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[[File:ARTS1918Plate108.jpg|thumb|300px| '''Clear Range Indicator Mark III'''<ref>''Annual Report of the Torpedo School, 1918'', Plate 108.</ref>]] 
[[File:ARTS1918Plate117.jpg|thumb|300px| '''Clear Range Indicator Mark IV'''<ref>''Annual Report of the Torpedo School, 1918'', Plate 117.</ref>]] 
The '''Clear Range Indicator''' was a British [[Torpedo Control|torpedo-control]] instrument developed in a series of Marks.

Two designs, which appear to be those of Marks I and II, were discussed in the ''Annual Report of the Torpedo School, 1916'', having been outlined in .<ref>''Annual Report of the Torpedo School, 1916'', p. 27.  (T.O. 39/1916)</ref>

These were supplied to "all modern ships" by the end of 1917.  One was apparently fitted to the holding down ring of the [[Torpedo Deflection Sight Mark II]], and a third type was added to the spindle of the [[Torpedo Deflection Sight Mark III|T.D.S. Mark III]], an arrangement that was found to be more compact and convenient.<ref>''Annual Report of the Torpedo School, 1917'', p. 195.</ref>  Even the Spartan [[Torpedo Deflection Sight Mark VI|T.D.S. Mark VI]] had one.

==Mark I==
This original model was for use in conning towers.<ref>''Annual Report of the Torpedo School, 1918'', p. 165.</ref>  It appears that it was separate from the director or sight, and had a graduated disc that could allow the gyro angle to be read off.<ref>''Annual Report of the Torpedo School, 1916'', p. 27.</ref>

==Mark II==
This model was for use with [[Torpedo Deflection Sight Mark II]].<ref>''Annual Report of the Torpedo School, 1918'', p. 165.</ref>

==Mark III==
This model was for use with [[Torpedo Deflection Sight Mark III]] and could also help determine how much of a course alteration would be required to bring the sights on.<ref>''Annual Report of the Torpedo School, 1918'', p. 165.</ref>

==Mark IV==
<small>([[Clear Range Indicator Mark IV|main article]])</small>

This was a new model was for use in conning towers with restricted arcs.  It could serve the functions of the previous Marks but also:<ref>''Annual Report of the Torpedo School, 1918'', p. 165.</ref>
* show "the arcs between which torpedoes can be fired in connection with the restricted arcs of 70 degrees to 110 degrees."
* the [[Gyro Angle|torpedo gyro angles]] corresponding to those limits

==See Also==

==Footnotes==
{{reflist}}

==Bibliography==
{{refbegin}}
*{{BibUKHandbookOfTorpedoControl1916}}
*{{BibUKARTS1917}}
*{{BibUKARTS1918}}
{{refend}}

[[Category:Torpedo Control]]
[[Category:Shipboard Equipment]]