The Australian understands that the central keel block of the first AWD warship, HMAS Hobart, was built to inaccurate dimensions as a result of faulty welding and inadequate quality control at the Williamstown shipyards, operated by an AWD subcontractor, BAE Systems Australia.
"The difficulties resulted in an unexpected distortion in a component of one of the blocks."
It said two other hull blocks were found to be at risk of distortion but the issue was identified and production processes were changed.
The distortion of the central keel block - which weighs about 200 tonnes, measures 20m by 17m and supports some of the most important heavy machinery on the warship - made it potentially incompatible with other blocks of the ship that are being built in Adelaide and in Newcastle.
Sounds like a some QC problem in that particular shipyard.