Sirius was originally expected to remain in service for approximately 15 years.[1] In 2012, the ship was predicted to remain in service until the early 2020s.[2] The 2013 Defence White Paper stated that the replacement of Sirius and HMAS Success would be brought forward.[3] As well as building replacement vessels (either in Australia, overseas, or a combination), leasing existing vessels was also to be considered.[3]
The Australian Department of Defence predicted in 2006 that Success will reach the end of her useful operational lifespan sometime between 2015 and 2017.[4] Following her double-hull refit, this was extended to the early 2020s, with the decision on the replacement vessel (acquisition project SEA 1654 Phase 3) to be made between 2016 and 2018, and the new ship in service by 2023.[5] The 2013 Defence White Paper stated that the replacement of Success and HMAS Sirius would be brought forward.[3] As well as building replacement vessels (either in Australia, overseas, or a combination), leasing existing vessels was also to be considered.[3]
In June 2014, the Minister for Defence announced that two companies had been invited to a restricted tender competition.[6] Spanish shipbuilder Navantia is offering the Cantabria design, while South Korea's DSME is proposing the downsized Aegir variant of the Tide-class tanker.[6][7] The 20,000+ tonne ships will be too large to build in Australian shipyards, particularly in the timeframe required to bring them into service.[6]
The German Berlin class was also suggested,[5] but didn't make the cut
Gillett50
was invoked but never defined (see the help page).