L and M class destroyer

The L and M class was a class of sixteen destroyers which served in the British Royal Navy during World War II. The ships of the class were launched between 1939 and 1942.

Design details

The armament of the class was subject of considerable debate, as the proponents of heavier anti-aircraft armaments for such vessels were at last beginning to be listened to by the Admiralty. This came mainly as a result of the lessons learned during the Spanish Civil War - "i.e"., military aircraft were now sufficiently advanced to pose a major threat to land and sea targets.

The ships of the L and M class had single funnels, like the previous J class, a tripod foremast and a short mainmast just aft of amidships. One feature of note was the bridge design. From the I class to the Weapon class, all Royal Navy destroyers shared a distinctive wedge-shaped face to the bridge, incorporating an armoured wheelhouse, raised in order that the helmsman could see over the guns. The increased height of the new gunhouses of the L class meant that the wheelhouse was raised further, and the sloped roof of the wheelhouse (to direct the airflow over the compass platform) was almost flat. This feature was unique to the L and M's.

As ordered, the class comprised a leader and 7 destroyers. Each ship was to mount 6 x convert|4.7|in|mm|sing=on guns and 8 torpedo tubes. Close range armament had still to be decided, with the expected time of delivery being a crucial factor.

They were the first British destroyers to have their guns in fully enclosed mountings. They also continued the practice (first introduced in the Js) of making the leader "Laforey" almost indistinguishable from the rest of the class, having only more extensive cabin accommodation and better W/T ("wireless telegraph" a.k.a. radio) equipment.

Main armament

As ordered, the ships were to have six QF Mark XI convert|4.7|in|mm|sing=on guns in Mark XX twin mountings in 'A', 'B', and 'X' positions. The 'X' mount was especially interesting in that it gave an estimated arc of fire of 320 degrees at low elevations and 360 degrees at elevations above around 20 degrees. The Mark XI gun itself was a major improvement on the previous version in that it threw a convert|62|lb|abbr=on shell (as opposed to the 50 lb (23 kg) in the preceding 'J's). The Mark XX mount was fully enclosed and supposedly weatherproof; in service, crews found otherwise. It also allowed the guns to be elevated independently. The Mark XX is not technically a turret, as the ammunition feed system was distinct from the weapon mounting, and did not train with the revolving mass. This meant that ammunition supply when the guns were at the limit of training was somewhat difficult. This also meant that the ammunition hoists had to be located "between" the guns. As a result, the axes of the guns were very widely spaced, a feature instantly obvious with the Mark XX mounting.

The Mark XX mounting permitted an increased elevation to 50 degrees (compared to 40 for previous marks). However, even this was to prove totally inadequate for dealing with the threat posed by enemy aircraft, particularly dive bombers. The Imperial Japanese Navy had already introduced a 5-inch (127 mm) gun with 70 degree elevation into service, while the United States Navy's 5"/38 cal Mark 32 mount could elevate to 85 degrees. The 4.5-inch (114 mm) guns fitted to "Ark Royal" were already in service and capable of elevations of 70 degrees plus, although the mountings were not suitable for a destroyer-size ship. Coupled with the lack of powered elevation, the Mark XX mounting was compromised in its chosen anti-aircraft role.

Another development regarding the main armament was the adoption of a combined High Angle / Low Angle director tower, the HA/LA Mk.IV (TP). Unfortunately this was never entirely satisfactory in the HA mode, and was at least a ton overweight. It was later reworked, somewhat unsuccessfully again, as the Mk.I "K tower" of the Z class.

As originally ordered, the class had no close-range armament at all, as the various departments could not agree on what to fit. Arguments as to one or two 4-barrelled 2 pdr "pom poms", one pom-pom and one of the convert|0.661|in|mm|sing=on multiple machine guns then in development, one pom-pom and the traditional 0.5-inch (12.7 mm) Vickers machine gun raged, stoked by the manufacturing schedules (a second pom-pom "per" ship would not be available until 1942), the poor performance of the development models of the 0.661 and the campaign by a number of younger officers (led by Lord Louis Mountbatten) as to the effectiveness of all three weapons. Eventually, development of the 0.661 was dropped as it clearly would not be available and effective in a sensible timescale, this simplified the arguments somewhat.

The outbreak of war focussed minds somewhat. Apart from the AA armament issue concerns started to be raised about progress generally. By February 1940 the two factors led to a proposal to change the design of four of the 'L's and fit a main armament of 4-in (102mm) Mark XVI* guns in Mark XIX High Angle/Low Angle (HA/LA) twin mounts as used as secondary armament in the "Southampton"-class cruisers already in service and main armament in the "Black Swan" class of sloops then under construction. Associated changes were dropping of the pom-poms altogether and provision of two quadruple 0.5-inch (12.7 mm) machine guns.

The lessons of the Norwegian campaign and Dunkirk drove home the need for this change and it was agreed in July 1940, there were also to be four of the twin mounts instead of the originally proposed three. The fourth was to be at the forward end of the after superstructure which cut down on the fire arcs of both mounts but ensured the fourth would still be available for use in heavy weather.

Not all senior officers were in favour, and some openly expressed opinions it would mean the ships could not successfully fight their foreign equivalents. Experience in the Mediterranean, especially that of Force K which contained two of the 4-inch (102 mm) 'L's, made a mockery of the idea, with the reduced weight of each shell being compensated for by the much higher rate of fire.

Review of AA armament continued, and in October a decision was taken to remove the after bank of torpedo tubes and fit a single 4-inch (102 mm) HA gun instead, and that is how the convert|4.7|in|mm|sing=on gunned ships eventually got to sea.

hips

L class

The L class (also known as the "Laforeys") were approved under the 1937 Naval Estimates. Four of these ships ("Lance", "Lively", "Legion" and "Larne") were built with convert|4|in|mm|sing=on armament. Six of the eight were war losses, with the surviving pair being broken up in 1948.

*"Laforey", flotilla leader, built by Yarrow & Company, Scotstoun, laid down 1 March 1939, launched 15 February 1941 and completed 26 August 1941. Lost on 30 March 1944.
*"Lance", built by Yarrow, laid down 1 March 1939, launched 28 November 1940 and completed 13 May 1941. Lost on 9 April 1942.
*"Gurkha", originally named "Larne" but renamed (after the loss of the former "Gurkha" on 9 April 1940), built by Cammell Laird & Company, Birkenhead, laid down 18 October 1938, launched 8 July 1940 and completed 18 February 1941. Lost on 17 January 1942.
*"Lively" , built by Cammell Laird, laid down 20 December 1938, launched 28 January 1941 and completed 20 July 1941. Lost on 11 May 1942.
*"Legion", built by Hawthorn Leslie & Company, Hebburn, laid down 1 November 1938, launched 26 December 1939 and completed 19 December 1940. Lost on 26 March 1942.
*"Lightning", built by Hawthorn Leslie, laid down 15 November 1938, launched 22 April 1940 and completed 28 May 1941. Lost on 12 March 1943.
*"Lookout" built by Scotts Shipbuilding & Engineering Company, Greenock, laid down 23 November 1938, launched 4 November 1940 and completed 30 January 1942. BU 1948.
*"Loyal", built by Scotts, laid down 23 November 1938, launched 8 October 1941 and completed 31 October 1942. BU 1948.

M class

The M Class were built under the 1939 Naval Estimates. They served in the Home Fleet until 1944 and then went to the Mediterranean. Three were wartime losses; of the five survivors, the "Musketeer" was broken up in 1955 and the other four sold to Turkey in 1958.

*"Milne", built by Scotts, laid down 24 January 1940, launched 30 December 1941 and completed 6 August 1942. Transferred to Turkey 1959 as "Alp Arslam".
*"Mahratta" originally named "Marksman", built by Scotts, laid down 7 July 1939, launched 18 August 1941 and completed 28 July 1942. Sunk by T5 (FAT acoustic torpedo) fired by "U-990" and sank quickly in position 71.17N 13.30E in Barents Sea on 25 February 1944. Only 17 out of a total of over 217 in the ship’s company were rescued by HMS "Impulsive".
*"Musketeer" built by Fairfield Shipbuilding & Engineering Company, Govan, laid down 7 December 1939, launched 2 December 1941 and completed 5 December 1942. Broken up at Sunderland 6 December 1955.
*"Myrmidon" built by Fairfield, laid down 7 December 1939, launched 2 March 1942 and completed 5 December 1942. Loaned to the Polish Navy and renamed ORP "Orkan". Sunk by torpedo from U-boat in the North Atlantic on 8 October 1943.
*"Matchless" built by Alexander Stephen & Sons, Linthouse, laid down 14 September 1940, launched 4 September 1941 and completed 26 February 1942. Transferred to Turkey 1959 as "Kilicali Pasha".
*"Meteor", built by Stephen, laid down 14 September 1940, launched 3 November 1941 and completed 12 August 1942. Transferred to Turkey 1959 as "Piyale Pasha".
*"Marne" built by Vickers-Armstrongs, Walker, laid down 23 October 1939, launched 30 October 1940 and completed 2 December 1941. Transferred to Turkey 1959 as "Maresal Fevzi Cakmak".
*"Martin" built by Vickers-Armstrongs, laid down 23 October 1939, launched 12 December 1940 and completed 4 August 1942. Sunk by torpedo from U-boat in the Western Mediterranean on 10 November 1942.

References

ee also