Mechanical Aid-to-Spotter Mark II
The Mechanical Aid-to-Spotter Mark II was a refined version of the Mechanical Aid-to-Spotter Mark I, and was likewise deployed in capital ships of the Grand Fleet.
This device is detailed in Manual of Gunnery for HM Fleet, Volume III, 1920.[6] Supply of these to the latest capital ships commenced in the early months of 1919.[7]
Installations generally followed this pattern:[8][9]
- one on each side of the foretop, driven by flexible shafting from the Evershed rack on the director
- one on each side of the Gun Control Tower employing an electrical F.T.P. system.
The deflection dials had an index marked "S.T.Z." for "Sight Testing Zero", which is the true zero-deflection mark. The zero mark used generally is at 6 knots left deflection, meant to be an average drift deflection at all ranges.[10]
Deployment
By 1920, it was fitted in 22 ships:[11] the four Iron Dukes, the five Queen Elizabeths, the five Revenges, Canada, Tiger, the two surviving Lions, the two Renowns, and the two Courageous class battlecruisers.
The control top instruments were driven off the director's Evershed rack by a flexible steel shaft enclosed in copper piping, and was also connected to the top's own Evershed transmitter by flexible tubing. The G.C.T. devices used an F.T.P. receiver connected to the slewing transmitter of the aloft director.[12]
With 44 various capital ships equipped with these and the Mark I devices, the Grand Fleet's heavy ships were just about fully furnished by the end of the war or soon thereafter. The next audience for such tools would be the light cruisers, and well over 60 of those vessels were outfitted with downsized installations of the Mechanical Aid-to-Spotter Mark II*.
See Also
- Spotting
- Mechanical Aid-to-Spotter Mark I
- Mechanical Aid-to-Spotter Mark II*
- Evershed Bearing Indicator
- Usborne Fall of Shot Indicator
Footnotes
- ↑ Manual of Gunnery for H.M. Fleet, Volume III, 1920, Plate 46.
- ↑ Manual of Gunnery for H.M. Fleet, Volume III, 1920, Plate 51.
- ↑ Manual of Gunnery for H.M. Fleet, Volume III, 1920, Plate 48.
- ↑ Manual of Gunnery for H.M. Fleet, Volume III, 1920, Plate 49.
- ↑ Manual of Gunnery for H.M. Fleet, Volume III, 1920, Plate 45.
- ↑ Manual of Gunnery for H.M. Fleet, Volume III, 1920, pp. 35-37, Plates 45, 47, 49, 51.
- ↑ The Technical History and Index, Vol. 3, Part 23. pp. 26.
- ↑ The Technical History and Index, Vol. 3, Part 23. pp. 25-26.
- ↑ Manual of Gunnery for HM Fleet, Volume III, 1920, p. 35.
- ↑ The Technical History and Index, Vol. 3, Part 23. pp. 26.
- ↑ Manual of Gunnery for HM Fleet, Volume III, 1920, p. 35.
- ↑ Manual of Gunnery for HM Fleet, Volume III, 1920, pp. 35-6.
Bibliography
- Admiralty, Technical History Section (1919). The Technical History and Index: Fire Control in H.M. Ships. Vol. 3, Part 23. C.B. 1515 (23) now O.U. 6171/14. At The National Archives. ADM 275/19.
- Handbook for this device (not read by me) C.B. 1285
