The I-class ships were improved versions of the preceding H-class. They displaced 1,370 long tons (1,390 t) at standard load and 1,888 long tons (1,918 t) at deep load. The ships had an overall length of 323 feet (98.5 m), a beam of 33 feet (10.1 m) and a draught of 12 feet 6 inches (3.8 m). They were powered by two Parsons geared steam turbines, each driving one propeller shaft, using steam provided by three Admiralty three-drum boilers. The turbines developed a total of 34,000 shaft horsepower (25,000 kW) and were intended to give a maximum speed of 35.5 knots (65.7 km/h; 40.9 mph).[1]Intrepid only reached a speed of 34.4 knots (63.7 km/h; 39.6 mph) from 33,827 shp (25,225 kW) during her sea trials.[2] The ships carried enough fuel oil to give them a range of 5,500 nautical miles (10,200 km; 6,300 mi) at 15 knots (28 km/h; 17 mph). Their crew numbered 145 officers and ratings.[1]
The ships mounted four 4.7-inch (120 mm) Mark IX guns in single mounts, designated 'A', 'B', 'X' and 'Y' from bowtostern. For anti-aircraft (AA) defence, they had two quadruple mounts for the 0.5 inch Vickers Mark IIImachine gun. The I class was fitted with two above-water quintuple torpedo tube mounts for 21-inch (533 mm) torpedoes.[3] One depth charge rack and two throwers were fitted; 16 depth charges were originally carried,[1] but this increased to 35 shortly after the war began.[4]Intrepid was one of the four I-class destroyers fitted with minelaying equipment in late 1938 – January 1939 at Malta. This consisted of mounts for rails on the deck on which to carry the mines and an electric winch to move the mines down the rails. A pair of sponsons were added to the stern to allow the mines to clear the propellers when dropped into the sea. 'A' and 'Y' guns and both sets of torpedo tubes were modified to allow them to be removed to compensate for the weight of the mines.[5] The ships could carry a maximum of 72 mines.[6] The I-class ships were fitted with the ASDIC sound detection system to locate submarines underwater.[7]
In the Second World War, Intrepid attacked and sank the U-45 south-west of Ireland on 14 October 1939 in company with the destroyers Ivanhoe and Inglefield.
During naval manoeuvres on the 17 March 1940 Intrepid collided with the Leith-based fishing trawler MV Ocean Mist, sinking the smaller ship and killing two of her crew but rescuing the other eight[8]
Crabb, Brian James (2014). Operation Pedestal. The Story of Convoy WS21S in August 1942. Donington, Lincolnshire, UK: Shaun Tyas. ISBN978-1-907730-19-1.
English, John (1993). Amazon to Ivanhoe: British Standard Destroyers of the 1930s. Kendal, England: World Ship Society. ISBN0-905617-64-9.
Friedman, Norman (2006). British Destroyers & Frigates: The Second World War and After. Annapolis, Maryland: Naval Institute Press. ISBN1-86176-137-6.
Haarr, Geirr H. (2010). The Battle for Norway: April–June 1940. Annapolis, MD: Naval Institute Press. ISBN978-1-59114-051-1.
Hodges, Peter & Friedman, Norman (1979). Destroyer Weapons of World War 2. Greenwich: Conway Maritime Press. ISBN978-0-85177-137-3.
Lenton, H. T. (1998). British & Empire Warships of the Second World War. Annapolis, Maryland: Naval Institute Press. ISBN1-55750-048-7.
March, Edgar J. (1966). British Destroyers: A History of Development, 1892-1953; Drawn by Admiralty Permission From Official Records & Returns, Ships' Covers & Building Plans. London: Seeley Service. OCLC164893555.
Rohwer, Jürgen (2005). Chronology of the War at Sea 1939–1945: The Naval History of World War Two (Third Revised ed.). Annapolis, Maryland: Naval Institute Press. ISBN1-59114-119-2.
Smith, Peter C. (2005). Into the Minefields: British Destroyer Minelaying 1918–1980. Barnsley, UK: Pen & Sword Books. ISBN1-84415-271-5.
Whitley, M. J. (1988). Destroyers of World War Two: An International Encyclopedia. Annapolis, Maryland: Naval Institute Press. ISBN0-87021-326-1.
Winser, John de D. (1999). B.E.F. Ships Before, At and After Dunkirk. Gravesend, Kent: World Ship Society. ISBN0-905617-91-6.