Of the Pathfinder-class with as sister ship the Patrol. Although intended to be named Fastnet she was called Pathfinder before being laid down. She was laid down 15 August 1903 at Cammell Laird, launched on 16 July 1904, completed on 18 July 1905 and torpedoed by the German submarine U-21 off the Scottish East coast on 5 September 1914. With a displacement of 2,940 tons were her dimensions 385 (over all) x 38’4” x 13’8”. The two 4 cylinder triple expansion engines qad 12 Laird-Normand boilers driving twin screws allowed a speed of 25 knots. Her coal bunker capacity was 160 tons (other sources claimed 300 and even 600 tons) which was far from being sufficient. Her loss was caused by lacking coal forcing a maximum speed of 5 knots. Her crew numbered 268 men. The original armament was 10-12pdr quick firing guns, 8-3pdr quick firing guns and 2-18” surfaced torpedo tubes. In 1911-1912 her armament was changed into 9-4” quick firing guns, 6-6pdrs while the torpedo tubes remained. She was slightly armoured, the conning tower was protected by 3”, the deck by 5/8”-1,5” and she had a 2” belt.
