Moresby was one of sixteen s ordered by the British Admiralty in September 1914 as part of the First War Construction Programme. The M-class was an improved version of the earlier destroyers, required to reach a higher speed in order to counter rumoured German fast destroyers. The remit was to have a maximum speed of 36kn and, although the eventual design did not achieve this, the greater performance was appreciated by the navy. It transpired that the German ships did not exist.
Moresby was 265feet long overall, with a beam of 26feet and a draught of 8feet. Displacement was 1004LT normal and 1028LT full load. Power was provided by three White-Forster boilers feeding Parsons steam turbines rated at 25000shp and driving three shafts, which gave a design speed of 34kn. Three funnels were fitted. The destroyer carried 296LT of oil, giving a design range of at .
Armament consisted of three single QF 40NaN0 Mk IV guns on the ship's 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 mounts for 21inches torpedoes. A single QF 2-pounder 401NaN1 "pom-pom" anti-aircraft gun was mounted between the torpedo tubes. After February 1916, for anti-submarine warfare, Moresby was equipped with two chutes for two depth charges. The number of depth charges carried increased as the war progressed. The ship had a complement of 80 officers and ratings.
Marlion was laid down by J. Samuel White at East Cowes on the Isle of Wight on 1 January 1915 with the yard number 1456, and launched on 20 November. The ship was completed on 7 April 1916 and joined the Grand Fleet. By this time, the ship's name had already been changed to Moresby. to honour Admiral Fairfax Moresby. The vessel was deployed as part of the Grand Fleet, joining the Thirteenth Destroyer Flotilla.[1]
On 30 May 1916, the destroyer sailed with the Grand Fleet to confront the German High Seas Fleet in the Battle of Jutland. Moresby was one of fourteen M-class destroyers that were allocated to form part of the screen to protect the battlecruisers of the fleet. However, along with sistership, the destroyer was detached to cover the seaplane tender . The tender had launched a Short Type 184 to observe the German fleet movements and was stationary waiting for it to return. After the reconnaissance seaplane had been recovered, Lieutenant commander Jack Tovey, who commanded Onslow, led the two destroyers back into the action.
Moresby rejoined the flotilla and, led by the light cruiser, steamed towards the German High Seas Fleet. The two fleets met and Moresby was soon in the centre of the action. The destroyer attacked the German battlecruisers, and shortly after 17:10 on 31 May, launched a torpedo at the dreadnought battleship . The destroyer also narrowly escaped an attack from the light cruiser, two torpedoes streaking past, one ahead and the other astern. As the battlesfleets broke apart, Champion sped away in pursuit of the German fleet, leaving the majority of the destroyers behind, with only Moresby and able to keep up.
The small flotilla sought for the main German fleet, and at 02:15 the following day turned westwards towards gunfire. They saw four German cruisers with their attendant destroyers. However, through the mist, Moresby saw what were initially taken to be four pre-dreadnought battleships. The destroyer sped off and launched a torpedo at a range of at the third ship in the line. The destroyer reported a hit and then withdrew. In fact, two of the vessels were German battlecruisers, and the torpedo narrowly missed . Instead, the torpedo hit the torpedo boat . Returning to the British lines, the three ships were spotted by the German torpedo boats and, which launched torpedoes, but both sides escaped without recording a hit.
The destroyer was transferred to Buncrana, Ireland, with the Second Destroyer Flotilla during the latter part of 1917. The vessel served as a convoy escort, and on 2 October 1917, was also involved in the ultimately unsuccessful efforts to save the armoured cruiser . On 15 March the following year, the destroyer was patrolling with sistership when they surprised shortly after the submarine had sunk the ocean liner . The submarine dived but was brought back to the surface when the destroyers attacked with depth charges and was finished by gunfire. Six of the crew were rescued.
AAfter the Armistice of 11 November 1918 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. Moresby was taken out of active service and initially placed alongside fifty-two other destroyers in reserve at Nore. On 9 May 1921, the vessel was sold to Thos. W. Ward of Grays and was broken up in 1923.
| HC1 | 1914 |
| F02 | 1917 |
| H27 | 1918 |