Torpedo Director
File:TorpedoAttackTrainerDiagramARTS1915.jpg A Torpedo Director is merely a sight for torpedo fire, more similar to a settable gunsight than to a gunnery director.
Director Triangle
The Royal Navy began the 20th century with a series of sights that characterized the torpedo firing problem according to the Director Triangle formed by the path of the torpedo, the line of sight at the moment of firing to the target, and the path of the target between firing and impact. It delivered a number of sights which embodied this geometry, including the Pattern 2006 Torpedo Director.
Deflection Triangle
Later, the Royal Navy started to migrate toward a different geometric model called the Deflection Triangle, formed by the path of the torpedo, the line of sight, and the speed-across of the target.Template:TMBW
Tangent Bars
Basic torpedo directors were constructed such that they only worked precisely when mounted on or very near the torpedo tube they aimed. In some circumstances, it was desirable or necessary to have the sight function remotely from the torpedo tube by a considerable distance. In this case, a small additional arm called a "Tangent Bar" would be affixed to a director to offset the rear sighting arch a suitable distance so that the torpedo would converge on the target at the proper range. A consequence of adding this to the problem was that the range to the target had to be known (at least approximately... inaccuracy in ranging would just reduce the value of the correction).
See Also
Footnotes
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