Tasmanian Ports Corp (TasPorts) has contracted for the removal of the wrecks of two sunken tugs from the bottom of Mersey River in Devonport, in the Australian state of Tasmania
Heavy-lift ship AAL Melbourne lifted wrecked tug York Cove from the Mersey River 7 August and the salvage operation on ???????? ???? tug began 10 August. Both Tasmanian tugs sank January 2022, after allisions with cement carrier Goliath.
194-m heavy-lift ship AAL Melbourne was engaged by United Salvage, the Australia-based company appointed to recover the wrecked tugs.
TasPorts’ chief operating officer Stephen Casey said, “The lift of the first tug was a slow process, but it needed to be.”
York Cove lift faced complexities caused by lifting methodology, weather and river currents that have been affected by recent rain, and the condition of the wrecks themselves in the water, according to Mr Casey.
“The initial allision resulted in an estimated 60,000 litres of fuel being spilled into the river, meaning about 10,000 litres was unaccounted for across both tugs. York Cove weighs 310 tonnes. The two cranes used to lift the tug provide a lifting capacity of 500 tonnes, but the water, marine growth and fuel left in the vessel means the exact weight is unknown until we start lifting. Further, as the weight of the tug comes under tension, the lifting ship needs to remain upright, so it is constantly pumping its ballast tanks,” he said.
Concerns remain over oil recovery and the complexity of the second lift, according to those involved.
“Oil recovery is a not a set and forget exercise – you need to be monitoring and adjusting the whole time.”
“In the Mersey River, we do not only have the challenge of what the tide is doing but we also have natural eddies in the area. I have worked on a lot of incidents where you can actually see the oil on top of the water and you know what it is doing,” Oil Response Company of Australia chief executive Ben Cropley said.
“In this case, what was unknown was just how much diesel or oil was still in the wrecked tugs.”
Campbell Cove was successfully lifted from the water but, unfortunately was sitting in an unbalanced position which made moving the tug to the specially constructed cradle on the deck of AAL Melbourne nearly impossible. This meant the tug was returned to the water.
Mr Casey said, “Campbell Cove will dewater or drain while it is out of the water into the containment area which can be skimmed overnight of any diesel or oil that drains from the wreck. The Campbell Cove wreck will ultimately be welded to its cradle on the deck for transport to Brisbane where both wrecked tugs will be scrapped.”
A second lift will be attempted 11 August, the parties involved said.
