HMS Nepean (1916)

HMS Nepean was an Admiralty M-class destroyer which served in the Royal Navy during the First World War. The M class was an improvement on those of the preceding L-class destroyer, capable of higher speed. The second Royal Navy vessel to be named after Sir Evan Nepean, and the first not in Australian service, the destroyer was launched in 1916 and joined the Thirteenth Destroyer Flotilla of the Grand Fleet. In 1917, Nepean formed part of the escort for the light cruisers HMS Dublin (1912) and HMAS Sydney (1912) when they were attacked by the Zeppelin L 43 and the First Battlecruiser Squadron during the Second Battle of Heligoland Bight. Neither led to the warship being involved in any action with the enemy. The destroyer finished the war with the Fourth Destroyer Flotilla. After the Armistice, Nepean was placed in reserve before being sold to be broken up in 1921.

Design and development
Nepean was one of the sixteen Admiralty M-class destroyers ordered by the British Admiralty in September 1914 as part of the First War Programme. The M class was an improved version of the earlier L-class destroyer (1913), required to reach a higher speed in order to counter rumoured new German fast destroyers. The remit was to have a maximum speed of 36 kn and, although ultimately the destroyers fell short of that ambition in service, the extra performance that was achieved was valued by the navy. It transpired that the German warships did not exist.

The destroyer had a length of 265 ft between perpendiculars and 273 ft overall, with a beam of 26 ft and draught of 8 ft. Displacement was 971 LT normal. Power was provided by three Yarrow boilers feeding Brown-Curtiss rated at 23000 shp, driving three shafts and exhausting through three funnels. Design speed was 34 kn. Nepean managed 33.88 kn on 22500 shp during trials. A total of 228 LT of oil was carried. Design range was 2530 nmi at 15 kn, but actual endurance in service was less; sister ship HMS Murray (1914) had a range of 2240 nmi at 15 kn.

Nepean had a main armament consisting of three single QF 4 in Mk IV guns on the centreline, with one on the forecastle, one aft on a raised platform and one between the middle and aft funnels. Torpedo armament consisted of two twin torpedo tubes for 21 in torpedoes located aft of the funnels. Two single 1-pounder 37 mm "pom-pom" anti-aircraft guns were carried. The anti-aircraft guns were later replaced by 2-pdr 40 mm "pom-pom" guns. The ship had a complement of 80 officers and ratings.

Construction and career
Nepean was laid down by John I. Thornycroft & Company at their yard in Woolston, Southampton in February 1915, was launched on 22 January the following year and was completed three months later in March. The destroyer was the second vessel in the Royal Navy to be named after Sir Evan Nepean, and the first not to be in Australian service. The warship was deployed as part of the Grand Fleet, joining the Thirteenth Destroyer Flotilla. The flotilla was based at the naval base in Rosyth. On 30 May, Nepean was the only member of the flotilla not to sail with the Grand Fleet to confront the German High Seas Fleet in what would be the Battle of Jutland.

On 30 April 1917, the destroyer was the target of a torpedo launched by the German submarine SMU UC-77. It missed. On 3 May, the destroyer formed part of the escort for the light cruisers HMS Dublin (1912) and HMAS Sydney (1912), along with sister ships HMS Obdurate (1916), HMS Pelican (1916) and HMS Pylades (1916), on a routine patrol of the North Sea. During the following day, they were attacked by the Zeppelin L 43. The airship bombed the British ships, causing minor damage to Obdurate but otherwise causing no harm. During the attack, the destroyer had identified a torpedo attack from German submarines. Increasing activity from submarines against merchant shipping had led to the creation of a convoy system relying on destroyer escorts. The flotilla was called upon to accompany over 26 vessels a day. On 16 October, the destroyer joined with 53 other destroyers and 27 lights cruisers in an unsuccessful search for an escorted German minelayer. At the same time, German cruisers attacked a convoy crossing to Scandinavia. The loss of nine merchant ships and three escorts led to the Admiralty increasing the escort to nine M-class destroyers. During the following month, from 16 November, the destroyer formed part of the escort for the First Battlecruiser Squadron, led by HMS Lion (1910), which left Rosyth to attack German minesweepers. Nepean did not take part in the subsequent Second Battle of Heligoland Bight, which involved large numbers of ships from both sides.

At the end of the war, Nepean was part of the Fourth Destroyer Flotilla based at Devonport. After the Armistice that ended the war, the Royal Navy returned to a peacetime level of strength and both the number of ships and the amount of personnel needed to be reduced to save money. The destroyer was transferred to reserve at Nore. However, the harsh conditions of wartime operations, particularly the combination of high speed and the poor weather that is typical of the North Sea, exacerbated by the fact that the hull was not galvanised, meant that the ship was soon worn out. Nepean was declared superfluous to operational requirements, retired, and, on 15 November 1921, was sold to Cashmore of Newport, Wales, and broken up in 1923.