Who Invented the Computer? The Torpedo Data Computer

Who Invented the Computer? This is the tenth installment in our ongoing series.


The development of better torpedo targeting spurred computer growth.

When the Greek philosopher Heraclides declared war to be the father of us all, he wasn't glorifying war, but rather acknowledging that war is within our human psyches, a part of our makeup. Mankind's track record makes it difficult to argue with Heraclides' point. Wars have always been a part of our history and will probably continue as long as inequities and injustices exist in the world.


War is indeed a terrible thing. Edwin Star had it right when he crooned some 50 years past, that war "ain't nothing but a heart-breaker, friend only to the undertaker." And yet, as bad as war is for economies and individuals, Starr was wrong when he said it was good for "absolutely nothing."


As we've already seen repeated in this series, it turns out that war is actually very good for scientific advancement. Especially as nations turn their industries and science toward developing new methods of killing the enemy and preventing their own people from being killed in return. Two such scientific breakthroughs were canned food and ARAPANET, forerunner to the Internet.


The scientific fruits of war


Canned food was a result of Napoleon's need to feed his armies as they marched around Europe. He offered a cash prize for anyone who could come up with a method to successfully move vast quantities of food from production to the front lines.


The development of better torpedo targeting spurred computer growth.

Philippe de Girard was the individual who figured out the canning process and, for his efforts, collected 12,000 francs. Unfortunately for France and her armies, two enterprising Englishmen grabbed the idea and ran with it; keeping the British army equally well-fed and ultimately victorious at Waterloo.


ARAPANET wasn't the product of a live war, but of the Cold War between the United States and the Soviet Union. Concerned with maintaining vital communications in the event our infrastructure was bombed, the U.S. Department of Defense came up with the idea of networking computers across the country.


If one computer node was destroyed, information could continue traveling via a different node to its destination. Communication could survive even without all of the links in the chain. This pursuit of national security is the foundation for today's worldwide web.


An underwater computer?


Another aspect of war is its tendency to put technologies in unlikely locations, like the conning tower of a U.S. submarine. Being a submariner during World War II was anything but comfortable. Patrols were 75 days long, with surfacing done only at night.


For more than two months, 80 men would live and work in temperatures sometimes exceeding 100 degrees. The air in the vessel would become viciously foul: The crew could tell the air was bad due to a lack of oxygen when it would become difficult to light their cigarettes. Space was also at a premium, with each crewman allotted just one cubic foot of storage space for their gear.


Shoehorned into this foul-smelling and cramped environment was the Torpedo Data Computer (TDC) whose purpose was to increase torpedo accuracy. Developed by the Navy in 1943, the TDC was one of the most complex mechanical computers ever built. It was so complex that it required one sailor to operate it and another to maintain it. It was also large, taking up 30-cubic feet of valuable space.


Contrary to popular misconceptions, submarine warfare, like that portrayed in Run Silent, Run Deep (truly a man's movie) involved a lot more finesse than just pointing your sub at an enemy ship and firing torpedoes.


Challenges of submarine warfare


By the time the war to end all wars started in 1914, the nations with submarines had developed various complicated manual procedures involving lots of slide-rule computations to aim torpedoes. In an additional effort to increase accuracy, they soon realized that installing gyroscopes in the torpedoes themselves helped keep them running level and on course.


Just before World War II broke out, almost all navies had switched to analog guidance systems to aim and fire torpedoes. Successfully firing a torpedo required knowing the speed of your submarine and of the enemy ship, the length of the enemy ship, the distance between both vessels and the angle to one another at which they were travelling.


Above all else, a sub's captain needed to fire his torpedoes so that they struck not where the target was positioned when he gave the order to fire, but where the target would be in the next minute or two. As one might imagine, estimating the future location of a moving enemy ship was never an easy task.


In the U.S. Navy's first submarine attack of World War II, on December 14, 1941, the USS Sea Wolf fired off 8 torpedoes at an enemy tanker. Seven completely missed the target and the eighth failed to detonate. It was an inauspicious beginning.


Things hadn't improved six months later at the Battle of Midway, widely viewed as the "turning point" of the Japanese-American theater of the war, where 18 U.S. subs failed to sink a single enemy ship.


Computers to the rescue


As a firing-control and guidance system, the TDC was a giant step forward compared to systems used by other navies because it enabled a torpedo to automatically track its target after firing. The device consisted of two electro-mechanical analog computers that worked in unison. One would calculate the torpedo's gyro angle and the other would continuously update its position.


In battle, the operator received verbal targeting information from the officer manning the periscope and would then feed the data into the TDC by rotating and setting dials and switches. By performing integrated equations in real-time, the TDC could mechanically set the angle of the torpedo's gyroscope and more accurately estimate a target's future location.


The development of better torpedo targeting spurred computer growth.

When a torpedo was fired, it would rotate on its way out of the launch tube. Because the TDC had set the torpedo's interior gyroscope to simultaneously rotate, it would direct the torpedo to travel a straight course for a predetermined distance and then release the gyro to steer a new course to the target.


Thanks to the TDC, the Silent Service was no longer just silent, but now increasingly deadly. From the end of 1943 on, Japanese shipping losses skyrocketed. Although less than two percent of the U.S. Navy's war-time commitment, submarines sent more than five-and-a-half-million tons of enemy shipping to the sea-floor � accounting for 55 percent of all Japanese vessels lost.


Harmful ends, good outcomes


War may indeed be the father of us all, but it's also the mother of invention. Technology formerly used to cause death is often later turned to improving life for everyone.


For example, during the Cold War, the fear of space being weaponized led to a race between the United States and the Soviet Union. Solving the problems of space travel resulted in the development and widespread implementation of 2,000 different commercial products that make life easier here on earth.


So too with the Torpedo Data Computer: When first installed, the device took up valuable real estate in a submarine, causing operators and engineers to continue to conceive of ever smaller and more powerful computing devices, placed in even more unlikely locations.


Would you like more insight into the history of hacking? Check out Calvin's other articles about historical hackery:
About the Author
Calvin Harper

Calvin Harper is a writer, editor, and publisher who has covered a variety of topics across more than two decades in media. Calvin is a former GoCertify associate editor.