Barr and Stroud Mark I Fire Control Instruments

Barr and Stroud's Mark I series of step-by-step fire control instruments were evaluated and employed in limited fashion as part of the Royal Navy's early embrace of such materiel. The Mark I family showed promise, but little of the equipment was widely deployed for long except the order instruments. It was not until the Mark II family that the product line gained some maturity.

Prototype Design and Testing

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. 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.

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

In 1910, Indomitable, Inflexible and Invincible tested Mark I instruments and Telaupads as a means of tying the Torpedo Control Tower to the submerged aft torpedo tube. The TCT was able to send "Load", "Stand by" and "Fire", and the tube being able to signal "Loaded", "Ready", "Fired". Their report concluded:

• that the bell was not loud enough and a reply bell was needed.
• A fourth order, "Flood" was needed.
• the system was better than using Navyphones, but "abolition of voice-pipes regretted."

Invincible also suggested this system should be fitted in the after broadside flat, and it was observed that the submerged tubes in the City class could also benefit from the gear.

Coming so late in the Mark I epoch, it seems likely that these trial instruments were based upon dated Mark I equipment, and that the Mark I torpedo order instruments described below answered to a much more modern basis.^[Inference]

Adoption

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 instruments for range, deflection and orders.

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.

1906 saw complaints arise about flimsy dials on the Mark I range receivers. A fix was issued and tested in Exmouth, but the entire model was presently stricken in favor of Mark II range instruments which did away with dials altogether.

Advances and alterations were rapid. In 1906, the Mark II family was being tested and embraced. By 1908, the Mark I instruments were considered obsolete to the point that the Torpedo Drill Book explicitly declined to describe them. By 1908 only Mark I order instruments remained in use anywhere, though they remained in service in some ships in 1914, possibly never being replaced.^[Inference]

By 1909, dissatisfaction with the Mark I range instruments was apparent, as the ships that had been equipped with Mark I range instruments were now upgraded to Mark II models. Moreover, 4 of the 18 ships listed in 1905 were apparently fitted with Barr and Stroud Mark II instruments throughout and 2 others with Vickers equipment and Barr and Stroud rate instruments of uncertain Mark. There is no indication whether plans changed before the Mark I installation or whether an upgrade occurred afterward.

Obsolescence

By 1908, most Mark I installations were being replaced by equipment of later Marks. It is not clear whether this would encompass those devices labelled Mark I whose genesis was much later.

Range Instruments

Although cyclometric design (where numbers were on cylindrical drums, as in old odometers) would come 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.

In 1904, the left dial was numbered 0 to 9, and denoted thousands. By 1905, this design had been adapted so the left dial now could run from 0 to 12. The maximum range that could be conveyed, therefore, was 9975 or 12975 yards. This conservative incremental thinking seems to illustrate poor future-proofing.

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".

The Mark I range instruments proved immature and were replaced in service by Mark II versions soon after first installation or possibly before widespread adoption.

Deflection Instruments

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," which I interpret as meaning 3 possible basic forms, the first appearing most strongly implied:

• 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)

Order Instruments

Order Transmitter

Order Receiver

	As Described in 1905		As Described in 1914
	Handle Down (power on)	Handle Up (power off)	Handle Down (power on)	Handle Up (power off)
Slot 1	blank	"Cease fire"	blank	"Cease"
Slot 2	"Controlled"	"Independent"	"Indep."	blank
Slot 3	"Commence"	blank	"Fire"	blank
Receiver Gong	Rang when any command changed		Rang when shutter 3 went to "Fire"

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 and moved a different command into view on the transmitter to reflect the order being sent.

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.

The Pattern 53 Order Receiver required four wires to control its 3 separate shutters and provide a return. It outwardly resembled the transmitter, but lacked the handles and included a single-stroke gong which was criticised in 1905 for being too quiet. 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.

In 1906, it was realised that the order receiver's use of a gong to draw attention whenever an indication changed was creating confusion with the widespread use of single-stroke fire gongs. It was decided to alter the function so that it would act in the same way as the fire gong — only when an instantaneous salvo was being ordered. This alteration may have coincided with the change in the labeling of the orders detailed in the table. The wiring change that effected this had a minor fault, however. If the "Cease" command on the top slot were moved to its blank state while "Fire" was showing in the lowest slot, the gong would ring. The workaround employed was to train those men working the transmitters to always establish "Cease"/blank/blank when a cessation of fire was being ordered.

Rate Instruments

Rate Transmitter

Rate Receiver

The Pattern 811 Rate Receiver and Pattern 812 Rate Transmitter are described in the Handbook for Fire Control Instruments, 1914.

The devices resembled each other strongly, as the transmitter had a receiver within it to act as a tell-tale. 4 wires (one being a return) were run between the receiver and the transmitter, with the transmitter taking an additional wire for power.

The receiver display had two concentric cylinders with the outer one noting "Open" or "Close" and the inner one designating the Royal Navy's old means of expressing range rate, in number of seconds required to alter range by 50 yards. This implies that the instruments were installed relatively early. They would sorely have desired replacement or rework when the move to expressing rate in yards/minute was made c1905.^{[Citation needed]}

Bearing Instruments

Bearing Transmitter

Bearing Receiver

The Pattern 2590 Bearing Receiver and the Pattern 2591 Bearing Transmitter are described in the Handbook for Fire Control Instruments, 1914. The instruments conveyed compass bearings in quarter-degree granularity.

The receiver had three receiving elements to express the bearing according to the old Compass Quadrant Bearing system. The first of these was a digital cyclometric display with 3 drums able to convey bearings in 2 digits and ¹/₄ degrees, up to 89³/₄. The other 2 elements were 2 position shutters positioned at each end of the cyclometric drums, the left one indicating N. or S. and the right one E. or W.

The transmitter had two transmitting elements and a tell-tale receiver as described above. One transmitter was of the Mark II type and the other a simple commutator connected to a switch handle on the face of the device indicated the quadrant (N/E, N/W, S/E, S/W). The transmitter received 7 wires, one being a positive supply and the other 6 going to the receiver. The transmitter handle to work the cyclometric display was geared so that a quarter rotation of the handle advanced the display by a quarter-degree.

It is not clear to me how this display would signal due East or due West unless the description is a bit off and the cyclometer could go to 90 degrees.

Fall-of-Shot Instruments

Fall-of-Shot Transmitter

The Mark I fall-of-shot instruments were modified versions of Barr and Stroud's recent designs of single order transmitter and receiver, altering the text on the 10-slot displays to pertain to different spotting reports. The observer could signal:

• ALL OVER
• ALL SHORT
• STRADDLE
• ALL RIGHT
• ALL LEFT
• ONLY ONE SHORT
• ONLY ONE OVER

These devices were first installed in Queen Elizabeth around 1915, and apparently found popular and reliable, as the same Mark was planned for use in the Courageous class which were not to be completed before 1917.

Despite the Mark number, these devices were created far after the first Mark I instruments. Both transmitter and receiver were repurposed forms of later-Mark single order instruments. The transmitter shown is intriguing, as it seems to incorporate a repeater pointer in the red index on the left. I believe the lower appearance of the word "STRADDLE" in the image is actually stamped onto the machine.

Torpedo Order Instruments

Torpedo Order Instruments
This sketch illustrates the tie between a director position and a broadside tube.

In 1909, trials of adapted versions of the contemporary order instruments to the purpose of relaying orders to submerged tubes in noisy areas were conducted on the three Invincible class ships whose stern tube was in a notoriously noisy location. The same need was also realised in a variety of other ship's aft broadside tubes, presumably owing to their proximity to engine rooms. The trials were completed by July, 1909 and results were guardedly positive. Telaupads were also tried to good effect, but it was decided that voicepipes and bells would be better if practical.

The decision was taken to

• not add to the voicepipe installation in any ship
• fit improved order instruments to the stern and broadside tubes in Invincible
• add telaupads to the existing navyphones in the stern tube flats

By December 1910, modern torpedo control requirements along these lines was drawn up for all ships from King Edward VII to Lion and King George V classes. As part of this plan, proper order instruments were to be manufactured by Barr and Stroud for installation in some ships.

The concept as sketched in ARTS 1911 was that gongs at the tube would sound when orders changed or a fire key press was issued, and the tube position would acknowledge by use of a gong as well. The fire key would also cause a white blank shutter at the tube to display "FIRE" in red when it was pressed.

The two instruments could send one of several commands from a list (with a local tell-tale), and the remotely signaled command would appear on a separate drum, heralded by the gong. Stern tubes could be supported as easily as by marking the command slots differently. In a broadside configuration, the director position could signal the following commands:

• LOAD
• FLOOD OUT BAR
• STAND BY
• IN BAR DRAIN

and the tube could reply:

• LOADED
• FLOODED
• BAR OUT
• READY
• FIRED
• DRAINED

The next installations likely occurred in stern tubes for Lord Nelson and later classes and for broadside tubes in Lion, Indefatigable, King George V classes, as plans for their wiring were ordered in 1911.

Conning Tower/Torpedo Control Tower Torpedo Control Telegraphs

Torpedo Control Telegraphs

In June 1911, a need was realised to permit the conning tower to exert top-level control of torpedo fire that would be directed from the aft torpedo control tower. It was ordered to directly wire 2 pairs of navyphones (port and starboard) between the positions, and a design for data instruments to augment this was issued. Mark I of the resulting instruments were created in 1913. Both devices were transmitters, really, but the one in the conning tower assumed an authoritative role in the communication.

The Pattern 3121 transmitter in the conning tower was similar to the Torpedo Order Transmitter, but used an on/off toggle in lieu of a firing key to work the shutter. The shutter had two positions: blank and FIRE AS SIGHTS COME ON, and a similar shutter would move at the receiver. Any one of 5 command indications (5 blank slots were arrayed below) could be sent by working the transmitter handle and was indicated in a list with a tell-tale at the bottom of the instrument:

• STARB^D TUBE
• PORT TUBE
• STERN TUBE
• CEASE FIRE
• REPORT WHEN
  IN RANGE

Presumably, ships having more torpedo tubes could bring more of the 10 slots into service.

The Pattern 3120 receiver at the torpedo control tower was quite similar, but it had a shutter and no toggle switch. Any one of 6 indications (4 blank slots were arrayed below) could be sent by working the transmitter handle and was indicated in a list with a tell-tale at the bottom of the instrument:

• TORPEDO FIRED
• WITHIN RANGE
• READY TO FIRE
• YAW TO STARB^D
• YAW TO PORT
• STEADY

The plan in 1911 was that the navyphones should be installed in King Edward VII and later classes and that the data instruments be retrofitted to Dreadnought and later classes.

Gyro Angle Instruments

Gyro Angle Instruments

In 1911, trials with angled gyro torpedo fire were underway and Vernon designed instruments for the director position to order a specific setting on the torpedo in anticipation of the likely adoption of this technology. Vernon chose the then-contemporary Mark II* Single Order instruments as the tools to repurpose for this task, allowing angles from 40 degrees left to 40 degrees right to be expressed in 10-degree increments, leaving one of the 10 slots blank. This probably became the Mark I Gyro Angle instrument, which served in both director and tube positions.

The top tell-tale worked off the local transmitter, and the red caret was what was being sent from the remote station.

This platform was soon to prove too limited as the granularity of gyro settings was soon further reduced to 5 degrees, prompting a switch in design in 1913 to the Mark II.

Course and Speed of Enemy Instruments

Course and Speed of Enemy Instruments

A need was realised to allow TSes to signal course and speed of the enemy to the torpedo director position. In August 1909, a process of specification and design culminated in a design based on Mark II internals and these were tested in Bellerophon. In 1911, however, work commenced on a purpose-built design with 3 transmitters:

• (relative?) course of enemy, 0 to 358 degrees in 2 degree steps
• PORT or STARBOARD
• speed in knots, 0 to 50 in 0.5 knot steps

These first instruments were to be supplied to ships of the Orion, Lion, Indefatigable and King George V classes.

Destroyer Range and Order Instruments

Barr and Stroud-made Instruments

Graham-made Range and Order Instruments

At the end of 1915, a set of range and order instruments was in hand for use in destroyers of the "M" Class and later and also flotilla leaders of the Faulknor class and later. Each ship received a Pattern 3840 combined range and order transmitter on its forebridge (two each for Faulknor and Broke, seemingly one per broadside), and each gun received a Pattern 3841 receiver near its sightsetting position.

The system could convey ranges from 0 to 9900 yards in 100 yard increments (the double zeroes were painted on the face plate) and any of three orders: "Fire", "Control" and "Independent". The range altered by 100 yards per revolution of the range handle on the right side, and the order handle on the left side moved a shutter that read "Control" and "Fire" over a fixed part labelled "Independent" when it was shifted between its three labelled positions as precisely limited by a spring plunger.

Although the system was noted as offering the most recent Barr and Stroud improvements, it was noted as being covered by a patent from 1906, and some of the devices were slightly different in details of watertightness, manufactured by Graham's. Each instrument had a single gland in the bottom to admit 8-core wires (generally similar to Pattern 2550) and the indications were illuminated from within the watertight, non-corrosive chassis by a pair of Pattern 666 lamps in holders Pattern 693.

If the current failed, the Barr and Stroud-made receivers (only) displayed a red indicator flag to the left of their range readout.

In a typical installation, the batteries (ten Fuller Block accumulator types C.D. 12 in a teak rubber-lined box), junction box and wiring would remain below deck and a charging box with a switch could switch the network between a charge and discharge state. Forty hours of initial charge was advised. Additionally, the bridge would have a local power switch for the transmitter, and in some ships the receivers would have their own as well.

See Also

• Barr and Stroud Fire Control Instruments
• Barr and Stroud Mark II Fire Control Instruments

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, 1911, with Appendix (Wireless Telegraphy). Copy 15 at The National Archives. ADM 189/31.
• H.M.S. Vernon. (Feb 1914) Annual Report of the Torpedo School, 1913, with Appendix (Wireless Telegraphy). Copy 42 at The National Archives. ADM 189/33.
• H.M.S. Vernon. (Jan 1916) Annual Report of the Torpedo School, 1915. C.B. 1166. Copy 1025 at The National Archives. ADM 189/35.
• 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.