After purchase, the Royal Navy was uncertain whether to complete
Swift as a torpedo-boat catcher or as a normal torpedo boat, before deciding to use her as a torpedo boat, and fitting her with the appropriate armament of three torpedo tubes and four guns. She was renamed
TB 81 in 1887. and in July 1896 again took part in the Manoeuvres, while in 1897 she took place in the Jubilee Fleet Review at Spithead. On 3 August 1901, during the 1901 Naval Manoeuvres,
TB 81 was trying to intercept the prototype turbine-powered destroyer when both ships ran aground on the Renonquet reef off
Alderney in the
Channel Islands. While
TB 81 was refloated and repaired,
Viper was wrecked.
TB 81 served as a patrol boat during the
First World War, operating out of
Portsmouth and
Portland, and being fitted with
hydrophones and
depth charges. On 15 May 1917,
TB 81 was directed by a
seaplane towards a submarine which the aircraft had spotted and attacked in the English Channel.
TB 81 detected a possible submarine contact on her hydrophone, and waited until a submarine (possibly or ) surfaced.
TB 81 gave chase, and the submarine dived. The torpedo boat dropped a depth-charge and brought up a patch of oil. The attack was credited as a "possible" success by naval intelligence.
TB 81 was paid off in 1919 and was sold for scrap to J. E. Thomas of
Newport on 22 October 1921. ==Citations==