A Deflection Totaliser was a component created for the Dreyer Fire Control Table consisting of several handles and geared differentials which permitted spotting corrections, corrected Dumaresq Deflection and other adjustments to be tallied into a gun deflection. Its function largely mimicked the Spotting Corrector's role in handling adjustments required to convert clock range to gun range.
The totaliser was an adding machine for various components of gun deflection to be added together. The inputs were:
The separate inputs each had a dial and a handle to set its value, and on the side of the device a large handle could chase the final sum to send it to the Deflection Master Transmitter on the bulkhead. For convenience, the Spotting column had a resettable index pointer so that successive increments could be precisely added in.
The Drift column was to account for "uncorrected drift", which may have been important if the director were firing with its 6 degree super-elevation prisms shipped, as these would cause the drift correction in use to be that of a range requiring 6 degrees less elevation.[Inference]
- Admiralty, Gunnery Branch (1918). Handbook of Captain F. C. Dreyer's Fire Control Tables, 1918. C.B. 1456. Copy No. 10 at Admiralty Library, Portsmouth, United Kingdom.