The SS Mongolia was a steam turbine-driven twin-screw passenger-and-cargo ocean liner launched in 1922 for the Peninsular and Oriental Steam Navigation Company (P&O) for service from the United Kingdom to Australia. Later in P&O service she sailed for New Zealand, and in 1938 she was chartered to a P&O subsidiary, the New Zealand Shipping Company, as SS Rimutaka. In 1950 she was sold to become the SS Europa, carrying immigrants to the United States from Europe; later, she became a Bahamas cruise ship, the SS Nassau. Its final incarnation was under a Mexican flag as a Los Angeles to Acapulco cruise liner, SS Acapulco, making her the only ocean liner to ever fly the Mexican flag. The ship was scrapped in 1964. The P&O ordered Mongolia from Sir W G Armstrong, Whitworth & Co. Ltd. of Newcastle upon Tyne on 22 November 1918, but construction was delayed by postwar refits of existing ships and she was not launched until 24 August 1922. After fitting out and sea trials the Mongolia was delivered to P&O on 26 April 1923. The ship cost an estimated £1 million. She left London on her maiden voyage to Sydney on 11 May 1923 on what was at first a 4-weekly mail service, that service being increased to fortnightly from 1925. She was converted to oil fuel in 1928. Notable incidents included a collision on 16 July 1933 with the tanker and a breakwater in Copenhagen, followed by running aground; and a collision with off Marseille on 3 December 1936. She was laid up for sale in 1937. She was captained by Harry Ramsey Rhodes for 9 years. The SS Mongolia was renamed the Rimutaka by at least 15/10/1922, this from the ships cook ID. In 1938, the P&O transferred the ship under long-term charter to their subsidiary, the New Zealand Shipping Company, who renamed her SS Rimutaka, the third ship of that name, registered at Plymouth. She was reconfigured at this time to carry 840 tourist class passengers; before entering service, she was in collision with off the Nore. After repairs, she departed for New Zealand for the first time on 12 December 1938.