of service since then.

Mr MacIntyre said the recovery operation should start next week and take two days from start to finish, if all went well.

The propeller was "exactly" on the track the ferries used, he said.

"She was still on track when all this happened. Vessels will all have to divert around us where we're working, Strait Shipping included."


Mr MacIntyre said the propeller was sitting on a "nice flat seabed".

"It's got stones, small ones about half the size of your hand. It's definitely not like a rugged canyon. It's a benign seabed bottom that trawlers could work on. It couldn't have been easier."

There would be at least two Seaworks vessels involved in the recovery, Mr MacIntyre said. They were Brandywine, which worked out of Picton for a long time carrying components for the Meridian wind farm, and SeaSurveyor, with the remote operated vehicle on board, he said.

The remote operated vehicle, effectively a small unmanned submarine, would attach the rigging to the propeller, and then the ships would pull it up.

"The current is obviously a big factor. We can only work in slack water, for the sub on the bottom.

"Hopefully, we pull it up with no problem. It sounds quite easy when you put it like that. I hope it goes that well."

Seaworks had done similar type of work in Cook Strait, Mr MacIntyre said.

"We haven't lifted propellers before, but lifting one thing is pretty much like another.

"We do a lot of work on the power cable (taking electricity from the South Island to the North Island).

"It's our backyard. This is pretty much our bread and butter, working in that part of the strait."

Where the propeller had sunk was within the jurisdiction of the Marlborough harbourmaster, and Alex van Wijngaarden confirmed he was discussing the recovery operation with Seaworks.

"We have been talking with them." 

The Marlborough Express