The battle of Jutland and the Royal Navy’s steampunk computers

It’s Jutland day again – 101 years since the great fleets of Britain and Germany clashed in the North Sea in what was expected to be a kind of second Trafalgar in which the German High Seas Fleet was supposed to be sunk.

It wasn’t. The British won it strategically: the German fleet scuttled back to harbour, leaving the Royal Navy’s Grand Fleet in unchallenged control of the North Sea. However, higher British numeric losses smacked of a defeat, and so began the so-called ‘Jutland’ controversy that raged for years afterwards. It was facile in a way: the arbiter was the strategic outcome, in which the Germans were the decisive losers. However, the popular notion that victory could be measured by inflicted losses muddied those waters.

HMS Lion, Beatty’s flagship, crippled at Dogger Bank by only a few hits. Public domain, via Wikipedia.

There were a number of reasons why the British hadn’t scored a numeric victory despite their huge preponderance in numbers and fire-power. One of them was time: the fleets clashed in poor visibility at the end of a day. Another was the quality of the shells, which tended to burst before penetrating German armour.  And another was fire-control, which – certainly for the British Battlecruiser Fleet under Sir David Beatty that had been in combat since mid-afternoon – was terrible. One battlecruiser, HMS New Zealand, blew off 420 heavy shells through the battle and is thought to have scored only four hits. Ouch.

So what happened? The main problem was insufficient practise – the British battlecruiser force, based at Rosyth, didn’t have anywhere to engage in live-fire drills.

But in any case, gun-laying (‘getting a firing solution’) was a dark art back then. Guns had to be pointed not where the target was, but where it was going to be at the end of the flight-time. That relied on knowing the range, the direction the target was going in, relative to you – the ‘heading’ – along with your own heading and speed. Once that information was to hand, it had to be calculated mathematically – using trigonometry –  pretty much in real time. All of this was possible, but as ship speeds rose and gun ranges extended out to beyond the horizon in the years leading up to the First World War, it became – well, a bit of a problem.

Dreyer Mk III fire control table. 3d model by Rob Brassington via the Dreadnought Project. CC2.5 license.

Enter the Dreyer Fire Control Table – a Heath Robinson steampunk-style mechanical computer that whirred and clanked and whipped its bicycle chain around, and (eventually) spat out the details. It was usually paired with a related mechanical computer known as a Dumaresq. Both were named after their inventors.

HMS Orion during the First World War. Public Domain, via Wikipedia.

I heard quite a bit about this first hand because my father’s uncle, Bert Wright – a Royal Marine – was heavily involved with hands-on First World War fire-control. He was at Jutland, on board the super-dreadnought HMS Orion, running a Graham Navyphone in the forward Transmitting Station, calling down range data from the director range-finder in the spotting top.

This rangefinder worked on the ‘coincident’ principle. Basically it was a binocular telescope with wide-spread lenses. Each projected a half-image, separately, on to the eyepiece in the centre. By twiddling knobs, the operator could bring the two halves into alignment – at which point it was possible to read the range off a dial. The system worked by triangulation, so the wider the baseline, the more accurate a reading you got. Early range-finders were as little as 9 feet (3 metres), which didn’t work well at some of the battle ranges being achieved by the First World War. Even before Jutland that was being extended in some ships to 15 feet (5 metres).

The data it produced, along with other observations of the enemy bearing, was sent down to the ship’s Transmitting Station and poured into the Dreyer Fire Control Table and Dumaresq.

Mk III Dumaresq of 1920, via the Dreadnought Project. Click to enlarge.

This array of cogs, plotters and bicycle chains whirred and clanked, and after a while, spat out information on where to point the guns – particularly range (in 25 yard increments) and deflection (based on the relative enemy speed, in 1-knot increments). It didn’t quite do it in real time, which meant that during a period of sustained firing the fire control solutions progressively lagged – but it was better than doing it by hand. And the system had the ability to handle other inputs, including direct observations from the spotting top, where the fire-control officer could watch the fall of shot and call down for corrections.

The problem was getting all this to work properly. The British learned from Jutland. A few months after the battle, while posted to HMS Repulse, Uncle Bert was involved in the post-battle reform of fire-control methods. For him, that involved being woken up at insane hours of the night and having to rattle up the mast to his battle-station, working the director range-finder. The timing was part of a general subterfuge to prevent the Germans learning about new British methods; and, I suppose, at nineteen years of age, Uncle Bert was well able to handle interrupted sleep.

If you want to find out what I’ve written on naval history, including my account of New Zealand’s part in the Battle of Jutland, don’t forget to check out my book Blue Water Kiwis, available right now on Kindle.

Copyright © Matthew Wright 2017

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