World War II served as perhaps the greatest innovative event of the 20th Century. Jet airplanes, modern weaponry, nuclear technology, and numerous communication technologies had their birth during our planet’s greatest struggle. This includes computers.

Computers were introduced to the U.S. Navy on the eve of war for submarines. The computers used trigonometry to help the submariners know when to fire their torpedoes at a moving target. These devices were expanded to surface ships to provide more accurate firing of the guns. Ships of the time now had computer-firing rooms placed in them along with other rooms dedicated to new technologies like radar.

The Mark 1 fire control system electronically linked gun mounts to the electronic gun director (mounted high on the ship) and could acquire a target either optically or via radar. It was kept safe deep in a ship’s superstructure in a watertight armored plotting room and was on every vessel. Battleships had four of them! The device weighed 3,000 pounds. A team of sailors stood around the device, which was about four feet tall, and they would enter the average muzzle velocity of the round leaving the gun, which took into account the type of projectile and its weight. The Mark 1 would then compute the angles needed to fire the gun taking into account the wind, distance, roll and pitch of the ship, the magnus effect (the projectile’s spin) and parallax (the different locations of the ship’s guns). The information was electronically transmitted to the gunners and could produce continuous fire control solutions during combat. It was also effective in developing solutions for anti-aircraft fire, though jet aircraft began to render it obsolete. The Mark 1’s next generation, the Mark 1A remained in service until 1969 when digital fire control solutions replaced it.

On the German side Konrad Zuse developed the world’s first electromechanical programmable computer, the Z3, for the Germans in 1941, expanding a device he developed in 1939. A keyboard was used to input information and that information was stored on punched film. While computers were added to Kriegsmarine vessels to aid in firing control the computer played very little role in the German war effort, a curious omission given the Germans technological prowess in other areas.

Before the use of firing computers it would be necessary to fire and, knowing the angle that the gun was at, reasonably guess the distance to the target. Some instruments could be used to also gauge the distance but were not entirely accurate. Adjustments would be made and so on until one ship found the other or both got close enough in range. One famous instance of this was when the Kriegsmarine battleship Bismarck took on the Royal Navy’s famous heavy cruiser HMS Hood. The Bismarck, equipped with the FuMO23 radar instrument which had three optical range finders with a 25,000 meter range, found the Hood and fired four salvos sending her to the bottom. This was as accurate as World War 2-era fire control could be and still did require human observation but the battle lasted eight minutes and the pride of the Royal Navy was lost with only 3 survivors.

The British and Americans embraced the computer and the possibilities it offered. With German codes becoming ever more complex using their Enigma machines, it was necessary for automation to do some of the work. British codebreakers at Bletchley Park developed a device called Colossus, the world’s first electronic digital programmable computer. It used paper-tape input and used vacuum tubes. It helped to break the Enigma code and win the war (of course it was not solely responsible for that). The Americans of course were not to be outdone. ENIAC was our brainchild, though not completed until just after the war. Similar to Colossus it was more flexible and faster and used patch cables and switches to program. It was, in essence, a huge calculator. It was capable of adding or subtracting 5,000 times a second. It could also multiply, divide, or do square roots. It weighed 30 tons and consumed 200 kilowatts of electric power. But with quicker calculations came more accurate fire, which could have aided in the Allied victory.

While the soldiers and sailors came home to a heroes welcome, these devices lived out their usefulness in some cases complete anonymity. Zuse’s work, the Z3 was destroyed by Allied bombing in 1943 and he never received the credit that was due to him for his genius. Colossus was a classified secret known to only a handful of people. All documentation was destroyed and most of the machines were broken apart. It was whispered about in the 1960s and was publicly revealed in the 1970s only after it was included in a British servicemen’s memoirs. In 2007 a reconstruction of Colossus was completed at Bletchley Park to take part in a codebreaking challenge. While modern technology completed the challenge much faster, given the learning curve of the replica’s users and the limitations of the time all were impressed at Colossus’ performance. You might have even seen the recent movie about the program as well. ENIAC continued to run until 1955 when it was replaced and it was no secret as it was unveiled through the press in 1946. Parts of it can be found at museums all throughout the world, the nearest to us at Nicely Done Sites is the Ordnance Museum in Aberdeen, MD.

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