HMS Alarm was an Acorn-class destroyer constructed for the British Royal Navy, built by John Brown and Company at their Clydebank shipyard between 1910 and 1911. She was launched on 28 August 1910 and completed in March 1911. The vessel measured 240 feet (73.15 meters) between perpendiculars and 246 feet (74.98 meters) overall, with a beam of 25 feet 3 inches (7.70 meters) and a draught ranging from approximately 7 feet 4.5 inches to 8 feet 10 inches (2.248 to 2.69 meters) depending on load. Displacement was around 760 long tons (770 tonnes) at normal load and 855 long tons (869 tonnes) at full load. Powered by four Yarrow boilers feeding Parsons steam turbines, Alarm's machinery was rated at 13,500 shaft horsepower, enabling her to reach a top speed of approximately 27 knots (50 km/h). Her armament comprised two 4-inch (102 mm) BL Mk VIII guns—placed fore and aft—along with two 12-pounder (76 mm) guns amidships. She was also equipped with two 21-inch (533 mm) torpedo tubes with two reload torpedoes, positioned aft of the funnels. By 1918, her armament was augmented with a 3-pounder anti-aircraft gun and depth charges for anti-submarine warfare. Alarm’s service began with the 2nd Destroyer Flotilla of the Royal Navy’s Home Fleet. She experienced early operational issues during the 1911 Naval Manoeuvres, suffering hull leaks during high-speed steaming. She was fitted with anti-submarine sweep gear in early 1912. During World War I, Alarm served initially at Scapa Flow and later in Devonport, participating in patrols and convoy escort duties. Notably, on 16 October 1914, she narrowly escaped attack from the German U-9 submarine. In 1916, she played a role in defending the transport Idaho from U-49 and later escorted battleships and merchant ships. In 1917, she transitioned to the Mediterranean Fleet, patrolling the Otranto Straits and engaging Austro-Hungarian vessels in April 1918, where she supported efforts to protect the Otranto Barrage. After the war, Alarm was placed in reserve at Portsmouth and was eventually sold for scrap in 1921. Her service reflects the typical operational profile of early 20th-century destroyers, combining fleet patrols, anti-submarine efforts, and convoy protection during wartime.

This description has been generated using GPT-4.1-NANO based on the Vessel's wikidata information and then modified by ShipIndex.org staff.