and industrial action causing delays. She finally met her contract speed during February 1909, when a speed of was reached, although this required forcing the ship's engines to give . Service Afridi was commissioned on 10 September 1909, 26 months after the contracted date, the last destroyer to be built by Armstrongs, joining the 1st Destroyer Flotilla. By 1913, Afridi 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 Afridis bow. In February 1914, the Tribals, whose range was too short for effective open sea operations, were sent to Dover, forming the 6th Destroyer Flotilla. On the outbreak of the First World War, the 6th Flotilla formed the basis of the Dover Patrol, with which the Tribal class, including Afridi, served for the duration of the war. Early in the war, the main means of detecting submerged submarines was the indicator net, in which a submarine would get caught up in the net, with movement of an attached buoy indicating the location of the submarine. On 20 February 1915, the destroyer spotted a disturbance in indicator nets in the Dover Straits, and signalled to Afridi to deploy her explosive anti-submarine sweep, but no submarine was found. On 6 April 1915, the drifter Hyacinth spotted a periscope of the German submarine and called up Afridi, which was nearby. While the submarine carried away a section of the netting, the indicator buoys did not deploy, so U-33 was able to escape unscathed. On 24 March 1916, the cross-Channel ferry was torpedoed by the German submarine . Afridi was one of a number of destroyers sent to respond to distress signals from the damaged ferry, and helped in the rescue operations. In order to counter German destroyers armed with 105 mm guns, which outgunned British destroyers of the Dover patrol, a number of the Tribal class were rearmed. Afridi had her 12-pounder guns replaced by two 4.7-inch (120 mm) QF guns between April and October 1917, also receiving a single 2-pounder "pom-pom" autocannon anti-aircraft gun and a Maxim machine gun. On 22–23 April, Afridi took part in an attack on the German-held port of Ostend in Belgium, which took place at the same time as a similar attack on Zeebrugge, with the objective of denying the use of these ports for German