View source for Vickers Dial Fire Control Instruments

Although [[Vickers]] made its greatest impact on history with its later [[Vickers F.T.P. Fire Control Instruments|F.T.P. instruments]], its first offerings were a precursor that was widely deployed through 1906.

Vickers "dial instruments" were step-by-step devices more accurately referred to as "cyclometric instruments", like those of [[Barr and Stroud Fire Control Instruments|Barr and Stroud]].  That is, they did not indicate on a clockface, but digitally, as an old-time speedometer.<ref>All information in this article, unless otherwise indicated, based on ''Handbook for Fire Control Instruments, 1914'', pp 14-18.</ref>

==Allocation and Use==
A set of nine range receivers and a single transmitter were tested in early 1905 at the company, connected by coils of wire intended to replicate the harness that would be installed on a ship.  Ten minutes of rough handling of the transmitter defied efforts to cause a misstep despite the receivers being held in a variety of positions, and even upside down.  Small defects only were observed and noted for correction before sets were to be delivered for {{UK-Dominion}} and {{UK-Victorious}}.{{PQDNO1905|pp. 466-7}}

Despite this promising test, competitive testing in 1906 determined that Barr and Stroud's range and deflection instruments Mark II were the best available, and so a considerable spree of adoption of Vickers dial instruments came to an abrupt end after their use in {{UK-Dreadnought}}.

By 1914, these were still listed as being used in thirty-seven ships, battleships up to ''Dreadnought'', as well as in an assortment of armoured cruisers.  The [[King Edward VII Class Battleship (1903)|''King Edward VII'']] class is evenly split between these instruments and [[Barr and Stroud Mark II Fire Control Instruments]] which are also used by later vessels, it seems fair to judge that the Barr and Stroud family had replaced Vickers for the time being, though the 1908-1909 advent of her {{FTP}} instruments used in {{UK-Boadicea}} was to return her to the top.

==Range and Deflection Transmitters==
[[File:HFCI1914Plate7.jpg|thumb|240px|''''Range Transmitter'''{{HFCI1914|Plate 7}}]]

The separate range and deflection transmitters had tell-tale receivers built into them to indicate the value, and a single handle by which to drive the value through its range.  They were identical except for the drums of the integral tell-tale.

Early patterns (Pattern 319 for range and 318 for deflection) had <sup><small>1</small></sup>/<sub><small>4</small></sub> inch figures and were geared such that a single revolution of the range handle would alter range by 100 yards (or 4 knots?), but this was changed in the later Pattern 103 and Pattern 102 to have larger <sup><small>1</small></sup>/<sub><small>2</small></sub> inch figures one revolution equal 25 yards or one knot of deflection.

==Combined Range and Deflection Receiver==
[[File:HFCI1914Plate8.jpg|left|thumb|200px|''''Combined Range and Deflection Receiver'''{{HFCI1914|Plate 8}}]]

The range and deflection receiver armatures differed only in the markings and the contact surfaces of their display drums.  The range receiver could indicate up to 19,975 yards on four drums, the rightmost of which had 00, 25, 50 and 75 markings only.  The deflection receiver had two independent pairs of drums to indicate right and left deflections, each capable of going to 50 knots.  A pair of shutters were arranged such that only the deflection drum set that was reading above zero would be visible.  A set of stops prevented the drums fro reading past their last indication, and served as the means to synchronise transmitter and receiver.

A lower, single shutter displayed simple order information being transmitted by the "Check Fire Switch".  It showed a white disc to indicate "control fire" and a red disc for "check fire".

A single 8-core cable was required (2 for the motor fields, 2 to power each armature, and two common returns, one for each armature.

A threaded plug with a butterfly head could be removed so that a mechanical key could be used to quickly reset the drums should a speedy synchronisation be required without having to drive the transmitter through the entire range of indictions.  Curiously, these appear absent on the transmitter diagram.

The original Pattern 99 combined receiver (with <sup><small>1</small></sup>/<sub><small>4</small></sub> inch figures?) was later replaced with a Pattern 320, which had larger, <sup><small>1</small></sup>/<sub><small>2</small></sub>> inch figures.  

==Single Deflection Receiver==
There was a single deflection receiver, Pattern 317.

==Check Fire Switch==
[[File:HFCI1914Plate9.jpg|thumb|240px|''''Check fire switch'''{{HFCI1914|Plate 9}}]]

There were no separate order instruments, but each set of instruments featured a 3 position "check fire switch" (Pattern 101) near the transmitters that could be set to "Control Fire" or "Check Fire" to cause the receivers to expose a white or a red disc, respectively.  The intermediate position of this switch was labelled "Off" and removed power from the attached instruments entirely. 

==Footnotes==
{{reflist}}

==Bibliography==
{{refbegin}}
*{{ARTS1903}}
*{{ARTS1904}}
*{{ARTS1906}}
*{{TorpDB1905}}
*{{TorpDB1908}}
*{{TorpDB1912}}
*{{TorpDB1914}} 
*{{HFCI1909}}
*{{HFCI1914}} 
{{refend}}

[[Category:Fire Control]]
[[Category:Shipboard Equipment]]