SS Dieppe ( 1905 ) Dieppe was a steamship which was built in 1905 for the London , Brighton and South Coast Railway . She was requisitioned during the First World War for use as a troopship and later as a hospital ship HMS " Dieppe , returning to her owners postwar . She passed to the Southern Railway on 1 January 1923 . In 1933 , she was sold to W E Guinness and converted to a private yacht , Rosaura . She was requisitioned during the Second World War for use as an armed boarding vessel , HMS " Rosaura . She struck a mine and sank off Tobruk , Libya on 18 March 1941 . Description . The ship was built by Fairfield Shipbuilding & Engineering Co Ltd , Govan . She was yard number 439 and was launched on 6 April 1905 with completion in May 1905 . The ship was long , with a beam of and a depth of . She was powered by three steam turbines , which were made by Fairfield . The turbines could propel her at a speed of . When converted to a private yacht , the turbines were replaced by two 8 - cylinder Atlas diesel engines . One of her propellers was removed as was one of her funnels . Her speed was reduced to . As built , her GRT was 1 , 210 . This had increased to 1 , 426 by 1930 , and further increased to 1 , 536 in 1933 . History . " Dieppe " was built for the London , Brighton and South Coast Railway . She was used on their Newhaven - Dieppe route . She was requisitioned by the Royal Navy during the First World War for use as a troopship and a hospital ship . " Dieppe " was returned to her owners postwar and was taken over by the Southern Railway at Grouping . On 27 November 1924 , " Dieppe " had a mishap in which she ended up hitting the breakwater at Newhaven Harbour stern first . The tugs " Alert " and " Richmere " were sent to her aid . " Richmere " became disabled when a cable became entangled around her propellor . The Newhaven Lifeboat " Sir Fitzroy Clayton " was sent to her aid . " Richmere " ended up being dashed against the harbour wall and sank . Her crew were rescued by the lifeboat and the tug was later raised and repaired . " Dieppe " managed to dock some five hours after the drama began . In September 1933 , " Dieppe " was sold to W E Guinness for conversion to a private yacht . She was renamed " Rosaura " , replacing " Roussalka " which had been lost earlier that year . In August 1934 , the Prince of Wales and Wallis Simpson took a cruise on " Rosaura " . According to Wallis , it was during this cruise that she fell in love with the Prince . Also in 1934 , Winston Churchill and his wife Clementine cruised on " Rosaura " in the eastern Mediterranean . On 26 September 1936 , " Rosaura " was in collision with the Dutch coaster at Amsterdam , Netherlands and was severely damaged . She was subsequently repaired . " Rosaura " was requisitioned by the Royal Navy in the Second World War for use as an armed boarding vessel in the Contraband Control Service . In February 1940 , " Rosaura " was involved in Operation Abstention . On 18 March 1941 , " Rosaura " struck a mine off Tobruk and sank with the loss of 78 lives . Official number and code letters . Official Numbers were a forerunner to IMO Number s . " Dieppe " and " Rosaura " had the United Kingdom Official Number 105655 . " Dieppe " used the Code Letters HCRB .