Very Special Ships. Arthur Nicholson
that the ‘offensive’ in the term ‘offensive minelayer’ meant the minefield they were to lay rather than the ship itself and the emphasis on maintaining high speed had to be pointed out in connection with additional fittings that would decrease their speed.
Sir Stanley Goodall, Director of Naval Construction during the design of the Abdiel class. (NPG × 89436, undated portrait by Elliott & Fry, © National Portrait Gallery, London)
The result was a class of ships that was larger than any British destroyer and smaller than any British cruiser and plenty faster than any of them. Specifically, at 2650 tons standard displacement, the Abdiels were larger than the largest British destroyers of the day, the 1850-ton ‘Tribal’ class, an example of which was the legendary HMS Cossack, and were smaller than the smallest modern British light cruisers of the day, the 5419-ton3 Arethusa class, an example of which was the similarly legendary HMS Penelope. The Abdiels’ displacement was 3780 tons in deep condition, their length overall was 417ft 11in, their maximum beam was 40ft, their draught forward was 10ft and 12ft aft.4
Many regarded the Abdiels as very attractive ships. Rear Admiral Sir Morgan Morgan-Giles, who as a veteran of the war in the Mediterranean when they were operating there likely had plenty of opportunities to observe them, said it best: ‘What lovely ships those Abdiels were.’5 Captain John S Cowie, who had a hand in the 1935 memorandum that eventually led to their construction, referred to them as ‘these beautiful little ships’. Samuel Elliot Morison, the official American naval historian of the Second World War, described the Ariadne as ‘handsome’.6
A profile of the 1938 Fast Minelayer design. (Eric Leon)
The Abdiels had a raked stem and a cruiser stern and were flush-decked, with the sheer line of the upper deck running straight most of their length but then rising gently from the bridge to the stem. Their bridge was much more like a destroyer’s than a cruiser’s. They shipped a tripod foremast aft of the bridge and forward of the first funnel and a shorter tripod mainmast aft of the third funnel, with both masts upright, not raked. The two twin 4in gun mounts forward and the single one aft gave their appearance a certain balance and a look of truculence.
One of the most distinctive features of the class was their three funnels, of almost equal height, the middle one larger in cross-section than the first and third ones. The fore funnel was 46ft 8in above the waterline. In having three funnels, they were unique among warships built during the Second World War.
The Abdiels’ twin 4in (102mm) Mk XVI guns were in shielded Mk XIX mounts. They fired a 67lb fixed round with a firing cycle of five seconds. The guns were 45 calibres long, i.e. 45 × 4in, and could elevate to 80° and could depress to 10° below the horizontal.7 The Abdiels were to carry 250 rounds per gun for their 4in guns.8 In spite of reports to the contrary, which began at least as early as the 1941 edition of Jane’s Fighting Ships and persisted for decades, the Abdiels never, ever, carried 4.7in guns.
The disposition of the 4in guns enabled the Abdiels to ship a Mk M (or Mk VII) four-barrel, 2pdr (40mm) pom-pom mount to be placed on a bandstand aft of the third funnel with excellent arcs of fire, instead of between the second and third funnels with much poorer ones. The pompoms had barrels 39 calibres long, with elevation of 80° and a rate of fire of about 100 rounds per minute per gun. The projectile weighed 1.684lb. – not 2lb – and the entire fixed round weighed 3lb. The Abdiels were to carry 1800 rounds per barrel. The ships were designed so that the four-barrel pom-pom could later be replaced by an eight-barrel pom-pom, but this was never done.
The Abdiel s’ gun armament also included two quadruple Mk III .5in (12.7mm) Vickers machine guns, which were fitted in the port and starboard bridge wings and for which the Abdiels carried 2500 rounds per barrel. The Vickers machine guns were soon replaced or at least supplemented by up to seven single-mounted, Swiss-designed 20mm Oerlikon cannon, a much better weapon with a slower rate of fire (465–480rpm vs. 650–700rpm) but a much heavier HE shell, weighing 0.272lb (vs. 1.326 oz. for the .5in gun). The Vickers machine gun was 62.2 calibres in length and the Oerlikon cannon was 70 calibres in length, which resulted in a higher muzzle velocity.9 The Abdiels were to carry 2400 rounds per gun for the Oerlikons.
As for fire control and ‘sensors’, the Abdiels’ 4in guns were controlled by a Mk III director, or High Angle Control System (HACS), sited aft of the bridge, which was equipped with a rangefinder and a Type 285 radar aerial. The pom-pom was controlled by a Mk III director that was sited just forward of the mount. Neither director was optimal. The Vickers machine guns and later the Oerlikons had to make do with local control. The initial four ships sported a Type 286 radar aerial on the foremast, and were equipped with a Type 128 Asdic – now called sonar – for detecting submarines and a DF coil forward of the wheelhouse.
Last but surely not least, the Abdiel s’ armament naturally included an outfit of mines. At first, they were designed to carry 100 mines, but the number was fortunately increased to 150 and in practice they could carry a maximum of 160. The mines were loaded through four hatches in the upper deck and were stowed on tracks in a completely enclosed mining deck that ran much of their length. The mines were disgorged through two mining doors at the stern. The fast minelayers were fitted with the ‘chain conveyor’ system for moving the mines around and laying them, with the older ‘wire and bogie’ system as a backup.
A profile of the final design of the Abdiel class. (Eric Leon)
To facilitate their minelaying operations, the Abdiels were equipped with taut wire measuring gear, which fulfilled the very important function of allowing the positions of their minefields to be assessed with greater accuracy. The gear was first designed for ships laying submarine telegraph cables and consisted of ‘in simple terms a long length of piano wire paid out astern of the minelayer, the amount of wire run off being measured with a high degree of accuracy and recorded on a form of cyclometer’.10 It would prove to be a vital tool for the fast minelayers, when it worked.
The Abdiels’ capacious mining deck was a salient feature of the ships, designed for mines weighing 1¼ tons to run on a ‘Clapham Junction’ network of rails. The ships were equipped with two large cranes, one to port and another to starboard. A post-war history of the Navy’s Construction Department recognised that the fast minelayers were often used for carrying stores and naively claimed that the stores carried on the mining deck were limited to 200 tons.11 That may have been the official policy, but someone must have neglected to tell the Construction Department that in practice the Abdiels carried at much as 373 tons of stores and equipment on the mining deck.12
The ships were unarmoured, with only 10lb protective plating on the bridge. Their hulls were too small for any special protection against torpedoes, other than their normal compartmentation, which unfortunately featured fairly large machinery spaces prone to flooding over a large area with a single torpedo. In hindsight, the bigger problem was their large, undivided mining deck, which did not improve their chances of survival in the event of flooding.
The Abdiel s’ accommodation was to be that of a cruiser or above and their designed complement was twelve officers and 224 men; in practice they accommodated more, by one count 260.13 They were also capable of carrying many passengers and sometimes carried ‘special’ ones, such as brass hats, wounded men and POWs. Their designed complement of boats included a 25ft motor cutter and a 14ft sailing dinghy to port, a 27ft whaler and a 25ft motor boat to starboard, and a 16ft planing dinghy atop the after deckhouse.
The heart of the design of the fast minelayers was, naturally, their machinery. The design provided for four boilers with a working pressure of 300lb/sq.