Warship project starts underwater

Three Navantia F100 series warships will be built at Port Adelaide by the AWD Alliance – a consortium of ASC, the federal government’s Defence Materiel Organisation and Raytheon Australia – with construction of the ships starting in the final quarter of 2009, and the first destroyer scheduled to be launched in 2014.Lucas Earthmoving civil manager Regan Armstrong said the project involved excavating a section of the Port River for the construction of a ship lifter to put the completed hulls in the water.The initial excavation works were carried out in the dry using 30t excavators, but below a certain depth the hole had to be filled with water to prevent the sheet piles from moving, Armstrong said.“Once we went underwater, we used the 120-tonne long reach excavator fitted with the Topcon system, working from both dry land, and later from a 3000-tonne barge,” he said.“The ship lift piles go 80 metres out into the Port River, and our job was to excavate that area prior to a dredge coming in and dredging the rest of the port.”“If we hadn’t had this system, the job would have been nearly impossible,” Armstrong said. “Because of the depth we had to go to, without the system, we would have been shooting blind the whole time.”Because of the 22m depth of the excavation, Lucas Earthmovers and Topcon distributor Position Partners did face some challenges.“We had a few difficulties with the system, just because we were going so deep,” Armstrong said. “Initially the connectors couldn’t really cope with the pressures of the water we were digging to.“However, we put our heads together and quickly came up with a method for thoroughly sealing the connectors and, in the end, it all worked well.”

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