Mechanical Aid-to-Spotter Mark II*: Difference between revisions

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An installation was generally a pair mounted on each side of the fore top.<ref>''Manual of Gunnery for HM Fleet, Volume III, 1920'', p. 37.</ref>
An installation was generally a pair mounted on each side of the fore top.<ref>''Manual of Gunnery for HM Fleet, Volume III, 1920'', p. 37.</ref>


==Deployment==
Supply of the instruments commenced in June, 1918.  The great variety in gun types on light cruisers warranted removal of the "S.T.Z." (Sight testing Zero) index used in the earlier models in favor of a movable pointer that could be positioned as any given gunsight would prefer for average drift correction.  These were not driven by Evershed racks, but from a gearbox at the director tower, immediately over the center of the director.  Some worked with the Elliott Bearing Transmitter, which lacked deflection arrangement and which therefore required the Aids to Spotter to have a separate deflection box installed on the bearing transmission line.{{FCHMShips|pp. 26}}
Supply of the instruments commenced in June, 1918.  The great variety in gun types on light cruisers warranted removal of the "S.T.Z." (Sight testing Zero) index used in the earlier models in favor of a movable pointer that could be positioned as any given gunsight would prefer for average drift correction.  These were not driven by Evershed racks, but from a gearbox at the director tower, immediately over the center of the director.  Some worked with the Elliott Bearing Transmitter, which lacked deflection arrangement and which therefore required the Aids to Spotter to have a separate deflection box installed on the bearing transmission line.{{FCHMShips|pp. 26}}


Latest revision as of 17:09, 8 August 2013

Mark II* with Binoculars[1]
Sample Installation[2]
w/ Evershed Bearing Transmitter[3]
w/ Elliott Bearing Transmitter[4]

The Mechanical Aid-to-Spotter Mark II* was a Mechanical Aid-to-Spotter the British designed for use in light cruisers so that they might enjoy the advantages the Mark I and Mark II devices had offered capital ships.

It is described in Manual of Gunnery for HM Fleet, Volume III, 1920.[5]

An installation was generally a pair mounted on each side of the fore top.[6]

Deployment

Supply of the instruments commenced in June, 1918. The great variety in gun types on light cruisers warranted removal of the "S.T.Z." (Sight testing Zero) index used in the earlier models in favor of a movable pointer that could be positioned as any given gunsight would prefer for average drift correction. These were not driven by Evershed racks, but from a gearbox at the director tower, immediately over the center of the director. Some worked with the Elliott Bearing Transmitter, which lacked deflection arrangement and which therefore required the Aids to Spotter to have a separate deflection box installed on the bearing transmission line.[7]

By 1919, it was supplied to the Hawkins, Capetown, Caledon, Danae, Centaur and Birmingham classes, with plans to eventually fit it in Chatham, Weymouth, Cambrian, Caroline, Arethusa, Furious, Eagle and Hermes.[8]

By 1920, it was fitted in 67 ships, 16 with an Elliott Bearing Transmitter and Deflection Box, and 52 with an Evershed Bearing Transmitter (details as to which are recorded on their class pages):[9] the eight Danaes, five Hawkins class cruisers (including Vindictive), the five Capetowns, the two Emeralds (Euphrates was also listed, though she'd never be completed), the five Ceres class light cruisers, three surviving Caledons, two Centaurs, four Cambrians, two Birkenheads, two Calliopes, six Carolines, the seven surviving Arethusas, the two surviving Birminghams, six Chathams, three surviving Weymouths, Glatton, Furious, Hermes, and Eagle.

See Also

Footnotes

  1. ↑ Manual of Gunnery for H.M. Fleet, Volume III, 1920, Plate 52.
  2. ↑ Manual of Gunnery for H.M. Fleet, Volume III, 1920, Plate 56.
  3. ↑ Manual of Gunnery for H.M. Fleet, Volume III, 1920, Plate 57.
  4. ↑ Manual of Gunnery for H.M. Fleet, Volume III, 1920, Plate 58.
  5. ↑ Manual of Gunnery for HM Fleet, Volume III, 1920, pp. 37-39, Plates 52-55, 59, 60.
  6. ↑ Manual of Gunnery for HM Fleet, Volume III, 1920, p. 37.
  7. ↑ The Technical History and Index, Vol. 3, Part 23. pp. 26.
  8. ↑ The Technical History and Index, Vol. 3, Part 23. pp. 26.
  9. ↑ Manual of Gunnery for HM Fleet, Volume III, 1920, p. 35. I have screwed up the count somehow, but I think 67/16/51 is correct

Bibliography

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