Destroyer

USS Winston S.Churchill, a US Navy Arleigh Burke-class destroyer

In naval terminology, a destroyer is a fast and maneuverable yet long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against smaller, short-range but powerful attackers (originally torpedo boats, later submarines and aircraft).

Before World War II, destroyers were light vessels without the endurance for unattended ocean operations; typically a number of destroyers and a single destroyer tender operated together. During and after the war, larger and more powerful destroyers capable of independent operation were built, particularly as cruisers ceased to be used in the 1950s and 60s.

At the dawn of the 21st Century, destroyers are the heaviest surface combatant ships in general use, with only four nations (the United States, Russia, France and Peru) operating cruisers and none operating battleships.[1] Modern destroyers, also known as guided missile destroyers, are equivalent in tonnage but vastly superior in firepower to cruisers of the World War II era, capable of carrying nuclear missiles that are able to destroy cities.

Contents

Early history

The emergence of the destroyer and development up until World War II was related to the invention of the self-propelled torpedo in the 1860s. A navy now had the potential to destroy a superior enemy battle fleet using steam launches to drop torpedoes. Fast boats armed with torpedoes were built and called torpedo boats. By the 1880s, these had evolved into little ships of 50-100 tons, fast enough to evade enemy picket boats, but still weighed a lot.

One response to the torpedo boat threat was the building of faster and more heavily-gunned picket boats called "catchers". At first, the danger to a battle fleet was considered only to exist when at anchor, but as faster and longer range torpedoes were developed, the threat extended to cruising at sea. As catchers were then needed to escort the battle fleet at sea, they needed the same seaworthiness and endurance, and as they necessarily became larger, they became officially designated "torpedo boat destroyers", soon contracted to destroyer in English. The anti-torpedo boat origin of this type of ship is retained in its name in other languages, including French (contre-torpilleur), Italian (cacciatorpediniere), Spanish (cazatorpedero), Polish (kontrtorpedowiec), Czech (torpédoborec), Greek (antitorpiliko,αντιτορπιλικό) and so on.

Once destroyers became more than just catchers guarding an anchorage, it was realised that they were also ideal to take over the role of torpedo boats themselves, so they were fitted with torpedo tubes as well as guns. At that time, and even into World War I, the only functions of destroyers was to protect their own battle fleet from enemy torpedo attacks and to make such attacks on the battleships of the enemy. The task of escorting merchant convoys was still in the future.

An important development came in 1884 with HMS Swift,[2] a large torpedo boat with six 47 mm quick-firing guns and three torpedo tubes. While still not fast enough to engage torpedo boats reliably, she at least had the armament to deal with them.

The Imperial Japanese Navy's Kotaka (1887)

The Japanese Kotaka (Falcon) of 1885, was "the forerunner of torpedo boat destroyers that appeared a decade later".[3] Designed to Japanese specifications and ordered from the London Yarrow shipyards in 1885, she was transported in parts to Japan, where she was assembled and launched in 1887. She was armed with four 1-pounder (37 mm) quick-firing guns and six torpedo tubes, reached 19 knots (35 km/h), and at 203 tons, was the largest torpedo boat yet. In her trials in 1889, Kotaka demonstrated that she could go beyond a role of coastal defense, and was capable of following larger ships on the high seas. The Yarrow shipyards, builder of the parts for the Kotaka, "considered Japan to have effectively invented the destroyer".[4]

The Spanish Navy's Destructor (1886)

Almost immediately after the order of Kotaka was placed, Fernando Villaamil, second officer of the Ministry of the Navy of Spain where he was put in charge of developing the concept of a new ship designed to combat torpedo boats,[5] placed an order for a large torpedo gunboat in November 1885, with the British builder James and George Thompson, of Clydebank, not far from where the Yarrow shipyards would move from London twenty years later. The ship, named Destructor (literally Destroyer), was laid down at the end of the year, launched in 1886, and commissioned in 1887. Her displacement was 380 tons, and she was armed with one 90 mm Hontoria cannon, four 57 mm Nordenfeldt cannon, two 37 mm Hotchkiss guns and 3 Schwartzkopff torpedo tubes. Her complement was 60 men. In terms of gunnery, speed (22.5 knots in trials) and dimensions, the specific design to chase torpedo boats and her high seas capabilities, Destructor is widely considered the first destroyer ever built.[6]

The Spanish Destructor is thought to have influenced the designation and concept of later destroyers developed by the British Navy.[7][8]

Shortly afterwards, Britain began experiments with the Rattlesnake class 'torpedo boat catcher', a class of 17 large torpedo boats - the first precursors of destroyers to be built as a class, rather than as single ships. On tests, Rattlesnake proved to be marginally faster than torpedo boats, but not fast enough to be decisive.

HMS Havock (1893)

The first ships to bear the formal designation "Torpedo boat destroyer" (TBD) were the Havock class of two ships of the Royal Navy, developed in 1892 under the newly appointed Third Sea Lord Rear Admiral "Jackie" Fisher, and launched by Yarrows in London in 1893. Havock had a 240 tons displacement, a speed of 27 knots (50 km/h), and was armed with a single 12-pounder (76 mm) gun, three 6-pounders (57 mm), and three 46 cm torpedo tubes. She also had the range and speed to effectively travel with a battle fleet.

The French navy, an extensive user of torpedo boats, built its first destroyer in 1899, with the Durandal-class 'torpilleur d'escadre'.

The United States commissioned its first destroyer, USS Bainbridge, Destroyer No. 1, in 1902 and by 1906 there were 16 destroyers in service with the US Navy.

Pre World War I

Destroyer design evolved around the turn of the 20th century in several key ways. The first was the introduction of the steam turbine. The spectacular unauthorised demonstration of the turbine powered Turbinia at the 1897 Spithead Navy Review, which, significantly, was of torpedo boat size, prompted the Royal Navy to order a prototype turbine powered destroyer, HMS Viper of 1899. This was the first turbine warship of any kind and achieved a remarkable 36 knots (67 km/h) on sea trials. By 1910 the turbine had been widely adopted by all navies for their faster ships.

The second development was the replacement of the boat-style turtleback foredeck by a raised forecastle, which provided better sea-keeping as well as more space below deck.

Paulding class 1909 destroyer USS Perkins.

The British experimented with oil propulsion for the Tribal class of 1905 but switched temporarily back to coal for the later Beagle class in 1909. Other navies also adopted oil, for instance the USN with the Paulding class of 1909. In spite of all this variety, destroyers adopted a largely similar pattern. The hull was long and narrow, with a relatively shallow draft. The bow was either raised in a forecastle or covered under a turtleback; underneath this were the crew spaces, extending 1/4 to 1/3 the way along the hull. Aft of the crew spaces was as much engine space as the technology of the time would allow: several boilers and engines or turbines. Above deck, one or more quick-firing guns was mounted in the bows, in front of the bridge; several more were mounted amidships and astern. Two torpedo tube mountings (later on, multiple mountings) were generally found amidships.

Between 1890 and 1914 destroyers became markedly larger: initially 300 tons was a good size, but by the start of the First World War 1000 tons was not unusual. However, construction remained focused on putting the biggest possible engines into a small hull, resulting in a somewhat flimsy construction. Often hulls were built of steel only 1/8in thick.

By 1910 the steam-driven displacement (i.e. not hydroplaning) torpedo boat had become redundant as a separate type. Germany nevertheless continued to build such torpedo boats until the end of WW1, although these were effectively small coastal destroyers. In fact Germany never distinguished between the two types, giving them pennant numbers in the same series and never giving names to destroyers. Ultimately the term torpedo boat came to be attached to a quite different vessel - the very fast hydroplaning motor driven MTB.

Life on early destroyers

Early destroyers were extremely cramped places to live. In the Havock-class no crew member could ever get undisturbed rest, with officers sleeping on cushioned chairs around the wardroom instead of beds. Spray and condensation made life miserable. The first British class to have separate cabins for officers, or a heating stove for the captain, was the River class of 1902.

Early Destroyer tactics and engagements

The destroyer's initial purpose was to protect against torpedo boats, but navies soon appreciated the flexibility of the fast, multi-purpose vessel that resulted. Vice-Admiral Sir Baldwin Walker laid down for the Royal Navy:[9]

The destroyer's first major use came in the devastating Japanese attack on the Russian fleet in Port Arthur at the opening of the Russo-Japanese War in 1904. Three destroyer divisions attacked the Russian fleet in port, firing a total of 18 torpedoes, and severely damaging two Russian battleships.

World War I

USS Wickes DD-75 a Wickes class destroyer

While capital ship engagements were scarce in World War I, destroyer units were almost continually engaged in raiding and patrol actions. The first shot of the war at sea was fired on 5 August 1914 by a destroyer of the 3rd Flotilla, Lance, in an engagement with the German auxiliary minelayer Königin Luise. The first British naval casualty was Amphion, the light cruiser leading the 3rd Flotilla, which ran into a mine laid by Königin Luise.

Destroyers were involved in the skirmishes that prompted the Battle of Heligoland Bight, and filled a range of roles in the Battle of Gallipoli, acting as troops transports and fire support vessels, as well as their fleet-screening role. Over 80 British destroyers and 60 German torpedo-boats took part in the Battle of Jutland, which involved pitched small-boat actions between the main fleets, and several foolhardy attacks by unsupported destroyers on capital ships. Jutland also concluded with a messy night action between the German High Seas Fleet and part of the British destroyer screen.

The threat evolved by World War I with the development of the submarine, or U-boat. The submarine had the potential to hide from gunfire and close underwater to fire torpedoes. Early-war destroyers had the speed and armament to intercept submarines before they submerged, either by gunfire or by ramming. Destroyers also had a shallow enough draft that torpedoes would find it difficult to hit them.

The desire to attack submarines underwater led to rapid destroyer evolution during the war, which were quickly equipped with strengthened bows for ramming, depth charges and hydrophones for identifying submarine targets. The first submarine casualty to a destroyer was the German U-19, rammed by Badger on 29 October 1914. While U-19 was only damaged, the next month Garry successfully sank U-18. The first depth-charge sinking was on 4 December 1916, when UC-19[10] was sunk by Llewellyn.

The submarine threat meant that many destroyers spent their time on anti-submarine patrol; once Germany adopted unrestricted submarine warfare in January 1917, destroyers were called on to escort merchant convoys. US Navy destroyers were among the first American units to be dispatched upon the American entry to the war, and a squadron of Japanese destroyers even joined Allied patrols in the Mediterranean. Patrol duty was far from safe; of the 67 British destroyers lost in the war, collisions accounted for 18, while 12 were wrecked.

At the end of the war the state-of-the-art was represented by the British W class.

Inter-war

The trend during World War I had been towards larger destroyers with heavier armaments. A number of opportunities to fire at capital ships had been missed during the War, because destroyers had expended all their torpedoes in an initial salvo. The British 'V' & 'W' classes of the late war had sought to address this by mounting six torpedo tubes in two triple mounts, instead of the four or two on earlier models. The 'V'and 'W's set the standard of destroyer building well into the 1920s.

The next major innovation came with the Japanese Fubuki class or 'special type', designed in 1923 and delivered in 1928. The design was initially noted for its powerful armament of six five-inch (127 mm) guns, together with three triple torpedo mounts. The second batch of the class gave the guns high-angle turrets for anti-aircraft warfare, and the 24-inch (60 cm) oxygen fueled 'Long Lance' Type 93 torpedo. The later Ariake class of 1931 further improved the torpedo armament by storing its reload torpedoes close at hand in the superstructure, meaning reloading could be accomplished in 15 minutes.

Most other nations replied with similar larger ships. The US Porter class adopted twin five-inch (127 mm) guns, and the subsequent Mahan class and Gridley class (the latter of 1934) increased the number of torpedo tubes to 12 and 16 respectively.

France's Le Fantasque, the fastest destroyer class ever built.

In the Mediterranean, the Italian navy's building of very fast light cruisers of the Condottieri class prompted the French to produce exceptional destroyer designs. The French had long been keen on large destroyers, with their Chacal class of 1922 displacing over 2000 tons and carrying 130 mm guns; a further three similar classes were produced around 1930. The Le Fantasque class of 1935 took performance to an exceptional level. The class carried five 5.5-inch (140 mm) guns and nine torpedo tubes, but their speed was truly exceptional - reaching 45 knots (83 km/h), which remains the record speed for a steamship and for any destroyer. The Italians' own destroyers were almost as swift, most Italian designs of the 1930s being rated for 38 knots (70 km/h), and carrying four or six 120 mm guns as well as torpedoes.

Germany started to build destroyers again during the 1930s as part of Hitler's rearmament programme. The Germans were also fond of large destroyers, but while the initial Type 1934 displaced over 3,000 tons their armament was no better than many smaller classes. The later Type 1936 did, however, adopt heavy 150 mm guns. German destroyers also used innovative high-pressure steam machinery: while this should have helped their efficiency, it more often resulted in mechanical problems.

Once German and Japanese armament became clear, the British and American navies consciously focused on smaller, more numerous units. The British built a series of destroyers the A Class to I Class which were about 1400 tons standard displacement, had four 4.7-inch (119 mm) guns and eight torpedo tubes; the American Benson class of 1938 similar in size, but carried five 5-inch (127 mm) guns and ten torpedo tubes. The British realising the need for heavier gun armament built the Tribal class of 1936 (sometimes called "Afridi" after one of two lead ships). These ships displaced 1850 tons and were armed with eight 4.7-inch (119 mm) guns in four twin turrets and four torpedo tubes. These were followed by the J Class and L class destroyers with six 4.7-inch (119 mm) guns in twin turrets and 8 torpedo tubes

Anti-submarine sensors included sonar (or ASDIC), although training in their use was indifferent. Anti-sub weapons changed little, and ahead-throwing weapons, a need recognized in WWI, had made no progress.

Operations in the inter-war period

During the 1920s and 1930s destroyers were often deployed to areas of diplomatic tension or humanitarian disaster. British and American destroyers were common on the Chinese coast, even supplying landing parties to protect colonial interests.

World War II

USS McGowan, a Fletcher-class destroyer during World War II
Main articles: British World War II destroyers, German World War II destroyers, Japanese World War II destroyers

By World War II the threat had evolved once again. Submarines were more effective, and aircraft had become important weapons of naval warfare; once again the fleet destroyers were ill-equipped for combatting these new targets. They were fitted with new anti-aircraft guns, radar, and forward-launched ASW weapons, in addition to their existing light guns, depth charges, and torpedoes. By this time the destroyers had become large, multi-purpose vessels, expensive targets in their own right rather than expendable vessels for the protection of others; moreover, they were one of the most sunk kinds of ships even though they were mass produced. This led to the introduction of smaller and cheaper specialized anti-submarine warships called corvettes and frigates by the Royal Navy and destroyer escorts by the USN. These ships had the size and displacement of the original torpedo boat destroyers the contemporary destroyer had evolved from.

Post-war

Polish ORP Błyskawica destroyer currently preserved as a museum ship in Gdynia.

Some conventional destroyers were completed in the late 1940s and 1950s which built on wartime experience. These vessels were significantly larger than wartime ships and had fully automatic main guns, unit Machinery, radar, sonar, and antisubmarine weapons such as the Squid mortar. Examples include the British Daring class, US Forrest Sherman-class, and the Soviet Kotlin-class destroyers.

Some World War II-vintage ships were modernised for anti-submarine warfare, and to extend their service lives, to avoid having to build (expensive) brand-new ships. Examples include the US FRAM I programme and the British Type 15 frigates converted from fleet destroyers.

The missile age

The advent of surface-to-air missiles and surface-to-surface missiles, such as the Exocet, in the early 1960s changed naval warfare. Guided missile destroyers (DDG in the US Navy) were developed to carry these weapons and protect the fleet from air, submarine and surface threats. Examples include the Soviet Kashin-class, the British County class, and the American Charles F. Adams-class.

Modern destroyers

HMCS Algonquin, an Iroquois-class destroyer

The Canadian Navy currently operates the Iroquois-class destroyers, a class of four helicopter-carrying, anti-aircraft, guided missile destroyers. Launched in the 1970s, the Iroquois were the first Canadian all gas turbine powered military ships, using two turbines for cruise power, and another two fast-starting "boost" turbines for speeds of up to 29 knots (54 km/h) (such an arrangement is known as COGOG). Previously the Soviet Navy had used all-gas turbine propulsion on their Kashin class destroyers of the 1960s but the Iroquois were the first to be built to this scheme either in Canada or in the US. The design of the Iroquois was a major inspiration for the US's later Spruance class ships. They were originally fitted out for anti-submarine warfare, but the entire class underwent major retrofits as a part of the Tribal Class Update and Modernization Program, or TRUMP, in the 1990s. These refits had the effect of re-purposing the ships for air-defence, and the ships are now referred to as area air-defence destroyers.

INS Mysore D60, of the Indian Navy during an exercise with the US Navy.

The Indian Navy operates the Delhi class destroyers. These ships are armed with Kh-35 missiles, which have a range of 130 km, in the anti-ship role. These missiles will be replaced by the Brahmos cruise missiles. Shtil (AKA SA-N-7 Gadfly) system is installed to counter airborne threats. The Barak point-defense missile system has been installed in INS Delhi and will soon be installed in the other two ships of its class. These destroyers also carry the RBU-6000 rockets in the anti-submarine role and are provided with five 533 mm torpedo launch tubes that can launch the SET-65E, Type 53-65 torpedoes. Another strength of these destroyers lies is the capability to carry two Sea King helicopters. The Delhi class will be augmented by the new Kolkata class destroyers, the first of which was launched in March 2006.

The Italian navy (Marina Militare) currently operates 2 Luigi Durand de la Penne destroyers and 2 Orizzonte Class

Type 052C destroyer of the People's Liberation Army Navy

The Chinese People's Liberation Army Navy has recently commissioned a number of new modern destroyers in addition to the four Sovremenny-class. Three new classes were launched since 2003, known as the Luyang, Luyang II and Luzhou class. The latter two are armed with long range air defense missiles, the indigenous HQ-9 and the Russian S-300 respectively. It has been speculated that once the PLAN has been satisfied with one of the two designs (either the 052C or 051C), it would be selected for series production as the next generation of advanced air defense destroyers for China.

In the US Navy, destroyers operate in support of carrier battle groups, surface action groups, amphibious groups and replenishment groups. The destroyers currently in use by the US Navy are the Arleigh Burke-class. Destroyers (with a DD hull classification symbol) primarily perform anti-submarine warfare duty while guided missile destroyers (DDGs) are multi-mission (anti-submarine, anti-aircraft, and anti-surface warfare) surface combatants. The relatively-recent addition of cruise missile launchers has greatly expanded the role of the destroyer in strike and land-attack warfare. As the expense of heavier surface combatants has generally removed them from the fleet, destroyer tonnage has grown (a modern Arleigh Burke-class destroyer has the same tonnage as a World War II light cruiser). Arleigh Burke is billed by her builders as ton-for-ton the most powerful warship in history.

The Royal Navy currently operates 7 ships of the Type 42 class with HMS Southampton reducing to extended readiness in 2008. The destroyers (as well as frigates) are, as always, the workhorses of the fleet, the former optimised for air defence and the latter for surface and subsurface warfare. They are equally at home in large task groups or on independent operations which may include sanctions enforcement, humanitarian relief or anti-drug patrols. British destroyers (of recent times) have an average displacement of around 5000 tonnes, and are armed with a mixture of guns and missiles including 114 mm (4.5 inch) Mk 8 guns, Sea Dart Missiles, 20 mm Close range guns, Vulcan Phalanx close in weapons system (CIWS), and anti submarine torpedo tubes. These ships are due to be replaced by the new Type 45 or Daring Class destroyers which will displace roughly 7,200 tonnes.

The Russian Navy and the People's Liberation Army Navy of the People's Republic of China operate the Sovremenny class, a class of large multi-purpose missile destroyers. They are powered by pressure-fired boilers, making them capable of speeds in excess of 30 knots (56 km/h). Their armament consists of 8 SS-N-22 Sunburn anti-ship missiles, launchers for SA-N-7 Gadfly anti-air missiles and two AK-130 twin-barreled 130 mm automatic naval guns which can fire laser-guided shells. While they also carry 533 mm torpedo tubes and RBU-6000 rocket launchers for use against submarines, their primary mission is to attack surface ships. Their anti-aircraft missiles have a surface attack mode, and both the 130 mm guns and the torpedoes are useful against ships at close range.

Future destroyers

HMS Daring, a Type 45 Destroyer anti-aircraft destroyer of the Royal Navy, which will enter service on 23 July 2009.
Concept drawing for USS Zumwalt, the lead ship of the DD(X) class.

The Royal Navy's current Type 42 destroyers are being replaced by the new Type 45 Daring-class from 2009 onwards. A class of 6 ships is envisaged. Displacing around 7,200 tons, they will be equipped with the UK variant of the Principal Anti-Air Missile System (PAAMS) and BAE Systems SAMPSON radar. The ships are assembled at Scotstoun, by BVT Surface Fleet. HMS Daring, the first of her class, was launched on 1 February 2006.

The last US Navy Spruance-class destroyer in service, USS Cushing, was decommissioned on September 21 2005. The Zumwalt class are planned to replace them; on November 1, 2001, the US Navy announced the issuance of a revised Request for Proposal (RFP) for the Future Surface Combatant Program. Formerly known as DD 21, the program will now be called DD(X) to more accurately reflect the program purpose, which is to produce a family of advanced technology surface combatants, not a single ship class. DD(X), also called Zumwalt class, is much larger than traditional destroyers, being nearly three thousand tons heavier than a Ticonderoga-class cruiser (c.12,500 tonnes). It will potentially employ advanced weaponry and an all-electric Integrated Power System; however, the construction programme was subsequently reduced to just two vessels, and there is currently only funding for three in total. With the retirement of the Spruance class, the Navy began commissioning an advanced variant of the Arleigh Burke class with expanded ASW capabilities, the Arleigh Burke Flight IIA, beginning with USS Oscar Austin. As of 2006, 22 of these vessels are in service, with at least seven more under construction.

The $5.2 billion Command & Control and Air-Defence Capability Replacement project is meant to replace Canada’s Iroquois class destroyers whose primary role shifted to area air-defence after TRUMP refits in the 1990s. Although the area air-defence capability had not previously existed, the Canadian Navy now regards “wide area air defence” as part of Canada’s core naval capabilities. When the project began, Canadian Navy destroyers were expected to need replacing by 2005, they are now expected to serve until 2010. There was some work on a replacement design, known to Navy-watchers as the Province class destroyers, but this was confined largely to studies of a much-improved multi-function three dimensional phased array radar system being developed in conjunction with the Dutch and German navies, known as Active Phased Array Radar. Current speculation is that the ships themselves would be similar to a "stretched" Halifax-class frigate.

See also

Notes

  1. Although there are currently no active battleships in any navy the United States navy still maintains two Iowa-class battleships, and could reactivate one or both if necessary though unlikely.
  2. "Torpedo Boats". Battleships-Cruisers.co.uk.
  3. Evans and Peattie, David C. and Mark R. (in English). 'Kaigun: Strategy, Tactics, and Technology in the Imperial Japanese Navy, 1887-1941'. Annapolis, Maryland: Naval Institute Press. ISBN 0870211927. 
  4. Howe, Christopher (in English). 'The Origins of Japanese Trade Supremacy: Development and Technology in Asia from 1540 to the Pacific War'. Chicago, Illinois: University of Chicago Press. ISBN 0226354857. 
  5. Biography of Villaamil
  6. From an article about the American Greyhounds
    • Quote:
    Torpedo boats were considered a major threat and the navies of the world set out to defend against them. In 1884 Capitan de Navio Fernando Villaamil was appointed the second officer in the Ministry of the Spanish Navy and was tasked with the design of a new class of warship intended to fight the then new torpedo boats. Once he reached a conclusion, he chose the J & G Thomson shipyards in Clydebank, Scotland, to build the new vessel. On January 19, 1887, the DESTRUCTOR, the first torpedo boat destroyer, was turned over to the Spanish Navy, with great expectations from the European naval community. Twenty-four hours after leaving Falmouth England, the DESTRUCTOR reached the Spanish coast, making 18 knots (33 km/h) through a stormy Bay of Biscay. The ships new design and functions were so different from any past man-of-war, many thought it couldn’t survive at sea. In one day the doubts about the vessel's seaworthiness were answered forever, and her designer and commander had every reason to feel proud.
  7. Lion, page 18: J&G Thomson's 1892 design for a TBD is, not unsurprisingly, somewhat reminiscent of their "Destructor" built for the Spanish Navy.
  8. Lion, page 66: It was already (J&G Thomson Clydebank shipyard), when asked to tender for TBDs for the Royal Navy, building trasatlantics liners and cruisers to the navy, and had built an interesting torpedo vessel under the prophetic name of "Destructor" ("Destroyer") for Spain. Its first design (for the British navy in 1892) was cleary a successor of the "Destructor".
  9. Brett, Bernard: "History of World Sea Power", Deans International (London) 1985. ISBN 0-603-03723-2
  10. U-Boats Destroyed, Paul Kemp (1997), ISBN 1 85409 515 3

References

External links