Abdiel-class minelayer

The Abdiel class were a class of six fast minelayers commissioned into the Royal Navy and active during the Second World War. They were also known as the Manxman class and as "mine-laying cruisers".

These ships were armed with a wide variety of defensive weapons from 0.5-inch (12.7mm) machine guns to 4.7 in main armament. They were also equipped with a wide array of radars, along with their normal complement of mines. They were easily mistaken for destroyers.

Half the class was lost through enemy action during World War II; the others saw post-war service, the last example was scrapped in the early 70s.

Design
The Royal Navy ordered the first four ships in 1938, with a further two acquired as part of the War Emergency Programme. They were specifically designed for the rapid laying of minefields in enemy waters, close to harbours or sea lanes. As such they were required to be very fast and to possess sufficient anti-aircraft weaponry to defend themselves if discovered by enemy aircraft.

A large mineload of up to 150 mines was required to be carried under cover, therefore a long, flushdecked hull with high freeboard was required. The mines were laid through doors in their sterns; the ships carried their own cranes for loading. In size these ships were almost as long as a cruiser, but laid out much like a large destroyer. However, the three straight funnels were an instant identifying feature. Top speed was specified as 40 kn. To achieve this they were given a full cruiser set of machinery and with an installed output of 72000 shp on two shafts, they made 39.75 kn light and 38 kn deep load. To put this into perspective, the contemporary Town class cruisers had 80000 shp and a full load displacement of 12,980 tons, just short of four times that of the Abdiels.

The ships were initially to be armed much as destroyers, with three twin CP Mark XIX mounts for the QF 4.7 in Mark XII gun (which had a maximum elevation of only 40°) in 'A', 'B' and 'X' positions, a quadruple "multiple pom-pom" mounting Mark VIII for the QF 2-pdr Mark VIII and a pair of quadruple 0.5 inch Vickers machine guns.

Wartime modifications involved adding a Type 279 Radar at the masthead, a primitive metric wavelength air warning set, later replaced by a Type 286 then a Type 291, as they became available. A Type 285 Radar was fitted to the rangefinder-director on the bridge, this was a metric set and could provide target ranging and bearing information. The centimetric Type 272, a target indication radar with plan position indicator (PPI), was fitted to the front leg of the foremast. Following the loss of Latona to air attack, the surviving ships were re-armed with three twin HA/LA Mark XIX mounts for the QF 4 in L/45 Mark XIV gun with an elevation of 70° to remedy the shortcomings in anti-aircraft defence. Those on the stocks were armed with these mountings from new, but 'B' mount was suppressed and replaced (in Ariadne only) by a twin Mark IV "Hazemeyer" mounting for the 40 mm Bofors. Both Ariadne and Apollo had two such mountings sited amidships, replacing the pom-pom in 'Q' position, and these mounts carried their own Type 282 Radar for target ranging. Six single 20 mm Oerlikon guns were initially added on P Mark III pedestal mountings, although these were later replaced by powered twin Mark V mountings. In 1945 Ariadne was refitted in the United States in July 1945 for far eastern service, when the Bofors mounts were replaced by American pattern models (Mark I) with off-mounting "simple tachymetric directors" (STD) fitted with Type 282 Radar and the Oerlikon mounts regunned with Bofors guns (this combination was known as the "Boffin").

Service
Although they were effective ships in their intended role, the combination of high internal capacity and exceptionally high speed meant that they were equally valuable as fast transports. As such, for much of their service, they were used for running supplies, particularly men and matériel, to isolated garrisons such as during the siege of Tobruk and Malta in Operation Harpoon. With three funnels and the outline of a destroyer, HMS Welshman (M84) was camouflaged to appear like the Vichy French "contre torpilleurs" (large destroyer) Le Tigre. For this, a false bow was fitted, funnel caps were added, the mine chutes were plated over and a false deckline was painted on to camouflage the high flush-deck. Manxman received a similar disguise to pass for the Vichy cruiser Leopard so she could pass Corsica and mine the approaches to Livorno.

On 25 October 1941, Latona was hit by a 250-pound bomb in the engine room, causing a serious fire that spread to the munitions she was carrying and caused her loss. Welshman was torpedoed and sunk by GS U-617 in 1943. Manxman took a torpedo in her engine room but survived, although repairs took two years.

Apollo, Ariadne and Manxman survived the war and saw post-war service, with their pennant numbers changed from "M" to "N". Apollo served as a despatch vessel and Manxman as a mine warfare support ship. In 1953, Manxman was used to depict a German raider in the re-made film of C. S. Forester's novel Brown on Resolution; for this her funnels were enlarged to alter her outline, dummy 6-inch barrels were fitted over her 4-inch guns, and her bow was painted to indicate 'torpedo damage'.

1938 group

 * HMS Abdiel (M39) — built by J. Samuel White & Company, Cowes, laid down on 29 March 1939, launched on 23 April 1940, completed on 15 April 1941, sunk by mines on 9 September 1943 in Taranto Bay
 * HMS Latona (M76) — built by John I. Thornycroft & Company, Woolston, laid down on 4 March 1939, launched on 20 August 1940, completed on 4 May 1941, bombed by Italian aircraft off Libya north of Bardia and foundered on 25 October 1941
 * HMS Manxman (M70) — built by Alexander Stephen & Sons, Linthouse, laid down on 24 March 1939, launched on 5 September 1940, completed on 20 June 1941, sold for scrap in 1972
 * HMS Welshman (M84) — built by Hawthorn Leslie & Company, Hebburn, laid down on 8 June 1939, launched on 4 September 1940, completed on 25 August 1941, torpedoed by GS U-617 off Crete on 1 February 1943

War Emergency Programme (WEP) group

 * HMS Ariadne (M65) — built by A. Stephen & Sons Ltd, laid down on 10 October 1941, launched on 5 April 1943, commissioned on 12 February 1944, sold for scrap in June 1965
 * HMS Apollo (M01) — built by Hawthorn Leslie and Company, laid down on 15 November 1941, launched on 16 February 1943, completed on 9 October 1943, sold for scrap in 1962