First issued in 1980, the Navigator was intended as a replacement for the H.S.3 deck watch and was for use in navigational tasks where the date was used frequently - for looking up tide tables for the calculation of tidal heights and times; and in astronomical publications for sun rise, setting and twilight times and for calculation of position lines for celestial navigation. As well as (more mundanely) for drafting of signals, reports and orders.
It was based on the standard G10, and specified in two variants - a luminous version with NSN 6645-99-541-7362 approved for use in all departments of the Ministry of Defence except HM Submarines, and a non-lume version NSN 6645-99-541-7363 appropriate for use in nuclear submarines. The movements in the Navigators were the same as in the standard G10s, which already had a date function; so the only real difference to the G10 was the addition of a date window in the dial. Occasionally normal G10s are found with holes cut in the dial to reveal the date below - as can be seen in the example in the gallery below.
The lumed Navigator was issued in 1980, 1981 and 1982, and then again in 1994, 1996 and 1997, with batch details as below:
1980 - old logo; SWISS at bottom of the dial; no service code in front of NSN; known serial number range 032 to 560.
1981 - old logo; SWISS at bottom of the dial; no service code in front of NSN; known serial number range 655 to 962.
1982 - new logo in oval; SWISS at bottom of the dial; no service code in front of NSN; known serial number range 1015 to 1199.
1994 - new logo in oval; SWISS MADE at bottom of the dial; appears to be a conversion of civilian G10 with no broad arrow, with the original NSN ground out, the new NSN re-engraved, the Royal Navy 0555 code added and the serial number and year on the side by the crown; known serial number range 002 to 075.
1996 - new logo in oval; SWISS MADE at bottom of the dial; NSN and broad arrow factory stamped on case back; no service code; serial number and year lightly engraved; known serial number range 0004 to 0049.
1997 - new logo in oval; SWISS MADE at bottom of the dial; case back the same as 1996 but with 0555 added above NSN and deeper engraving of serial number and year; known serial number range 008 to 030.
However, some of the late 90s Navigators without issue numbers have also turned up at MoD disposal sales, so it looks like either the MoD or individual units could have been buying these unmarked to meet demand at the time.
Some lumed prototypes also exist from the early 1990s converted from standard G10s, which bear the entire G10 NSN (6645-99-541-5317) and then 7362 added to denote the conversion.
The non-lume Navigator was issued in 1980, 1981, 1990 and 1996, with batch details as below:
1980 - old logo in the same place on the dial as on lumed version; SWISS at bottom of the dial; no service code in front of NSN; no circled T on the dial, and dial and hands finished in white; only one serial number known - 606 - although one other watch with this dial is also known.
1981 - old logo slightly lower on dial than on lumed version; SWISS at bottom of the dial; no service code in front of NSN; no circled T on the dial, and dial and hands finished in white; known serial number range 1012 to 1092.
1990 - new logo in oval; SWISS MADE at bottom of the dial; circled T on the dial, and dial and hands finished in white; a white on black date wheel; known serial number range 1130 to 1138.
1996 - new logo in oval; SWISS MADE at bottom of the dial; no circled T on the dial, and dial and hands finished in white; appears to be a G10 conversion with last number of NSN modified from 2 to 3, with an engraved s/n and date and 0555 prefix above the NSN; known serial number range 003 to 034.
More details about all the issued navigators can be found in this MWR post.
In 1999 the Pulsar G10 entered service with a date window as standard, and non-radioactive Luminova which effectively made the need for a separate Navigator in both lume and non-lume redundant. Another version of the CWC Navigator was manufactured in 2000 - the "GS2000" - also with Luminova and with the same NSN as the Pulsar, 6645-99-6052627 . According to CWC and other sources (in the comments section of the HODINKEE article about the 1980 dive watch, for instance!), 500 watches were issued to the RAF. The GS2000 watches are marked 6B, but none have been seen with the "normal" British military issue markings of 'serial number / year'. However, some ex-servicemen have said that these were issued without those markings - possibly with just a C or a C and a serial number. This is despite the fact that the C marking on CWC watches normally means it is a Civilian (non-issued) watch.
An early Navigator with the H.S.3 deck watch that it replaced; a much more convenient tool for use day-to-day! An interesting account of the role of the Royal Observatory in repairing marine chronometers can be found on their website. Photo Credit: Ed875 on MWR
Three watches representing the different dials of the luminous Navigators; from left to right - 1981 with old CWC logo and "SWISS" at the bottom of the dial, 1982 with new CWC logo and "SWISS", and 1994 with new CWC logo and "SWISS MADE". Note how the box around the date cuts off the minute track on the 1981 dial, but not on the 1982 dial.
The case backs of these three watches.
Case backs from the first two years that the Navigator was issued; note that the service is not stated before the NSN, similarly to the first G10 in 1980.
Dial of the non-lume Navigator from 1980, with white painted numerals and indices on the dial, and plain white hands. Two watches with this dial are known, although one has had the hands replaced with lumed hands and the caseback changed, probably during military service.
Dial of the non-lume Navigator from 1981; the tritium has been replaced with white paint, and - unlike the 1980 version - the CWC logo has been slightly lowered on the dial due to the absence of the circle T. Photo Credit: j.swatches on Instagram