A- and B-class destroyer

HMS Achates
Class overview
Name:	A and B class
Operators:	Royal Navy  Royal Canadian Navy  Royal Hellenic Navy
Preceded by:	Ambuscade and Amazon
Succeeded by:	C and D class
Subclasses:	A, B
Built:	1928–31
In service:	1930–45
Completed:	20
Lost:	10
Scrapped:	10
General characteristics (as built)
Type:	Destroyer
Displacement:	1,350–1,360 long tons (1,370–1,380 t) (standard) 1,778–1,790 long tons (1,807–1,819 t) (deep load)
Length:	323 ft (98 m) (o/a)
Beam:	32 ft 3 in (9.83 m)
Draught:	12 ft 3 in (3.73 m)
Installed power:	34,000 shp (25,000 kW) 3 × Admiralty 3-drum boilers
Propulsion:	2 × shafts; 2 × geared steam turbines
Speed:	35 knots (65 km/h; 40 mph)
Range:	4,800 nmi (8,900 km; 5,500 mi) at 15 knots (28 km/h; 17 mph)
Complement:	138
Armament:	4 × single QF 4.7-inch (120 mm) Mk IX guns 2 × single QF 2-pounder anti-aircraft guns 2 × quadruple 21-inch (533 mm) torpedo tubes
General characteristics Saguenay and Skeena (where different)
Displacement:	1,337 long tons (1,358 t) (standard) 1,805 long tons (1,834 t) (deep load)
Length:	321 ft (98 m) (o/a)
Draught:	12 ft 3 in (3.73 m)
Propulsion:	32,000 shp (24,000 kW)
Range:	5,000 nmi (9,300 km; 5,800 mi) at 15 knots
General characteristics Codrington (A-class flotilla leader)
Displacement:	1,540 long tons (1,560 t) (standard) 2,012 long tons (2,044 t) (deep load)
Length:	343 ft (105 m) (o/a)
Beam:	33 ft 9 in (10.29 m)
Installed power:	39,000 shp (29,000 kW)
Complement:	185
Armament:	5 × single QF 4.7-inch (120 mm) Mk IX guns
Notes:	(where different)
General characteristics Keith (B-class flotilla leader)
Displacement:	1,400 long tons (1,400 t) (standard) 1,821 long tons (1,850 t) (deep load)
Complement:	157
Notes:	(where different)

The A- and B-class destroyers were a group of 18 destroyers built for the Royal Navy during the late 1920s, with two additional ships built for the Royal Canadian Navy. The British ships were divided into two flotillas of eight destroyers, each with a flotilla leader.

Design and description

The A-class design was derived from the 1926 prototypes Amazon and Ambuscade for the 1927–28 Naval Construction Programme. The initial staff requirements were unrealistic and would have resulted in a much larger, unaffordable ship; they were scaled back, both to reduce the size of the ship and to save money.^[1] Nonetheless, the design had an improved gun armament, heavier torpedo armament, and greater range, at the cost of 2 knots (3.7 km/h; 2.3 mph) of speed, in comparison with the prototypes. The As were fitted with the Two-Speed Destroyer Sweep (TSDS) minesweeping gear and only had a residual anti-submarine ability while the Bs were equipped with Type 119 Asdic (sonar) and had a full complement of depth charges, but could not use the TSDS. This was the beginning of the Admiralty's policy of alternating TSDS and anti-submarine capabilities between destroyer flotillas.^[2] The ships displaced 1,350–1,360 long tons (1,370–1,380 t) at standard load and 1,778–1,790 long tons (1,807–1,819 t) at deep load. They had an overall length of 323 feet (98.5 m), a beam of 32 feet 3 inches (9.8 m) and a draught of 12 feet 3 inches (3.7 m).^[3] The A class had a metacentric height of 1.76 feet (0.54 m) at deep load.^[4] The ships' complement was 138 officers and ratings as built,^[5] but increased in size up to 162 during the war.^[6]

The destroyers were powered by two Parsons geared steam turbines, each driving one propeller shaft, using steam provided by three water-tube boilers equipped with superheaters. Five of the As and all of the Bs had Admiralty three-drum boilers that operated at a pressure of 300 pounds per square inch (2,068 kPa; 21 kgf/cm²) and a temperature of 600 °F (316 °C) while Ardent and Anthony were fitted with Yarrow boilers of 275 psi (1,896 kPa; 19 kgf/cm²) pressure at the same temperature. Acheron was given experimental Thornycroft boilers that had a working pressure of 500 psi (3,447 kPa; 35 kgf/cm²) and a temperature of 750 °F (399 °C) to examine the weight and economy savings.^[7] Her specific fuel consumption was reduced from 0.8 lb (0.36 kg)/hp/hour in her sisters to 0.6 lb (0.27 kg)/hp/hour,^[8] although she was plagued by mechanical problems for her whole life.^[9] In the event the trials were inconclusive, and the Admiralty continued to use the lower-temperature and pressure Admiralty three-drum boiler until the Battle class of 1942, nearly ten years after other major navies began to use higher-pressure and temperature boilers.^[10] The turbines developed a total of 34,000 shaft horsepower (25,000 kW) for a designed speed of 35 knots (65 km/h; 40 mph) and the ship exceeded that during their sea trials.^[11] The destroyers carried a maximum of 388–390 long tons (394–396 t) of fuel oil that gave them a range of 4,800 nautical miles (8,900 km; 5,500 mi) at 15 knots (28 km/h; 17 mph).^[5]

All of the ships had the same main armament, four quick-firing (QF) 4.7-inch (120 mm) Mark IX guns in single mounts with enlarged gun shields, designated 'A', 'B', 'X', and 'Y' from front to rear. Although the A class were intended to be equipped with gun mounts that could elevate up to 40°, and 'B' gun on a high-angle mount capable of 60°, all four guns ultimately had a maximum elevation of 30°.^[12] They fired a 50-pound (23 kg) shell at a muzzle velocity of 2,650 ft/s (810 m/s) to a range of 16,970 yards (15,520 m).^[13] Each gun was provided with 190 rounds. For anti-aircraft (AA) defence, the A- and B-class ships carried two 40-millimetre (1.6 in) QF two-pounder Mark II AA guns mounted on platforms between the funnels, each with 500 rounds. They were fitted with two quadruple mounts for 21-inch (533 mm) torpedo tubes.^[14] The A-class ships were initially going to be fitted with two throwers and four chutes for eight depth charges, but they interfered with the TSDS equipment so the throwers, one chute and two depth charges were removed.^[15] The Bs were equipped with two throwers and one rack for twenty depth charges.^[16] While not initially fitted with ASDIC, space was reserved for it, and at least some of the As received it beginning in the late 1930s.^[17]

The fire-control system for these ships was little advanced over their First World War-era predecessors. A pedestal-mounted, manually operated Destroyer Director Sight and a separate nine-foot (2.7 m) rangefinder positioned to its rear were situated above the bridge; the director sent elevation and traverse orders to the main guns and the searchlight using data derived from the rangefinder. They had no capability for anti-aircraft fire and the anti-aircraft guns were aimed solely by eye. No fire-control computer was initially installed, but an Admiralty Fire Control Clock Mark II was retrofitted after it had been proven in the subsequent C-class destroyers.^[18]

Canadian ships

The two Canadian ships were designed to be of a similar performance to the A-class ships to allow them to tactically combine. More flare was given to the bow to keep it drier and the forward part of the hull was strengthened to withstand ice. Their metacentric height was increased to allow for the build-up of ice and snow on the upperworks and they were three feet (0.9 m) shorter than their British counterparts. Although the ships had an additional 50 long tons (51 t) of fuel, 2,000 shp (1,500 kW) fewer horsepower and lacked superheaters for their boilers, they had the same range and speed as their brethren of the A and B classes. They displaced 1,337 long tons (1,358 t) at standard load and 1,805 long tons (1,834 t) at deep load. The ships were built by John I. Thornycroft & Company in Woolston, Hampshire and had the broad, slab-sided funnels characteristic of that builder.^[19]

Flotilla leaders

Codrington was built to an enlarged design to accommodate the commander of the destroyer flotilla (Captain (D)) and his staff, some 47 additional officers and ratings. The ship displaced roughly 200 long tons (200 t) more than the private ships (1,540 long tons (1,560 t) at standard load and 2,012 long tons (2,044 t) at deep load); she was 20 feet (6.1 m) longer overall and had a beam 1 foot (0.3 m) wider. She shipped a fifth 4.7-inch gun between the funnels, which forced the two-pounders to be repositioned abaft the rear funnel,^[5] and was not fitted with TSDS. To compensate for her greater size, Codrington's oil tanks were increased by 40 long tons (41 t) and her turbines were rated at 39,000 shp (29,000 kW) to give her the same range and speed as the private ships, but she proved to be significantly faster as she made 37.7 knots (69.8 km/h; 43.4 mph) during her sea trials. However, the increased length made her somewhat unhandy, having a turning circle much greater than the standard A class, which complicated manoeuvres with her flotilla.^[20]

Unlike Codrington, Keith was built upon the same hull as her sisters to save money and to make her tactically identical to her flotilla-mates. The initial proposal was to enlarge the aft deckhouse to make room for the Captain (D) and his staff at the expense of 'Y' gun and the TSDS gear, but the gun was reinstated while she was under construction. The ship was too small to accommodate the entirety of the staff, and Blanche was fitted as a divisional leader to carry the surplus.^[21] Keith was 40 long tons (41 t) heavier than the private ships at standard load and nearly 100 long tons (100 t) heavier at full load (1,400 long tons (1,400 t) and 1,821 long tons (1,850 t), respectively) and carried 19 additional officers and ratings.^[5]

Wartime modifications

The initial wartime modifications were limited and mostly related to the survivability of the crew, aside from the addition of 50 rounds per gun of 4.7-inch ammunition and the increase of depth charge stowage to 42 (the Canadian ships carried 33). Beginning in May 1940, the after bank of torpedo tubes was removed in most ships and replaced with a QF three-inch (76 mm) 20-cwt anti-aircraft gun,^{[Note 1]} the after mast and funnel being cut down to improve the gun's field of fire.^[22] Of the early war losses, only Codrington^[23] and Acheron received this modification before they were sunk.^[24] By October, all of the surviving A-class ships plus Beagle, Boadicea, Boreas and Brilliant had been modified and the rest of the Bs had received theirs by April 1941.^[25]

Beginning in 1941, most ships had 'Y' gun and the TSDS gear replaced by racks and throwers for a pattern of 10 depth charges, with stowage increased to 70 charges. Their light AA armament was augmented by a pair of QF Oerlikon 20-millimetre (0.79 in) guns, one each abreast the bridge, and a Type 286 short-range, surface-search radar, adapted from the Royal Air Force's ASV radar, was also added. The early models, however, could only scan directly forward and had to be aimed by turning the entire ship. The Canadian ships replaced their two-pounders with a pair of quadruple 0.5-inch (12.7 mm) machine guns and were not fitted with Oerlikons by 1942.^[26]

Late that year, some of the surviving ships were further modified into what became known as escort destroyers. These ships had either 'A' or 'B' gun replaced by a Hedgehog anti-submarine spigot mortar. Achates, Beagle, Boreas, and Bulldog were among the first ships to be so converted. Around this same time many ships had their Destroyer Director Sight and rangefinder exchanged for a Type 271 target-indication radar. Beagle and Bulldog were later fitted with a two-pounder bow chaser to engage German E-boats in the English Channel while Boadicea received two elderly six-pounder (57 mm) Hotchkiss guns to deal with U-boats on the surface at close range.^[27]

Beginning in 1943, the three-inch gun was removed to allow for the installation of a Huff-Duff radio direction finder on a short mainmast; the aft torpedo tubes were sometimes reinstalled. The single 20 mm guns abreast the bridge were replaced by Mark V powered mountings for twin weapons later in the war, the singles replacing the two-pounder or .50 caliber guns amidships, with a further pair of Oerlikons that replaced the searchlight between the torpedo tubes.^[28]

Ships

A class ships

Navy	Pennant number	Name	Builder	Laid down	Launched	Commissioned	Fate
Royal Navy	D65	Codrington	Swan Hunter & Wigham Richardson, Wallsend	1928-06-20	1929-08-07	1930-06-04	Bombed and sunk off Dover 1940-07-27
	H09	Acasta	John Brown & Company, Clydebank	1928-08-13	1929-08-08	1930-02-11	Sunk by the German battleships Scharnhorst and Gneisenau off Narvik, 1940-06-08
	H12	Achates	John Brown	1928-09-11	1929-10-04	1930-02-11	Sunk by the German cruiser Admiral Hipper in Battle of the Barents Sea, 1942-12-31
	H14	Active	Hawthorn Leslie & Company, Hebburn	1928-07-10	1929-07-09	1930-02-09	Sold for breaking up 1947-07-07
	H36	Antelope	Hawthorn Leslie	1928-07-11	1929-07-27	1930-02-20	Sold for breaking up 1946-01-28
	H40	Anthony	Scotts Shipbuilding & Engineering Company, Greenock	1928-07-30	1929-04-24	1930-02-14	Sold for breaking up 1948-02-21
	H41	Ardent	Scotts	1928-07-30	1929-06-26	1930-04-14	Sunk by the German battleships Scharnhorst and Gneisenau off Narvik, 1940-06-08
	H42	Arrow	Vickers Armstrongs, Barrow-in-Furness	1928-08-20	1929-08-22	1930-04-14	Damaged by the explosion of SS Fort Lamontee in Algiers 1943-08-04 and written off as a constructive total loss
	H48	Acheron	John I. Thornycroft & Company, Woolston	1928-08-20	1929-08-22	1930-04-14	Mined off the Isle of Wight, 1940-12-17
Royal Canadian Navy	D79	Saguenay	Thornycroft	1929-09-27	1930-07-11	1931-05-22	Damaged in a collision 1942-11-15 and de-rated to training ship, sold for breaking 1945
	D59	Skeena	Thornycroft	1929-10-14	1930-10-10	1931-06-10	Wrecked in Kollafjord, Iceland, 1944-10-25

B-class ships

Service

The class saw much service in the Second World War, being involved in convoy protection and anti-submarine warfare in home waters and the North Atlantic. Seven of the eleven ships of the class were sunk in World War II. Acasta and Ardent were sunk on 8 June 1940 by the German battleships Scharnhorst and Gneisenau west of Narvik during the Norwegian campaign. Codrington was sunk by German air attack at Dover on 27 July 1940. Acheron was sunk by a mine off the Isle of Wight on 17 December 1940. Achates was sunk by two large German heavy cruisers, Admiral Hipper and Lützow. Arrow was so badly damaged when the ammunition ship Fort La Montee blew up on 4 August 1943 at Algiers that she could not be repaired and was towed to Taranto and paid off. Skeena was wrecked in a storm off Iceland on 25 October 1944. Saguenay was heavily damaged in a collision with the merchant ship Azara and was consigned to the role of a training ship after being repaired.

The surviving ships were worn out from war duties and were scrapped soon after the war.

Notes

Footnotes

References

• Campbell, John (1985). Naval Weapons of World War II. Annapolis, Maryland: Naval Institute Press. ISBN 0-87021-459-4. 
• Colledge, J. J.; Warlow, Ben (2006) [1969]. Ships of the Royal Navy: The Complete Record of all Fighting Ships of the Royal Navy (Rev. ed.). London: Chatham Publishing. ISBN 978-1-86176-281-8. OCLC 67375475. 
• English, John (1993). Amazon to Ivanhoe: British Standard Destroyers of the 1930s. Kendal, England: World Ship Society. ISBN 0-905617-64-9. 
• Friedman, Norman (2009). British Destroyers From Earliest Days to the Second World War. Annapolis, Maryland: Naval Institute Press. ISBN 978-1-59114-081-8. 
• Haarr, Geirr H. (2010). The Battle for Norway: April – June 1940. Annapolis, Maryland: Naval Institute Press. ISBN 978-1-59114-051-1. 
• Haarr, Geirr H. (2009). The German Invasion of Norway, April 1940. Annapolis, Maryland: Naval Institute Press. ISBN 978-1-59114-310-9. 
• Hodges, Peter; Friedman, Norman (1979). Destroyer Weapons of World War 2. Greenwich: Conway Maritime Press. ISBN 978-0-85177-137-3. 
• Lenton, H. T. (1998). British & Empire Warships of the Second World War. Annapolis, Maryland: Naval Institute Press. ISBN 1-55750-048-7. 
• Rippon, P. M., Cmdr. (1988). The Evolution of Engineering in the Royal Navy. Vol. 1: 1827–1939. Tunbridge Wells, UK: Spellmount. ISBN 0-946771-55-3. 
• Rohwer, Jürgen (2005). Chronology of the War at Sea 1939–1945: The Naval History of World War Two (Third Revised ed.). Annapolis, Maryland: Naval Institute Press. ISBN 1-59114-119-2. 
• Whitley, M. J. (1988). Destroyers of World War Two: An International Encyclopedia. Annapolis, Maryland: Naval Institute Press. ISBN 0-87021-326-1. 
• Winser, John de D. (1999). B.E.F. Ships Before, At and After Dunkirk. Gravesend, Kent, UK: World Ship Society. ISBN 0-905617-91-6. 

External links

Wikimedia Commons has media related to A class destroyer (1930).

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A- and B-class destroyer A class  Royal Navy Codrington [leader] Anthony Ardent Active Antelope Acasta Arrow Acheron Achates  Royal Canadian Navy Part of Canadian River class Saguenay Skeena B class  Royal Navy Keith [leader] Basilisk Beagle Blanche Boadicea Boreas Brazen Brilliant Bulldog  Royal Hellenic Navy Salamis (ex-Boreas) Preceded by: Shakespeare class Followed by: C and D class List of destroyers of the Royal Navy List of destroyers of the Royal Canadian Navy

Interwar standard destroyer classes of the Royal Navy A class B class C class D class E class F class G class H class I class List of destroyers of the Royal Navy