Reardon Smith's wartime losses were initially replaced in 1919 when seven ships were acquired from the
Swansea-based Letricheux & David Co. and then in 1920–21 by nine German vessels surrendered as
War reparations which were purchased for £468,000. Immediately following the end of the War, there was a perceived shortage of ships due to wartime losses, whereas in reality, the total tonnage of the British merchant fleet in 1919 was only 700,000 gross tons less than it had been in 1913, while the worldwide merchant fleet had actually increased. Many ships were still operating on
government wartime contracts far from their normal commercial trading routes, reducing the number available to service mercantile trade. From March 1919, the government began deregulating the
shipping markets as it released ships from its service. In May 1919,
HMG lowered the excess profit duty from 80 to 40 per cent. These factors in combination with post-war optimism lead to vastly inflated ship values to create a boom which lasted until the late spring of 1920. In June 1923, Reardon Smith established
Reardon Smith (
Union of South Africa)
Ltd with capital of £250,000. In 1926, he was a founding member of the
Honourable Company of Master Mariners. In the late 1920s, in response to the continued deterioration in maritime trade, Reardon Smith began to reduce the size of his fleet, with seventeen of the older ships eventually being sold. He did, however, purchase some replacements including four
motor ships. The Reardon Smith Line started a regular service from
Great Britain to the
West Coast of the United States. To reduce costs, the downturn gave a stimulus to innovation, and in particular to use of the marine diesel engine. Despite British tramp owners being notoriously distrustful of foreign-designed machinery, Reardon Smith eventually ordered two motor ships and had delivered in 1928 the
East Lynn from
William Doxford and the
West Lynn from
Napier & Miller. While the former had four-cylinder Doxford engines, the latter had six-cylinder engines from
Harland & Wolff/
Burmeister & Wain. While both vessels gave very satisfactory service, the Doxford engines proved to be superior, leading to the building of seven more Doxford diesel-engined motor ships before the outbreak of the Second World War. In 1928, Reardon Smith established a
pension fund for his seagoing staff employees and later extended it to cover all employees. Reardon Smith died peacefully in his eightieth year after a short illness on the evening of 23 December 1935 at his home,
Cornborough in Cardiff, surrounded by his family. In his
will he left over £200,000. By the time of Reardon Smith's death in 1935, his various business interests owned twenty-eight ships. In addition to his direct business interests, Reardon Smith had also served at various times on the boards of numerous maritime related organisations and businesses. Sir William was buried at
Cathays Cemetery in
Cardiff. ==Philanthropy==