HMAS Rankin is the sixth and final submarine of the Collins class, which are operated by the Royal Australian Navy (RAN).

Named for Lieutenant Commander Robert William Rankin, the boat was laid down in 1995, and commissioned into the RAN in March 2003, following major delays.

[1][7] The hull is constructed from high-tensile micro-alloy steel, and are covered in a skin of anechoic tiles to minimise detection by sonar.

[1][12][13] Each submarine is equipped with three Garden Island-Hedemora HV V18b/15Ub (VB210) 18-cylinder diesel engines, which are each connected to a 1,400 kW, 440-volt DC Jeumont-Schneider generator.

[16] The film crew was on board from February to April 2004, during which the boat completed pre-deployment trials, participated in the submarine rescue exercise Pacific Reach, and made a diplomatic visit to Kure, Japan.

[22] Rankin was docked for a long maintenance period in 2008, but workforce shortages and malfunctions on other submarines requiring urgent attention have drawn this out: in 2010 RAN and ASC officials predicted that she would not be back in service until 2013.