Latest posts by Matthew Wright (see all)
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- Battlecruisers – both over-gunned and under-armoured - 07/30/2017
Britain’s King George V class battleships have often been regarded as the worst of the Second World War’s new-generation battleships. It’s unwarranted criticism, though perhaps understandable.
By popular measure, their ten Mk VII 14-inch/45 calibre guns firing a 1590 lb shell gave them less hitting power than other new battleships of the day. They had issues, including limited operating range and an air conditioning system not up to tropical service. A Board of Admiralty requirement for zero-elevation forward fire from A-turret meant they had only 5 feet of bow flare, making them wet. Early war experience was dogged with mechanical problems in the main battery gun mounts – specifically, clearances with the anti-flash safety interlocks – and they had detail design issues with watertight trunking and generator arrangement that contributed to the loss of HMS Prince of Wales.
However, those early mechanical issues were rectified – in the case of Anson and Howe, during construction – and once put in context of the engineering and cost limits the British faced, the general design was excellent. In absolute terms the class was better armoured than any other operational Second World War battleship except Yamato, which had a standard displacement some 183 percent higher than King George V.
Put another way, the usual guide for adequacy of armour protection was that it had to resist the fire of a ship’s own main battery, and the King George V’s armour was designed against against fire considerably heavier than their main guns could develop. None of the ten US new-build battleships of the war were armoured to meet more than their own main battery, and six of them were below that benchmark. These outcomes partly reflected differing design philosophies, but were also a result of the interaction between Treaty limits, disengagement from those limits, and differing national industrial capacities.
The Chief Constructor, Herbert Staddon Pengelly – who prepared the general design – knew what he was doing. The issue was the compromises needed to meet conflicting requirements that ran beyond Treaty limits, principally financial but including a 104-foot beam limit imposed by the Portsmouth and Rosyth dockyards. Other parameters included a Board of Admiralty requirement for zero-elevation ahead fire from A-turret, and a last-minute decision to improve the armouring around the magazines, which led to two guns being dropped from the main armament. That was apart from budgetary constraints that stopped the British using high-tensile steel – ‘Ducol’ or ‘D’ steel in Admiralty parlance – as extensively as they wanted.
Into this was mixed the fact that preparing the detail construction drawings for any battleship occupied up to two million man-hours. However, the design and drafting teams of the First World War era had dissipated on the back of the naval building drought of the inter-war period. This slowed down the British ability to develop new gun mountings and led to some of the detail flaws of the King George V’s – which had to be corrected during initial operational service.
These were not the only constraints. Battleship design in the inter-war years was framed by international limits, founded in the ‘Washington Treaty’ of 1922 and extended by subsequent treaties, primarily at British behest. The main constraints were 35,000 tons standard displacement and 16-inch guns. Britain, for cost reasons, always pressed for lower figures – and managed to get maximum gun calibre lowered to 14 inches in early 1936 during negotiations for the Second London Naval Treaty with the US, France, Italy and Japan. However, Japan pulled out and Italy refused to sign. The upshot was that this Treaty, signed in March 1936 by the US, Britain and France only – with Germany coat-tailing on the restrictions via the Anglo-German Naval Treaty of 1935 – contained an ‘escalator clause’ by which main gun calibre would revert to 16-inch if Japan or Italy refused to sign it after 1 April 1937.
That was a problem for the British. By 1936 work was well under way on the 14-inch gunned King George V design, with the aim of laying the ships down at the beginning of 1937. The gun mounts had to be ordered by mid-1936 if they were to be ready by 1940.
It was possible to design the ship in such a way that 14-inch quad mountings could be swapped, during construction, for triple 16-inch mountings. However, building in the ability to do this carried a displacement penalty that forced other compromises. US naval planners were prepared to accept those, meaning that their two Washington class battleships – originally designed to carry a dozen fourteen-inch guns – could be upgraded before completion. The British did not build that option into the King George V design, however, because it compromised other features which were regarded as non-negotiable.
Many compromises still had to be made. Fuel capacity was reduced during design from 4000 to 3700 tons, including diesel for the auxiliary generators. In theory this still gave the specified endurance of 3900 miles at 22 knots. However, in service it turned out that consumption was higher than estimated. Worse, the oil fuel was stored in tanks that were topped up with seawater as they were emptied of oil, because they were part of the torpedo defence system and had to be kept liquid-loaded. In theory it made more efficient use of displacement than a ship that had separate tanks. The way it was done was ingenious: fuel oil floats, and to avoid any mixing at the interface the fuel was separated from the water with detergent, which created an emulsion. However, in practise it proved difficult to keep the emulsion from being pumped into the boilers, and about 150 tons of oil were rendered unusable every fill. Some of the double-bottom spaces eventually had to be converted to fuel oil tanks, cutting the effectiveness of the underwater protection.
The relative lack of gun-power in the King George V’s drew criticism – notably from Winston Churchill – but in early 1937 the Admiralty believed they would only be building two ships to this design. The three battleships authorised for 1938 were going to have 16-inch guns. However, at that stage the treaty-imposed displacement limit remained 35,000 tons and the DNC’s department found that a 16-inch armed battleship with King George V speed and protection would displace 41,000 tons. Pengelly thought it could be done on a King George V hull by adding 450 tons displacement and and losing half a knot’s speed; but that would still have broken the Treaty. Nobody wanted to compromise the armour. The result was that the 1938 battleships were repeat King George V’s. Ironically, the displacement issue went away that year, when an agreement was reached to lift the Treaty limit to 45,000 tons – although the British were practicably limited to 40,000 tons by their dockyard dimensions.
The US did not face Britain’s non-Treaty limits but also did not share the British focus on armour. The outcome was that the two Washington class ships – built to the same 1936 Treaty constraints but able to take advantage of the gun calibre escalator clause – emerged with nine 16-inch guns and a good immunity zone against 14-inch gunfire; whereas the King George V class emerged with ten 14-inch and a good immunity zone against 16-inch fire. The British also had superior anti-torpedo protection; there were official doubts about the efficacy of Washington‘s in US circles, including from her own first commander who shifted crew bunks to avoid casualties in case of a hit. But against this, US battleships were built from high-tensile steel, which gave them tremendous damage resistance. For cost reasons the British could not afford to use it outside specific areas. At the same time, British armour plate was superior to US “A” class armour by about 20-25 percent. And the King George V class was designed for 28.5 knots at standard displacement, against the US ship’s 27 knots, but at the same time the British ship had shorter range. In terms of overall design balance the British ship veered, by intent, towards defence; the US one towards offence, but in general it was all swings and roundabouts with similar technologies.
What all this adds up to is that Pengelly came up with an optimum compromise to meet an incredible array of conflicting issues, starting with the Treaty limits that applied when construction was committed, and including the Admiralty requirement for protection, which was a direct outcome of hard experience in the First World War. The Admiralty certainly drew this conclusion in 1938 when exploring options for a 16-inch gun class to the same limits.
Furthermore, in action the King George V’s did not fall short. Once in service, worked up and with teething troubles ironed out, the King George V’s did all that was asked of them militarily. They were well armoured against the fire of any other European battleship of the day and all Japanese battleships except the Yamato class; and their guns were adequate against most opponents across a reasonable spread of ranges. When HMS Duke of York took on Scharnhorst at the end of 1943, it was a one-horse race. And when King George V was bombarding targets on Honshu in July 1945 her guns were as effective on ground targets as any other. It was also, incidentally, the last time any British battleship fired its guns at an enemy.
I have not talked about the loss of the Prince of Wales – although that has always been upheld as a sign of how poor these ships were. Actually there was a lot more to it, but that’s a post in itself, another time, and let’s discuss that then.
Meanwhile, any thoughts on the King George V class overall?
If you would like to read more on twentieth century naval engineering, check out my book Dreadnoughts Unleashed, available on Kindle.
Copyright © Matthew Wright 2017