The battlecruiser was the brainchild of Admiral Sir John ("Jacky") Fisher, the man who had sponsored the construction of the world's first "all big gun" warship, HMS Dreadnought. He visualised a new breed of warship with the armament of a battleship, but faster, lighter, and less heavily armoured. The first three battlecruisers, the Invincible class, were laid down while Dreadnought was being built in 1906.[1]
This design philosophy was most successful in action when the battlecruisers could use their speed to run down smaller and weaker ships. The best example is the Battle of the Falkland Islands where Invincible and Inflexible sank the German armoured cruisers SMS Scharnhorst and SMS Gneisenau almost without damage to themselves, despite numerous hits by the German ships.[2] They were less successful against heavily armoured ships, as was demonstrated by the loss of Invincible, Indefatigable, and Queen Mary during the Battle of Jutland in 1916. All three ships were destroyed by more heavily armoured German battlecruisers,[3] with the British failure to prevent fires or explosions in the gun turrets from reaching the magazines also playing a role in the losses.[2]
Of the battlecruisers built before the First World War, the Invincible class and Indefatigable class all had 6 inches (152 mm) of armour on their waterline, a top speed of 25 knots (46 km/h; 29 mph), and eight 12-inch (305 mm) guns. The more advanced battlecruisers—the two Lion-class ships, Queen Mary, and HMS Tiger—all had an armour belt of 9 inches (229 mm), speeds over 28 knots (52 km/h; 32 mph), and eight 13.5-inch (343 mm) guns.[4] The Renown and Courageous classes, built during the war, were begun when Admiral Fisher was appointed First Sea Lord for the second time in late 1914. Each of these classes in turn served as the fastest capital ships in the world and were heavily armed with four or six 15-inch (381 mm) guns, but they paid for their speed and armament by having less armour than battleships.[5] HMS Hood was laid down during the war, but was extensively reworked with more armour based on the experience gained at the Battle of Jutland, and was not completed until after the war.[6]
Following the war, the British planned to build the G3 class, which had the same armament and armour as battleships of the time and were rated as battlecruisers only by comparison to the more heavily armoured and slower battleships also planned. They were cancelled as they exceeded the tonnage limits of the Washington Naval Treaty.[7] Of the first nine battlecruisers, only HMS Tiger survived the Washington Treaty and into the 1930s. The three Courageous-class ships were converted to aircraft carriers during the 1920s and only Repulse, Renown and Hood served in the Second World War as battlecruisers. All three went through substantial refits between the wars. Hood was lost in the battle of the Denmark Strait, Repulse was sunk by Japanese aircraft at the start of the war in the Pacific, and Renown survived the war to be scrapped in 1948.[8]