HMS Cossack was a Tribal-class destroyer of the Royal Navy launched in 1907 and sold in 1919. Construction and design HMS Cossack was one of five Tribal-class destroyers ordered as part of the 1905–06 shipbuilding programme. While the Admiralty laid down the basic requirements of an oil-fuelled, steam turbine-powered ship with a speed of , a range of at cruising speed and an endurance of eight hours at full speed, the details of the design of individual ships was left to the builders, which meant that individual ships of the class differed significantly from each other. Cammell Laird's design was powered by steam turbines rated at fed by five boilers to drive three propeller shafts, and had three large funnels. Armament was the specified three 12 pounder (3 inch, 76 mm) 12 cwt guns, two side by side on the ship's forecastle and one aft, with two 18 in (450 mm) torpedo tubes. Cossack was laid down on 13 November 1905 and launched on 16 February 1907. After successfully undergoing trials where she reached a speed of , Cossack was commissioned in April 1908. Service Shortly after Cossack entered service, it was decided to strengthen the armament of the first batch of Tribals by adding another two 12 pounder guns, this being done in 1909. Cossack was considered by her Captain to be a poorer sea boat than River-class destroyers, but a better gun platform. In 1909, following a re-organisation of the Royal Navy's Home and Atlantic Fleets, Cossack was part of the First Destroyer Flotilla of the Home Fleet. 1910, Cossack remained part of the First Flotilla in 1910. By 1913, she had joined the 4th Destroyer Flotilla, based at Portsmouth. In October that year, the Tribals were officially designated the F class, and as such the letter "F" was painted on Cossacks bows. While still a part of the 4th Flotilla in January 1914, but by February had transferred to the 6th Destroyer Flotilla. During the First World War she served in the North Sea and the English Channel with the 6th Destroyer Flotilla. On 23 August 1914, Cossack was involved in a collision with her sister Tribal-class destroyer, Ghurka. In October 1914, Cossack was one of a number of warships of the Dover Patrol that were deployed to help support Belgian ground forces during the Battle of the Yser, with all available ships being used to carry