Scott-Class Destroyer Leader, HMS Mackay (I70) (1943 refit)

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Scott Class Destroyer Leader, HMS Mackay (l70) (1943 refit)

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Design History:

HMS Mackay was the fourth of five Admiralty type flotilla leaders ordered from Cammell Laird in April 1917, which would form the bulk of the orders of a class that would ultimately include a total of 8 vessels. Mackay was laid down with the name Calverhouse at Laird’s shippyard at Birkenhead on 5 March 1918 and was named after the Scottish Mackay clan, under which name she would be launched on the 21st december 1918 before ultimately entering commission in june of 1919. The Admiralty type, also known as the Scott class, were designed to meet a requirement from Admiral Sir John Jellicoe, commander of the Grand Fleet, for a large, fast and heavily armed destroyer leader to match and outclass the rumoured large German destroyers that were alledgedly being built. To meet this demand the ship was sized accordingly, creating a ship 320 feet 0 inches (97.54 m) long between perpendiculars and 332 feet 5 inches (101.32 m) overall, to a beam of 31 feet 9 inches (9.68 m) and a draught of 12 feet 6 inches (3.81 m). This design displaced around 1,580 long tons (1,610 t) under normal conditions and 2,050 long tons (2,080 t) when under full load. The ship’s machinery consisted of four Yarrow boilers feeding steam at 250 pounds per square inch (1,700 kPa) to two sets of Parsons single-reduction geared-steam turbines. This configuration was rated at 40,000 shaft horsepower (30,000 kW) giving the design a respectable top speed of 36.5 knots (67.6 km/h; 42.0 mph). The engines themselves were powered by the 504 tons of oil fuel carried on board, giving the vessel a range of 5,000 nautical miles (9,300 km; 5,800 mi) at 15 knots (28 km/h; 17 mph).

The class initially had a main gun armament consiting of five 4.7/45 calibre BL Mark I guns mounted on CP VI mountings capable of elevating up to 30 degrees, which were arranged in two superfiring pairs fore and aft of the main superstructure, with the final gun located on a platform between the two funnels. In addition to this a single 3 inch gun was mounted on a platform abaft of the rear funnel along with a pair of single two pounder pom pom autocannons to allow close protection. This suplimented the torpedo armament, which consisted of two triple mounts for 21-inch (533 mm) torpedo tubes between the 3-inch AA gun and the rear pair of 4.7-inch guns. This loadout would remain more of less unchanged during the interwar period, though this would soon change once WW2 began. The first early change was the replacement of the amidship 4.7-inch gun by two 2-pounder (40 mm) “pom-pom” autocannons, with the rear funnel in tern shortened to improve the field of fire for the cumbersome 3 inch gun. At all points the torpedo tubes were retained, though the ship was also equipt with depth charge racks allowing it to launch a 10-depth charge pattern. Later the 3 inch gun would be moved to the x turret position, and two 20mm Oerlikon autocannons were mounted on the ship’s bridge wings further increasing its AA protection. During this time a Type 271 radar was also mounted above the ship’s bridge, replacing the ww1 vintage low-angle director and its rangefinder. This was suplimented by a Type 291 radar which was mounted upon the ships mast. The final modification occured in 1943, when the ship received the rare twin 6-pounder (57 mm) replaced the 4.7-inch gun at A-position, for use against German E-boats, giving the boat the distinction of being one of only 8 royal navy vessels to be equipt with this weapon system.

The Twin QF 6-pounder 10 cwt Gun:

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The British QF (quick-firing) 6-pounder 10 cwt gun was a 57mm twin mount light coastal defence and naval gun developed during the thirties to try and counter the threat posed by fast enemy torpedo boats. Its development came about due to the emergence of small fast attack craft, which had the speed to evade the heavy coastal defence guns which defended British ports. Because of this the design called for a twin-barrelled weapon capable of sustained semi-automatic fire. to fulfill this role the barrels could be fired singly or together, creating a susttained rate of fire, which with sufficiently trained crews could provide a 80 rounds per minute rate of fire from the twin weapon system. Official War Office acceptance occurred on 28 February 1934, with a coastal defence trial taking place with the gun and barbette in 1936. It was deemed to be fit for purpose, and around 150 units were made during the run up and war period, with the majority made by the machinery manufacturer, Baker Perkins, who took over production in march 1939, though their first guns were not shipped until march of 1941. during this time a simplified version was made dubbed the Mark II, which had a monobloc barrel cast in a single forging, instead of the standard lined barrel of the Mark I.

The first twin 6-pounders were installed at Singapore in 1937, with more ports following as guns were manufatured. The first unit in the United Kingdomwas installed was at Dover, just in time for the outbreak of WW2. The most important installation though was likely the nine pairs of guns installed at the grand harbour at Valletta Maltra, which played a pivitol roll during a massed italian attack of 19 MAS fast attack boats on the 26th of july 1941. The MAS boats suffering heavy damage, and within the space of only two minutes 5 of them were sent to the bottom in balls of flame. Seeing this the navy immediately saw a solution to one of their pressing issues when it came to convoy defence, which had persisted since the war had started. The issue being that of surface night attacks by fast E-boats, which would lie in wait for convoys, before springing forth at the ideal moment to sweep across the convoy firing torpedos and then fleeing into the night. The small vessels easily able to escape into the darkness, as the larger 4.7 and 4 inch guns found on destroyers were not fast firing enough to deal with this form of attack, where as the smaller 20mm oerlikons mounted on escort destroyers at the time lacked the size of shell heavy enough to sucessfully cripple the vessels during the short window of an attack. Because of this the Twin QF 6-pounder 10 cwt Gun was approved for naval use, and was mounted in place of the number 1 gun on five W class destroyers (HMS Walpole, Windsor, Whitshed, Worcester and Wivern), and three Scott class destroyer leaders (HMS Campbell, Mackay and Montrose). These ships would go on to be the only royal navy vessels equipt with the gun system, as the admiralty deemed the need for anti-submarine capability was more vital, and unfortunately the 6 pounder installation competed for space with the new ahead-throwing Hedgehog anti-submarine mortar coming into service at the time. Regardless of this limited adoption, the weapon system was effective, and offered a new lease of life to a group of outdated destroyers, that would see much sucess in their anti E-boat screening.

Service History:

Mackay joined the 3rd Destroyer Flotilla of the Atlantic Fleet upon entering service in 1919, and was based at Rosyth. In september of that same year she was deployed to the baltic as part of the British campaign there during the Russian civil war, where she supported the advance of Estonian forces against Petrograd ( Saint Petersburg). This involved the bombardment of the Bolshevik-held Krasnaya Gorka fort, a role she preformed with the monitor HMS Erebus, the cruisers HMS Delhi and HMS Dunedin, along with her fellow destroyer leaders HMS Shakespeare and HMS Spenser and four other destroyers on 27 October. Unfortunately, in spite of the support from the Royal Navy, the assault failed, and Mackay returned to British waters at the end of november. Her next deployment would be on british soil, when she was deployed to Pembroke Dock in responce to industrial unrest in south wales in april to june 1921. HMS Mackay would then go for refitting at Chatham dockyard from july to august of that year, afterwhich she was allocated as the leader of the 4th destroyer flotilla. From here her service was a series of accidents and going in for repair after standard patrols, until she was recomissioned as leader of the 5th destroyer flotilla when HMS Wallace had to undergo refitting for turbine repairs. She would be in this role for 4 months, before she herself had to undergo refit at sheerness dockyard in november of 1927. The ship during this time was deemed worn out and surplus to requirements, and it was proposed that she would be transfered to the Royal Australian Navy to replace Anzac, but in the end, HMS Stuart was transferred instead.

Because of this HMS Mackay remained under British service, and after a patrol of the mediterranean, she returned to uk waters to become part of the 2nd Submarine Flotilla based at Devonport in April 1933. It was during this role that she attended to submarine l26, which suffered a battery explosion while docked in Campbeltown harbour. The blast killed two of the submarines crew, and seriously injured 14 more, resulting in the vessels hull being holed. Mackay attended to the damaged sub from the 8th to the 11th of october, which managed to save the submarine, which would go on to serve until 1946. HMS Mackay remained with the 2nd Submarine Flotilla until September 1935, when the Abyssinia Crisis resulted in her joining the 1st Destroyer Flotilla based at Malta. she served in this role until the end of March 1936, before she returned to british waters and was placed in reserve, until she was recommissioned again on the 25th of july 1938, again as part of the 2nd Submarine Flotilla. She would remain at this posting, for the rest of the pre war period up until the eve of ww2, bar a short 13 day assignement to the 12th destroyer flotilla during the Munich crisis in 1938.

With the outbreak of the second world war, Mackay joined the 11th destroyer flotilla, and formed part of the western approaches command, with the intended role of performing anti sub patrols and convoy escort duties, a designation it would hold for the duration of the war. Her first action occured on the 15th of september, when uboat u-53 torpedoed the tanker Cheyenne, forcing the crew to abandon ship. Cheyenne remained afloat though, and Mackay interrupted u-53’s attempt to sink the ship with gunfire, as the destroyer easily drove it off, though by that point Cheyenne was too far gone, and had to be scuttled by the destroyer. During this period HMS Mackay took part in convoy OB 48 and OB 74, where she rescued the crews from San Alberto and Cairnross respectfully. She was detoured from escort duty on the 26th of may 1940, to take part in operation dynamo, the evacuation of British and Allied troops from Dunkirk and nearby beaches. HMS Mackay reported for evacuation duties on the 27th of may, and arrived at Dover early in the morning of the 28th. one the first run she successfully picked up 581 troops and was returning for a second run when she ran aground off Zuydcoote. The destroyer was sucessfully refloated, but the evacuation run was abandoned, as the resulting damage required immediate repair at Sheerness. With these repairs complete she took part in operation Aerial, which was the evacuation of British troops from ports in west france. Because of this, HMS Mackay took part in the final evacuation of Saint-Jean-de-Luz, in the far South-West of France, on 24 June.

After this excitement, Mackay continued her operations with the 11th flotilla until october 1940, when yet again she returned to port for refit, as at this point the aging destroyer needed her boilers replacing. The refit went sucessfully, and Mackay joined the 16th flotilla, where she escorted convoys off the east coast of Britain, where during an exercise, she and 6 other elderly destroyers were ordered to intercept the German battleships Scharnhorst and Gneisenau and the heavy cruiser Prinz Eugen, it what would later be called the channel dash. One of the destroyers Walpole suffered a boiler issue and had to turn back, but the rest of the ships managed to encounter the german force off the Scheldt estuary. The british ships instantly came under heavy german fire, as they attempted their torpedo attack, with Worcester being hit badly, though all five ships managed to launch their torpedos, though unfortunately all missed, though thankfully none of the British destroyers were lost in the action even after closing to under 4000 yards (3,700m).

After this, Mackay was temporarily detached to the Home Fleet in support of the Arctic convoy PQ 18 to Northern Russia and the return convoy QP 14. Mackay formed part of the distant cover force (led by the battleships Anson and Duke of York) for PQ 18 and QP 14, before returning to Harwich on before returning to Harwich on 27 September 1942. With that out of the way, Mackay was attatched to screening operations with the home fleet, allowing more modern destroyers to be deployed elsewhere. As part of this new role she was equipt with the twin 6 pounder mount to provide better defense against enemy E-boats. This refit would prove useful, as on the night of the 7th of march, Mackay along with three motor gun boats, repelled a pack of german E-boats near the sunk lightship in the Thames estuary, during which two of the boats collided allowing the british to sink one of them. These e-boat attacks proved persistant, and Mackay again held back a flotilla of 32 E-boats which were attempting to raid Convoy FN 1160. During this engagement, Mackay damaged E-boat S63, which she then proceeded to ram sinking it.

In June of 1944 Mackay was then deployed to support the Normandy landings, where she escorted convoys to the beaches from d-day onwards, supporting the follow-up convoys until july when she returned to her east coase escort role. Mackay’s last action of the war was to assist in the liberation of Norway, where she escorted the destroyer Viceroy and nine minesweepers to Trondheim, to accept the german surrender on may 17th 1945. After the war HMS Mackay was placed in the reserve list, and was then allocated by BISCO to metal Industries, Limited for disposal in early 1947, though it would take until june of 1949 for her to eventually be towed to Charlestown breaking yard for scrapping.

Vehicle specification:

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Displacement: 1,801 long tons (1,830 t)

Length: 332 ft 6 in (101.35 m)

Beam: 31 ft 9 in (9.68 m)

Draught: 12 ft 6 in (3.81 m)

Installed power: 40,000 shp (30,000 kW)

Propulsion: 2 ×Parsons Turbines

2 X shafts

Speed: 36.5 knots (42mph/ 67kph)

Complement: 164

Armament:

2 × BL 4.7-inch (120 mm) guns

1 x twin QF 6-pounder 10 cwt gun mount mk 1 (1 x 2 6 pounders)

1 × QF 3-inch 20 cwt anti-aircraft gun

2 × 2-pounder pom pom guns in single mounts

2 x Oerlikon 20mm cannon

2 x triple 21-inch (533 mm) torpedo tubes

50 x depth charges fired in patterns of 10

Additional data for the twin 6 pounder 10 cwt gun mount:

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Additional Photos:

Photo of HMS Mackay in her original ww1 design configuration:

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Image showing shell storage, the rounds were stored in standard 6 pounder ammo boxes, which each held 6 rounds, giving this storage box below 36 rounds:

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View from the bridge of HMS Mackay:

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Veiw of the twin 6 pounder aboard HMS Mackay when buttoned up:

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Side view of the turret:

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Photos showing how there was enough clearance from the top of the turret casemate for the twin 6 pounder to safely turn:

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Photo showing the twin 6 pounder about to perform firing excersises, not the number of loaders and the ammount of ammunition stowed in the ready racks:

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Additional photos can be found in the second link in the source :).png “:)”)

Sources: