Mechanical Aid-to-Spotter Mark I
The Mechanical Aid-to-Spotter Mark I was the first Mechanical Aid-to-Spotter deployed by the Royal Navy to better ensure that all members of the fire control staff were in harmony as to which ship their own was targeting.
It seems likely that supply commenced in late 1916 at the earliest.[1]
The deflection dial has an index marked "S.T.Z." for "Sight Testing Zero", which is the true zero-deflection mark. The zero mark used generally is at 5 knots left deflection, meant to be an average drift deflection at all ranges.[2] This design feature reflects the difference between turret facing and line of sight.
By 1920, it was fitted in 22 ships:[3] Dreadnought, the three Bellerophons, Agincourt, Erin, the two surviving ships of the St. Vincent class, Neptune, the two Colossus class, the two surviving Invincible class, the two surviving Indefatigables, the four Orions, and the three surviving King George Vs.
See Also
- Mechanical Aid-to-Spotter Mark II
- Mechanical Aid-to-Spotter Mark II*
- Evershed Bearing Indicator
- Usborne Fall of Shot Indicator
Footnotes
Bibliography
- Template:BibUKFireControlInHMShips1919
- Template:BibUKManGunnery1920
- Handbook for this device (not read by me) C.B. 1285
