Much of this section is based on the work of Terry Andrews, reproduced with his kind permission from his posts on MWR.
CWC won the contract to supply an automatic dive watch to replace the Rolex milsub in 1980, and in 1980 and 1981 they supplied watches with a dial similar to the Omega Seamaster 300 from the 1960s and an acrylic bezel insert. In 1983, the watch was changed to a quartz movement and was issued sporadically up until 2000, with most of the watches being issued during the 1990s. The case was similar to the Monnin case popularised by the Heuer reference 844 from the late 1970s, although with some small variations across the years. The automatic dive watch NSN ends 9237697, and the quartz dive watch NSN ends 7573314.
1980 – Manufactured by Dodane France. Dial signed with small CWC logo and small circled T below the hands; no SWISS or SWISS MADE; luminous indices and 3, 6 and 9 numerals; and an acrylic bezel insert. Fitted with an ETA 2783 automatic movement. Approximately 100 watches were issued in this year.
1981 – Case switches to an M.R.P. SA case. Dial signed with slightly larger CWC logo with medium circled T below the hands; SWISS MADE below the 6 index; luminous indices but 3, 6 and 9 numerals now just printed in white. Fitted with an ETA 2872 automatic movement. Approximately 100 watches were issued in this year.
1982 – It is unclear whether this was issued in a batch, was just a few prototypes or were made up from parts, as not many have been seen so far. The logo is the new CWC logo in an oval (dating the watch to 1982), and the dial is similar to the 1983 CWC Quartz dial but without the Quartz marking.
1983, 1985 and 1986 – Dial now has new CWC logo, larger circled T above the hands and QUARTZ below the hands. Fitted with an ETA 555.115 1J quartz movement, although 555.112 is often seen as well. Approximately 850 watches were issued across the three years (400, 350 and 100 respectively), with serial numbers sequential across the years.
1992 – Movement changes to ETA 955.122 7J. Bezel insert changes to a metal insert, with wide hash marks for the minutes. Sequential numbering continues from the Precista dive supervisor watch batches in 1988 and 1989, with probably 250 or 300 issued in 1992.
In the remaining issue years, the bezel insert changes to narrow hash marks for the minutes and the batch numbering becomes specific to the year; between 300 and 500 were issued each year in 1994, 1995, 1996, 1997, 1999 and 2000.
The watch began to be replaced in the early 2000s with the SBS watch, which became the standard issue of dive watch for anyone in the British military; although the RN watches continued in use for some years, when the RN watches were returned to stores or were broken, a new SBS was issued instead.
In all, over the 20 years between 1980 and 2000, CWC supplied probably around 3,000 dive watches to the Royal Navy.