Fast battleship

The extra speed of a fast battleship was normally required to allow the vessel to carry out additional roles besides taking part in the line of battle, such as escorting aircraft carriers.

Technological advancements such as propulsion improvements and light, high-strength armor plating were required in order to make fast battleships feasible.

From about 1900, interest in the possibility of a major increase in the speed of Royal Navy battleships was provoked by Sir John ("Jackie") Fisher, Commander-in-Chief of the Mediterranean Fleet.

Meanwhile, in the UK, Fisher continued to press for still higher speeds, but the alarming cost of the new battleships and battlecruisers provoked increasing resistance, both within the Admiralty and from the Liberal government that took office in 1906.

However, it was realised that by dispensing with the amidships turret, it would be possible to free up weight and volume for a much enlarged power plant and still fire a heavier broadside than the Iron Dukes.

Compared to Fisher's idea of speeding up the entire battlefleet, the advantages of this concept were that there would be no need to compromise the fighting power of the main fleet, and that it would be possible to retain the use of the existing 21-knot ships.

However, it also reinforced the views of Commander-In-Chief Sir John Jellicoe that the Queen Elizabeth ships were too slow to operate with the Battlecruiser Fleet on a permanent basis.

Although two new battlecruisers (Renown and Repulse) had been ordered in 1914, and were being constructed remarkably quickly, Jellicoe argued that, although their speed was adequate, their armour protection was insufficient.

As a result, the ships were radically redesigned in order to achieve the survivability of the Queen Elizabeths while still meeting the requirement for 32-knot (59 km/h; 37 mph) battlecruisers, although this reworking was flawed.

[15] Although the Royal Navy designated Hood as a battlecruiser, some naval historians such as Antony Preston characterise her as a fast battleship, as she theoretically had the protection of the Queen Elizabeth ships while being significantly faster.

However, from 1912 to 1923 there was a series of advances in marine engineering which would lead to a dramatic increase in the speeds specified for new battleship designs, a process terminated only by the advent of the Washington Naval Treaty.

These advances included:[19] By the early 1920s, the wealth of the U.S. and the ambition of Japan (the two Great Powers least ravaged by World War I) were forcing the pace of capital ship design.

[20] As a result, the U.S. Navy, which had hitherto adhered steadily to a 21-knot (39 km/h) battlefleet, settled for a modest increase to the same speed in the abortive South Dakota class of 1920.

The Japanese planned to follow up the Nagatos with the Kii class, (ten 16-inch (406 mm) guns, 29.75 knots, 39,900 tons) described as "fast capital ships" and, according to Conway's, representing a fusion of the battlecruiser and battleship types.

The treaties extended the definition of capital ship to cover all warships exceeding 10,000 tons standard displacement or carrying guns exceeding 8-inch (203 mm) calibre; imposed limits on the total tonnage of capital ships allowed to each signatory; and fixed an upper limit of 35,000 long tons (36,000 t) standard displacement for all future construction.

These restrictions effectively signaled the end of the battlecruiser as a distinct category of warship, since any future big-gun cruiser would count against the capital ship tonnage allowance.

It also greatly complicated the problem of fast battleship design, since the 35,000-ton limit closed off the most direct route to higher speed, as the increasing length-to-beam ratio would have meant a bigger ship; it required the development of more compact and powerful propulsion plants and lighter high-strength armour plating over the next two decades to make fast battleships feasible within the displacement limit.

In 1937, the Soviet Union signed the Anglo-Soviet Quantitative Naval Agreement and also agreed to abide by the terms of the Second London Treaty when beginning to design their Sovetsky Soyuz class (never completed due to the German invasion), although they added a proviso that allowed them to build ships of unlimited size to face the Japanese navy if they notified the British.

[24] Four capital ships of the treaty era were built to displacements appreciably less than the 35,000-ton limit; the French Dunkerque and Strasbourg and the German Scharnhorst and Gneisenau.

The Panzerschiffe were, in effect, a revival of the late 19th century concept of the commerce-raiding armoured cruiser; long-ranged, heavily armed, and fast enough to evade a conventional capital ship.

On the other hand, as a member of the line of battle, alongside the elderly and slow dreadnoughts that made up the rest of the French battlefleet, the design would make no sense, since her speed would lose its value and neither her armament nor her protection would be at all effective against a modern 16-inch gunned battleship such as Nelson.

The treaties also allowed the reconstruction of surviving battleships from the First World War, including up to 3,000 long tons (3,000 t) additional protection against torpedoes, high-altitude bombing and long-range gunnery.

It rather uncharacteristically settled for a moderate speed of 27 knots, for the sake of exceptionally high levels of protection and firepower in the 18.1-inch (460 mm)-gunned, 64,000-long-ton (65,000 t) displacement Yamato class.

Due to treaty restrictions, firepower and protection were emphasised first, although both did manage respectable speed increases compared to their World War I contemporaries to be able to operate as carrier escorts.

The US signed the Second London Treaty but was quick to invoke the "escalator clause" to increase the main battleship caliber from 14 to 16 inches as Italy and Japan refused to adopt it.

This made the North Carolinas somewhat unbalanced ships, being designed to resist shells from the 14-inch guns that it was originally intended to carry, but being up-gunned during construction.

In order to counter the increase in armor weight and stay within tonnage limits, the South Dakota class had to go with a shorter hull to reduce the length of the required protected area, compensating by installing more powerful machinery than in the North Carolinas, and this made the ships somewhat cramped in terms of accommodation.

With the additional tonnage, the Iowas had new 16-inch guns with a greater maximum range, and they had even more powerful engines and a lengthened hull for a significantly faster speed over the North Carolinas and South Dakotas.

With a raised tonnage allowance but still required to pass through the Panama Canal's existing locks, the Iowas mounted improved 16-inch guns with a greater maximum range, and they had even more powerful engines and a lengthened hull for a significantly faster speed over the North Carolinas and South Dakotas.

Although firing the same shells and having a protection scheme largely identical to the preceding South Dakotas, the more spacious accommodations and higher speed (of which the ten thousand tons increase was mostly due to) of the Iowas would enable them to be retained for post-WWII service.