The schooner-rigged steam yacht Branwen was designed and built by J.I. Thornycroft & Co. at Southampton in 1905. Registered at 122 tons gross (69 net & 151 Thames) and measuring 120 feet in length with a 16½ foot beam, she was powered by one of her builder's own triple-expansion 3-cylinder engines and was a very attractive example of her breed. Originally owned by Lord Howard de Walden, by 1914 she belonged to Captain Alwyn Foster who hired her to the Admiralty for wartime duties between 1915 and 1917. Sold to A. Salvin Bowlby of Gilston Park, Harlow, Essex after the War, she changed hands again several times and was still afloat after the end of the Second World War.