Rare 1983 CWC G10 offset hatch 'Medium Fatboy' Army issue
Rare watch in good condition
£395.00
Out of stock
The early CWC G10s, from 1980-82 were the real 'Fatboy' G10s, with the deep case to accommodate the ESA/ETA 536.121 movement. From 1987 onwards, CWC G10s were produced with a thin case and low profile case back. In-between, from 1983-85 were a sequence of variants collectively knows as the 'Medium Fatboy' G10s.
Although the mid-case of the 83 variant is almost the same as the later thin case watches (just slightly thicker), the case back is much deeper and includes an anti-magnetic plate inside the case back. This gives the watch a bit of extra heft compared to the later watches.
The '83 version also has the characteristic 'offset' battery hatch. The hatch is the same size as the earlier Fatboy watches, but offset to the right, due to the position of the battery compartment in the movement.
The dial also retains the earlier 'Swiss' marking at the 6 position, which was replaced with 'Swiss Made' after 1987.
The movement for the '83 watches is the ISA 947.111. This quartz movement has a plastic base plate with integrated circuit and was only used for one year of production before being superseded by the ETA 555/955 series movements. The movement can be repaired and serviced so it is a practical and maintainable watch to own in the long run. The case back is also far easier to open than the 1980-82 Fatboys, again enhancing its maintainability. It also has a 'trimmer' allowing the movement to be regulated for accuracy.
One other feature of the 1983 G10s is that the movement has a date disc although there is no window in the dial so this is hidden.
The majority of 1983 G10s - like this example - were issued under an Army contract and marked with the W10 service code.
This example is in good condition, as described in the condition report, and has just been fully serviced.
The watch is supplied on a new quality heat welded admiralty grey NATO strap.
The case and back are clean and with some general minor marks from use, but overall very good. The case back has the correct markings including the W10 Army service code, NATO stock number, serial number and issue year. The crystal is a flat profile replacement with matte tension ring fitted. The dial and hands are in very good condition with good lume colour. Please refer to the images to make your own judgement about the cosmetic condition of the watch. The images form an important part of the description.
The watch was subject to a full stripdown, clean and service in November 2025. The case parts were stripped and ultrasonically cleaned. The originaI SA 947.111 movement was damaged an not repairable so a New Old Stock ISA 947.111 movement was fitted.
The NOSA movement was fully stripped, mechanically and ultrasonically cleaned using waterless solutions and hot air dried. The movement was rebuilt and lubricated using Moebius oils. Images of the movement rebuild are included in the listing. The movement has the stock ISA positive battery contact which takes a 381 battery and not the 386 originally fitted to the 1983 G10, but the battery can still be changed via the battery hatch.The watch hacks and sets from the crown correctly. All the seals were also replaced and greased, including the back gasket, the battery hatch and crown gaskets.
One noteworthy feature of the 947.111 movement is the fact that it has a date disc, even though there is no date aperture in the dial. This was simply a case of the available movement being produced in volume and available at the time had a date disc. Often the calendar works are subsequently removed when the watches are serviced/repaired, but where they are present we make sure that are properly serviced along with the rest of the watch and are in full working order - even if you can't see it! It even turns over at midnight.
The watch was regulated on a quartztester machine and is running on the bench at - 0.01 seconds per day, equivalent to - 0.3 seconds per month, which is well within the +/-10 seconds per month specification. This measurement is under bench conditions and accuracy may differ from this when in use.
The watch is absolutely suitable for everyday use, but it is vintage watch so is not recommended for sports or use in extreme conditions. The watch has not been pressure tested so water resistance is not guaranteed. This watch is covered by our waterproof 6 month guarantee.
Issued: Yes
Issue details: UK MoD, Army
Date of manufacture: 1983
Production numbers: 5374
Movement: ISA 947.111
Diameter: 36mm
Lug width: 18mm
Hacking: Yes
Case back: Snap
Screwdown crown: No
Bracelet: NATO
UK MoD issue
1985 'Medium Fatboy'
OEM ISA 555.115 quartz movement
Recently serviced and regulated
Excellent condition
Supplied on new heat welded NATO strap
6 months non-waterproof guarantee
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