As we saw in the previous post, the German battleship KM Bismarck has been subject to its fair share of mythology. Much flowed from exaggerated claims about Bismarck’s characteristics. In fact the only real advantage of Bismarck was size.
In the 1930s, battleships were limited to standard displacement of 35,561 tonnes (35,000 long tons) by international treaties dating to 1922, to which Germany was party via the Naval Agreement of 1935. At British insistence this was defined with specific consumables aboard. The only way to get around Treaty limits was by cheating, and Bismarck flouted the rules by a wide margin. Bismarck’s standard displacement was 42,321 tonnes, full load 45,928 tonnes and extreme battle load 50,933 tonnes. The real limit faced by her design team, led by Hermann Burkhardt, was the width of the lock gates on the Kiel canal, through which Bismarck was required to pass.
The Germans didn’t have access to data available to the British from WWI battle experience and subsequent experiments. But in any event, German philosophy remained that of WWI. Although Bismarck followed trend in higher speed – 136,000 shp/29 knots without forcing – her design was WWI-era, with a low sloped armour deck, optimised for short-range battles. The deck was thin – maximum 120 mm, against the maximum 232 mm adopted by the British in their contemporary King George V, over the magazines.
One of the design team, Heinrich Schulter, wasn’t happy with the extent of Bismarck’s belt armour, which didn’t extend far enough below the waterline, but couldn’t enlarge the ship to support more. In the Battle of the Denmark Strait, HMS Prince of Wales hit Bismarck below the armour, causing substantial flooding.
Part of the reason why Bismarck ran into that armour limit – despite being well over the legal displacement figure – was because the design was inefficient. The main armament followed Baden of 1913, eight 380-mm (14.96-inch) guns in four double turrets. This wasted displacement by comparison with battleships that used triple and quad turrets. Other retrograde features included a displacement-wasting double secondary battery of 150 mm (surface) and 110 mm (AA) guns, when other navies were adopting single batteries with dual-purpose weapons.
Another down side was the decision to provide triple screws, which resulted in a cut-away stern, causing loss of reserve buoyancy as well as vulnerability to whipping – oscillation of the hull girder under explosive forces. This was evidenced in Bismarck’s case by the fact that the stern suffered structural failure and broke off at Frame 10, probably as the ship sank, after suffering torpedo damage the day before.
Plus sides included underwater subdivision – 22 major compartments – and the usual German attention to construction detail. Some structural members were ‘Wotan Weich’ steel, high-tensile steel that combined armour and structural characteristics. The technique originated in the US and had been developed by the Carnegie Steel Company in 1910, but was hugely expensive. The British were sparing with their equivalent, ‘D’ steel, for that reason. Indeed, only the US navy was able to enjoy much use of high-tensile steels in ordinary construction.
The upshot was that Bismarck was a tough-built ship, but otherwise very average by world standards, with less fire-power than many contemporary battleships. The Germans knew it too; they built two ships to Bismarck design, but then moved on to a larger and more heavily armed ‘H’ type. The outbreak of war prevented any of those being completed.
Needless to say, the real story of Bismarck is one of people – and it is difficult to envisage her 210-hour sortie without thinking of the 2,065 sailors on board, young men who knew their fate – but faced it stoically, dutifully, and of whom just 117 survived. The British sailors who pulled the survivors from the storm-tossed Atlantic certainly knew the score – which for them was a simple one. ‘There, but for the grace of God, go I’.
A truth of war, and one that we must not forget.
Copyright © Matthew Wright 2014
That’s the last of the military for a while. Coming up – more writing posts, some news, and history.