Torpedo Data Computer: Difference between revisions

Revision as of 18:18, 2 May 2023

Revision as of 17:13, 4 October 2023

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The problem of aiming a [[torpedo]] has occupied military engineers since [[Robert Whitehead]] developed the modern torpedo in the 1860s. These early torpedoes ran at a preset depth on a straight course (consequently they are frequently referred to as "straight runners"). This was the state of the art in torpedo guidance until the development of the [[homing torpedo]] during the latter part of [[World War II]].<ref name=othertorps>There were other forms of torpedo guidance attempted throughout WWII. Notable are the Japanese human-guided ''[[Kaiten]]'' and German [[G7e#G7e/T3|pattern running]] and [[acoustic homing]] types for attacking convoys. Today, most submarine-launched torpedoes are wire-guided with terminal homing.</ref> The vast majority of submarine torpedoes during World War II were straight running, and these continued in use for many years after World War II.<ref name=USMk14his>{{cite web|url = http://www.geocities.com/Pentagon/1592/ustorp5.htm|title= Part Five: Post WW-II Submarine Launched/ Heavyweight Torpedoes|access-date=2006-07-26|author= Frederick J Milford|date= October 1997|work= US Navy Torpedoes|archive-url=https://web.archive.org/web/20060523064716/http://www.geocities.com/Pentagon/1592/ustorp5.htm|archive-date=2006-05-23}}</ref> In fact, two World War II-era straight running torpedoes — fired by the British nuclear-powered submarine {{HMS|Conqueror|S48|6}} — sank {{ship|ARA|General Belgrano}} in 1982.

During [[World War I]], computing a target intercept course for a torpedo was a manual process where the fire control party was aided by various [[slide rule]]s<ref name=fleetsub>{{cite web | title = Torpedo Data Computer | work = FleetSubmarine.com | year = 2002 | url = http://www.maritime.org/tdc.htm | access-date = 2006-07-03 | archive-date = 2012-07-17 | archive-url = https://web.archive.org/web/20120717035001/http://maritime.org/tech/tdc.htm | url-status = dead }}</ref> (the U.S. examples were the [[Mark VIII Angle Solver]] (colloquially called the "banjo", for its shape), and the "Is/Was" circular sliderule ([[Nasmith Director]]), for predicting where a target will be based on where it is now and was)<ref>Holwitt, Joel I. ''"Execute Against Japan"'', Ph.D. dissertation, Ohio State University, 2005, p.147; Beach, Edward L., Jr. ''Run Silent, Run Deep''.</ref> or mechanical calculator/sights.<ref name = dread>{{cite web |title = Firing a Torpedo Using A Mechanical Computing Sight |work=The Dreadnought Project |url =http://www.dreadnoughtproject.org/tfs/index.php/Torpedo_Director|year=2000

|access-date=2006-07-11}}</ref> These were often "woefully inaccurate",<ref>Holwitt, p. 147.</ref> which helps explain why torpedo spreads were advised.

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The TDC needed to be positioned near other [[fire-control system|fire control]] equipment to minimize the amount of electromechanical interconnect. Because submarine space within the pressure hull was limited, the TDC needed to be as small as possible. On World War II submarines, the TDC and other fire control equipment was mounted in the [[conning tower]], which was a very small space.<ref name=silent>{{cite video | people = Wise, Robert (Director-One scene shows how cramped a conning tower could be.) |date = 1958 | title = Run Silent, Run Deep | medium = Film | ___location = Pacific Ocean}}</ref>

The packaging problem was severe and the performance of some early torpedo fire control equipment was hampered by the need to make it small.<ref name=USSubHis>{{harvnb|Friedman|1995|p=350}}</ref> It had an array of handcranks, dials, and switches for data input and display.<ref>{{Cite web|url = http://www.fleetsubmarine.com/tdc.html|title = Torpedo Data Computer|date = November 2015|access-date = 2006-07-29|archive-date = 2011-02-26|archive-url = https://web.archive.org/web/20110226082027/http://www.fleetsubmarine.com/tdc.html|url-status = dead}}</ref> To generate a fire control solution, it required inputs on

*submarine course and speed, which were read automatically from the submarine's [[gyrocompass]] and [[pitometer log]]

*estimated target course, speed, and range information (obtained using data from the submarine's [[periscope]], [[Target Bearing Transmitter]] (TBT),<ref>{{cite web |url=http://www.bowfin.org/website/bowfin/bowfin_systems/TBT/tbt.htm |title=USS Bowfin - Target Bearing Transmitter |access-date=2006-07-28 |url-status=dead |archive-url=https://web.archive.org/web/20060720074815/http://www.bowfin.org/website/bowfin/bowfin_systems/TBT/tbt.htm |archive-date=2006-07-20 }}</ref> [[radar]], and [[sonar]])