contract that the ships must achieve at least , and a graduated penalty clause in case the actual speed increase should fall short of that figure. In the same year, Lord Essendon succeeded in getting RML's competitors to accept a 19-knot speed limit on the South American route. Harland and Wolff fitted each ship with three water-tube boilers supplying superheated steam at 435 lbf/in2 to a set of six turbines that drove her twin propeller shafts by single reduction gearing. The National Physical Laboratory helped the shipyard to design new aerofoil-section manganese bronze three-bladed propellers; the rudders were also streamlined. The new machinery succeeded in increasing each ship's nominal horsepower by 25% and increased their speed to about . Asturias was converted first, going to Belfast in May 1934 and returning to service in October. Only after Asturias had successfully completed a voyage from Southampton to Rio de Janeiro and back did RMSP send Alcantara to Harland and Wolff at Belfast in November. She returned to service in May 1935. Each ship had two funnels, of which the forward one was a dummy. As built the funnels were low, which was a fashion for some 1920s and '30s motor ships. When the ships were re-engined in 1934 each funnel was increased in height. Second World War service In 1939 the Admiralty requisitioned Alcantara and Asturias and had each ship converted into an armed merchant cruiser. The mainmast and forward dummy funnel of each ship were removed to increase the arc of fire for their anti-aircraft guns. Alcantara was sent to Malta for further modifications, but en route she had a major collision with the Cunard ship . As a result, Alcantara continued to Alexandria for hull repairs. The beds from Alcantara were sent to Malta, installed in Admiralty House and used for bombed out civilians and naval staff. On 28 July 1940 Alcantara encountered the German in the South Atlantic. With her steam turbines Alcantara made for four hours to chase Thor, and two shells from Alcantaras six-inch main guns hit the German ship. But three shells from Thor hit Alcantara and one flooded her engine room. This forced Alcantara to reduce speed, enabling Thor to escape. In 1943 Alcantara was converted into a troop ship. Final years and artefacts Alcantara remained a troop ship well after the end of the war, and did not return to civilian service until