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[[Barr and Stroud]] manufactured a large and evolving family of [[Step-by-Step]] [[Fire Control Instruments]] to convey ranges, deflections, orders and similar information throughout a ship.  By 1909, 2 main generations and one minor generation had been introduced.  By 1914, another 2 main generations and a minor generation had been introduced.
[[Barr and Stroud]] manufactured a large and evolving family of [[Step-by-Step|step-by-step]] [[Fire Control Instrument|fire control instruments]] to convey ranges, deflections, orders and similar information throughout a ship.  Over time, the Royal Navy would come to rely on many Barr and Stroud devices, as they edged out competing product lines such as [[Siemens Fire Control Instruments]] and achieved a healthy proportion of adoption alongside those of [[Vickers Fire Control Instruments]].


==Prototype Design and Testing==
==Early Designs==
todo: Range and Vision photo p. 35.
Part of the Royal Navy's advertisement for workable rangefinding equipment that inspired Barr and Stroud's formation and their main line of business also specified that the rangefinders should be able to instantaneously send their indications.  Barr and Stroud delivered range and order instruments in 1894 and refined it over a period of 4 years and started installations on Japanese capital ships.<ref>Moss & Russell, ''Range and Vision'', p. 34.</ref>


In 1903, some Barr and Stroud prototype instruments were bolted onto plates, the backside of which were fired upon by a Maxim machine gun in bursts of 3-20 rounds in order to ascertain their resilience to shock.  There were some failures, but most were simply cases of the transmitter and receiver being put out of step.  In some tests, a sledgehammer was used to deliver the shock.<ref>''Annual Report of the Torpedo School, 1903'', p. 80.</ref> No conclusion is stated in the report, but an area of exploration mentioned in the nature of their mounting in order to absorb and reduce shock.
In 1903, some pointer-and-dial Barr and Stroud instruments were bolted onto plates, the backside of which were fired upon by a Maxim machine gun in bursts of 3-20 rounds in order to ascertain their resilience to shock.  There were some failures, but most were simply cases of the transmitter and receiver being put out of step.  In some tests, a sledgehammer was used to deliver the shock.{{ARTS1903|p. 80}} No conclusion is stated in the report, but an area of exploration mentioned in the nature of their mounting in order to absorb and reduce shock.


It appears that the early prototype instruments used pointers on dials to display the data.  By the Mark I era, however, it was seen as superiour for the range receiver to have the dials rotate inside the chassis and have only the proper entry displayed through an aperture.  This would have the benefit of allowing the eye to read the components of the range in proximity to each other.<ref>''Annual Report of the Torpedo School, 1904'', p. 96.</ref>
It appears that these early instruments used pointers on dials to display the data.  By the Mark I era, however, it was seen as superior for the range receiver to have the dials rotate inside the chassis and have only the proper entry displayed through an aperture.  This would have the benefit of allowing the eye to read the components of the range in proximity to each other.{{ARTS1904|p. 96}}


In 1904, reports from ships were uniformly favourable, although a minor adaptation was required in the instruments in ''London''.<ref>''Annual Report of the Torpedo School, 1904'', p. 95.</ref>
In 1904, reports from ships were uniformly favourable, although a minor adaptation was required in the instruments in {{UK-1London}}.{{ARTS1904|p. 95}}


==Mark I Instruments==
==Mark I Instruments==
The Mark I family showed promise, but none of the equipment was truly deployed except the order instruments.
{| border="1" cellpadding="3" cellspacing="0" align=right padding=12
 
|-valign="top"
The 1904 ''Annual Report of the Torpedo School'' outlined a scheme for fire control from primary and secondary control positions which would use Barr and Stroud Mark I instruments for range, deflection and orders.<ref>''Annual Report of the Torpedo School, 1904'', p. 96.</ref>
!align=right|Range
 
|0 to 9975 (later 12975) in 25 yard steps
However, by 1905, the deflection instrument was found wanting in some fashion, as the Mark I range and order instruments were now to be paired with [[Vickers]] deflection instruments, as an "approximately correct" list of 18 ships to be so equipped reveals, although no explanation is offered.<ref>''Annual Report of the Torpedo School, 1905'', p. 74.</ref>
|-valign="top"
 
!align=right|Deflection
Advances and alterations were rapid.  By 1908, the Mark I instruments were considered obsolete to the point that the ''Torpedo Drill Book'' explicitly declined to describe them.<ref>''Torpedo Drill Book, 1908'', p. 238.</ref>  By 1908 only order instruments remained in use anywhere,<ref>''Handbook of Fire Control Instruments, 1909'', p. 22.</ref> but they remained in service in some ships in 1914.<ref>''Torpedo Drill Book, 1914'', p. 290.</ref> 
|50 knots left or right
 
|-valign="top"
By 1909, dissatisfaction with the Mark I range instruments was apparent (see below), as the ships were now equipped with Mark II range instruments, Mark I order instruments, and the Vickers deflection instruments.  Moreover, ''King Edward VII'' and ''New Zealand''/''Zealandia'' from the original list were apparently fitted with Barr and Stroud Mark II/II* instruments throughout.<ref>''Handbook of Fire Control Instruments, 1909'', p. 56.</ref>
!align=right|Orders
 
|3 binary orders, with gong
===Mark I Range Instruments===
|-valign="top"
{|align="right" border="2" cellpadding="2" cellspacing="0" style="margin: 0 0 1em 0.5em; background: #f9f9f9; border: 1px #aaa solid; border-collapse: collapse; font-size: 95%;" width="300"
!align=right|Rate
!colspan=2 style="color: white; height: 30px; background: crimson;"| Mark I Pattern Numbers
|in seconds to alter 50 yards
|-
|-valign="top"
|'''Single Range Transmitter'''
!align=right|Bearing
!align=center|unknown
|[[Compass Quadrant Bearing]]s in <small><sup>1</sup></small>/<small><sub>4</sub></small> degree steps
|-
|'''Single Range Receiver'''
!align=center|unknown
|}
|}
Although cyclometric design (where numbers were on cylindrical drums, as in old odometers) came to characterise Barr and Stroud equipment, the Mark I range transmitter and receiver used numbered dials, with one numeric entry on each dial being visible through an aperture on the face of the instrument.  The rightmost dial contained 40 3 digit entries from 000 to 975 in increments of 25 yards.  The left dial was numbered 0 to 12, and denoted thousands.<ref>''Annual Report of the Torpedo School, 1904'', p. 96.</ref><ref>''Annual Report of the Torpedo School, 1905'', p. 75.</ref>  The maximum range that could be conveyed, therefore, was 12975 yards.
:[[Barr and Stroud Mark I Fire Control Instruments|Main article]]


It is not certain whether the two dials in the transmitter and receiver were mechanically connected (so that advancing a single handle to work the right dial from 975 to 000 would cause the left dial to index) or entirely separate with each being directly workable.  It seems more likely that the latter case was true, as they were described as being "double".<ref>''Annual Report of the Torpedo School, 1904'', p. 96.</ref>
The 1904 ''Annual Report of the Torpedo School'' outlined a scheme for fire control from primary and secondary control positions which would use Barr and Stroud Mark I instruments for range, deflection and orders.{{ARTS1904|p. 96}} Some problems seem to have arisen, as these first installations used only the Mark I order instruments, though Mark II Barr and Stroud range instruments were substituted for the earlier models. As these installations were being made, other ships received [[Siemens Fire Control Instruments]]


===Mark I Deflection Instruments===
Advances and alterations were rapid. By 1908, the Mark I instruments were considered obsolete to the point that the ''Torpedo Drill Book'' explicitly declined to describe them.<ref>''Torpedo Drill Book, 1908'', p. 238.</ref>
{|align="right" border="2" cellpadding="2" cellspacing="0" style="margin: 0 0 1em 0.5em; background: #f9f9f9; border: 1px #aaa solid; border-collapse: collapse; font-size: 95%;" width="300"
!colspan=2 style="color: white; height: 30px; background: crimson;"| Mark I Pattern Numbers
|-
|'''Single Deflection Transmitter'''
!align=center|unknown
|-
|'''Single Deflection Receiver'''
!align=center|unknown
|}


These were described as a planned part of initial orders and installation, but by 1905 planning soon shifted in favour of Vickers instruments for this.  The instruments probably had pointers on dial faces or numbered dials with an aperture.  It could handle deflections "from 0 to 50 knots, right or left,"<ref>''Annual Report of the Torpedo School, 1904'', p. 96.</ref> which I interpret as  meaning 3 possible basic forms, the first appearing most strongly implied:
By 1909, dissatisfaction with the Mark I range instruments was apparent (see below), as the ships were now equipped with Mark II range instruments, Mark I order instruments, and the Vickers deflection instruments.  Moreover, ''King Edward VII'' and ''New Zealand'' a.k.a. ''Zealandia'' from the original list were apparently fitted with Barr and Stroud Mark II/II* instruments throughout.{{HFCI1909|p. 56}}
* a dial with 51 positions and a 2 position (Left, Right) shutter
* a dial with 101 positions
* a dial with 50 positions and a 3 position shutter (Left, None, Right)


===Mark I Order Instruments===
Judging by their pattern numbers, the Mark I rate and bearing instruments seem to have been designed much later than the other Mark I instruments, perhaps being assigned the lower mark number simply because they were the first Barr and Stroud instruments made for these purposes.  This apparent practice was continued by the appearance of a modified form of a later Mark's single order instruments as the "Mark I" fall-of-shot instruments first installed in ''Queen Elizabeth'' in 1915.{{ARTS1915|p. 250}}
TODO: plat4s 17 and 18 from 1914 FCI handbook


{|align="right" border="2" cellpadding="2" cellspacing="0" style="margin: 0 0 1em 0.5em; background: #f9f9f9; border: 1px #aaa solid; border-collapse: collapse; font-size: 95%;" width="300"
==Mark II Instruments==
!colspan=2 style="color: white; height: 30px; background: crimson;"| Mark I Pattern Numbers
{| border="1" cellpadding="3" cellspacing="0" align=right padding=12
|-
|-valign="top"
|'''Single Order Transmitter'''
!align=right|Range
!align=center|57
|0 to ???? in 25 yard steps
|-
|-valign="top"
|'''Single Order Receiver'''
!align=right|Deflection
!align=center|53
|?? knots left or right
|-valign="top"
!align=right|Orders
|1 order selected from menu of 8-10
|-valign="top"
!align=right|Rate
|0 to 1990 yards / minute, opening or closing, in steps of 10
|-valign="top"
!align=right|Bearing
|No Mark II instruments? (see Mark II*)
|}
|}
The upper portion of the pattern 57 order transmitter's case had three apertures through which the indications could be read. The indications were on vulcanite sleeves on spindles which protruded out the sides of the case where handles permitted them to be rotated up or down through 90 degrees or so to on of two commands.  A spring pin within the transmitter grabbed the spindle to secure it within either of the two of the positions.  Moving a handle to the down position completed the corresponding circuit to the receiver.
todo: range and vision photo p. 69.
:[[Barr and Stroud Mark II Fire Control Instruments|Main article]]


Each sleeve's face was marked with either two command indications or a command and a blank face, and the reverse side contained contacts that would complete a circuit in one position and break it in the other.  When the handles were in their down position, the corresponding order circuit was energized, and they were otherwise off.  
Initial testing of the new Mark II instruments occurred at ''Vernon'', ''Excellent'' and on board ''Britannia'' during gun trials.  Troubles in getting the transmitter to stop at the desired range was solved by employing a fast and slow speed setting for the handle (100 yards per revolution versus 25 yards).


{|border="2" cellpadding="2" cellspacing="0" style="margin: 0 0 1em 0.5em; background: #f9f9f9; border: 1px #aaa solid; border-collapse: collapse; font-size: 95%;" width="420"
Competitive testing run by ''Vernon'' and ''Excellent'' using instruments from [[Vickers]] and the Facsimile Syndicate Company showed Barr and Stroud the best overall choice.
|-
|
!colspan=2|Orders as of 1905
!colspan=2|Orders as of 1914
|-
!align=center|
!align=center|Handle Down<br>(power on)
!align=center|Handle Up<br>(power off)
!align=center|Handle Down<br>(power on)
!align=center|Handle Up<br>(power off)
|- align=center
!align=center|Slot 1
|''blank''
|"Cease fire"
|''blank''
|"Cease"
|- align=center
!align=center|Slot 2
|"Controlled"
|"Independent"
|"Indep."
|''blank''
|- align=center
!align=center|Slot 3
|"Commence"
|''blank''
|"Fire"
|''blank''
|-
!align=center|Gong
!colspan=2|Rang when any command changed
!colspan=2|Rang when shutter 3 went to "Fire"
|}


The Mark II family introduced the classic pattern of design for Barr and Stroud, centered on cyclometric displays augmented by indicating shutters.  A notable improvement in thinking was to agglomerate range, deflection and order indications into a single combined receiver to simplify wiring and produce a more compact arrangement at both ends.  However, standalone products for single range, single order and single deflection would continue to be produced through Mark III &mdash; perhaps with an eye to updating Mark I ships or simply to provide flexibility.  Additionally, the Mark II family included single range instruments and new rate instruments.


The pattern 53 single order receiver resembled the transmitter, but lacked the handles and included a single-stroke gong which was criticised in 1905 for being too quiet.<ref>''Annual Report of the Torpedo School, 1905'', p. 75.</ref>  Although the outward appearance of the windows was similar, the shutters had just one command written on them which was either swung up out of view to allow a fixed command underneath to be seen, or drawn down by electromagnet to cover the fixed command. 
==Mark II* Instruments==
 
{| border="1" cellpadding="3" cellspacing="0" align=right padding=12
A single-stroke gong is fitted to the top of the receiver, and the circuit is such that the gong sounds a single time when the lower shutter switches from its blank state to "Fire".  In this manner, the operator of the transmitter sounds firing gongs at the receivers when he moves the lowest handle to the "Fire" position.  The receiver requires four wires to control its 3 separate shutters and provide a return.
|-valign="top"
 
!align=right|Range
===Mark I Rate Instruments===
|0 to ??? in 25 yard steps
{|align="right" border="2" cellpadding="2" cellspacing="0" style="margin: 0 0 1em 0.5em; background: #f9f9f9; border: 1px #aaa solid; border-collapse: collapse; font-size: 95%;" width="300"
|-valign="top"
!colspan=2 style="color: white; height: 30px; background: crimson;"| Mark I Pattern Numbers
!align=right|Deflection
|-
|?? knots left or right
|'''Single Rate Transmitter'''
|-valign="top"
!align=center|812
!align=right|Orders
|-
|1 order selected from menu of 10
|'''Single Rate Receiver'''
|-valign="top"
!align=center|811
!align=right|Rate
|??? yards per minute opening or closing in steps of 25
|-valign="top"
!align=right|Bearing
|relative bearings in <small><sup>1</sup></small>/<small><sub>4</sub></small> degree steps
|}
|}
===Mark I Bearing Instruments===
:[[Barr and Stroud Mark II* Fire Control Instruments|Main article]]
{|align="right" border="2" cellpadding="2" cellspacing="0" style="margin: 0 0 1em 0.5em; background: #f9f9f9; border: 1px #aaa solid; border-collapse: collapse; font-size: 95%;" width="300"
!colspan=2 style="color: white; height: 30px; background: crimson;"| Mark I Pattern Numbers
|-
|'''Single Bearing Transmitter'''
!align=center|2591
|-
|'''Single Bearing Receiver'''
!align=center|2590
|}
==Mark II Instruments==
Mark II introduced the classic pattern of design for Barr and Stroud, in which cyclometric digital displays predominated.  A notable improvement in thinking was to agglomerate range, deflection and order indications into a single combined receiver to simplify wiring and produce a more compact arrangement at both ends.  However, standalone products for single range, single order and single deflection would continue to be produced through Mark III &mdash; perhaps with an eye to updating Mark I ships or simply to provide flexibility.
 
===Testing===
 
{|align="right" border="2" cellpadding="2" cellspacing="0" style="margin: 0 0 1em 0.5em; background: #f9f9f9; border: 1px #aaa solid; border-collapse: collapse; font-size: 95%;" width="512"
!style="color: white; height: 30px; background: crimson;"| 1906 Testing between:
!style="color: white; height: 30px; background: crimson;"| Vickers
!style="color: white; height: 30px; background: crimson;"| B & S
!style="color: white; height: 30px; background: crimson;"| F.S.C.
|-
|Wires up mast for one group transmitters to<br>one group receivers, any number of guns,<br>including repeat receivers aloft
!align=center|17
!align=center|12
!align=center|&mdash;
|-
|Number of Orders
!align=center|&mdash;
!align=center|8
!align=center|10
|-
|Easy to stop at required indication?
!align=center|Yes
!align=center|Yes
!align=center|Not so easy<br>as Vickers
|-
|Reliability to keep step
!align=center|Very Good
!align=center|Very Good
!align=center|Good
|-
|Durability in order of merit
!align=center|2
!align=center|1
!align=center|3
|-
|Ease of repair in order of merit
!align=center|2
!align=center|1
!align=center|3
|-
|Lowest voltage receivers will work at
!align=center|12.5
!align=center|10
!align=center|14
|-
|Suitability for placing conveniently for sightsetter
!align=center|3
!align=center|2
!align=center|1
|-
|Size of combined receiver, inches
!align=center|7 x 5.5 x 10
!align=center|10 x 6 x 6.5
!align=center|4.5 x 2.5 x 3
|-
|Size of figures
!align=center|7/16 inch
!align=center|5/16 inch
!align=center|5/16 inch
|}
 
Mark II instruments were tested by ''Vernon'' and ''Excellent'' in 1906 in comparative trials with Vickers relay and some very small devices from the Facsimile Syndicate Company.  The conclusion was that Barr and Stroud had the best system for heavy guns but could be improved by reducing receiver size for use at [[Q.F.]] guns.<ref>''Annual Report of the Torpedo School, 1906'', p. 84.</ref>


These were outwardly indistinguishable from the Mark II instruments, but their internal wiring and brushes differed.  The function would have been identical, and the changes were perhaps to enhance problems maintaining connectivity in Mark II plugs &mdash; the most common type of failure particular to that series. 


==Mark II* Instruments==
The Mark II* family included combination instruments as well as separate instruments for ranges, range rates, orders, and bearings.


As the Royal Navy's thinking on best practices matured, the instruments kept pace:  Mark II* bearing instruments differed from those of the Mark I generation by moving to relative bearings from the quaint use of [[Compass Quadrant Bearing]]s, and the Mark II* rate instruments used steps of 25 yards per minute rather than 10 as had been used in the Mark II instruments.


==Mark III Instruments==
==Mark III Instruments==
{| border="1" cellpadding="3" cellspacing="0" align=right padding=12
|-valign="top"
!align=right|Range
|0 to ??? in 25 yard steps
|-valign="top"
!align=right|Deflection
|?? knots left or right
|-valign="top"
!align=right|Orders
|1 order selected from menu of 10
|-valign="top"
!align=right|Rate
|??? yards per minute opening or closing in steps of 25
|-valign="top"
!align=right|Bearing
|relative bearings in <small><sup>1</sup></small>/<small><sub>4</sub></small> degree steps
|}
:[[Barr and Stroud Mark III Fire Control Instruments|Main article]]
The Mark III family was probably introduced sometime shortly after 1909.<ref>not mentioned in ''Handbook for Fire Control Instruments, 1909''</ref>


The family included combination instruments as well as some for single ranges, orders, rates and bearings.  The range instrument sported some new features that recommended its use for reporting range cuts from rangefinders down to the TS, but generally the differentiating feature was that the external wiring to the instruments was consolidated so all cores would be admitted through a single gland.


==Mark III* Instruments==
==Mark III* Instruments==
:[[Barr and Stroud Mark III* Fire Control Instruments|Main article]]
Not much is known of the Mark III* family.  It appears that it included rate instruments and single order instruments, but perhaps no more than that.


==Mark IV Instruments==
==Mark IV Instruments==
 
:[[Barr and Stroud Mark IV Fire Control Instruments|Main article]]
Appearing during or before 1914, the Mark IV family had rate and bearing instruments, but perhaps no more than that.


==See Also==
==See Also==
*[[Siemens Fire Control Instruments]]
*[[Vickers Fire Control Instruments]]
*[[Barr and Stroud Rangefinders]]


==Footnotes==
==Footnotes==
Line 208: Line 132:


==Bibliography==
==Bibliography==
<small>
{{refbegin}}
*{{BibUKARTS1903}}
*{{ARTS1903}}
*{{BibUKTorpedoDrillBook1905}}
*{{ARTS1904}}
*{{BibUKTorpedoDrillBook1908}}
*{{ARTS1906}}
*{{BibUKTorpedoDrillBook1912}}
*{{TorpDB1905}}
*{{BibUKTorpedoDrillBook1914}}  
*{{TorpDB1908}}
*{{BibUKHandbookFireControlInstruments1909}}
*{{TorpDB1912}}
*{{BibUKHandbookFireControlInstruments1914}}  
*{{TorpDB1914}}  
</small>
*{{HFCI1909}}
*{{HFCI1914}}  
{{refend}}


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

Latest revision as of 18:06, 1 May 2015

Barr and Stroud manufactured a large and evolving family of step-by-step fire control instruments to convey ranges, deflections, orders and similar information throughout a ship. Over time, the Royal Navy would come to rely on many Barr and Stroud devices, as they edged out competing product lines such as Siemens Fire Control Instruments and achieved a healthy proportion of adoption alongside those of Vickers Fire Control Instruments.

Early Designs

todo: Range and Vision photo p. 35. Part of the Royal Navy's advertisement for workable rangefinding equipment that inspired Barr and Stroud's formation and their main line of business also specified that the rangefinders should be able to instantaneously send their indications. Barr and Stroud delivered range and order instruments in 1894 and refined it over a period of 4 years and started installations on Japanese capital ships.[1]

In 1903, some pointer-and-dial Barr and Stroud instruments were bolted onto plates, the backside of which were fired upon by a Maxim machine gun in bursts of 3-20 rounds in order to ascertain their resilience to shock. There were some failures, but most were simply cases of the transmitter and receiver being put out of step. In some tests, a sledgehammer was used to deliver the shock.[2] No conclusion is stated in the report, but an area of exploration mentioned in the nature of their mounting in order to absorb and reduce shock.

It appears that these early instruments used pointers on dials to display the data. By the Mark I era, however, it was seen as superior for the range receiver to have the dials rotate inside the chassis and have only the proper entry displayed through an aperture. This would have the benefit of allowing the eye to read the components of the range in proximity to each other.[3]

In 1904, reports from ships were uniformly favourable, although a minor adaptation was required in the instruments in London.[4]

Mark I Instruments

Range 0 to 9975 (later 12975) in 25 yard steps
Deflection 50 knots left or right
Orders 3 binary orders, with gong
Rate in seconds to alter 50 yards
Bearing Compass Quadrant Bearings in 1/4 degree steps
Main article

The 1904 Annual Report of the Torpedo School outlined a scheme for fire control from primary and secondary control positions which would use Barr and Stroud Mark I instruments for range, deflection and orders.[5] Some problems seem to have arisen, as these first installations used only the Mark I order instruments, though Mark II Barr and Stroud range instruments were substituted for the earlier models. As these installations were being made, other ships received Siemens Fire Control Instruments

Advances and alterations were rapid. By 1908, the Mark I instruments were considered obsolete to the point that the Torpedo Drill Book explicitly declined to describe them.[6]

By 1909, dissatisfaction with the Mark I range instruments was apparent (see below), as the ships were now equipped with Mark II range instruments, Mark I order instruments, and the Vickers deflection instruments. Moreover, King Edward VII and New Zealand a.k.a. Zealandia from the original list were apparently fitted with Barr and Stroud Mark II/II* instruments throughout.[7]

Judging by their pattern numbers, the Mark I rate and bearing instruments seem to have been designed much later than the other Mark I instruments, perhaps being assigned the lower mark number simply because they were the first Barr and Stroud instruments made for these purposes. This apparent practice was continued by the appearance of a modified form of a later Mark's single order instruments as the "Mark I" fall-of-shot instruments first installed in Queen Elizabeth in 1915.[8]

Mark II Instruments

Range 0 to ???? in 25 yard steps
Deflection ?? knots left or right
Orders 1 order selected from menu of 8-10
Rate 0 to 1990 yards / minute, opening or closing, in steps of 10
Bearing No Mark II instruments? (see Mark II*)

todo: range and vision photo p. 69.

Main article

Initial testing of the new Mark II instruments occurred at Vernon, Excellent and on board Britannia during gun trials. Troubles in getting the transmitter to stop at the desired range was solved by employing a fast and slow speed setting for the handle (100 yards per revolution versus 25 yards).

Competitive testing run by Vernon and Excellent using instruments from Vickers and the Facsimile Syndicate Company showed Barr and Stroud the best overall choice.

The Mark II family introduced the classic pattern of design for Barr and Stroud, centered on cyclometric displays augmented by indicating shutters. A notable improvement in thinking was to agglomerate range, deflection and order indications into a single combined receiver to simplify wiring and produce a more compact arrangement at both ends. However, standalone products for single range, single order and single deflection would continue to be produced through Mark III — perhaps with an eye to updating Mark I ships or simply to provide flexibility. Additionally, the Mark II family included single range instruments and new rate instruments.

Mark II* Instruments

Range 0 to ??? in 25 yard steps
Deflection ?? knots left or right
Orders 1 order selected from menu of 10
Rate ??? yards per minute opening or closing in steps of 25
Bearing relative bearings in 1/4 degree steps
Main article

These were outwardly indistinguishable from the Mark II instruments, but their internal wiring and brushes differed. The function would have been identical, and the changes were perhaps to enhance problems maintaining connectivity in Mark II plugs — the most common type of failure particular to that series.

The Mark II* family included combination instruments as well as separate instruments for ranges, range rates, orders, and bearings.

As the Royal Navy's thinking on best practices matured, the instruments kept pace: Mark II* bearing instruments differed from those of the Mark I generation by moving to relative bearings from the quaint use of Compass Quadrant Bearings, and the Mark II* rate instruments used steps of 25 yards per minute rather than 10 as had been used in the Mark II instruments.

Mark III Instruments

Range 0 to ??? in 25 yard steps
Deflection ?? knots left or right
Orders 1 order selected from menu of 10
Rate ??? yards per minute opening or closing in steps of 25
Bearing relative bearings in 1/4 degree steps
Main article

The Mark III family was probably introduced sometime shortly after 1909.[9]

The family included combination instruments as well as some for single ranges, orders, rates and bearings. The range instrument sported some new features that recommended its use for reporting range cuts from rangefinders down to the TS, but generally the differentiating feature was that the external wiring to the instruments was consolidated so all cores would be admitted through a single gland.

Mark III* Instruments

Main article

Not much is known of the Mark III* family. It appears that it included rate instruments and single order instruments, but perhaps no more than that.

Mark IV Instruments

Main article

Appearing during or before 1914, the Mark IV family had rate and bearing instruments, but perhaps no more than that.

See Also

Footnotes

  1. ↑ Moss & Russell, Range and Vision, p. 34.
  2. ↑ Annual Report of the Torpedo School, 1903. p. 80.
  3. ↑ Annual Report of the Torpedo School, 1904. p. 96.
  4. ↑ Annual Report of the Torpedo School, 1904. p. 95.
  5. ↑ Annual Report of the Torpedo School, 1904. p. 96.
  6. ↑ Torpedo Drill Book, 1908, p. 238.
  7. ↑ Handbook for Fire Control Instruments, 1909. p. 56.
  8. ↑ Annual Report of the Torpedo School, 1915. p. 250.
  9. ↑ not mentioned in Handbook for Fire Control Instruments, 1909

Bibliography

  • H.M.S. Vernon. Annual Report of the Torpedo School, 1903, with Appendix (Wireless Telegraphy). Copy 478 at The National Archives. ADM 189/23.
  • H.M.S. Vernon. Annual Report of the Torpedo School, 1904, with Appendix (Wireless Telegraphy). Copy 237 at The National Archives. ADM 189/24.
  • H.M.S. Vernon. Annual Report of the Torpedo School, 1906, with Appendix (Wireless Telegraphy). Copy 46 at The National Archives. ADM 189/26.
  • H.M.S.O., London Torpedo Drill Book, 1905 (Corrected to December, 1904). Copy in Tony Lovell's library.
  • H.M.S.O., London Torpedo Drill Book, 1908 (Corrected to December, 1907). Copy in Tony Lovell's library.
  • H.M.S.O., London Torpedo Drill Book, 1912 (Corrected to April, 1912). Copy in Tony Lovell's library.
  • H.M.S.O., London (1914). Torpedo Drill Book, 1914 (Corrected to May 15) Copy in Tony Lovell's library.
  • Admiralty, Gunnery Branch (1910). Handbook for Fire Control Instruments, 1909. Copy No. 173 is Ja 345a at Admiralty Library, Portsmouth, United Kingdom.
  • Admiralty, Gunnery Branch (1914). Handbook for Fire Control Instruments, 1914. G. 01627/14. C.B. 1030. Copy 1235 at The National Archives. ADM 186/191.

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