Armored cruiser The armored cruiser was a type of warship of the late 19th and early 20th centuries . It was designed like other types of cruiser s to operate as a long - range , independent warship , capable of defeating any ship apart from a battleship and fast enough to outrun any battleship it encountered . Varying in size , it was distinguished from other types of cruiser by its belt armor — thick iron ( or later steel ) plating on much of the hull to protect the ship from shellfire much like that on battleships . The first armored cruiser , the Imperial Russian Navy ' s , was launched in 1873 and combined sail and steam propulsion . By the 1890s cruisers had abandoned sail and took on a modern appearance . For many decades naval technology had not advanced far enough for designers to produce a cruiser which combined an armored belt with the long range and high speed required to fulfill its mission ; for this reason , many navies preferred to build protected cruiser s in the 1880s and early 1890s . It was often possible to build cruisers which were faster and better all - round using this type of ship , which relied on a lighter armor ed deck to protect the vital parts of the ship ; however , by the late 1880s the development of rapid - fire cannon and high - explosive shells made the reintroduction of side armor a necessity . The invention of face - hardened armor in the mid - 1890s offered effective protection with less weight than previously . In 1908 the armored cruiser was supplanted by the battlecruiser which , with armament equivalent to that of a dreadnought battleship and steam turbine engines , was faster and more powerful than armored cruisers . At around the same time , the term " light cruiser " came into use for small cruisers with armored belts . Despite the fact they were now considered second - class ships , armored cruisers were widely used in World War I . Most surviving armored cruisers from this conflict were scrapped under the terms of the Washington Naval Treaty of 1922 , which imposed limits on warships and defined a cruiser as a ship of 10 , 000 tons or less carrying guns of 8 - inch caliber or less — rather smaller than many of the large armored cruisers . A handful survived in one form or another until World War II . Background : armor , guns and engines . The armored cruiser was developed in the 1870s as an attempt to combine the virtues of the armored ironclad warship and the fast and long - ranged , but unarmored , cruisers of the time . Such a ship was desirable to protect overseas trade and , especially for the French and British , to police their vast overseas empires . The concern within higher naval circles was that without ships that could fulfill these requirements and incorporate new technology , their fleet would become obsolete and ineffective should a war at sea arise . Concern over obsolescence in official circles was further fueled by the race between the increasing size of naval guns and of armor strong enough to withstand such fire . In 1860 , one of the largest naval cannons in standard use had a bore of and fired a shell . By 1884 , guns with as wide a bore as , firing an exploding shell , were being mounted on naval vessels . This gun could penetrate up to 34 inches of wrought iron , the earliest form of naval armor . These were muzzle - loading guns , as had been used on ships from the 1500s . Breech - loading cannon , which were readopted into naval use in the 1870s , were more destructive than muzzle loaders due to their higher rate of fire . The development of rifled cannon , which improved accuracy , and advancements in shells were other factors . Although a cruiser would not likely face the largest - caliber guns of a battleship and many navies commonly used smaller weapons as they did not wear out as fast as larger ones did , cruisers still needed some form of protection to preclude being shot to pieces . The adoption of rolled iron armor in 1865 and sandwich armor in 1870 gave ships a chance to withstand fire from larger guns . Both these protective schemes used wood as an important component , which made them extremely heavy and limited speed , the key factor in a cruiser ' s ability to perform its duties satisfactorily . While the first ocean - going ironclads had been launched around 1860 , the " station ironclads " built for long - range colonial service such as the British and French were too slow , at 13 and 11 knots respectively , to raid enemy commerce or hunt down enemy commerce raiders , tasks usually assigned to frigates or corvettes . Powered by both sail and steam but without the additional weight of armor , these ships could reach speeds of up to 16 or 17 knots . The most powerful among them were the British , the U . S . Navy ' s and the French . The British especially had hoped to rely on these vessels to serve the more distant reaches of its empire . In the aftermath of the Battle of Hampton Roads in 1862 , where United States wooden warships were defeated by the Confederate ironclad , the Admiralty realized that its ships could theoretically encounter an ironclad in any theater of operation . Ship propulsion was improving but was also taking time to develop . Naval engines in the 1860s were single - expansion types , in which steam was expanded into a cylinder , pushed a piston and was released . Compounding , where steam is passed through a series of cylinders of increasing size before being released , was a more efficient process ; it allowed the steam to generate more energy and use less coal to go the same distance . With greater efficiency came increasingly complex machinery and the larger potential for breakdown . However , advances in metallurgy and engineering , the potential for smaller bunkerage and the successful use of compounding in commercial engines made it an attractive option for naval engines , as well . By the 1870s , compound engines had become standard for warships . Compounding by itself did not increase power or speed significantly , although it allowed for a much greater operating range . Forced - draught systems would help increase power and speed but would not come into use until the early 1890s . 1870s : First armored cruisers . The Russian navy became the first to produce an armored warship intended for commerce raiding , with the , begun in 1870 and launched in 1873 , often referred to as the first armored cruiser . Armed with six and two guns , she and her sister were not fully armored but protected only by a narrow belt along the waterline . This belt , moreover , was so heavy that it sat below the ships ' waterlines , which limited its benefit still further . Since they were iron - hulled , however , they were more durable than their wooden counterparts . With a top speed of only 12 . 3 knots and a high coal consumption , which necessitated a full sailing rig , they were not really suited for the role of cruiser . Nevertheless , these ships were considered a new threat to British commerce in the event of war , the rationale being that any vessel , regardless of its speed , could technically be a threat to overseas commerce . The British responded with , begun in 1873 , launched in 1875 and armed with two and seven rifled guns . Two ships of the followed , armed with four and eight guns . These early armored cruisers were essentially scaled - down versions of the first - rate ironclad warships of the time and , like their Russian counterparts , were essentially belted cruisers . Their belts were thicker than that of the Russians but did not extend the full length of the hull due to weight but tapered off at both ends . Past this belt , the designers placed a armored deck , situated deepest in the ships , to guard magazines and machinery against plunging fire . Above this deck , space was allocated for coal bunkers and storerooms . These areas served a two - fold purpose . The bunkers served as added protection , since two feet of coal was considered the equivalent of one foot of steel . Also , if either of the ships became flooded from battle damage , it was hoped the contents of the bunkers and storerooms would aid in their continued buoyancy . Because of this unarmored protection , these ships could be considered the first protected cruisers . However , these ships also shared the liabilities of the Russian ones and because of this , the British Navy was never happy with them . " Shannons " top speed of 12 . 25 knots and " Nelsons " of 14 knots made them too slow to deal with fast cruisers and they were not armored well enough to take on a first - class battleship . Their armor belts also sat below the ships ' waterlines , which made them of limited benefit . The underlying problem with these early warships was that technology had not caught up to the demands being made of them ; therefore , they represented a series of compromises and could not be fully effective . They were typically powered by double - expansion steam engines fed by boilers which generated steam at perhaps 60 or 70 psi pressure , which gave relatively poor efficiency and short range . Even with improved engines , the dearth of overseas refueling stations made a full sailing rig a necessity . As sailing ships required a high freeboard and a large degree of stability , the use of armored turrets as used on monitors and some battleships was ruled out , because a turret was a very heavy weight high in the ship and its placement necessitated a lower freeboard than was warranted for an oceangoing vessel . ( The loss of H . M . S . " Captain " in 1870 with nearly all of her 500 - man crew illustrated graphically what could happen in a heavy sea with a turret - equipped steam - and - sail vessel . ) Consequently , armored cruisers retained a more traditional broadside arrangement . Their armor was distributed in a thick belt around the waterline along most of their length ; the gun positions on deck were not necessarily armored at all . The limitations of these ships would not be rectified fully until decades after their construction . Meanwhile , a battle in May 1877 between the British unarmored cruiser and the Peruvian monitor demonstrated the need for more and better - protected cruisers . " Shah " and the smaller wooden corvette hit " Huáscar " more than 50 times without causing significant damage . The Peruvian ship had an inexperienced crew unused to its cumbersome machinery , and managed to fire only six rounds , all of which missed . The engagement demonstrated the value of cruisers with armor protection . 1880s : Rise of the protected cruiser . During the 1870s , the rapid increase in the size and power of armor - piercing guns caused problems for the designers of battleships and cruisers alike . Even a ship designed with adequate armor protection from the current generation of guns might technically be vulnerable to new guns powerful enough to penetrate its armor . Consequently , naval designers tried a novel method of armoring their ships . The vital parts — engines , boilers , magazines and enough hull structure to keep the ship stable in the event of damage — could be positioned underneath an armored deck just below the waterline . This deck , which would only be struck very obliquely by shells , could be thinner and lighter than belt armor . The sides of the ship would be entirely unarmored but would be as effective as an armored belt which would not stop shellfire . Cruisers designed along these guidelines , known as protected cruiser s , superseded armored cruisers in the 1880s and early 1890s . As mentioned earlier , the armored cruiser " Shannon " was the first ship to make use of an armored deck . However , by the end of the 1870s , ships could be found with full – length armored decks and little or no side armor . The Italian of very fast battleships had armored decks and guns but no side armor . The British used a full - length armored deck in their of corvettes started in 1878 ; however the " Comus " class were designed for colonial service and were only capable of 13 knots speed , not fast enough for commerce protection or fleet duties . The breakthrough for the protected cruiser design came with the Chilean , designed and built by the British firm Armstrong at their Elswick yard . " Esmeralda " , with a high speed of 18 knots , dispensed entirely with sails and carried an armament of two 10in and six 6in guns , considered very powerful for a ship her size . Her protection scheme , inspired by the " Italia " class , included a full – length protected deck up to 2in thick , and a cork - filled cofferdam along her sides . " Esmeralda " set the tone for cruiser construction for the years to come , with " Elswick cruisers " on a similar design being constructed for Italy , China , Japan , Argentina , Austria and the United States . Protected cruisers became attractive for two reasons . First , the concept of the armored cruiser was not embraced wholeheartedly in naval circles . Second , several navies were caught in a race between armor thickness and the size of main guns and did not have the money to spend on battleships and armored cruisers . The use of smaller , lighter cruisers was an affordable alternative . The French navy adopted the protected cruiser wholeheartedly in the 1880s . The Jeune Ecole school of thought , which proposed a navy composed of fast cruisers for commerce raiding and torpedo - boats for coast defense , was particularly influential in France . The first French protected cruiser was the , laid down in 1882 , and followed by six classes of protected cruiser – and no armored cruisers until the , laid down in 1888 but not finished until 1895 . " Dupuy de Lôme " was a revolutionary ship , being the first French armored cruiser to dispose entirely of masts , and sheathed in steel armor . However , she and two other were not sufficiently seaworthy , and their armor could be penetrated by modern quick - firing gun s . Thus from 1891 – 7 the French reverted to the construction of protected cruisers . The British Royal Navy was equivocal about which protection scheme to use until 1887 . The large , begun in 1881 and finished in 1886 , were built as armored cruisers but were often referred to as protected cruisers . While they carried an armored belt some 10 in thick , the belt only covered a 140 ft of the 315 ft length of the ship , and was submerged below the waterline at full load . The real protection of the class came from the armored deck 4 in thick , and the arrangement of coal bunkers to prevent flooding . These ships were also the last armored cruisers to be designed with sails . However , on trials it became clear that the masts and sails did more harm than good ; they were removed and replaced by a single military mast with machine guns . The next class of small cruisers in the Royal Navy , the , were protected cruisers , but the Royal Navy then returned to the armored cruiser with the , begun in 1885 and completed in 1889 . The navy judged the " Orlando " s inferior to protected cruisers and built exclusively protected cruisers immediately afterwards , including some very large , fast ships like the 14 , 000 - ton . However , the " Orlando " s were the first class of cruiser to use the triple - expansion engine . Because this type of reciprocating engine used the steam in three stages , it was more fuel - efficient than earlier compound engines . It also used steam of higher pressure , 60 poundforce per square inch , as compared to the 25 to 30 poundforce in earlier engines . With these engineering developments , warships could now dispense with sails and be entirely steam - driven . The only major naval power to retain a preference for armored cruisers during the 1880s was Russia . The Russian Navy laid down four armored cruisers and one protected cruiser during the decade , all being large ships with sails . 1890s : Armored cruisers in the pre - dreadnought era . The development of rapid – fire cannons in the late 1880s forced a change in cruiser design . Since a large number of hits at or near the waterline could negate the effect of water – excluding material used in protected cruisers , side armor again became a priority . Four inches was considered adequate . However , it had to cover not just guns and the waterline but also much of the hull structure in – between ; otherwise , the equally – new high – explosive shells could penetrate and destroy much of the unarmored portion of the ship . Another development was the publication in 1890 of American naval strategist Alfred Thayer Mahan ' s book " The Influence of Sea Power upon History " . While Mahan emphasized the importance of battleships above all other types of warships in obtaining command of the sea , armored cruisers and large protected cruisers could still be used as second - class battleships to maintain control of the sea lanes and potentially as fighting units of a battle fleet . The armored cruisers built in the mid – to late – 1890s were often as large and expensive as pre - dreadnought battleship s . They combined long range , high speed and an armament approaching that of battleship with enough armor to protect them against quick - firing gun s , considered the most important weapons afloat at the time . Their speed was made possible due to another development , Case - hardened steel armor — first Harvey armor and then crucially Krupp armor . The higher tensile strength of these armors compared to nickel steel and mild steel made it feasible to put a light yet useful armor belt on a large cruiser . They saved further weight by not requiring a heavy timber backing , as previous armor plating had , to soften and spread the force of the impact from oncoming shells ; of teak to give a fair surface upon which to attach them was all that was needed . Moreover , this belt could also be much wider than previously , covering the center of the hull , where the ammunition and engines were located , from the main deck to five feet below the waterline . Steel bulkheads added strength to the hull , while armor as thick as the belt covered the guns and heavier protection surrounded the conning tower . With these improvements , the ships became more fully protected than was possible previously . They were also expensive to maintain at fighting strength as they required a greater number of stokers to feed the boilers than a battleship when steaming at flank speed . The ideas presented by Mahan prompted French Admiral François - Ernest Fournier to write his book " La flotte necessaire " in 1896 . Fournier argued that a fleet of technologically advanced armored cruisers and torpedo craft would be powerful and flexible enough to engage in a wide range of activity and overwhelm potential enemies . French naval and government circles embraced this ideal mutually and even advocates of battleships over cruisers admitted the latter ' s potential usefulness in scouting and commercial warfare . The result was the building of increasingly large armored cruisers . The , laid down in 1896 , displaced 11 , 000 tons , carried a mixed armament of and guns , and had a belt of Harvey armour over her machinery spaces . The 12 , 300 - ton and 14 , 000 - ton followed . With a speed of 22 . 5 knots , the " Léon Gambetta " s were armed with four guns in twin turrets and 16 in four single and six twin turrets and were protected by up to six inches ( 150 mm ) of Krupp belt armor and nearly eight inches ( 200 mm ) on their conning towers and turrets . The " Edgar Quinet " s , slightly faster at 23 knots , were armed with 14 7 . 74 - inch ( 194 mm ) guns and carried up to 6 . 7 inches ( 170 mm ) of armor on their belts , almost four inches ( 99 mm ) on their decks and six inches ( 150 mm ) on their turrets . Britain , which had concluded as early as 1892 that it needed twice as many cruisers as any potential enemy to adequately protect its empire ' s sea lanes , responded to the perceived threat from France , Russia and , increasingly , Germany with a resumption of armored cruiser construction in 1898 with the . At 21 knots , the " Cressy " s were slower than the newer French cruisers . However , their belt of Krupp steel was expected to keep out armor - piercing shells from a quick - firing gun at likely battle ranges , while their two 9 . 2 - inch ( 233 . 7 mm ) and 12 6 - inch ( 152 mm ) guns offered comparable firepower . The 2500 - ton weight of their belt armor was an improvement over the 1809 tons of the otherwise similar and very similar to that of the of battleships . The " Cressy " s were the beginning of a rapid expansion in British cruiser construction . Between 1899 and 1905 , seven classes of armored cruisers were either completed or laid down , a total of 35 ships . Japan , which now received British technical assistance in naval matters and purchased larger vessels from France and Britain , began an armored cruiser program of its own . With the end of the First Sino - Japanese War in 1895 and the return under pressure from Russia ( in what became known as the " Triple Intervention " ) of the Liaotung peninsula to China , Japan began a 10 - year naval build - up program , under the slogan " Perseverance and determination " ( , Gashinshōtan ) in preparation for further confrontations . The core of this 109 - ship build - up was the " Six - Six Program " of six battleships and six ( eventually eight ) armored cruisers comparable to the British " Cressy " class . The followed the basic pattern for these cruisers — on a displacement , she carried four and twelve guns , was protected by a main belt , armored deck and turret armor and steamed at . They were considered a compromise between cruiser and battleship and were intended to augment capital ship strength in battle squadrons . This practice would persist until World War I . The first United States armored cruiser , the , was launched in 1889 but not completed until 1895 due to a three - year delay in the delivery of her armor plate . Armed with four guns , mounted en echelon ( with the fore turret sponsoned to starboard and the aft turret to port ) to allow end - on fire for both turrets , and six guns on broadside , she carried between 7 and 12 inches ( 178 to 305 mm ) of belt armor and between 1 and 4 inches ( 25 to 102 mm ) on her decks . However , " Maine " was laid down before Harvey or Krupp armor was available and could not benefit from the advantage in weight these much lighter armors offered . She was redesignated a " second - class battleship " in 1894 , an awkward compromise reflecting that , at 16 . 45 knots , she was considerably slower than other cruisers and weaker than first - line battleships . Her destruction in Havana harbor in 1898 was a catalyst in starting the Spanish - American War . " Maines " immediate successors , and , launched in 1895 and 1896 respectively , carried thinner but newer armor than " Maine " , with on her belt and 3 to 6 inches ( 76 to 152 mm ) on her deck but better protected overall against rapid - fire weaponry . Their armor was comparable in thickness to that of " Dupuy de Lôme " but the French ship ' s armor covered a much greater area of the hull . The hull protection of both ships was superior to their main rival , the British , which were the largest cruisers at the time but had no side armor . Armed with six guns , " New York " carried more heavy weapons than the French ship . Moreover , " New Yorks " builder diverged from the Navy blueprint by rearranging her boilers during construction ; this allowed the installation of additional transverse and longitudinal bulkheads , which increased her underwater protection . " Brooklyn " was an improved version of the " New York " and designs , more heavily armed ( with eight and 12 guns ) and with better sea - keeping abilities through the addition of a forecastle . After these two ships , the Navy concentrated on battleship construction until the Spanish - American War showed how cruisers could be " useful , " in the words of General J . B . Crabtree , " and [ showed ] how desirable others would be . " Shortly after the war ended , the Navy laid down six armored cruisers to take advantage of lessons learned and better control the large sea areas the nation had just inherited . Much larger than their predecessors ( displacing 14 , 500 tons as compared to 8150 for " New York " ) , the " Pennsylvania " s " were closer to light battleships than to cruisers , " according to naval historian William Friedman . They carried four and 14 guns , of armor on their belts , on their turrets and on their conning towers . Their deck armor was light at for flat surfaces and for sloped , a compromise made for faster speed ( 22 knots , compared with 20 knots for " Brooklyn " ) . Improved ammunition made their main guns as powerful as the guns of the battleship and their use of state instead of city names , usually reserved for capital ships , emphasized their kinship . The Spanish - American and First Sino - Japanese War s proved instrumental in spurring cruiser growth among all the major naval powers , according to naval historian Eric Osborne , " as they showcased the abilities of the modern ships in warfare . " The only time cruisers were seen in any of their traditional role , he continues , was as blockade ships during the Spanish - American War . More often , they were seen fighting in a battle line . They would not been seen in their designed role until World War One . Even with all their improvements and apparent performance , opinion on the armored cruiser was mixed . The 1904 edition of the " Encyclopedia Americana " quotes an otherwise unidentified Captain Walker , USN , in describing the role of the armored cruiser as " that of a vessel possessing in a high degree offensive and defensive qualities , with the capacity of delivering her attack at points far distant from her base in the least space of time . " The same source defines an armored cruiser as " a battleship in which the qualities of offense and defense have been much reduced to gain high speed and great coal capacity " and adds , " . . . there are many who hold that the armored cruiser is an anomaly , something less than a battleship and more than a protected cruiser , performing satisfactorily the duties of neither , with no special function of her own and lacking the great desideratum in warships , ability to fight in proportion to her great size and cost . " 1900s : Battle of Tsushima and the battlecruiser . Armored cruisers were used with success in the line of battle by the Japanese at the Battle of Tsushima in 1905 . Of the battle damage received by the Japanese , the armored cruiser received eight hits , which destroyed three of her guns , killed five crew members and injured 90 more ( one of the wounded being Isoroku Yamamoto , who would later plan the attack on Pearl Harbor ) . None of the other Japanese armored cruisers suffered serious damage or large loss of life . The was hit 16 times but no one onboard was killed and only 15 were wounded . Except for the , all the cruisers present at Tsushima that morning were still battle - ready in the evening . The performance of the Japanese armored cruisers led to a boom in the construction of armored cruisers in the world ' s navies as some naval authorities concluded that the armored cruiser ' s superior speed could ensure survivability in a naval action against battleships ; they did not take into account the Russian Baltic Fleet ' s inefficiency and tactical ineptitude during the battle . First Sea Lord " Jacky " Fisher , an advocate of armored cruisers as more useful than battleships to safeguard British trade and territorial interests , saw his efforts justified ; his belief that " speed is armor " would lead him to create the battlecruiser . Danish Navy Commander William Hovgaard , who would later become president of New York Shipbuilding and serve on the U . S . Navy ' s Battleship Design Advisory Board , a group which would help plan the fast battleships in the 1930s , said , " The fighting capacity of the armored cruiser has reached a point which renders its participation in future fleet actions almost a certainty " and called for a " battleship - cruiser " which would possess the speed of a cruiser and the firepower of a capital ship Other naval authorities remained skeptical . Mahan called the interest in armored cruisers " a fad , " then explained : She is armored , and she is a cruiser ; and what have you got ? A ship to " lie in the line " ? as our ancestors used to say . No , and Yes ; that is to say , she may at a pinch , and at a risk that exceeds her powers . A cruiser ? Yes , and No ; for , order to give her armor and armament which do not fit the line , you have given tonnage beyond what is needed for the speed and coal endurance proper for a cruiser . By giving this tonnage to armor and armament you have taken it from other uses ; either from increasing her own speed and endurance , or from providing another cruiser . You have in her more cruiser than she ought to have and less armored vessel , or less cruiser and more armored ship . I do not call this a combination , though I do call it a compromise . . . I do not say you have a useless ship . I do say that you have not as useful a ship as , for the tonnage , you ought to have . Buoyed with their success at Tsushima , Japan laid down the four s between 1905 and 1908 . At a speed of 20 . 5 knots , they carried an extremely heavy main armament of four guns , of belt and turret armor and of deck armor . The " Tsukuba " s were intended to take the place of aging battleships and thus showed Japan ' s intention of continuing to use armored cruisers in fleet engagements . The U . S . Navy raised the main gun caliber of its cruisers with its , laid down between 1902 and 1904 . These mounted four and 16 guns , the former a size previously allocated to battleships . While they had thinner armor than the " Pennsylvania " s ( on their belts and on their decks ) due to newly imposed congressional restraints on tonnage , they could still steam at 22 knots . They were built as a fast , powerful response in the eventuality of a Pacific war and were the largest and last American armored cruisers built . The British also considered and guns for its cruisers , the culmination of its armored cruiser building program . They displaced 14 , 600 tons , were capable of 23 knots and were armed with four and 10 guns . By the time these ships were commissioned , Britain possessed the largest armored cruiser force in the world . Undaunted and fully engaged in a naval arms race with the British , the Germans also continued to build armored cruisers , partly from their faith in them as fighting units and commerce raiders , partly from Japan ' s success . Between 1897 and 1906 they laid down eight of them for use on overseas stations . The initial two , and , were armed with guns ; the six that followed had guns of a more modern design . The final pair , and , displaced 12 , 781 tons , steamed at 23 . 5 knots , carried of belt and of deck armor and were armed with eight guns . Another powerful armored cruiser was the Russian , completed in 1908 . Armed with four in two twin turrets fore and aft and eight in turrets along the ship ' s sides , she displaced 15 , 190 tons and carried a belt , two armored decks and armor on her turrets and conning tower . Her top speed was 21 knots . " Rurik " was unusual in that she was Russian designed but British built ; the Russian Navy was not usually a customer of British shipyards . She was reportedly one of the best armored cruisers built , with an advanced sprinkler protection for the magazines . Intended as the first of a three - ship class , " Ruriks " sisters were cancelled with the advent of the battlecruiser . " The supreme embodiment of the armored cruiser , " in historian Robert K . Massie ' s words , was the German ship . An enlarged version of the " Scharnhorst " class with a speed of 24 . 25 knots , armed with 12 and eight guns , " Blücher " was planned as an armored cruiser in part because the British had misled the Germans on the " Invincible " s then being constructed . The Germans expected these new British ships to be armed with six or eight guns . One week after the final decision to construct " Blücher " , the German naval attache learned they would carry eight guns , the same type mounted on battleships . With no funds available to redesign " Blücher " , work was ordered to proceed as scheduled . She was , Massie writes , " almost a battle cruiser , but not quite . " Blücher " would have been successful in dealing with British armored cruisers , but she could not stand up to — or keep up with — real battle cruisers . " By the time these ships were entering service , the armored cruiser as it was then known had reached the end of its development . Tactics and technology favored fighting power over long to medium ranges , which demanded an armament of primarily large caliber guns and a speed higher than that of battleships , preferably by at least 30 percent , to fulfill its traditional role as scout for the fleet and the newly acquired one of participating with battleships in a naval encounter . Thirty percent was the ratio by which frigates had been faster than ships of the line in the days of sail . If a battleship sailed at 20 knots , this would mean that an armored cruiser would have to steam at least 26 or 27 knots . To fulfill these criteria , however , armored cruisers would have to be built much larger and take on a different form than they had in the past . The battlecruiser and her two sister ships were designed specifically to fulfill these requirements . In a sense they were an extension of the armored cruiser as a fast , heavily armed scout , commerce protector and cruiser - destroyer , reflected in the term originally ascribed to them , " large armored cruiser . " However , they were much larger , faster and better - armed than armored cruisers , able to outpace them , stay out of range of their weapons and destroy them with relative impunity . Because they carried the heavy guns normally ascribed to battleships , they could also theoretically hold their place in a battle line more readily than armored cruisers and serve as the " battleship - cruiser " for which Hovgaard had argued after Tsushima . All these factors made battlecruisers attractive fighting units , although Britain , Germany and Japan would be the only powers to build them . They also meant that the armored cruiser as it had been known was now outmoded and no more were built after 1910 . The United States Naval Institute put the matter bluntly in its 1908 written proceedings : It is very doubtful if an armored cruiser of the " Colorado " class would dare even tackle a monitor , for fear that one of the latter ' s shot " might " hit a vital spot , and if it did she would lose her only raison d ' etre , for a crippled cruiser would be useless as a cruiser , and still not fit to " lie in the line . " . . . It may be urged that an armored cruiser was never intended to fight a battleship . Then what " is " she intended for ? Surely not as a scout or a commerce destroyer , for vessels a fifth the displacement could do this work as well , and numbers are required here , not strength . . . If she is to overtake a weaker enemy , you must first assume a smaller enemy , otherwise she could not have superiority in both speed and strength . By escaping from a stronger enemy she will never win wars . Later in the same address is this : " Every argument used against [ armored cruisers ] holds true for battle - cruisers of the " Invincible " type , except that the latter , if wounded , would be fit to lie in the line , owing to her great armament . If it is hoped to fight at such great ranges that her 7 - inch belt and 5 - inch side will be of value , then the armor of battleships is wrong , not in principle , but in distribution . " World War I . Although pre - dreadnought battleships and armored cruisers were outclassed by modern battleship and battlecruiser designs , respectively , armored cruisers still played an active role in World War I . Their armor and firepower was sufficient to defeat other cruiser types and armed merchant vessels , while their speed and range made them particularly useful for extended operations out in the high seas . Some German and Royal Navy vessels , like the , were allocated to remote naval squadrons . Many other vessels however , were formed into independent squadrons for patrolling European waters and accompanied capital ships every time the latter made forays out of port . At the Battle of Coronel , the German armored cruisers and scored a resounding victory over British naval forces in the West Indies . With newer ships , superior gunnery and optimal logistics , the Germans sank the Royal Navy armored cruisers and , with the loss of over 1 , 500 British sailors and officers ( including Rear - Admiral Christopher Cradock ) . This was one of the last battles involving armored cruisers as the chief adversaries ; all subsequent engagements were dominated by battlecruisers and dreadnought battleships . Moreover , the timing could not have been worse for British morale . Six weeks earlier , the armored cruisers , and had all been sunk on the same day by a single German submarine . Two weeks later , the Battle of the Falkland Islands showed graphically how much technology and tactics had changed . and were sunk by the battlecruisers and . The German armored cruisers were too slow to outrun their pursuers , and their initially accurate gunnery failed to inflict serious damage on the British battlecruisers . The British 12 - inch guns turned the tide of battle once they started scoring hits on the Germans , and the German armored cruisers were fatally crippled before they had a chance to close the range and use their superior secondary armament . This victory seemed to validate Lord " Jacky " Fisher ' s justification in building battlecruisers — to track down and destroy armored cruisers with vessels possessing superior speed and firepower . The German force commander Admiral Maximilian von Spee had been wary of the Allies ' battlecruisers , especially the Imperial Japanese Navy and the Royal Australian Navy — in fact he described the latter ' s flagship , the battlecruiser , as being superior to his entire force by itself . At the Falklands , he had already deduced the battle was lost when he missed the chance to attack the British battlecruisers in port . During the Battle of Dogger Bank , the was crippled by a shell from a British battlecruiser , which slowed " Blücher " to 17 knots and eventually sealed her fate . Admiral Franz von Hipper chose to let the " Blücher " go down so his more valuable battlecruisers could escape . , and were lost at the Battle of Jutland when they inadvertently came into sight and range of the German Navy ' s battle line , which included several battlecruisers and dreadnought battleships . Post - World War I : Panzerschiffe and end . After the end of World War I , many of the surviving armored cruisers were sold for scrap . The Washington Naval Treaty of 1922 placed strict limits on the numbers of " capital ships " possessed by the navies of the great powers . A " capital ship " was defined as any vessel of over 10 , 000 tons displacement or with guns over 8in caliber , and several more armored cruisers were decommissioned to comply with the terms of the treaty . The London Naval Treaty of 1930 introduced further limits on cruiser tonnage . Only a small number of armored cruisers survived these limitations , though a handful saw action in World War II . The armored cruiser enjoyed a brief and limited resurgence in the late 1920s and early 1930s , albeit for mainly political reasons , with the three " Panzerschiffe " ( literally " armored ships " ) that Germany built , the , , and . The German Navy , renamed the " Reichsmarine " after the end of World War I , chose the name for this class with great care . Although in French the term effectively described a battleship , in German the term referred to the armored cruiser , which had been considered a class below capital ships . The impression the " Reichsmarine " attempted to give by using it was that it was developing a modest vessel in line with the Treaty of Versailles . According to this treaty , which Germany signed at the end of World War I , the " Reichsmarine " could replace the six pre - dreadnought s it had been left as capital ships when they were twenty years old . New vessels were to displace at most ; gun calibers for these ships was not regulated . The Allies , who at this time were limited to building vessels of by the Washington Naval Treaty and subsequent agreements , assumed that with the 10 , 000 - ton limit , only coastal defense ship s similar to those operated by the Scandinavian navies could be built . Instead , Germany built a trio of ships fast enough to evade most enemy capital ships , armed with larger main guns than permitted for cruisers built under the Washington and London Naval Treaties . Though they were stated to displace , the " panzerschiffe " actually displaced at standard displacement . Despite this violation , their design incorporated several radical innovations to save weight , such as welding ( which saved 15 percent in hull weight ) and all - diesel propulsion ( which failed to save weight but gave the ships substantial range ) . Due to their heavy armament of six guns , the British began referring to the vessels as " pocket battleships " . The " Kriegsmarine " reclassified them as heavy cruisers in February 1940 . None of them survived World War II . Despite the moniker of " armored ships " , or pocket battleships , the " Deutschlands " were actually heavy cruisers albeit upgunned with slower speed , and they were not related in design to the armored cruisers from WWI and earlier . One late - design armored cruiser is still considered to be in active duty : the Hellenic Navy ' s , constructed in 1909 – 1911 , is preserved as a museum in Palaio Faliro , Greece and it is the only armored cruiser worldwide still in existence . Differences between Armored Cruisers and Heavy Cruisers . The armored cruiser was not a close ancestor of heavy cruiser s , even though the name sometimes suggests this . By 1905 the armored cruiser had grown in size and power to be very close to the pre - dreadnought battleship s of the day , with a displacement of around 15 , 000 tons : considerably larger than the 10 , 000 tons of the heavy cruiser . This trend resulted in the battlecruiser , which was initially conceived as an armored cruiser on the same scale as the dreadnought battleship . By 1915 , both battleships and battlecruisers had grown markedly ; , for instance , designed at around that time , displaced 45 , 000 tons . Armored cruisers were part of the main battleline along with pre - dreadnoughts , and some armored cruisers did maintain their place around dreadnoughts and battlecruisers . In the interwar period , the great gap between heavy cruisers and the capital ships of the same generation meant that the heavy cruiser could not be expected to serve as a junior battleship . There were also important technical differences between the heavy cruiser and the armored cruiser , some of which reflected the generational gap between them . Heavy cruisers , like all contemporary ships , were typically powered by oil - fired steam turbine engines and were capable of far faster speeds than armored cruisers had ever been ( propelled by coal - fired reciprocating steam engines of their era ) . Like their protected cruiser predecessors and contemporary light cruiser s , heavy cruisers lacked a side armored belt , saving weight to achieve high speeds . The main armament of a heavy cruiser at a maximum 203 mm ( 8 - inch ) was smaller than the typical 233 mm ( 9 . 2 - inch ) guns of later armored cruisers , although some vessels designed without Treaty limitations such as the " Panzerschiffe " and " Alaska " - class did mount larger sizes ( 11 - inch and 12 - inch , respectively ) . Nonetheless , heavy cruisers often had a larger number of main guns ( some armored cruisers had a mixed instead of uniform complement of main guns ) , and discarded the mounting of main guns in casemate s in favor of center - line superfiring turrets which saved tonnage and enabled the ship to fire all guns on one broadside . Heavy cruisers also benefited from the introduction of fire control in the 1920s and 30s , considerably improving accuracy .