Barr and Stroud Mark II* Fire Control Instruments

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.

Mark II* Instruments

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.

Mark II* Bearing Instruments

todo: plate 28+29 These were similar to the Mark I. instruments, but worked in relative bearings, not compass quadrant bearings. An additional digit drum was fitted to permit angles of 0 to 180 in 1/4 degree increments, and a single remaining shutter located underneath the digital bearing drums could be in either STARBOARD or PORT position (starboard was in the higher position, and so would be visible when the shutter was lowered). I guess that this shutter was also in the raised position when the coil was off.

One small difference was that the transmitter handle had to be pushed in before would engage the drums inside. A spring would keep it out, otherwise. The degree handle was on the right side near the bottom, and the shutter setting handle on the left near the bottom. I am not sure if the degree drums and the shutter position were interconnected, or what behaviour would result if the angle was driven to (or past) its maximum reading.

The Pattern 2607 Transmitter had an integral tell-tale for angle and port/starboard. It was fed by six wires, 5 of which it passed to the Pattern 2608 Receiver.

The Mark II.* Rate of Change transmitter was fundamentally similar, with CLOSING and OPENING on the shutter.

Mark II* Combined Range Deflection and Order Instruments

Pattern 2596 Combined Receiver Pattern 2597 Combined Transmitter

Mark II* Single Range Instruments

The Pattern 2598 Single Range Receiver

The Pattern 2599 Single Range Transmitter

Mark II* Single Order Instruments

Pattern 2600 Single Order Receiver Pattern 2601 Single Order Transmitter

See Also

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

Bibliography

• Template:BibUKARTS1903
• Template:BibUKTorpedoDrillBook1905
• Template:BibUKTorpedoDrillBook1908
• Template:BibUKTorpedoDrillBook1912
• Template:BibUKTorpedoDrillBook1914
• 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.