The Cysne II was a 71 gross ton steel steam yacht with a schooner rig. 87tons Thames Measurement. 108.9’oa, 87.9’x15.05’x8.6′. Engine room 21.8′. A. G. Mumford & Co. Ltd of Colchester supplied her with a compound engine with cylinders measuring 11″ and 22″bore and 16″stroke which delivered 140 indicated horse power. One boiler made by Davey Paxman also of Colchester. She was completed in May 1906 by Forrestt & Co. Ltd as yard number 538 for Thomas Edward Thorpe who was the principle chemist of the Government Laboratory in London, and registered at Colchester. (ON 117949). She does not seem to have been requisitioned for the Royal Navy during the first World War. In Decamber 1918 she was sold to Charles Henry Robert Baldwin of Gothenburg, but still registered at Colchester, but in August 1919 she was sold to a Swedish owner and renamed Aradne. Sold in again in 1922 to a Southampton owner and given back her old name of Cysne II.
In February 1940 she was requisitioned for the Royal Navy as a harbour defence patrol craft. In November 1940 she became an accommodation ship, and was returned to her owner in 1943.