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.
CWC also supplied a redesigned version of the Heuer Monte Carlo aircraft timer. There is a gallery of photographs of the Aircraft Timer below and a blog post on its history and development here.
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)
Issued under two NSNs by CWC, this is the same type of watch as one of the earliest Royal Navy watches.
NSN: 523-9007
(some also seen marked 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 use the 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
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
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, and either a red or black 100 seconds
Run Time: 8-12 hours
Note: Some 523-9007s also seen with 1/100 minute dials, with red 100 seconds and 30 minutes
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 Monte Carlo, 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. Another batch of 20 non-luminous pocket watches were ordered by the Royal Australian Navy in 2004.
NSN: 520-8049
Hours, minutes, and sub seconds at six o'clock,
DHSS
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)
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
STOPWATCH Photo Gallery
Three variations of the 1/5 second stopwatch from 1977, 1978 and 1986 (left to right); note small changes in the dial printing from year to year, the new logo in the 1980s, and the unusual hand and logo printing on the 1978 watch. This handset and printing style is common across other 1978 CWC stopwatches including 1/10 second and DHSS.
Two dial variations for 1/100 minute watches; on the left from 1990 on a Royal Navy (0552) watch, and on the right from 1976 on a British Army (W10) watch.
Calibration sticker on the back of a 1/5 second stopwatch. This shows the long useful life of these watches - issued in 1981 and still good to 2007! It also shows that the watches were used by all the Services, as this is a RAF sticker.
On the left is a 1973 DHSS 1/5 second watch and on the right is a military-issued watch from 1977. Note the lack of broad arrow on the DHSS watch, no 1/100 of a minute scale, the red minute counter hand and the red 15, 30, 45 and 60.
1973 DHSS stopwatch (on the left) and 1978 DHSS on stopwatch (on the right); the 1978 watch is in a very different style to all other years, but the logo printing and the handset is the same as the military-issued 1978 watch above.
DHSS case back markings.
Pocket watch Photo Gallery
Pocket watch from 1977, with luminous dial and hands and circled T on the dial; these luminous dial pocket watches were only issued in 1977. The 1977 watches have matt cases, and a coin-edge pattern on the front and back cases. Photo Credit: Ubique on MWR.
Case back of the 1977 luminous dial pocket watch. Based on observed watches so far, the 1977 batch was maybe 250-300 watches, with possibly only a small number having luminous dials. This is 085/77, but 173/77 also has a luminous dial. Numbers around these are all non-luminous (e.g. 082/77, 111/77, 112/77 and 214/77 are non-luminous) so it seems that an unknown number of the watches were refini
Dial and hands of the non-luminous 1977 pocket watch.
Case back of the 1977 non-luminous pocket watch; note that the NSN is the same as the luminous version, with the addition of "NON-LUM".
1994 non-luminous pocket watch; the case is slimmer than the 1977, and polished to a shine. The hands are also much slimmer.
The high shine on the case, and shallow case back engraving make this very hard to photograph! Note the full NSN, and the 0555 service code, which was used by the Royal Navy from 1993 onwards.
AIRCRAFT TIMER Photo Gallery
The CWC aircraft timer has been used by the RAF, the Royal Navy Fleet Air Arm, and the US Marines in a variety of aircraft including the Harrier, Hawk and Tucana. The timer is still in active use - seen here in a Red Arrows Hawk. Hodinkee has an article on how mechanical stopwatches are still used by the USAF Thunderbirds here. Photo Credit: @pilotperty on Instagram, original post here.
Examples of the CWC timer from 1980 and 1988. On the left is a 1980 issued timer with original CWC logo (as seen in the cockpit above), and on the right is a 1988 issued timer with the logo in an oval and addition of the broad arrow. Both have lumed numerals, and minute and second hands. The minute hand is the wider hand with the arrow tip and the seconds hand is the longer, thinner hand.
The NSN is engraved on the left hand side of the timer.
The mounting plate also has its own NSN; 6645-99-6361092.
The CWC timer replaced the issued versions of the Heuer Monte-Carlo but was still made for CWC by Heuer. The movement is the Heuer 7714; details of the movement can be found on Ranfft Watches here.
Comparison with an issued Heuer timer (on the right) which predates the CWC model, but is otherwise almost identical. Both have 7714 on the bridge, but the CWC model has CWC stamped, whilst the Heuer model has their logo.