Courageous Class Battlecruiser - Design and Description

Design and Description

The first two Courageous-class battlecruisers were designed in 1915 to meet a set of requirements laid down by the First Sea Lord, Admiral Fisher, with his Baltic Project in mind. They were to be large enough to ensure that they could maintain their speed in heavy weather, have a powerful armament and a speed of at least 32 knots (59 km/h; 37 mph) to allow them to outrun enemy light cruisers. Their protection was to be light for a cruiser, with 3 inches (76 mm) of armour between the waterline and the forecastle deck, anti-torpedo bulges amidships and the machinery as far inboard as possible, protected by triple torpedo bulkheads. Shallow draught was of the utmost importance and all other factors were to be subordinated to this. The Director of Naval Construction (DNC), Sir Eustace Tennyson-d'Eyncourt, responded on 23 February 1915 with a smaller version of the Renown-class battlecruisers with one less gun turret and reduced armour protection. The Chancellor of the Exchequer had forbidden any further construction of ships larger than light cruisers in 1915, so Fisher designated the ships as large light cruisers to evade this prohibition. If this restriction had not been in place, the ships would have been built as improved versions of the preceding Renown class. The two ships were laid down a few months later under a veil of secrecy, so they became known in the Royal Navy as "Lord Fisher's hush-hush cruisers" and their odd design also earned them the nickname of the Outrageous class.

Their half-sister Furious was designed a few months later to meet a revised requirement specifying an armament of two BL 18-inch Mk I guns, the largest guns ever fitted on a Royal Navy ship, in single turrets with the ability to use twin 15-inch (381 mm) gun turrets if the 18-inch guns were unsatisfactory. Gunnery experts criticized this decision because the long time between salvoes would make spotting corrections useless and reduce the rate of fire and thus the probability of a direct hit. Her secondary armament was upgraded to BL 5.5-inch Mk I guns, rather than the 4-inch (102 mm) guns used by the first two ships, to compensate for the weakness of the two main guns against fast-moving targets like destroyers. Her displacement and beam were increased over that of her half-sisters with slightly less draught.

The Baltic Project was only one justification for the ships. Admiral Fisher wrote in a letter to the DNC on 16 March 1915: "I've told the First Lord that the more that I consider the qualities of your design of the Big Light Battle Cruisers, the more that I am impressed by its exceeding excellence and simplicity—all the three vital requisites of gunpower, speed and draught so well balanced!" In fact they could be considered the epitome of Fisher's belief in the paramount importance of speed over everything else. Fisher's adherence to this principle is highlighted in a letter he wrote to Churchill concerning the battleships of the 1912–13 Naval Estimates. In the letter, dated April 1912, Fisher stated: "There must be sacrifice of armour ... There must be further VERY GREAT INCREASE IN SPEED ... your speed must vastly exceed your possible enemy!"

Fisher's desire for a shallow draught was not merely based on the need to allow for inshore operations; ships tended to operate closer to deep load than anticipated and were often found lacking in freeboard, reserve buoyancy and safety against underwater attack. This experience led the DNC to reconsider the proportions of the hull to rectify the problems identified thus far. The Courageous-class ships were the first products of that re-evaluation.