Deflection Master Transmitter

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A Deflection Master Transmitter was an instrument mounted on the bulkhead of the TS in a Royal Navy vessel. Alterations in deflection arrived from the deflection totaliser of a Dreyer Fire Control Table by a flexible shaft. An operator would then note the change and "follow the pointer" to relay the data on to the guns and director.


The actual outputs of the Dreyer Fire Control Tables were flexible shafts coming from handles worked at the table. In the case of deflection, this came from the deflection totaliser which computed an aggregate deflection for use in firing. In order to avoid imposing undue load on the flexible shaft which conveyed this data, it was seen as wise to place another F.T.P. dislocation in the data path, and the deflection master transmitter provided such a buffer. The deflections output from the totaliser would move a red pointer on the clock face of this instrument, and its operator would chase it with a handle driving a black pointer. His action would also drive a series of "slave" deflection transmitters. one for each turret (and one for each director?) to pass the data on by a step-by-step circuitry.

Each slave transmitter had a knob by which a bias could be introduced in that transmission path only. It is not clear if this capability was intended to permit a willful increase in salvo pattern for deflection or to permit correction in the apparent misstep of one slave circuit only.

The deflection was probably altered 2 knots by each full revolution of the handle.[1]

See Also


  1. Manual of Gunnery (Volume III) for His Majesty's Fleet, 1915. p. 36.


  • Schleihauf, Bill (2001). "The Dumaresq and the Dreyer, Part I-III." Warship International 38 (1-3).
  • 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.