In June 1919,
Aquitania ran a Cunard "austerity service" between
Southampton,
Cherbourg, and New York. In December of that year
Aquitania was docked at the
Armstrong Whitworth yards in
Newcastle to be refitted for post-war service. The ship was converted from coal burner to oil-fired, which greatly reduced the number of engine room crew required. The original fittings and art pieces, removed when refitted for military use, were brought out of storage and re-installed. At some point during this time, a new wheelhouse was constructed above the original one as the officers had complained about the visibility over the ship's
bow. The second wheelhouse can be seen in later pictures of the era and the original wheelhouse area below had the windows plated in.
1920s Aquitania resumed her commercial service on 17 July 1920, leaving from Liverpool with 2,433 passengers on board. The crossing was a success; the ship maintained good speed while showing that now being oil-fueled was much cheaper than coal-fueled propulsion. The ship's arrival in New York Harbor was filmed as part of the pioneering 1921 documentary
Manhatta, in which she is seen being pushed to her destination by tugboats. The months that followed were just as promising, despite a stewards' strike in May 1921. At the beginning of the decade,
Aquitania was the only large liner in the service of Cunard Line as the
Mauretania was undergoing repair after a fire. The year 1921 was thus an exceptional year for her; she crossed the Atlantic 30 times (15 round trips) and broke a record by transporting a total of 60,587 passengers that year (including 26,331 in third class), averaging more than 2,000 passengers per crossing. In the following year, the
Mauretania rejoined her in Cunard service.
Aquitania operated in service with the
Mauretania and (formerly the German liner
Imperator) in a trio known as "The Big Three." In 1924, a
new restriction on immigration was passed in the United States, causing the number of third-class passengers to decline significantly. From more than 26,000 third-class passengers transported by
Aquitania in 1921, the figure fell to about 8,200 third-class passengers in 1925. The number of crew was thus reduced to around 850 people from the original 1,200. Still, the Cunard Line benefited from
prohibition in the United States, which started in 1919. American liners were legally part of the territory of the United States, and thus alcoholic beverages could not be served on them. Passengers who wanted to drink therefore travelled on British liners in order to do so.
Aquitania enjoyed great success, making much profit for her company. In 1929, she underwent a major refit. A bathroom was added to many first-class cabins, and the tourist class was renovated. While new competitors, such as the German liner
SS Bremen, entered service,
Aquitania remained particularly popular after fifteen years of service.
Crisis of 1929 and its consequences Following the
stock market crash of 1929, many ships were affected by the economic downturn and reduced traffic.
Aquitania found herself in a tough position. Only a few could afford expensive passage on her now, so Cunard sent
Aquitania on cheap cruises to the
Mediterranean. These were successful, especially for Americans who went on "booze cruises," tired of their country's prohibition. Another problem also arose: the two liners of the
Norddeutscher Lloyd, SS
Bremen and
SS Europa, successfully captured the
Blue Riband and many customers. In 1934, the number of passengers
Aquitania carried declined to around 13,000 from 30,000 in 1929. The ship, however, remained popular and she was the third busiest in the early 1930s behind those two German liners. Author C. R. Bonsor writing in 1963 states, "from 1936 on it became necessary to squeeze the maximum speed out of
Aquitania in order to make her a suitable running mate for
Queen Mary thus 24 knot passages became regular".
Aquitania ran aground in the Solent on 24 January 1934 but was refloated later the same day. The merger of the two companies into Cunard-White Star Line resulted in a large surplus of liners being owned by a single company. Thus, very old ships, such as the
Mauretania and the
Olympic, were removed from service immediately and sent to the scrapyard. However, the
Aquitania was retained, despite her age. On 10 April 1935,
Aquitania went hard aground on Thorne Knoll in the Solent near Southampton, England, but with the aid of ten tugboats, on the next high tide the ship was freed. ==World War II service==