HMAS Sirius (O 266)

HMAS Sirius (O 266) (formerly MT Delos) is a commercial tanker purchased by the Royal Australian Navy and converted into a fleet replenishment vessel to replace HMAS Westralia (O 195). Launched in South Korea on 2004, and converted in Western Australia, Sirius was commissioned in 2006; three years before a purpose-built vessel would have, and at half the cost. The tanker is expected to remain in service until the 2020s.

Construction and acquisition
Delos was built at Hyundai Mipo Dockyard in South Korea. Another five ships were built to the same design, all for civilian service. She was launched on 12 April 2004, and was purchased by the Australian Government on 3 June 2004. Delos was converted to her new role at Fremantle by Tenix Defence, and was commissioned into the RAN on 16 September 2006. Sirius is expected to remain in service for approximately 15 years.

Originally, the RAN planned to have a ship specially constructed for the role. The decision to instead purchase an under-construction civilian tanker and modify her for military service allowed Sirius to enter service three years before originally planned, at a saving of half the acquisition project's cost.

While HMAS Sirius is the first ship of this name to serve as part of the RAN, she is named after HMS Sirius (1786), the flagship of the First Fleet of British convicts sent to Australia in 1788.

Operational history
In October 2006, Sirius successfully undertook her first Replenishment at Sea; transferring fuel and water supplies to HMAS Toowoomba (FFH 156). The ship completed working up and passed her first Unit Readiness Evaluation on 12 December 2006. RAN reports show that although Sirius has the ability to have helicopters land on her deck, Sirius has yet to pass the stability test that allow a helicopter to land on its deck.

In June 2007, she participated in Exercise Talisman Sabre 2007.

On the morning of 13 March 2009, Sirius was one of seventeen warships involved in a ceremonial fleet entry and fleet review in Sydney Harbour, the largest collection of RAN ships since the Australian Bicentenary in 1988. Sirius did not participate in the fleet entry, but was anchored in the harbour for the review.

In 2010, Sirius was approved to carry and deploy boarding parties. This capability was tested during Exercise Kakadu 10, along with the ship's first ever dual replenishment.

Sirius was forced to turn back en route to the RIMPAC 2010 exercise in Hawaii due to problems with her engine room and did not participate in the exercise as a result.

The ship is predicted to remain in service until the early 2020s.