Battlecruiser



Battlecruisers (sometimes two words as battle cruisers) were large warships in the first half of the 20th century, similar in size and cost to a battleship.

The battlecruiser was developed in the first decade of the century as the successor to the armoured cruisers, but their evolution was more closely linked to that of the dreadnought battleships. Battlecruisers typically used the same large-calibre main armament as a battleship, but sacrificed armour protection in exchange for speed. Thus ships of this type could inflict much more punishment than they could absorb.

Throughout the First World War, the battlecruiser was principally used to provide a fast and hard-hitting addition to a battleship fleet. Battlecruisers formed part of the navies of Britain, Germany and Japan in World War I and took part in several raids and skirmishes as well as the Battle of Jutland.[1]

By the end of the First World War, there were very few differences between the design of a battlecruiser and that of a fast battleship. Britain, Japan and the United States all designed battlecruisers after the end of World War I which were as heavily armed as a battleship, though faster and not so heavily armored. The Washington Naval Treaty, which limited capital ship construction from 1922 onwards, treated battleships and battlecruisers identically. The new generation of battlecruisers planned was scrapped under the terms of the treaty.

From the 1930s, only the Royal Navy continued to use 'battlecruiser' as a classification for warships, for the WWI-era capital ships that remained in the fleet.[2] Nevertheless, the fast, light capital ships developed by Germany and France of the Scharnhorst and Dunkerque classes are often referred to as battlecruisers,[3] [4] as they were as well armoured but smaller and carried a lighter calibre of armament compared to follow-up designs which were considered fast battleships.

World War II saw battlecruisers in action again, these mostly consisting of modernized WWI ships as well as the ships built in the 1930s. There was also renewed interest in large "cruiser killer" type warships, but few were completed, as construction of capital ships was curtailed in favor of the more needed convoy escorts, aircraft carriers, and cargo ships. In the post-World War II era, a small number of ships have been described as battlecruisers, such as the Kirov class.

First battlecruisers
HMS Invincible, Britain's first BattlecruiserThe battlecruiser was a dramatic evolution of the armoured cruiser and 'second-class battleship' designs of the 1890s, principally due to the British Admiral Jackie Fisher.[5] At the turn of the century, the modern armoured cruiser was a fast and powerful vessel which was capable of threatening trade routes worldwide, or of working closely with a battleship fleet.[6] The Royal Navy, and Fisher in particular, was concerned with the damage armoured cruisers (particularly those of the French Navy) might inflict on British trade worldwide in the event of war.[7] Fisher envisaged British armoured cruisers becoming faster and more heavily armed to deal with this threat. He was also very fond of the "second-class battleship" HMS Renown, a lighter, faster battleship.[8] As early as 1901, there is confusion in Fisher's writing about whether he saw the battleship or the cruiser as the model for future developments.

In the period 1902–1904 the mainstream of British naval thinking was clearly in favour of heavily armoured battleships, rather than the fast ships which Fisher favoured. A shift away from the mixed-calibre armament of the 1890s pre-dreadnought to an "all-big-gun" design was already being considered, and preliminary designs circulated for battleships with all 12-inch or all 10-inch guns and armoured cruisers with all 9.2-inch guns.[9]

In mid-1904, after Fisher's appointment as First Sea Lord, the decision was taken to use 12-inch guns for the next generation of battleships, because of their superior performance at long range. The armament of the next armoured cruiser was much more controversial. The size and cost of the next generation of armoured cruisers meant that it was very desirable that they should be able to play a role in a battleship action, and this meant 12-inch guns.[10] This was the same logic which had led the Japanese to arm their latest cruisers with four 12-inch guns as their main armament.,[11] It is also quite possible that Fisher pushed for the cruiser to have the same armament as the battleship because he held out hope that the cruiser design would be the replacement for the battleship. The decision to give the next generation of armoured cruisers an 'all-big-gun' armament was the crucial moment in the development of the battlecruiser. If the ships had been armed with only 10-inch or 9.2-inch guns, they would merely have been better armoured cruisers.[12]

The radical changes to shipbuilding policy which Fisher was making across the board meant that he appointed a Committee on Designs in December 1904. While the stated purpose of the Committee was to investigate and report on the requirements of future ships, the key decisions had already been taken by Fisher and his associates.[13] The terms of reference for the Committee were for a battleship capable of 21 knots with 12-inch guns and no intermediate calibres, capable of operating from existing docks;[14] and a cruiser capable of 25.5 knots, also with 12-inch guns and no intermediate armament, armoured like HMS Minotaur, the most recent armoured cruiser, and also capable of working from the existing docks.[13] The battleship became the revolutionary battleship HMS Dreadnought, and the cruiser became the three ships of the Invincible class.

The construction of the new class was began in 1906 and completed in 1908, delayed perhaps to allow their designs to learn from any problems with Dreadnought.[15] The ships fulfilled the design requirement quite closely. The Invincibles had a displacement similar to that of the Dreadnought but twice the power to give a speed of 25 knots (46 km/h). They had eight 12-inch (305 mm) Mk X guns, compared to ten on Dreadnought. There was armour 6 or 7 inches (150 to 180 mm) thick along the side of the hull and over the gunhouses, whereas Dreadnought's armour was 11 inches (280 to 300 mm) at its thickest.<sup class="reference" id="cite_ref-15">[16] The class had a very marked increase in speed, displacement and firepower compared to the most recent armoured cruisers, but no more armour.

The Invincibles were to have the same role as the armoured cruisers they succeeded, but the new ships were expected to be more effective all-round. Specifically their roles were: Confusion about how to refer to these new battleship-size armoured cruisers set in almost immediately. Even in late 1905, before work was begun on the Invincibles, a Royal Navy memorandum refers to "large armoured ships" meaning both battleships and large cruisers. In October 1906, the Admiralty began to classify all post-Dreadnought battleships and armoured cruisers as "capital ships", while Fisher used the term "dreadnought" to refer either to his new battleships or the battleships and armoured cruisers together.<sup class="reference" id="cite_ref-16">[17] At the same time, the Invincible class themselves were referred to as "cruiser-battleship", "dreadnought cruiser"; the term "battlecruiser" was first used by Fisher in 1908. Finally, on 24 November 1911, Admiralty Weekly Order No. 351 laid down the decision that "All cruisers of the Invincible and later type are, for the future, to be described and classified as battlecruisers in order to distinguish them from armoured cruisers of the older type."<sup class="reference" id="cite_ref-17">[18]
 * Heavy Reconnaissance. Because of their power, the Invincibles could sweep away the screen of enemy cruisers to close with and observe an enemy battlefleet, before using their superior speed to retire.
 * Close support for the battlefleet. They could be stationed at the ends of the battle line to stop enemy cruisers harassing the battleships, and to harass the enemy's battleships if they were busy fighting battleships. Also, the Invincibles could operate as the fast wing of the battlefleet and try to outmanouevre the enemy.
 * Pursuit. If an enemy fleet ran, then the Invincibles would use their speed to pursue, and their guns to damage or slow enemy ships.
 * Commerce protection. The new ships would hunt down enemy cruisers and commerce raiders.<sup class="reference" id="cite_ref-oyaprk_11-1">[12]

Battlecruisers in the Dreadnought arms race
In the period from the launching of the Invincibles to just after the outbreak of the First World War, the battlecruiser played a junior role in the developing dreadnought arms race. The battlecruiser was never wholeheartedly adopted as the key weapon in British imperial defence, as Fisher had presumably desired.

Britain's strategic circumstances had changed markedly between the conception of the battlecruiser and the commissioning of the first ships. While the prospective enemy for Britain had previously been a Franco-Russian alliance with many armoured cruisers, it was now clearly Germany. Diplomatically, Britain had entered the Entente cordiale in 1904 and the Anglo-Russian Entente. Furthermore neither France nor Russia posed a particular naval threat; the Russian navy had largely been sunk or captured in the Russo-Japanese War of 1904-5, while the French were in no hurry to adopt the new dreadnought battleship technology.<sup class="reference" id="cite_ref-18">[19] Britain also boasted very cordial relations with two of the significant new naval powers; Japan (bolstered by the Anglo-Japanese Alliance, signed in 1902 and renewed in 1905), and the USA.

These changed strategic circumstances, and the great success of the Dreadnought, ensured that she rather than the Invincible became the new model capital ship. Nevertheless, battlecruiser construction played a major part in the renewed naval arms-race sparked by the Dreadnought.

For the first few years after their completion, the Invincibles entirely fulfilled Fisher's vision of being able to sink any ship fast enough to catch them, and run from any ship capable of sinking them. An Invincible would also in many circumstances, be able to take on an enemy pre-dreadnought battleship. The Invincibles were so far ahead of any enemy armoured cruiser that it was difficult to justify building more or bigger cruisers.<sup class="reference" id="cite_ref-19">[20] This lead was extended by the surprise both Dreadnought and Invincible produced, which prompted most other navies to delay their building programmes while radically revising their designs. This was particularly true for cruisers, because the details of the Invincible class were kept secret for longer; this meant that the next German armoured cruiser, Blücher was armed with only 8.2-inch guns, and was obsolete before she was even launched.

The Royal Navy's early superiority in capital ships led to the rejection of a design of 1905-6 which would essentially have fused the battlecruiser and battleship concepts. The 'X4' design combined the full armour and armament of Dreadnought with the 25-knot speed of Invincible. The additional cost could not be justified given the existing British lead and the new Liberal government's need for economy; the slower and cheaper Bellerophon, a relatively close copy of Dreadnought, was adopted instead.<sup class="reference" id="cite_ref-20">[21]

By 1911 Germany had built battlecruisers of her own, and the superiority of the British ships could no longer be assured. Von der Tann, begun in 1908 and completed in 1910, carried eight 11.1-inch guns but with 11.1-inch (280 mm) armour was far better protected than the Invincibles. The two Moltkes were quite similar but carried ten 11.1-inch guns of an improved design.<sup class="reference" id="cite_ref-21">[22] The German Navy did not share Fisher's view of what a battlecruiser should be; it was entitled to build armoured cruisers under the terms of the Navy Laws, and used this authority to match or better the British battlecruisers.<sup class="reference" id="cite_ref-22">[23]

The next British battlecruisers were three of the Indefatigable class. These ships were slightly improved Invincibles, which corrected some flaws in the earlier ships but were built to fundamentally the same specification. The British were hampered on this occasion by the secrecy surrounding German battlecruiser construction and particularly about the heavy armour of Von der Tann. Political pressure to reduce costs also played a role in the selection of the Indefatigable design,<sup class="reference" id="cite_ref-23">[24] and this class is widely seen as a mistake.<sup class="reference" id="cite_ref-24">[25]

The next generation of British battlecruisers were markedly more powerful. By 1909-10 the political climate had changed; the desire for cost-cutting was now outweighed by a sense of national crisis about rivalry with Germany. A brief political crisis and a naval panic resulted in the approval of a total of eight capital ships in 1909-10.<sup class="reference" id="cite_ref-25">[26] Fisher pressed for all of them to be battlecruisers,<sup class="reference" id="cite_ref-26">[27] but was unable to force his way, and had to settle for six battleships as well as two battlecruisers of the Lion class. These carried eight 13.5-inch guns; the standard armament of the British "super-dreadnought" battleships of the same period was ten 13.5-inch. Speed increased, to 27 knots. Lion also carried better armour than previous British battlecruisers, with 9 inches on the armour belt and barbettes; nevertheless, protection was not as good as in German designs. The two Lions were followed by the very similar Queen Mary <sup class="reference" id="cite_ref-27">[28]

In contrast to the British focus on increasing speed and firepower, Germany further improved the armour and staying power of their next battlecruiser. Seydlitz, designed in 1909 and finished in 1913, was a modified Moltke; speed increased by one knot to 26.5 knots, while armour was up to 12 inches thick, equivalent for the Helgoland class battleships of just one or two years earlier. Seydlitz was Germany's last battlecruiser to be completed before World War I.<sup class="reference" id="cite_ref-28">[29]

The next step in the battlecruiser design came from Japan. The Imperial Japanese Navy had been planning the Kongō class ships from 1909. The Japanese navy was determined that, since the Japanese economy could support relatively few ships, each ship would be more powerful than its likely competitors. Initially the class was planned with the Invincibles as the benchmark. On learning of the British plans for Lion, and the likelihood that new U.S. Navy battleships would be armed with 14-inch guns, the Japanese decided to radically revise their plans and go one better. A new plan was drawn up, carrying eight 14-inch guns, and capable of 27.5 knots, thus marginally having the edge over the British Lions in speed and firepower. The heavy guns were also better-positioned, being superfiring both fore and aft with no turret amidships. The armour scheme was also marginally improved over the Lions with 9 inches of armour on the turrets and 8 inches on the barbettes. The first ship in the class was built in Britain, and a further three constructed in Japan.<sup class="reference" id="cite_ref-29">[30] The Japanese also re-classified their strong armoured cruisers of Tsukuba and Ibuki classes, carrying four 12-inch guns, as battlecruisers, nonetheless they had weaker armament and were slower.<sup class="reference" id="cite_ref-30">[31]

The next British battlecruiser, Tiger, was broadly on the model of Lion but also influenced by the design of the Japanese ships.<sup class="reference" id="cite_ref-31">[32] She retained the eight 13.5-inch guns of her predecessors, though these were positioned for better fields of fire. She was faster (making 29 knots on trials), and carried a heavier secondary armament. Tiger was also more heavily armoured on the whole; while the maximum thickness of armour was the same at 9 inches, the height of the main armour belt was increased.<sup class="reference" id="cite_ref-32">[33]

1912 saw work begin on three more German battlecruisers of the Derfflinger class, the first German battlecruisers to mount 12-inch guns. These excellent ships, like the Tiger and the Kongō, had their guns arranged in superfiring turrets for greater efficiency. Their armour and speed was similar to the previous Seydlitz class.<sup class="reference" id="cite_ref-33">[34]

In 1913, the Russian Empire also began the construction of the four-ship Borodino class, which were designed for service in the Baltic Sea. These ships were designed to carry twelve 14-inch guns, with armour up to 12 inches thick, and a speed of 26.6 knots. The heavy armour and relatively slow speed of these ships makes them more similar to German designs than to British ships; construction of the Borodinos was halted by the First World War and all were scrapped during the Russian Revolution.<sup class="reference" id="cite_ref-jndjmt_34-0">[35]

By 1914, only Britain, Germany and Japan had battlecruisers, with Russia building some. On several occasions, it had already been possible to point to moments where the concepts of battlecruiser and battleship might be seen in the same vessel. This was true of the 1906 'X4' design,<sup class="reference" id="cite_ref-35">[36] and the Russian Borodinos<sup class="reference" id="cite_ref-jndjmt_34-1">[35] and arguably the entire German Battlecruiser program. It was even more true of the most recent British battleship design. The Queen Elizabeth class was designed to make 25 knots, as much as the first battlecruisers had achieved, while carrying eight 15-inch guns and armour up to 15 inches thick.<sup class="reference" id="cite_ref-36">[37] The Queen Elizabeths were the first true fast battleships, and could have brought the end of the development of the battlecruiser as an independent line. It was principally due to the influence of Jacky Fisher that the battlecruiser continued.<sup class="reference" id="cite_ref-37">[38]

World War I
The First World War saw British and German battlecruisers used in several theatres. Battlecruisers formed part of the dreadnought fleets which faced each other down in the North Sea, taking part in several raids and skirmishes as well as the Battle of Jutland. Battlecruisers also played an important role at the start of the War as the British fleet hunted down German commerce raiders, for instance at the Battle of the Falkland Islands, and also took part in the Mediterranean campaign.

[edit] Construction
For most of the combatants, capital ship construction was very limited during the War. Germany finished the Derfflinger class and began work on the Mackensen class. The Mackensens were a development of the Derfflinger class, with 13.8-inch guns and a broadly similar armour scheme, designed for 28 knots.<sup class="reference" id="cite_ref-38">[39]

In Britain, Jackie Fisher returned to the office of First Sea Lord in October 1914. His enthusiasm for big, fast ships was unabated, and he set design staff to producing a design for a battlecruiser with 15-inch guns. Because Fisher expected the next German battlecruiser to steam at 28 knots, he required the new British design to be capable of 32 knots. He planned to convert two Royal Sovereign class battleships, which had been approved but not yet laid down. Fisher finally received approval for this project on 28 December 1914 and they became the Renown class. With six 15-inch guns but only 6-inch armour they were a further step forward from Tiger in firepower and speed but returned to the level of protection of the first British battlecruisers.<sup class="reference" id="cite_ref-39">[40]

At the same time, Fisher resorted to subterfuge to obtain another three fast, lightly armoured ships which could make use of the several spare 15-inch gun turrets left over from battleship construction. These ships were essentially light battlecruisers, and Fisher can occasionally be found referring to them as such, but were officially classified as "large light cruisers". This unusual designation was required because construction of new capital ships had been placed on hold, while there were no limits on light cruiser construction. They became Courageous and her sisters Glorious and Furious, and there was a bizarre imbalance between their main guns of 15 inches (or 18 inches in 'Furious') and their armour, which at 3 inches thickness was on the scale of a light cruiser. The design was generally regarded as a bizarre failure (nicknamed in the Fleet Outrageous, Uproarious and Spurious), though the later conversion of the ships to aircraft carriers was very successful.<sup class="reference" id="cite_ref-40">[41] Fisher also speculated about a new mammoth but lightly built battlecruiser which would carry 20-inch guns, which he termed HMS Incomparable; this never got beyond the concept stage.

It is often held that the Renown and Courageous classes were designed for Fisher's plan to land troops (possibly Russian) on the German Baltic coast. Specifically, they were designed with a shallow draught, which might be important in the shallow Baltic. This is not clear-cut evidence that the ships were designed for the Baltic: it was considered that earlier ships had too much draught and not enough freeboard under operational conditions. Roberts argues that the focus on the Baltic was probably unimportant at the time the ships were designed, but was inflated later, after the disastrous Dardanelles Campaign.<sup class="reference" id="cite_ref-41">[42]

The final British battlecruiser design of the war was the Admiral class, which was born from a requirement for an improved version of the Queen Elizabeth battleship. The project began at the end of 1915, after Fisher's final departure from the Admiralty. While initially envisaged as a battleship, senior sea officers felt that Britain had enough battleships, but that new battlecruisers might be required to combat German ships being built (the British overestimated German progress on the Mackensen class as well as their likely capabilities). A battlecruiser design with eight 15-inch guns, 8 inches of armour and capable of 32 knots was decided on. The experience of battlecruisers at the Battle of Jutland meant that the design was radically revised and transformed again into a fast battleship concept with armour up to 12 inches thick but still capable of 31.5 knots. The first ship in the class, Hood, went ahead according to this design. The plans for her three sisters, on which little work had been done, were revised once more later in 1916 and in 1917 to improve protection.<sup class="reference" id="cite_ref-42">[43]

The Admiral class would have been the only British ships capable of taking on the German Mackensen type; German shipbuilding was drastically slowed by the war, and while two Mackensens were launched, none were ever completed. Work on the three additional Admirals was suspended in March 1917 to enable more escorts and merchant ships to be built to deal with the new threat from U-boats to trade. They were finally cancelled in February 1919.<sup class="reference" id="cite_ref-43">[44]

[edit] Operations
The German battlecruiser Goeben was perhaps the ship which made the most impact early in the War. Stationed in the Mediterranean, she and her escorting cruiser evaded British and French ships on the outbreak of war, and steamed to Constantinople with two British battlecruisers in hot pursuit. Goeben was handed over to the Turkish Navy, and this was instrumental in bringing Turkey into the war on the German side. Goeben herself, renamed Yavuz Sultan Selim, saw engagements against the Russian Navy in the Black Sea and against the British in the Aegean.

The original battlecruiser concept proved successful in December 1914 at the Battle of the Falkland Islands. The British battlecruisers Inflexible and Invincible did precisely the job they were intended for when they chased down and annihilated a German cruiser squadron, centered on the armoured cruisers Scharnhorst and Gneisenau, along with three light cruisers, commanded by Admiral Maximilian Graf Von Spee in the South Atlantic Ocean. Prior to the battle the Australian battlecruiser HMAS Australia had unsuccessfully searched for the German ships in the Pacific.

[edit] Battle of Heligoland Bight
Main article: Battle of Heligoland BightA force of British light cruisers and destroyers entered the Heligoland Bight to attack German shipping in August 1914, the first month of World War I. When they met opposition from German cruisers, Admiral Beatty took his squadron of four battlecruisers into the Bight and turned the battle, ultimately sinking three German light cruisers and killing a German commander, Rear Admiral Leberecht Maass.

[edit] Battle of the Falklands
Main article: Battle of the Falkland Islands====Battle of Dogger Bank==== During the Battle of Dogger Bank, the after turret of the German flagship Seydlitz was pierced by a British 13.5 inch shell from HMS Lion which detonated in the working chamber. The charges being hoisted upwards were detonated, and the explosion flashed up into the turret and down into the magazine, setting fire to charges in the process of being handled. The gun crew tried to escape into the next turret, allowing the flash to spread, destroying both turrets internally. Seydlitz was saved from near-certain destruction only by emergency flooding of her after magazines. This near-disaster was due to the way that ammunition handling was arranged and was common to both German and British battleships and battlecruisers, but the lighter protection on the latter made them more vulnerable to the turret or barbette being pierced. The "working chamber" had been introduced in HMS Formidable (1898) and was intended to prevent such a dangerous flash, but instead made such an event more likely. The Germans learned from investigating the damaged Seydlitz and instituted improved measures to ensure ammunition handling was flash tight. The British remained unaware of the weakness, to their great misfortune at the Battle of Jutland.<sup class="reference" id="cite_ref-44">[45]

Apart from the cordite handling, the battle was mostly inconclusive, though both Lion and Seydlitz were severely damaged. The British flagship Lion's lost speed causing her to fall behind the rest of the battleline and Admiral Beatty was unable to effectively command for the remainder of the engagement. A British signalling error allowed the German battlecruisers to withdraw, as most of Beatty's squadron mistakenly concentrated on the crippled armoured cruiser Blücher, sinking her with great loss of life. Blücher herself was obsolete, out of all the ships in the battle, and so she had proved to be a liability to the rest of the German squadron, which was otherwise an all battlecruiser squadron.

Battle of Jutland
At the Battle of Jutland 18 months later, both British and German battlecruisers were employed as fleet units. The British battlecruisers became engaged with both their German counterparts, the battlecruisers, and then German battleships before the arrival of the battleships of the British Grand Fleet. The result was a disaster for the Royal Navy's battlecruiser squadrons: Invincible, Queen Mary and Indefatigable exploded with the loss of all but a handful of their crews. This was due to the vulnerability of the working chamber which the Germans had discovered after the near-loss of Seydlitz at Dogger Bank and had taken preventative measures against. The British ships not only had lighter armour but also lacked flash tight ammunition handling arrangements, due in part to lack of awareness and experience, and also as it would improve their rate of fire to compensate for poor accuracy. Each was lost to a single salvo penetrating the turret and detonating in the working chamber. Beatty's flagship Lion herself was almost lost in a similar manner, save for the heroic actions of Major Harvey.

The better armoured and flash-tight German battlecruisers fared better, in part due to poor performance of British fuzes (their shells exploded on impact with the ships armour instead of penetrating the armour before exploding thus causing more damage). Lützow for instance only had 117 killed despite receiving more than thirty hits, though she had sufficient flooding that she was scuttled. The other German battlecruisers, Moltke, Von der Tann, Seydlitz, Derfflinger were all heavily damaged and required extensive repairs after the battle, Seydlitz barely making it home, for they had been in the very centre of enemy fire for much of the battle. No British or German battleship was sunk during the battle with the exception of the old German pre-dreadnought Pommern, the victim of torpedoes from British destroyers.

Interwar period
In the years immediately after World War I, Britain, Japan and the USA all began design work on a new generation of ever more powerful battleships and battlecruisers. The new burst of shipbuilding which each nation's navy desired was politically controversial and potentially economically crippling. This nascent arms race was prevented by the Washington Naval Treaty of 1922, where the major naval powers agreed to limits on capital ship numbers. The German navy was not represented at the talks; under the terms of the Treaty of Versailles, Germany was not allowed any modern capital ships at all.

Through the 1920s and early 1930s only Britain and Japan retained battlecruisers, often modified and rebuilt from their original World War I designs. The line between the battlecruiser and the modern fast battleship became blurred; indeed, the Japanese Kongō class were formally redesignated as battleships.

Plans in the aftermath of World War I
HMS Hood, launched in 1918, was the last First World War battlecruiser to be completed. Owing to lessons from Jutland, Hood was modified during construction to feature belt armour that was thought to be capable of resisting her own weapons - the classic measure of a "balanced" battleship. Hood was the largest ship in the Royal Navy when completed; thanks to her great displacement, she in theory combined the firepower and armour of a battleship with the speed of a battlecruiser, causing some to refer to her as a fast battleship. However her protection was markedly less than that of the British battleships built immediately after World War I, the Nelson class.

The navies of Japan and the USA, seeing a threat from Hood, laid down battlecruisers to rival her. The Imperial Japanese Navy began four Amagi class battlecruisers. These vessels would have been of unprecedented size and power, being as fast and well armoured as HMS Hood whilst carrying a main battery of ten 16" guns - the most powerful armament ever proposed for a battlecruiser. The United States Navy responded with the Lexington class battlecruisers, which if completed as planned would have been exceptionally fast and well armed with eight 16" guns, but would have carried armour little better than that of the very first battlecruisers. The final stage in the post-war battlecruiser race came with the British response to the Amagi and Lexington types: four 48,000 ton G3 battlecruisers. Royal Navy documents of the period often described any battleship with a speed of over about 24 knots (44 km/h) as a battlecruiser, regardless of the amount of protective armour, although the G3 was considered by most to be a well-balanced fast battleship.<sup class="reference" id="cite_ref-GWPDA_45-0">[46] <sup class="reference" id="cite_ref-NHistory_46-0">[47]

The Washington Naval Treaty meant that none of these designs came to fruition. Those ships which had been started were either broken up on the slipway or converted into aircraft carriers.

In Japan, Amagi and Akagi were taken in hand for conversion into aircraft carriers. In 1923 the Amagi was damaged beyond repair by an earthquake and was broken up on the slips, the hull of one of the proposed Tosa class battleships, Kaga, being converted in her stead.

In Britain, Fisher's "large light cruisers" were converted to carriers. Furious had already been converted to an aircraft carrier during the war and Glorious and Courageous, which had no place in the post-Treaty navy, were similarly converted.

The United States Navy also re-tasked two battlecruiser hulls as aircraft carriers in the wake of the Washington Treaty: USS Lexington and Saratoga were both designed as battlecruisers (the hull designations were originally CC-1 and CC-3) but converted part-way through construction, although this was only considered marginally preferable to scrapping the hulls outright (the remaining four: Constellation, Ranger, Constitution and United States were indeed scrapped).

Rebuilding programmes
In total, nine battlecruisers survived the Washington Naval Treaty. Their high speed made them valuable surface units in spite of their weaknesses so most of these ships were significantly updated before World War II, although the Royal Navy sold HMS Tiger for scrap in 1932 on the grounds that she was worn out, and in addition, the Turks did not have the means to upgrade the Sultan Yavuz Selim (ex Goeben of the Imperial German Navy).

HMS Renown and Repulse were modernized significantly in a series of refits between 1920 and 1939. Like several elderly British capital ships, the Renown underwent a total reconstruction between 1937 and 1939 to make her suitable for acting as a fast heavy escort warship for aircraft carriers. Similar rebuildings planned for the Repulse and the Hood were cancelled by the events of World War II.Unable to pursue new construction, the Imperial Japanese Navy also chose to improve its existing battlecruisers of the Kongō class (the Hiei, the Haruna, the Kirishima, and the Kongō) by increasing the elevation of their guns to 40 degrees, adding anti-torpedo bulges and additional armour, and building on a "pagoda" mast. The 3,800 tons of additional armour slowed their speeds, but between 1933 and 1940, replacement of heavy equipment and an increase in the length of the hull by 26 ft (8.0 m) allowed them to reach up to 30 knots (60 km/h) once again. They were reclassified as "fast battleships" and their high speed made them suitable as aircraft carrier escorts, although their armour and guns still fell short compared to surviving World War I–era battleships in the American or the British navies.

Naval rearmament
In the late 1930s navies began to build capital ships again, and during this period number of large commerce raiders and small, fast battleships were built. While the design philosophy behind these ships was very different from that of the original battlecruisers, the term was adopted from time to time for these new ships.

Germany, Italy, France and Russia all designed new vessels in this category, though only Germany and France completed them.Ultimately the Italians chose to upgrade their old battleships rather than build new battlecruisers, whereas the Russians laid down the 35,000 ton Kronshtadt Class, but were unable to launch them before the Germans invaded in 1941 and captured one of the hulls. The other Soviet ship was launched and scrapped after the war.

The German pocket battleships (German:Panzerschiffe - armoured ship), were ships built to meet the limitations of the Treaty of Versailles which forbad Germany from exceeding 10,000 tons or six 28.0 cm (11-inch) guns. While their 10,000-ton displacement was similar to that of a heavy cruiser, their armament was more powerful; heavy cruisers were restricted to 8-inch guns by the Treaty of London. This intermediate status and their superficial appearance to battleships resulted in the term "pocket battleship". However, their mission was long-range commerce raiding and their capabilities were inferior to those of any battleship or battlecruiser.

The first German capital ships of the 1930s were Scharnhorst and the Gneisenau. The Royal Navy categorized them as battlecruisers, while the German Navy referred to them as schlachtschiffe or battleship. At 31,500 tons standard displacement, they were intermediate in size between Repulse or Renown and the 35,000-ton limit for battleships. Their top speed of 33 knots exceeded that of existing battlecruisers and battleships and their armoured protection was modelled on that of a battleship. Their armament was light, for a capital ship; Scharnhorst and Gneisenau carried nine 280 mm (11-inch) gun turrets (though with provision to change to replace these with six 380 mm (15 inch)). Their design thus compromised on armament for high speed and strong protection.The French response to the "pocket battleships" was the Dunkerque class in the 1930s. Displacing 26,500 tons and armed with eight 330 mm (13 inch) guns arranged in two quadruple turrets located forward, they were significantly larger and more powerful than the pocket battleships. Their speed (30 knots) was in line with other fast battleships, and they were armoured as heavily as possible as their light displacement allowed.

Commerce raiding
In the early years of the war the German ships each had a measure of success hunting merchant ships in the Atlantic. The pocket battleships were deployed alone and sank a number of vessels, causing disruption to the trade routes which supplied the UK. They were pursued by the Royal Navy and on one occasion, at the Battle of the River Plate in 1939, the hunter became the hunted.

Admiral Graf Spee had been at sea at the start of World War II and engaged in a successful commerce raiding spree. Off the coast of South America, Admiral Graf Spee encountered the British heavy cruiser Exeter and light cruisers Achilles and Ajax. Admiral Graf Spee inflicted heavy damage on Exeter but in turn suffered considerable topside damage from the light cruisers. The pocket battleship's armour mostly held, but she sustained several critical hits which would have made the ship unseaworthy for returning to Germany, and she was forced to retire to neutral Uruguay. Unable to stay in port any longer without internment, and led to believe by the nature of British radio transmissions that aircraft carriers and 15-inch (381 mm) gunned battlecruisers were too close to evade, her captain elected to scuttle his ship, and then accepted responsibility for its destruction by committing suicide.

Allied battlecruisers such as Renown, Repulse, Dunkerque and Strasbourg were employed on operations to hunt down the commerce raiding German battlecruisers, but they rarely got close to their targets, Renown enjoying a brief clash against the German 11-inch battlecruisers, scoring three non-critical hits on Gneisenau but being unable to keep up in bad weather. The one stand-up fight was when the battleship Bismarck was sent out as a raider and was intercepted by HMS Hood and the battleship Prince of Wales in May 1941. The elderly British battlecruiser was no match for the modern German battleship and the Bismarck's 15 inch shells caused a magazine explosion in Hood reminiscent of the Battle of Jutland. Only three men survived.

Gneisenau and Scharnhorst hunted together and were initially successful at commerce raiding, sinking the British armed merchant cruiser Rawalpindi in 1939. Following repairs from damage during the Norwegian campaign, the two battlecruisers set out commerce raiding once again in 1941 and sank 22 merchant ships. They returned to Brest in northern France but found this port was vulnerable to Royal Air Force attacks and were obliged to return to Germany. They did so in the Channel Dash, a daring and successful run up the English Channel. They were both damaged by mines and although Scharnhorst was repaired, Gneisenau was damaged again in RAF bombing raids and was eventually disarmed and sunk as a blockship. Scharnhorst was employed once more to attack commerce and attempted to raid the Arctic convoys in December 1943. She was surprised by the battleship Duke of York with the cruisers Jamaica, Norfolk and Belfast at the Battle of North Cape and sunk on 26 December 1943. The 14-inch (356 mm) gunfire from Duke of York crippled her turrets and engine room, then the attendant British cruisers and destroyers closed in and finished her off with torpedoes.

The use of battlecruisers as commerce raiders was curtailed following an attack by the Admiral Scheer on a convoy guarded by the HMS Jervis Bay, an armed merchant cruiser. It persuaded the British Admiralty that convoys had to be guarded by battleships or battlecruisers. The older R-class battleships and the un-upgraded Queen Elizabeths (Malaya and Barham) were used for this task, for which they were quite adequate despite their age, and subsequently the smaller German ships were forced away from their quarry. Additionally, the air gap over the North Atlantic closed, Huff-Duff (radio triangulation equipment) improved, airborne centimetric radar was introduced and convoys received escort carrier protection. The results of some of these developments were illustrated by the successful defence of convoys at the Battle of the Barents Sea and the Battle of the North Cape.

By comparison with the critical role of submarines during the Battle of the North Atlantic the commerce-raiding role of battlecruisers was marginal in its impact on the outcome of the war.

[edit] Norwegian campaign
The Royal Navy and the Kriegsmarine both deployed battlecruisers during the Norwegian campaign in April 1940. The Gneisenau and the Scharnhorst were engaged by HMS Renown<sup class="reference" id="cite_ref-47">[48] in appalling weather and although they had stronger armour than their counterpart, the British ship could hit them harder and at a longer range due to the German ships having difficulty with their radars. They disengaged after Gneisenau sustained damage. One of Renown's 15-inch shells passed through Gneisenau's director tower without exploding, severing electrical and communication cables as it went. The debris caused by the passing shell killed one officer and five enlisted men, and destroyed the optical rangefinder for the forward 150 mm turrets. Main battery fire control had to be shifted aft due to the loss of electrical power to the director tower. The second shell from Renown struck the aft turret of Gneisenau, knocking it out of action.

Later in the campaign they returned and sank the light aircraft carrier HMS Glorious (a converted battlecruiser herself) and her destroyer escort. One of the destroyers (HMS Acasta) succeeded in damaging the Scharnhorst with a torpedo, and later a submarine did the same to Gneisenau, forcing both ships to spend several months in repair. The pocket battleship Lützow was similarly damaged by HMS Spearfish during the campaign.

[edit] Mediterranean
The French battlecruisers had fled to North Africa following the fall of France. In July 1940 Force H under Admiral James Somerville was ordered to force their surrender or destroy them. The Dunkerque was damaged by shells from HMS Hood at Mers-el-Kebir but escaped to join the Strasbourg at Toulon. Both ships were scuttled on 27 November 1942, although Strasbourg was raised and used by the Italian navy before being sunk again in an air attack on 18 August 1944.

[edit] Pacific War
The first battlecruiser to see action in the Pacific War was Repulse when she was sunk near Singapore on December 10, 1941 whilst in company with HMS Prince of Wales. She had received a refit to give extra anti-aircraft protection and extra armour between the wars. Unlike her sister Renown, Repulse did not receive a full rebuild as planned, which would have added anti-torpedo blisters. During the Sea Battle off Malaya, her speed and agility enabled her to hold her own and dodge nineteen torpedoes. Without aerial cover she eventually succumbed to the continuous waves of Japanese bombers, and without enhanced underwater protection she went down quickly after a few torpedo hits.

The Japanese Kongō class battlecruisers were significantly upgraded and re-rated as "fast battleships", and they were used extensively as carrier escorts for most of their wartime career due to their high speed. Their World War I-era armament was weaker and their upgraded armour was still thin compared to contemporary battleships.<sup class="reference" id="cite_ref-navweaps.com_48-0">[49] During the Naval Battle of Guadalcanal on 12 November the Hiei was sent out to bombard US positions. She suffered extensive topside damage from gunfire of US cruisers and destroyers, but, more critically, her steering gear was incapacitated by an 8-inch shell. The next day, Hiei was attacked by waves of aircraft from Guadalcanal’s American held airfield (Henderson Field), which eventually made salvage impossible, and so she was left to sink north of Savo Island. A few days later on 15 November 1942, Kirishima engaged the U.S. battleships South Dakota and Washington, and was sunk following mortal damage from at least nine 16-inch hits inflicted by the Washington, which disabled her forward main turrets, jammed her steering, and holed her below the waterline.<sup class="reference" id="cite_ref-navweaps.com_48-1">[49] In contrast South Dakota survived 42 hits (including only one 14-inch hit, but many 8-in. heavy cruiser shells), all to her superstructure, and was back in operation four months later. The Kongō survived the Battle of Leyte Gulf, but she was sunk on 21 November 1944 in the Formosa Strait by three torpedoes from the U.S. Navy submarine USS Sealion (SS-315). The Haruna was involved in bombardment operations at Guadalcanal, the Battle of the Philippine Sea, and the Battle of Leyte Gulf. She was attacked by American carrier aircraft of Task Force 38 and USAAF B-24 Liberator bombers while at Kure IJN naval base on 28 July 1945 and sank at her moorings.

Large cruisers or "cruiser killers"
On the eve of World War II, there was a late renaissance in popularity of ships between battleships and cruisers. While some considered them battlecruisers, they were never classified as capital ships, and they were variously described as "super-cruisers", "large cruisers" or even "unrestricted cruisers". They were optimised as cruiser-killers, fleet scouts and commerce raiders. The Dutch, Japanese, Soviets and Americans all planned new classes specifically to counter the large heavy cruisers being built by their naval rivals - especially the Japanese Mogami class cruisers. The Germans also designed a class of lightly protected battlecruisers.

The first such battlecruisers were the Dutch Design 1047. Never officially assigned names, the Dutch wanted them to protect their colonies in the East Indies in the face of Japanese aggression. Designed with the assistance of the Germans and Italians, they broadly resembled the German Scharnhorst class and had the same main battery, but would have been considerably lighter and only protected against 8-inch (203 mm) gunfire. Although the design was completed, work on the vessels never commenced as the Germans overran the Netherlands in May 1940, while the first ship would have been laid down in June of that year.

The Germans planned to build three battlecruisers of the O Class as part of the expansion of the Kriegsmarine (Plan Z). With six 15 inch (38 cm) guns, high speed, excellent range but very thin armour, they were intended as commerce raiders. Only one of these was ordered shortly before World War II broke out and no work was ever done on it. No names were assigned, and they were known as O, P, and Q. The new class was not universally welcomed in the Kriegsmarine, their abnormally light protection gaining the class the derogatory nickname Ohne Panzer Quatsch (without armour nonsense) within certain circles of the Navy.

The only class of these late battlecruisers to be laid down were the United States Navy's three Alaska class "large cruisers", Alaska, Guam and Hawaii - of which only Alaska and Guam were completed. The Alaskas were classified as "large cruisers" instead of battlecruisers, and their status as non-capital ships is evidenced by the fact that they were named for territories or protectorates (as opposed to battleships, which were named after states, or cruisers, which were commonly named after cities). But with a main armament of nine twelve-inch (305 mm) guns in three triple turrets and a displacement of 27,000 tons, the Alaskas were twice the size of the preceding Baltimore class cruisers and had guns some 50% larger in diameter. They lacked the thick armoured belt and torpedo defense system of true capital ships and, unlike most battlecruisers, they were considered a balanced design (according to cruiser standards) as their protection could withstand fire from their own caliber of gun, albeit only in a very narrow range band. They were designed to hunt down Japanese heavy cruisers, though by the time they entered service most Japanese cruisers had been sunk by American aircraft or submarines. Like the contemporary Iowa-class fast battleships, their speed ultimately made them more useful as carrier escorts and bombardment ships than as the sea combatants they were developed to be. Hawaii was 84% complete when hostilities ceased, and was laid up for years while various plans were debated to convert her large hull into a missile ship or a command vessel; she would eventually be scrapped incomplete.<sup class="reference" id="cite_ref-Hawaii_DANFS_49-0">[50] Three additional hulls, to be named Philippines, Puerto Rico and Samoa, were cancelled outright.

The Japanese started designing the B64 class, which were similar to the Alaska but with 12.2-inch (310 mm) guns. News of the Alaskas led them to upgrade the design, creating the B65. Armed with 14-inch (356 mm) guns, the B65's would have been the best armed of the new breed of battlecruisers, but they still would have had only sufficient protection to keep out 8-inch shells. Much like the Dutch battlecruisers, the Japanese got as far as completing the design for the B65s, but never laid them down. By the time the designs were ready the Japanese Navy recognised that they had little use for the vessels and that their priority for construction should lie with aircraft carriers. Like the Alaskas, the Japanese did not call these ships battlecruisers, referring to them instead as supersized heavy cruisers.

[edit] Cold War designs
In spite of the fact that World War II had demonstrated battleships and battlecruisers to be generally obsolete, Joseph Stalin's fondness for big gun armed warships caused the Soviet Union to plan several large cruiser classes in the late 1940s and early 1950s that would be a response for the Alaska class vessels. In the Soviet Union, as in many other languages, they were called "heavy cruisers" (thyazholyi kreyser).

The fruits of this program were the project 82 (Stalingrad) cruisers, with 36,500 tons standard load (42,300 tons full load), 9 guns 305 mm and a speed of 35 knots (65 km/h). Three ships were laid in 1951–52, but after Stalin's death they were canceled in April 1953. Apart from high costs, the main reason was that gun-armed ships became obsolete with an advent of guided missiles. Only a central armoured hull section of the first cruiser Stalingrad was launched in 1954 and then used as a target for rockets.The Soviet Kirov class of Tyazholyy Atomnyy Raketny Kreyser (Heavy Nuclear-powered Missile Cruiser), displacing approximately 26,000 tons, is classified as a battlecruiser in the 1996–7 edition of Jane's Fighting Ships, even though in actuality they are very large missile cruisers. Their classification as battlecruisers arises from their displacement, which is roughly equal to that of a World War I battleship, and the fact that they possess more firepower than nearly every other surface ship. The Kirov-class lacks the heavy armour that distinguishes battlecruisers from regular cruisers and they are classified as "heavy missile cruisers" in Russia. There were four members of the class completed, Kirov, Frunze, Kalinin, and Yuri Andropov. As the ships were named after Communist personalities, after the fall of the USSR they were given traditional names of the Imperial Russian Navy, respectively Admiral Ushakov, Admiral Lazarev, Admiral Nakhimov, and Pyotr Velikiy. Due to budget constraints two members of this class have been decommissioned, although Pyotr Velikiy and Admiral Nakhimov are in active service and funds are being gathered for possible repair of Admiral Lazarev. Nakhimov was returned to service early, at the beginning of 2006, possibly due to increasing tensions in the Middle East and potential Russian naval involvement therein.