Pulling 2 Sunken Tug Boats from The Muddy Bottom Of A River

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A bulk cement carrier rammed and sank two tugboats in Port Devenport, Tasmania, in January. The waterway is now open to normal commercial traffic after a salvage operation this month involving a commercial vessel with built-in cranes that normally is used to transport breakbulk and heavy lift project cargo such as wind turbines, transformers and mining equipment, reports American Shipper.

The incident

The Australian Transport Safety Bureau determined the cement carrier Goliath hit the two stationary tugs when the master incorrectly shifted into manual steering mode as he had difficulty maneuvering a tight turn. The rudders were not at the expected angle and the ship more than tripled its speed to 4.7 knots . No one was aboard the tugs at the time of the accident and there were no injuries.

United Salvage was hired to remove the tugs from the Mersey River in Devonport, on the northwest coast of Tasmania. It turned for help to AAL Shipping, which operates 25 breakbulk and heavy lift ships serving the oil and gas, mining, energy, construction, and agriculture industries — or anyone with a large shipment that won’t fit neatly in a container.

The salvage operator originally planned to use a floating crane and barge to recover the tugs, but AAL offered a turnkey solution because the geared vessel — with its own loading equipment — could also transport the tugboats up the coast for delivery to Brisbane, Australia.

The AAL Melbourne, a 31,000-deadweight-ton vessel, carefully removed the first tug on Aug. 7 using two mounted cranes working in tandem. Salvage teams previously cut large holes in the hull to allow trapped water and sediment to drain. The second tug, weighing more than 500 tons, was recovered and loaded onto the mega-vessel a few days later, according to an AAL news release.

Both tugs were securely lashed to the weather deck in specially designed cradles.

AAL officials said the recovery was carefully planned and modeled over several months and required cooperation with several parties, including the state-owned Tasmanian port operator, environmental officials and cargo insurers. The Australia Maritime Safety Authority had to confirm AAL’s calculations for the project with the company’s ship classification society, which sets safety, reliability and environmental standards that vessels in international waters must comply with.

Lifting took time because the tugs weighed significantly more than expected due to trapped water and fuel. AAL actually kept the full weight of the second tug on the ship’s cranes overnight until the salvage company could pump out water and silt still trapped inside.

AAL also coordinated the operation with the harbormaster and pilots to minimize disruption to other traffic because the AAL Melbourne was positioned in the turning basin used by larger vessels for maneuvering.

AAL’s multipurpose fleet

Frank Mueller, general manager of AAL Australia, complained in the news release that ocean terminals in Australia are misguided in prioritizing container and roll-on/roll-off vessels over multipurpose ships for berthing slots during extended periods of port congestion, resulting in severe wait times.

AAL operates scheduled service on key trade lanes connecting Europe, the Middle East, Asia and Oceania. It has frequent sailings to North and South America and offers vessels for ad-hoc charters. The vessels carry all types of cargoes, including steel, containers, yachts and dry bulk commodities.

The company is investing in new assets with recent orders for six “Super B-Class” multipurpose vessels capable of carrying more than 66,000 tons.

Specifications for the newbuilds include extendable pontoons that can increase stowage space, as well as allow certain cargoes, such as wind blades, to safely overhang the deck when required. AAL says the vessels will also be able to sail with open hatch covers, enabling extremely tall and over-dimensional equipment to be stored safely in a hold. Despite their size, the minimum-draft hull design will enable the vessels to access smaller, remote ports.

United Salvage, based in Port Kembla, Australia, dates back to before World War II, when a syndicate was formed to recover gold bullion from the sunken vessel RMS Niagara that struck a mine off New Zealand in 1938. The company had a couple of Australian owners before being taken over by Svitzer, part of the A.P. Moller Maersk group. United Salvage ceased operating in 2007 and was reactivated in 2020.

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Source: American Shipper

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