Stopwatches & pocket watches
Stopwatches, Timers & Pocket Watches
More than any other watch, the CWC stopwatches and pocket watches are rooted in the evolution of British military timekeeping through the 20th century.
The earliest stopwatch approved for British military service in 1900 was a simple, crown-operated 1/5 second timer - which was initially called the "Benson Pattern", then the Mk I and later became the Admiralty Pattern 3169 (which number eventually got incorporated in to the NSN for that watch). By 1903, the Mk II was in service - which was also a 1/5 second timer, but was a continuously running watch with start and pause operated by a side slider, and with the crown operating the fly back function. This watch became known as the Admiralty Pattern 3.
By 1912 a 1/10 second watch was in service, and by 1920 a 1/100 second watch, as measurement requirements became more precise. Other variations in use included the split second watch (known as the Admiralty Pattern 4, or the Mk VA or VB in the RAF) and the ASDIC sonar timer (Admiralty Pattern 6), as well as a 12 hour flight timer for aircraft.
However - due to the demands of two World Wars and the tendency of each Service to purchase its own equipment - by the end of the 1970s there were over 20 different designations of stop watches being used across the British military, although most fell in to the general categories above. The appendix in the 1980 General Service Wristwatch Defence Standard recategorized 15 different variations of stopwatch down to eight individual NATO Stock Numbers – whilst allowing another eight as "Items permitted only for maintenance purposes". A DefStan dedicated to Stopwatches was published in 1992, and recognised seven different types, the split second apparently having gone out of service by then, but ironically very few mechanical stopwatches appear to have been produced for the British military by then as electronic instruments took over measurement.
CWC has produced variations of all these stopwatches, as well as pocket watches for the Royal Navy. It has also supplied stopwatches to the DHSS (Department of Health & Social Security) and the BBC. Each type of watch is detailed briefly below, and then further pictures dig in to the details of dial and case variations in the galleries below that.
For each watch, I give the following information:
NSN – last seven numbers of the NATO Stock Number
Sweep – how long the central hand takes to travel around the dial once
Graduation – the smallest amount of elapsed time that can be read off the scale(s) on the dial when the watch is stopped
Recorder – the maximum amount of total elapsed time which the subdial can show
Control – means of operating the watch
Colour – dial and scale colours
Run Time – length of time that the watch should be able to run, fully wound
Watch Specifications
1/5 second
1/100 second
1/10 second
The original, crown-operated stopwatch, this is the most common of the CWC stopwatches, and is the same type that has been in service with the British military since 1900.
NSN: 521-3169
Sweep: 1 minute
Graduation: 1/5 second and 1/100 minute
Recorder: 30 minutes
Control: Push down crown
Colour: White dial with black numerals and graduation, and 1/100 minute in red
Run Time: 8-12 hours
1/10 second
1/100 second
1/10 second
With a sweep of 30 seconds, the scale is marked to show the first 30 seconds of a minute in black and the second in red, with the recorder also marked so the operator knows which half of the minute they are timing.
NSN: 910-1002
Sweep: 30 seconds
Graduation: 1/10 second
Recorder: 15 minutes
Control: Push down crown
Colour: White dial with black numerals and graduation for 0-30 seconds and red numerals and graduation for 31-60 seconds (and second half of the minute marked in red on the recorder sub-dial)
Run Time: 4-6 hours
1/100 second
1/100 second
1/5 second (Admiralty Pattern 3)
Probably the rarest CWC stopwatch, the sweep is only 3 seconds to allow timing down to 1/100 of a second.
NSN: 916-0180
Sweep: 3 seconds
Graduation: 1/100 second
Recorder: 90 seconds
Control: Push down crown
Colour: White dial with black markings
Run Time: 20 minutes
1/5 second (Admiralty Pattern 3)
1/5 second (Admiralty Pattern 3)
1/5 second (Admiralty Pattern 3)
Apparently issued under two NSNs by CWC, one of which is also used on the Works Study, this is the same type of watch as one of the earliest Royal Navy watches.
NSN: 523-9007 and 923-9007
Sweep: 1 minute
Graduation: 1/5 second
Recorder: 30 minutes
Control: Push down crown for start-flyback, side slide for pause (although 923-9007 appears to be crown for start-stop-reset and side slide for pause)
Colour: White dial with black numerals and graduation, and a red 60 seconds and 30 minutes
Run Time: 8-12 hours
1/100 minute, Works Study
1/5 second (Admiralty Pattern 3)
1/100 minute, Works Study
Apparently issued under two NSNs by CWC, this watch is also known as the "Works Study" as the "pause" function allows a process performed in multiple parts to be timed for a total elapsed time without resetting the watch.
NSN: 960-8411 and 523-9007
Sweep: 1 minute
Graduation: 1/100 minute
Recorder: 30 minutes
Control: Push down crown for start-flyback, side slide for pause
Colour: White dial with black numerals and graduation, although the 523-9007 has a red 100 seconds and 30 minutes
Run Time: 8-12 hours
Split Second
1/5 second (Admiralty Pattern 3)
1/100 minute, Works Study
The only stopwatch without CWC on the dial (although the movement is marked CWC), this was only issued in 1976 and 1977.
NSN: 521-6482
Sweep: 1 minute
Graduation: 1/5 second
Recorder: 30 minutes
Control: Push down crown for start-stop-reset, side pusher for split second
Colour: White dial with black numerals and graduation; red split second hand
Run Time: 8-12 hours
ASDIC Sonar Timer
ASDIC Sonar Timer
ASDIC Sonar Timer
The ASDIC was a sonar system for submarine detection developed by British, French and American scientists during WWI; the name is derived from the Anti-Submarine Detection Investigation Committee. The stopwatch is designed to tell a sonar operator how far away a submarine is, based on the time the sonar ping takes to travel to the enemy sub and return (the scale is calibrated for half the speed of sound in water).
NSN: 520-9365
Sweep: 6 seconds
Graduation: 100 yards and 1 second
Recorder: None
Control: Push down crown
Colour: White dial with seconds marked in red and yards marked in black
Run Time: 90 minutes (although should be marked on the case back “MAX RUN = 1 hour”)
Aircraft Timer
ASDIC Sonar Timer
ASDIC Sonar Timer
The CWC aircraft timer replaced the Heuer Monaco, and was made by Heuer for CWC; used in many different types of aeroplane including the Harrier jump jet.
NSN: 520-9604
Sweep: 1 minute and 1 hour
Graduation: 1/5 second
Recorder: Up to 12 hours (on disc in window)
Control: Push down crown for start-stop, side pusher for reset
Colour: Black dial with white luminized numerals and graduations
Run Time: 30 hours
Pocket Watch
ASDIC Sonar Timer
Pocket Watch
Pocket watch, issued by the Royal Navy in 1977, 1994 and 1996. There are both luminous and non-luminous versions from 1977, but the 1994 and 1996 versions are non-luminous.
NSN: 520-8049
Hours, minutes, and sub seconds at six o'clock,
DHSS
Broadcast (BBC)
Pocket Watch
The basic 1/5 second stopwatch, produced for the DHSS in at least four years (in red and black in 1973, 1974 and 1976 on the left, and in black in 1978 on the right); note the simplified scale (without the 1/100 minute marking), and no military broad arrow.
NSN: n/a
Sweep: 1 minute
Graduation: 1/5 second
Recorder: 30 minutes
Control: Push down crown
Colour: White dial with black and red numerals and recorder hand in red in 1973, 1974, and 1976; all black markings and hands in 1978
Run Time: 8-12 hours
Broadcast (BBC)
Broadcast (BBC)
Broadcast (BBC)
Produced for the BBC, and possibly other broadcast units, this watch has a large minute recorder with yellow hand to time programme segments. The watch was made famous by being featured in "Mission Impossible - Fallout". The script called for a stopwatch, and this was probably just being used by a production assistant!
NSN: n/a
Sweep: 1 minute
Graduation: 1/5 second
Recorder: 60 minutes
Control: Push down crown for start-stop, side pusher for flyback (whilst running) and reset (whilst stopped)
Colour: White dial with black second numerals and graduation and red 1/5 second graduation; red recorder markings and yellow recorder hand
Run Time: 8-12 hours