The Birth of the NATO Watch Strap – A History of the NATO Strap and Post WWII watches


In earlier articles the predecessors of the NATO watch strap were reviewed.

Some military watch specifications were in the process of revision after some years of experience in the field, and the need for more advanced watches was revealed.

The W.W.W. watch for the British army was a revision to the ATP watch, released at the end of WWII, and surplus watches were de-stocked back into the civilian market. Advanced navigation and dive watches were being planned and were specified after the end of the war.

Also, after the end of WWII, political considerations led to the NATO military alliance, and all issued military equipment of members and associates of NATO, including watches, and straps, had an identifying NATO stock number (NSN).

One such NATO watch strap, more than the others, has had its NATO NSN shortened by common usage to just NATO.


WWII revealed the need to coordinate the supply of military equipment, particularly when joint forces were in the field together.

stores: NATO watch strap

The Vocabulary of Army Ordnance Stores (VAOS) was the British Army system of cataloguing parts.  The Director of Stores maintained notes on all the in-service equipment and kept track of changes in patterns of equipment and stores. This list was updated and circulated on a regular basis.  The Vocabulary publication, which in the later years of its use was amended quarterly, required that units use the exact nomenclature that appeared in the Vocabulary. The Vocabulary system was used by the British Army for close to ninety years until it started to be displaced by the NSN system in 1956.

With the formation of NATO in 1949, common numbering systems were developed for items of equipment.   This system was based on the US Federal Stock Number (FSN), which itself commenced in 1953.   In 1974 two additional digits were added (the national identifier), and in the US this became the National Stock Number.

In all 64 other NATO affiliated countries this number is referred to as the NATO Stock Number (NSN), and has 13-digits, the first four indicating the group and classification of similar supply military items. The next two digits correspond with the country code of NATO member states (12 is Germany, 99 is Great Britain, 00 or 01 is USA). The last seven digits describe the exact object.


The NSN, or NATO Stock Number is most easily explained in the above diagram.  It commences with a NSC, and then a NCB, together with a 7 digit number.

The NSC for “Time Measuring Instruments” is 6645.  The first two digits called the Federal Supply Group (FSG), define the overall category of the item.  In the case of most issued watches, that is “66 – Instruments and Laboratory Equipment.”  Adding the FSG to the next pair of digits – the 2-digit Federal Supply Class (FSC) – narrows the item category even more.   For military watches, that becomes “6645 – Time Measuring Instruments.”

In the illustration above, the classification category code 1005 is “Guns, through 30mm”, 13 is Belgium, and the other non-significant numbers are meaningless.

Some 13 million items are identified with a NSN.



The US Marine Corps sourced new watches in about 1949, which were very similar to the ORD DEPT watches of WWII.  These included the Bulova 1917-H and the Hamilton 747.   They were stainless steel, and the major external difference was the sub-seconds dial where the numerals were oriented horizontally. The end of the blued seconds hand was enhanced with a luminous ball.     The specification for this watch is unknown, but there is a stock number, and ordnance drawing number for the Bulova.

The Buolva used a 15J 10BM movement.

Bulova 1917-H Box

Below is a Hamilton 747 on the right, with an ORD DEPT Hamilton on the left.

The case back reads USMC, OF-xxxxxx (the serial number).    Later, more crudely some were additionally stamped MODEL 747, HAM  or just 747.  The inside case back is stamped with the case manufacturer, Keystone, Stainless Steel.

Hamilton 747: NATO watch strap

Image courtesy MWR forum user: Steve Z

Hamilton 747 parts catalogue: NATO watch strap


The Hamilton 747 was issued from 1949 onwards, the complete assembly having part number 43011, and came with a strap, part number 43013.   The strap drawing specification was B7646909.


Hamilton 747: NATO watch strap



Below is a similar dialed Bulova 1917-H in a stainless steel gunmetal or parkerised case, on the original strap.

Bulova 1917-H: NATO watch strap

Image courtesy MWR forum user: pittsjock

The gunmetal finish stainless case back is a screw-down design stamped “U.S. 1917-H.”

The mechanism has a domed metal dust cover for further protection. Removing this reveals the original manual wind (non-hack) mechanism, signed Bulova Watch Co., USA – 15 Jewels, 10BM.

The original inside case back is stamped STAR WATCH CASE CO., STAINLESS STEEL – xxxxxxx – 7197108. The first number is the watch serial number while the second number (7197108) is an ordnance number for the case back.



During WWII improvements were sought to the A-11 watch, and manufacturers produced some prototypes, as the improvements were largely dial related.   As occurs often in product development, did the prototype proceed the specification? Nevertheless, MIL-W-6433 of 1950 describes the requirement for the A-17, with essentially much more luminosity, and a 24-hour dial when compared to the A-11.

Waltham produced the A-17, Watch, Wrist, Second setting, Navigation, Hack, from 1950 onwards, as shown below with a coin edge case back.

A17 waltham: NATO watch strap


Waltham A17: NATO watch strap

Image flickr: Luke Davidson

The A-17 watch shown above is on an aftermarket strap.

A spare strap in a delivery box for a 1956 dated Waltham A-17 might give a clue to the type of strap originally used for this watch.

NATO watch strap

The double loop continuous strap is most likely the original strap for the A-17, as this was the strap used for the A-11, and the strap below seems to have been on the watch for some time.

Waltham A-17: NATO watch strap


The Bulova and Elgin A-17A models were produced later to MIL-W-6433A of 1954 and overlapped, from approximately 1956 for the Elgin, and 1958 for the Bulova. An April 1957 model Elgin A-17A shown below was provided on the moulded nylon strap ORDNANCE DEPT. USA  PART NO. 7646909, as specified in MIL-S-3035.

Elgin A-17: NATO watch strap

Image courtesy MWR forum user :  Mr.D



After the war, having used the USAF A-11 in the RAF 6B/234 designation, the UK MoD also independently modified the A-11, and issued the 6B/346 specification in late 1946 or early 1947.

The specification called for a watch which was very similar to the A-11. The main difference was that chronometer-grade performance was specified, along with anti-magnetic properties.  (Type A-11 wristwatches were manufactured in accordance with military specification 94-27834, published in 1940).

The resulting watch, the 6B/346 Mk 11 “Navigator’s”, was produced by two companies, Jaeger-LeCoultre (JLC) and International Watch Company (IWC), and was issued to RAF and RAAF forces from 1948 to 1953.   The JLC watch was not a success compared with the IWC watch.

The 6B/346 had fixed bars and originally came on a 17.5mm clip stainless steel BONKLIP bracelet (6B/2763).  The RAAF models had spring-bars and were coded G6B/346. The BONKLIP strap could be closed at different positions which allowed it to be fixed at variable lengths, over or under a flying suit.

Every item of RAF equipment had a Store Ref. No. assigned, not only to the watch itself, 6B/346, but as well the BONKLIP straps. As three different versions of the BONKLIP were used by the RAF,  namely 6B/2763 (17.5 mm in width designated to be used with the Mk 11, 6B/3224 (19.0mm in width) and 6B/3033 (20.0 mm in width). The last two to fit the chronograph 6B/551 H.S 9. and the Watch, Wrist, General Service 6645-99-910-1000 or 6B9101000.


6B/346: NATO watch strap



Howlitt patent bonklip

D.R. Howlitt applied for and was granted the patent on the Bonklip strap in 1930 in both England GB349657 and later in Germany 577586 drawing above.

An American patent application US1779068A was earlier filed for virtually the same design on April 10, 1929, by Walter M. Krementz, but this Staybrite strap was expensive and not as popular as the Bonklip.


A 1933 advertisement for the Krementz band is shown below.

krementz advert: NATO watch strap


In Australia, in 1951 about 2000 replacement watch straps meeting US Military Specification, Strap, Wrist Watch, Nylon, MIL-S-3035 (dated 8 September 1949) were imported for the RAAF.   Drawing B7646909 specified the one-piece moulded strap, shown below.  With this type of strap, if one spring bar was lost, the watch would still remain on the wrist.

mil spec strap: NATO watch strap

In 1954 a nylon NATO strap (6B/2617) was introduced by the RAF to replace the BONKLIP.  As this band was very long, its length could be varied easily.  However, the BONKLIP had advantages, and they were re-introduced by the RAF in 1956, allowing the BONKLIP or the nylon strap to be used alternatively.   (Ref 1)


The 6B/2617 strap is a grey nylon strap with 8 longitudinal ribs.     It was a 2 part strap with a keeper to retain the watch.   It had welded seams and stainless steel hardware.



The 6B/2617 pre NATO strap, and the 6B/2763 Bonklip strap with 16mm wide links are shown above.   The Bonklip strap fitted onto the fixed bars of the 6B/346 watch, and hence appears shorter.

A RAAF stores document refers to the nylon G6B/2617 strap – BAND WATCH WRIST NYLON

6B/2617 strap manufacturer reference  Image Courtesy  :  Greg Steer.

Perhaps due to the distance involved the Manufacturer M Furst and Co of Treforest Pontypridd Wales has an incorrect address listed.



Ministry of Defence specification DEF-3 (provisional) dated 1 September 1951 was superseded by DEF-3-A dated 20 October 1959 for Wrist Watch, General Service for the British military.   DEF-3-A stipulated the Joint Service Number or NSN 6645-99-910-1000 for central sweep (non hack) watches to this specification.

In the late 1940s and early 1950s a combined forces Working Party met 20 times, and  produced a “provisional” Defence Specification No. 3 (DEF-3), General Specification for Wrist Watch, General Service, which was published on 1 September 1951.

The Omega 1953 (CK2777-1) purchased by the MoD for the RAF in 1953 was built to the DEF-3 specification.  It uses the Omega 283 caliber.    Below is the purchase order from 1952.

Image credit MWR forum user : jef33

The watch was to be issued on a DEF-3 strap.   The specification for the strap is given below, and as shown below, it has no preformed holes for the buckle tongue.

omega 53 def 3: NATO watch strap

Image courtesy MWR forum user: hq_sandman_ute

Omega 53: NATO watch strap

The case back of the Omega 1953 is shown above.  The NATO Stock Number NSN was in its infancy and only  6645 101000 is engraved on the case back. The RAF stores reference code was 6B/542, and xxx/53 was the serial number.

Feeding into the above Working Party, Smiths were contracted to produce a General Service wristwatch for issue to the British Armed Forces.  The British government was concerned about the reliance on overseas supply of wristwatches, which had been an issue during the second world war and enticed Smiths to foster British manufacture of wristwatches.

These watches were based on the DEF-3 specification, and were given the same 6B/542 stores reference as the Omega navigators watch, also based on the DEF-3 specification, so we can assume were issued to RAF pilots and navigators.  This makes some sense for a test order – the inside of a plane cockpit was a fairly harsh environment for a mechanical wristwatch due to the presence of electromagnetic fields. The watches were shielded from electromagnetic interference by an iron dial and mumetal dust cover, which formed an effective Faraday cage to prevent electromagnetic disturbance.

For whatever reason the Air Ministry decided not to proceed with extending the order and Smiths didn’t receive a military supply contract until the late 1960s for the W10 model.  (Still earlier Smiths had provided a 6B/159 watch, which appears only to have reached prototype stage).

This is a Smiths General Service (GS) wristwatch which was issued in 1956.  This is the rarest Smiths British military watch and arguably one of the rarest British military watches of all.       Photo Credit  : Mr. Jones Watches.

There were approximately 300 of these watches made up and issued to the RAF in 1954, 1955 and 1956, presumably as a test order.

The watch above is fitted with a recreation of the original A.F.0210. strap, a precursor to the ubiquitous NATO strap which is found on Military watches.

However, in 1954 the Air Ministry issued the 6B/2617 strap with a keeper loop.  One of the hardest to find military straps is this pre NATO strap from the 1950’s.  This strap which was used on the Mk.11 navigators watch, the 6B/346, has generally eluded collectors and is the early NATO grandfather strap in grey ribbed nylon, 5/8″ or 16mm wide.

The RAF GS Smiths Deluxe had the caseback marked with 6B/542 or 6b/542 designation, and NSN 6645 101000.  The Directorate of Overseas Surveys (D.O.S.) GS Smiths DeLuxe Cal 27CS caseback of 1959 or so, has D.O.S. and the full NSN 6645-99-910-1000 engraved.

Here is a Smiths Deluxe GS watch on a period VB Hygienique NATO strap.

Smiths GS on Hygienique: NATO watch strap

Image courtesy MWR forum user : Revo

NATO watch strap

And a 6B/542 version on a homage AF0210 strap with fabric keeper, a style which predated the NATO strap.

The Smiths Deluxe GS watch 0434E version of the Cal. 27CS is shown below on the cover of the Smiths manual on a woven nylon NATO strap.  This strap is the 6B/2617 strap.



In 1965 Hamilton provided a general service watch to the RAF.  This was supplied under DEF-3-A and was non hackable.   The watch was built to a similar specification to the Mk.11 watch and is sometimes called the Hamilton Mk.XI.  The watch is 6B-9101000.

The image below shows the watch and a sewn webbing strap.

Hamilton 6b-9101000


DEF-3-B dated September 1966 covered hackable central sweep watches to this specification, and stipulated the Joint Service Number or NSN 6645-99-961-4045. The B revision required “inclusion of a device to arrest and release the second hand”.

The General Service Smiths W10/6645-99-961-4045 (model GS4701) was issued from 1967 to 1971 under DEF-3-B, and used the DEF-3 strap.  The RAF version was engraved  6B-9614045.   Hamilton also made a model 6B-9614045 H-67.



Drawing 377-5: Image courtesy MWR forum user : hq_sandman_ute

The DEF-3 strap below has a rounded, rectangular stainless steel buckle made of 1/16 inch wire, as in the drawing above.

DEF- 3 buckle

Image courtesy MWR forum user : hq_sandman_ute

6B/2594 strap imprint

MRW forum user geo7863 has confirmed that the DEF-3 strap was designated by the RAF as a 6B/2594 strap, and was initially used on the 6B/2593 wrist compass, before being replaced by a long sewn in place strap.

A Hamilton watch on an earlier DEF-3 strap is shown below, with the characteristic doped tip.  The buckle and keepers are stainless steel, but this buckle is shouldered, like that of the A.F.0210. strap.  Earlier buckles were square shouldered, and these and the keepers were brass, and the later buckles were rounded wire stainless steel, as in the drawing.  The webbing is tropicalised to specification NF203/7, and the buckle tongue penetrates the NATO watch strap to make the positioning hole.

DEF3 strap

Commonly the older A.F.0210. webbing strap was used.  This was part of the revised 1944 or 44 pattern webbing issued as A6/AFxxxx, Jungle Equipment, for use in the far east. The A.F.0210. strap was a precursor to the DEF-3 strap above, with almost identical dimensions, but used folded webbing stitched all round, with a square end, and brass buckle and keepers.   The A.F.0210. strap and DEF-3 strap sometimes had virtually identical hardware, but the latter in stainless steel, not brass.

AF0210 strap with 6B/2593 compass on AF0034 pamphlet.


When the 44 pattern Jungle Equipment was introduced in 1945, a lightweight aluminium frame that could be configured to carry various loads was one of the many new innovations.   The complete frame was AF0034, Carrier, Manpack, General Service, and weighed 1.7kg.  Instructions for use are shown above, together with the AF0210 strap and a 6B/2593 compass.

The various components of the AF0034 manpack carrier were given stores numbers to allow for replacement components.  The ladder frame is reference AF0083, and the removable load board is AF0084.  The four bearer tension straps (marked AF0087) provide a large cushioned area for comfort.  The waist NATO watch strap is marked AF0088.   Frame brace straps are AF0086.   The manpack carrier also has two simple shoulder straps with wider shoulder sections for comfort and attached to these is a chest strap to help secure the load.  The shoulder straps are stamped with AF0091.  The two part chest strap is AF0085.  The reverse of the manpack carrier has two adjustable straps with 44 pattern style double buckle fasteners for securing loads to the frame, labelled AF0090. The fastenings are all in the same rust proof metal as used in the 44 pattern webbing set.

Below is an A.F.0210. strap with a 6B/2593 compass, and a A.F.0225 rectangular mess tin.     The mess tin is also marked MMS1945 and is also part of the 44 pattern webbing jungle system, A.F.xxxx issued in 1945.

AF0210 strap and AF0225 mess tin

Below is a mint A.F.2010. strap with an A.T.P. Revue 59 watch.


Image courtesy MWR forum user: Shane Reed

As earlier VAOS nomenclature for military equipment was reclassified under the NSN system the A.F.0210. strap finished it’s service life under NSN W10/6645-99-910-1003, Webbing, (Spec : STRAP, WRIST, INSTRUM).

W10 is the section of the Vocabulary of Army Ordnance Stores that includes magnetic compasses, drawing and optical instruments, watches, survey, hydrographic survey and underwater sound equipment.

Later A.F.0210. buckles and loops were selenium dioxide treated to make black (bonderised?).


Image courtesy:

A service life of some 35 years makes this a classic NATO watch strap, and the influence which it had on the design of the NATO strap can be seen in the similarity in design of the NATO watch strap below.

The nylon NATO strap, seen earlier as 6B/2617 was specified by the military from at least 1973 onwards, under under NSN 6645-99-124-2986.     It is 280mm long, compared with the A.F.0210. which was only 250mm long, with the design change acknowledging that wrists were becoming larger.

Despite predating the DEF-3 strap, and the NATO strap, the A.F.0210. strap was not discontinued, and remained in service alongside the DEF-3 strap, and the NATO strap, until taken out of service in February 1980.  Below is the order replacing it with the NATO NSN 6645-99-124-2986 (Nylon).



Below is a NOS Smiths W10 and the NOS A.F.0210. strap which came in the box with the Smiths W10.    The box reads W10/6645-99-961-4045.  The strap is W10/6645-99-910-1003.


Image courtesy MWR forum user: MBRADIO

GS smiths

The Smiths catalogue from 1968 shows the watch on a braided nylon strap.

Image courtesy MWR forum user : simonk



Bulova provided the A-17a navigation watch above, and also similar general service watches to the MIL-W-3818A specification.  The MIL-W-3818A specification covered 3 grades of GS watches, Grade I +/- 10 sec/ day,  Grade II +/- 30 sec/ day, and Grade III +/- 60 sec/ day

The MIL-W-3818 specification of 24 October 1952 was revised to the MIL-W-3818A specification dated 12 March 1956.   Figures 1 and 2 of the specification provide for a sub-second, and sweep the second dial respectively.

Bulova provided two sweep second watches to the MIL-W-3818A specification with a 10BNCH movement, a 12 hour to Figure 2a, and a 24 hour to Figure 2b.   The 24 hour dial is very similar to the A-17a dial, but the hour hand is heavy spade-shaped.  The NATO watch strap was specified to be MIL-S-3035 Strap, Wrist Watch, Nylon of 8 September 1949.

A NOS cordovan NATO watch strap is shown below with a Bulova MIL-W-3818A.

Bulova 3818A

Image courtesy Omega Forum user: Dre

MIL-S-3035 Strap, Wrist Watch, Nylon reads in clause 3.3 :

3.3 Design and Construction – The NATO watch strap shall be manufactured in accordance with Drawing B7646909. It shall be of one-piece construction with integrally moulded loops. Sewing, cementing or heat sealing shall not be used in the construction of the strap.

Strap 7646909: NATO watch strap

The NATO watch strap came in black or Cordovan/brown.

MIL-W-3818B specification dated 17 October 1962 revised the title to Watch, Wrist : DTU-2A/P and revised the dial, and the strap requirement.

Clause 3.8 reads :

3.8 Strap.  The strap shall be fabricated in accordance with Drawing C 8636227.

However, an interim amendment of 12 January 1966 substituted :

3.8 Strap. The strap shall be Type II as specified in MIL-S-46383.  The color of the strap shall be black.

Benrus provided these MIL-W-3818B specification watches to the military.

Perhaps due to the rigid nature of the  MIL-S-3035 straps, many MIL-W-3818A watches are seen on MIL-S-60127 straps.


Bulova: NATO watch strap

Above is a Bulova MIL-W-3818A 12 hour dial on a MIL-S-60127 strap.  Image courtesy MWR forum user : shepcs

The watch above has the 12 hour dial and is stock number 6645-542-0554 (NSN 6645-00-542-0554), and the 24 hour dial is 6645-808-1407 (NSN 6645-00-808-1407).

Hamilton and Elgin also provided a big crown Grade II watches under this specification MIL-W-3818. The Elgin (Cal.805) with thicker numerals than the Bulova above.  The Hamilton dial was signed.

Elgin grade II: NATO watch strapElgin grade II

Image courtesy MWR user: What Does Your Watch Say?

3818 watches

Image courtesy MWR user: siewming

These watches date to about 1957.

The BuShips canteen watch has a similar dial, and also has the correct NATO watch strap, marked ORDNANCE DEPT. USA  PART NO. 7646909, as specified  in MIL-S-3035 Strap, Wrist Watch, Nylon clause 3.3 :

The strap shall be manufactured in accordance with Drawing B7646909.

BuShips canteen hamilton: NATO watch strapBuShips canteen hamilton



MIL – W – 22176 A (SHIPS) of 24 March 1961 replaced MIL – W – 22176 (SHIPS) of 1 September 1959, and was for an amagnetic 400 foot deep capacity diver’s watch.  The US Navy specification for submersible watches was strict and only one manufacturer could meet the requirements

Allen Tornek, who was then importing pieces from the Rayville Watch Company who were already manufacturing a diver’s watch, the Blancpain ‘Fifty Fathoms’ bid for the contract, and produced the Tournek-Rayville.

Only 1000 watches were produced, and many have been destroyed as radioactive waste, so maybe only 20 to 30 currently survive.

The MIL – W – 22176 A (SHIPS) specification required :

3.9 Strap – Each watch supplied under this specification shall be equipped with a one-piece nylon strap conforming to the specification MIL-S-21382, and which has met the magnetic test requirement of that specification.

Mil spec 50 fathoms


Above is the dial diagram included in the MIL-W-22176A specification requirements (left), and the Tornek-Rayville instruction manual, showing the proposed light grey woven nylon strap (right).

The watches are commonly referred to as “Tornek-Rayville”, “TR-900” or sometimes just as “Tornek”, as these are the markings seen on the dial and on the movement. The initial order delivered to the US Navy was for 780 pieces in 1964 and another in 1965 for 300 pieces giving a total of just over a thousand for this model.

The as-issued tubular weave NATO watch strap is shown below.

tournek rayville: NATO watch strapTournek Rayville strap: NATO watch strap

MIL-S-21382(SHIPS) is for STRAP, WRIST INSTRUMENT, WOVEN NYLON and was issued on 21 August 1958.

The specification requirements were for an 11 inch, light grey herringbone weave nylon strap, with an 1/2 inch wide keeper of the same material fused to the NATO watch strap.  Also, “the buckle shall have a dull nonreflecting finish and be free from burrs.”

In 1963, before the first watches were supplied, MIL-S-21382(SHIPS), was subsumed into MIL-S-46383, STRAP, WRIST: INSTRUMENT of 20 July 1963. The strap became the Type I – Strap, Special Purpose: Non-Magnetic Buckle of the 46383 series of specification issues.

The strap colour grey changed to black with the specification change.


Antimagnetic strap

Above is the Type I special purpose strap drawing from MIL-S-46383.  The dimensions are as for the MIL-S-21382 specification strap, and the length allows the watch to be worn over a diving suit.


THE NATO WATCH STRAP NSN 6645-99-124-2986


The nylon NATO watch strap, seen earlier as 6B/2617,  as specified by the military from at least 1973 onwards, under NSN 6645-99-124-2986, and from 1992 there are actually two NATO stock numbers allocated to this item: Army/Navy NSN 6645-99-124-2986 and RAF NSN 6645-99-527-7059.

Through common usage, the full NATO NSN 6645-99-124-2986 for this strap is abbreviated to just NATO strap.

The current Defence Standard specification illustrates the requirements of this NATO watch strap.   It was initially specified in Def Stan 66-15 (Part 1) Issue 1 – Strap (Nylon) dated 30 November 1973.   The drawing below draws heavily on the dimensions of the 1954 6B/2617 strap, as all dimensions are identical except for the width.

NATO Strap


The commonly called NATO strap has several written characteristics, and probably many more unwritten characteristics.

The actual military specification strap comes in only one colour (Admiralty Grey) and one width (20mm). The hardware specification is chrome plated brass with a recessed buckle to receive the tongue.   Length 280mm, width 20mm, thickness 1.2mm.

It is currently defined in Ministry of Defence, Defence Standard 66-47 as Strap,Wrist Watch.

Wrist watch strap


Earlier, there was a nearly identical NATO style strap made in accordance with DEF STAN 66-15 (PART 1) Issue 1, Strap (Nylon), 30 November 1973.  It was specified as grey as well, and it was used (under NSN 6645-99-124-2986) by the Royal Navy and British Army from 1973 until 1992 when the NATO standard DEF STAN 66-47 (ISSUE 1) superseded it.

For soldiers to obtain a NATO strap, they had to fill out a form known as the G1098, or G10 for short.    Sometimes these straps are known as G10 straps, as they were used on W10 watches.

US MILITARY NSN 6645-00-333-5396


By contrast, the US Military NSN 6645-00-333-5396  Strap, Wrist Instrument; Plastic Polyamide, is just a pass through strap, manufactured according to military specification MIL-S-46383B Type II.

MIL-S-46383A Strap, Wrist: Instrument was issued on 1 June 1965, and superseded by MIL-S-46383B on 16 September 1970.


46383 strap

This requires a black strap with a buckle assembly which shall be black oxide coated and painted with a dull black enamel finish.  The NATO watch strap is of one-piece construction 9.750 inches long, 0.625 inches wide and 0.045 inches thick. The strap has a keeper loop to receive the strap end as shown below.   The specification allows for other colours than black to be procured.

MIL-W-46374 specification was issued in October 1964 to procure a low cost, disposable alternative to the MIL-W-3818B. The specification provided for either metal or plastic sealed cased watches with minimal shock or water protection, and a lower accuracy, and a non-hacking movement.  Specifically, the NATO watch strap was to be olive drab.

3.3.5 Strap. – The strap shall conform to the requirements of MIL-S-60127.

This Specification was later revised, and required fixed bars, and an olive drab pass through strap, manufactured according to military specification MIL-S-46383B Type II. Strap. – The strap shall be in accordance with MIL-S-46383, Type II. The color of the strap shall be olive drab matching color number X34087 of FED-STD-595.


Ranger tennare: NATO watch strapStrap

THE 7A28-7120 GEN. 1 RAF

In the mid 1980s, Seiko released its 7A28-7120 variant with reference number SPR047 and NATO Stock Number (NSN) 6645-99-768-3056 to be used by the Royal Air Force (RAF).

The MoD bought and issued a total of 11,307 these Gen 1’s, which makes it one of the most popular issued military chronographs to date.

It should seem obvious that NSN 6645-99-768-3056  (Chronograph, Wrist ) should be compatible with NSN  6645-99-527-7059 (Strap, Nylon/Leather, Wrist Watch).

NATO Leather: NATO watch strap

Image courtesy of Ned Frederick of

Here is such a combination.

NSN 6645-99-527-7059 (Strap,Nylon/Leather,Wrist Watch DEF STAN 66-15 (PART 2)) illustrates the Specification for a brown RAF strap.   This is the Kitchener style strap from WWI.

nylon leather strap

These brown combination leather straps were the standard RAF strap from the early 1970’s until the 1992.  Therefore, a properly dressed Gen 1. RAF Seiko Chrononometer should sport one of these rare Kitchener NATO straps.


From the earliest time at which men fought in organised companies, the corps have possessed some sort of insignia visible over all the field of battle, serving as a rallying point for the men of the corps and as an indication of the position of the leaders.

All military Regiments have had ribbon and patch colours based on their battle flag or colours.


Regimental colours

Variations in colour for one piece nylon and NATO straps derived from another military tradition, that of stable belts.

Originally, stable belts were worn by the cavalry in the working dress they used for stable duties, but in the 1950s they spread to all branches of the armed forces, adding a splash of colour and individuality to the khaki working uniforms. Initially they were resisted by many senior officers, who saw them as too individualistic, but due to Regimental rivalry they soon became accepted throughout the forces.

As an example, the Royal Marines stable belt is shown below.

This is worn over the barracks dress jacket.

Royal Marines stable belt

The NSN for a stable belt is simply NSN: 8440-99-571-2693 Belt.   However military uniform suppliers soon produced Regimental stable belts.

When worn without the jacket, but with NSN 8405-99-983-1241 Trousers, Mans, Barracks Dress,Army All Ranks, khaki it is worn through the belt loops.

The availability of woven nylon in various colours soon led to British Military Regiments ordering NATO straps in regimental colours, again from specialty outfitters.

royal marines nato strap


Above is the Royal Marines NATO strap on a NSN 6645-99-541-5317  Watch, Wrist.

James Bond, in Goldfinger, 1964 wore a RAF type nylon strap on his Rolex “Big Crown” Ref. 6538 Submariner, in alternating navy blue and olive stripes separated by a thin burgundy line.    Here is a recreation, it can be seen that the NATO watch strap is only 16mm wide, as was common at the time for military watches, and does not fit the lugs of the Rolex.

NATO watch strapNATO watch strap

Today, every Regiment  of the British Army has its own stable belt, together with its own NATO strap, often very colourful, to go with the regimental tie (NSN 84440-99-874-6348 Tie, Regulation)


Ref 1  ‘Man is Not Lost’ – an Account of the Mk 11 Navigational Wristwatch Matthias Christian, Thomas Koenig and Greg Steer.    Horological Journal January 2004.  pp 9-14.

IWC FIRST AQUATIMER – Vintage Collectors Guide



With the development of aqualung (scuba) gear post world war II, Dr Hans Haas and other experts brought a new and fantastic underwater world into the focus of beginner and amateur divers. Many films and books aroused the interest in diving of the post war public. Divers needed watches to monitor the remaining time available underwater, and a broad market for reliable dive watches was created.

Early dive watches were a single crown, with the important introduction of an external rotating bezel to help monitor scuba tank time.  This external bezel could be accidentally moved by contact with other objects.

In 1964 Enicar produced a variety of 2 crown diver watches, using Ervin Piquerez S.A. (EPSA) manufactured, and patented, waterproof cases, utilising an internal bezel.  These cases were either 36mm or 42mm in diameter and featured 2 oversize crowns.  EPSA made waterproof cases in these sizes for a variety of watch manufacturers, and IWC brought the first 2 crown watch with the name “Aquatimer” to the market in 1967, and perhaps as early as November 1966.

Some of the rarer and more prestigious examples of EPSA cases include the Univeral Geneve Polerouter Sub, the Longines 7150-1, the Vulcain Nautical Cricket diving alarm, the Lip Nautic-Ski and the Jaeger-LeCoultre Deep Sea Alarm, and the later Jaeger-LeCoultre Polaris with 3 crowns.


The first Aquatimer model carried the reference number 812, then 812 AD, and finally 1812 when IWC standardised on 4 digit model numbers in about 1972  It was waterproof up to 200m. The AD stood for the Automatic and Date functions provided by the IWC caliber 8541 movement used in the Aquatimer.

Below is a mint version of the Aquatimer 1812 on a Tropic strap, and early 812 models most commonly did not display the IWC logo.

Mint aquatimer 1812
Photo courtesy: member XX-FF


The watch was medium in size, 37mm diameter, and featured 2 large crowns, embossed with the IWC fish.  The large crowns supposedly made it easy to operate the watch with gloved hands.  The jury is out on the benefits of an internal bezel, versus the benefits of an external bezel, but the internal bezel gives a more “dressy” feel.

The dial featured an internal bezel, with tick marks at the 5-minute position, dual ticks at 12, numerals at 15, 30 and 45, and smaller minute tick marks from 0 to 15.  The hands were tritium painted baton shaped, with a paddle second hand.

The dial itself had raised fluted tritium painted baton indexes, and the date position is at 3 o’clock.

The internal bezel could be adjusted by the crown at 2 o’clock in one direction.

The IWC logo was or was not present, but the script, International Watch Co, in cursive, and SCHAFFHAUSEN below were a feature of the dial at 12 o’clock.  IWC watches from the middle 1950s to the late 1960s (such as the Ingenieur) did not feature the IWC logo, and if they were waterproof they used the fish logo crown.

Sometime in the late 1960s, (maybe 1970), an applied “IWC” logo was introduced on the dial above the script International Watch Co.  It is not certain whether this logo was used with much regularity and this is the source of some confusion.

The IWC AQUATIMER above AUTOMATIC featured at 6 o’clock, with T SWISS T below that index.

The case back featured a submarine image in a central ring, and the outside read AQUATIMER IWC WATERPROOF 20ATU, together with the EPSA case reference number.


Case back IWC Aquatimer
Image courtesy:


Four combinations of dial and bezel were available as in the extract below; black dial, black bezel; black dial, silvered bezel; white dial, silvered bezel; and white dial, black bezel.

The model number shown is 85353T, a short-lived numbering experiment by IWC.

1812 catalogue


Perhaps the earliest known model is the all white version below with a fish on the dial, thought to be a prototype, although IWC is embossed on the dial.  This has a thin pointer second hand and a short square-tipped baton hour hand.  The fish image is embossed on the crowns.  Model number 812 is engraved on the inside of the back case.

aquatimer 812
Photo courtesy: Konrad Knirim


The IWC caliber 8541 (23 jewels) powered the Aquatimer 812.

The mechanical automatic self-winding IWC caliber 8541 movement is rhodium-plated, with fausses cotes embellishment, and a shock absorber mechanism. It is constructed with 23 jewels, a straight-line lever escapement, and a Pellaton winding movement. It includes a monometallic balance that’s adjusted for heat, cold, and 5 positions, and a self-compensating Breguet balance spring.

In 1968 another Aquatimer was produced and manufactured in parallel, reference 816AD (or 1816), which, in contrast to the first model 812, had a pillow-shaped housing and a water-tightness of 300m. The caliber was the modified 8541, the 8541B (25 jewels).  The other characteristics are the same.

Aquatimer 816

This 816AD watch and succeeding Aquatimer models are not the subject of this article.

In August 1978, model 1822 was produced as a replacement watch for model 1816 due to technical difficulties in model 1816 with the 8541 caliber movement.  The only visible difference is the lack of the submarine engraving on the case back, but only in some watches. Both the 1812 and 1816/1822 models were offered jointly in the years of their production.

In 1982, after a total of 2000 copies of models 1812, and 1816/1822, production of these models ceased.

The all black Aquatimer is the most common model, the 812 did not feature the IWC logo.  The sweep second hand has a rectangular paddle tip, as opposed to the possible prototype above.


Aquatimer 812AD no IWC

Below, is a  later model 812AD with the IWC logo.  The 812AD model also came without the IWC logo as a transition model.

Aquatimer 812AD

A rare IWC stamped Gay Freres beads of rice bracelet shown below, as the tropic strap was more common.

Aquatimer bracelet


A black dial model with box and papers recently sold for $30,000.

1812 model IWC


1812 aquatimer


The black dial, silvered bezel model is shown below, without the IWC logo.


812 aquatimer
Image courtesy: Amsterdam Vintage Watches


And a model with IWC embossed.

aquatimer black dial white bezel
Image courtesy:


And, below, 2 images of the white dial, black bezel model.

This image shows the original Gay Freres strap, and the Cal 8541 engraving.
IWC 812
And, finally the white dial, silver bezel version.
white aquatimer
Image courtesy:  Meertz World of Time
White Aquatimer




Super Compressor is a trademarked name for specific case designs made by the case manufacturer Ervin Piquerez S.A. (EPSA). They designed a patented case sealing method that actually became more water tight the deeper the watch went. The deeper you went, the more pressure was applied to the case-back, pressing it against the O-ring gasket.

The patent extract is shown below.

epsa patent

The 2 crown Super Compressor case has crowns at 11 and 19 minutes, and the screw in version was covered by patents Brevet #317537 and Brevet #337462.   The EPSA logo is a dive helmet featured below on the inside of an Aquatimer case back.  The IWC Probus Scafusia motto also features on the case back.


IWC inside case back
Image courtesy:


Some later Aquatimer case backs did not feature the EPSA logo, but still referred to the EPSA patents, and had the IWC Probus Scafusia logo.

Aquatimer inside case back


Aquatimer crowns


IWC crowns


caseback Aquatimer


The IWC catalogue A01686/01.91  October 1989 describes the 8541 movement.

A patent, dated 7 June 1950, under the number 284841 effectively marked the birth of the Pellaton winding system that has remained such a central feature of IWC’s automatic movements to this day.

IWC’s Technical Director Albert Pellaton developed the revolutionary pawl-winding system that featured in the company’s first automatic movement, the 85 calibre. Pellaton’s design was destined to go down in the annals of watchmaking history.


IWC 8541 movement

The reciprocating motion transmitted to the ratchet support by the cam 1 had a dual function: it enabled the winding rotor mounted on the pivot 2 to rotate freely, and it also activated the shock absorber 3 which cushioned the rotor, the cam and the entire mounting from knocks in any direction. The heart-shaped cam (which had long been in use as a means of returning chronograph hands to the zero position) enabled maximum exploitation of energy, while both discs 4 on the prongs of the ratchet support, which rotated against the contact surface of the cam, considerably reduced the energy loss through friction. The rotary movement of the ratchet wheel 5 was transferred directly via its pinion 6 to the winding wheels 7 and 8 without the need for an intermediate geared coupling. Besides keeping the movement extremely slim, this also reduced production costs and, not least, eliminated a source of potential malfunction.

Two further IWC innovations were also protected by Swiss patent. Firstly, the combined automatic winding mechanism and movement and, secondly. the winding rotor mounting. One of the most outstanding external features of the IWC automatic wristwatch movement is the case with which it can be serviced: the winding rotor can be removed from its pivot 11 simply by loosening a single screw and pulling back the retaining fork 10.

IWC 8541 movement


The rotor mounting is likewise secured by one screw for easy removal, while the other two main elements in the automatic winding mechanism, the ratchet mounting with the fork and the ratchet itself, are both mounted under a single bridge, which is held in position by two screws. When the watch was being designed very special care was taken to ensure unimpeded access to the barrel. This can be detached easily, with no need for prior removal of other parts of the movement, once the two screws retaining the barrel bridge have been loosened. The efficiency of the winding rotor’s shock absorbing system has made it possible to fit the bearing with two sensitive rubies 12 and 13. These jewels, together with the slim, highly polished steel pinion 11, have helped to make the automatic winding mechanism highly efficient.

All this contributed to making the IWC watches with Calibre 8541 watchmaking masterpieces.

8541 cal aquatimer



Usually, in this series of articles, we make recommendations on watches in the series.  However, for the 812 Aquatimer, any version of the model is ultra-desirable.

However, the Gay Freres strap (type 12) is much rarer than the tropic strap.

812 aquatimer

Railrouter Universal Geneve


In the late 1950s, US and Canadian railways started to make the transition from pocket watches to wrist watches.

Until then, wrist watches were deemed too irregular for railroad use, primarily because of the oscillation variance which could be introduced to a mechanical balance wheel through normal rotational wrist motion, particularly on a rattling train. Pocket watches were not exposed to such rotational motion in normal use and tended to have better regulation.

But design improvements led to wrist watches such as the Omega Railmaster,  the Girard Perregaux Railtimer and the model with the classic name, the Railrouter.



The collision between two trains in Kipton, Ohio in 1891, caused the death of the engineers on both trains and nine train crew.  A 4-minute error by a watch carried by an engineer on one train caused the “Great Kipton Train Wreck”.  This meant both trains were on the same rail line, instead of one train waiting in a siding until the other passed.

Alarmed by the accident, railroad officials commissioned Webb C. Ball, a jeweller and watchmaker who was then managing the local standard time to investigate the accident and establish a system for reliable railroad operation.

The saying “On the Ball” relates to his subsequent manufacturing of pocket watches by upgrading movements provided by others and then marketing these accurate pocket watches.

Kipton memorial

In 1893 Ball established a set of “Railroad Approved” standards applicable to the watches used by railroad workers.   The RR symbol was applied to such watches.

Standardization was put in place throughout the USA and “Railroad Time” became the standard. Watch companies such as Howard, Waltham, Elgin, Hamilton, Hampden and Vacheron & Constantin worked with Mr Ball and his new company, the Ball Watch Company, providing him with movements that he then standardized and upgraded to Railroad Standards and that bore the name of Ball Watch Company on the outside.

The Ball Watch Company is still among the top dozen manufacturers worldwide in terms of certificates received from the C.O.S.C. (Controle Suisse des Chronometers).

Ball watch movement: Universal Geneve Railrouter


The RR specifications ensured that a railroad worker could check the time correctly in an instant in the field.

Compared to other watches, railroad watches required higher air tightness, greater durability against vibration, and superior overall reliability. They had to withstand the high temperatures and constant vibrations the engineers were exposed to when stoking the locomotive boilers with coal. The accuracy specification, deviation by no more than 30 seconds per week, was very strict for the day.

Waltham Railroad Pocket watch

Waltham, Elgin, and Hamilton successfully made the railroad pocket watches to meet these strict standards in America, and Longines and Zenith joined the market in Switzerland, as well.

Each manufacturer used a big detached balance and wind-up hair spring to achieve high precision, as well as a dual roller table called the “double roller” to control the oscillation angle of the impulse pin.  All of the watches were also equipped with a fast/slow regulator to allow time adjustment by the second.

American watch companies evolved in later decades, basing their technologies on the high precision and reliability of pocket watches learned from the manufacture of railroad watches.

Waltham’s watch was selected as a standard railroad watch in many countries by dint of its high reliability. The Japanese Ministry of railroads (later the Japanese National railroads) adopted it as a standard railroad watch in 1897 and continued using it until Seikosha’s railroad watch, the “Seikosha,” superseded it in 1929.

Hamilton also produced a famously accurate railroad watch called the Broadway Limited.  The Hamilton company was formed in part to produce high-quality railroad watches.  The Broadway Limited was first produced in 1893 and quickly gained popularity among employees of the US railroads due to its high level of timekeeping accuracy.

By 1923, just over half of Hamilton’s pocket watch production comprised Railroad Grade watches, consisting of 17 jewels and 42-hour mainsprings.

The American Expeditionary Forces in WWI embraced the timepiece and adopted it as their official watch, and it was adapted to become a wrist watch, one being worn by General Pershing.

The watch was also employed by Admiral Byrd on his polar expeditions, as well as Auguste Picard on his pioneering balloon ascents in the 1930s.

Broadway: Universal Geneve Railrouter

The Hamilton Broadway Limited with a Montgomery dial.

Hamilton ad: Universal Geneve Railrouter


cp advert: Universal Geneve Railrouter

The CP Rail General Operating Instructions were specific about watch accuracy, and hence, specified approved watch models, and maintenance procedures.

Employees were required to purchase their own approved watches from, and to have them serviced regularly by, an approved Watch Inspector.

The General Operating Instructions listed the personnel requiring a Railway Grade Watch, together with the purpose.

“The aim and purpose of using approved watches is to ensure efficiency and safety. Correct time is of the utmost importance where the movement of trains is involved. The closest co-operation of all concerned is therefore important.”

“Every conductor, locomotive engineer, trainman, pilot, foreman, snow plow foreman and such other employees as the company may direct, shall, when on duty, use a railway approved watch and shall;
(i) be responsible to ensure that it is kept in proper working condition so that it does not reflect a variation of more than thirty seconds in a twenty-four hour period;
(ii) set it to reflect the correct time if it reflects a variation of more than thirty seconds;
(iii) not regulate its movement. “

The General Operating Instructions specified Railway Grade Watches

“Watch movements and cases used in service must be of the approved standard in effect at date of entry. All watches entering service must be of the antimagnetic type, fitted with 24 hour dial, waterproof, shockproof with stainless steel screw-back case and equipped with tension ring crystal. Cases with gold plating on stainless steel and stainless steel with gold top are permissible.

Employees operating in two time zones must have their railway grade watch equipped with double hour hands, one red and one black to reflect both time zones.”

An example of such double hour hands was the Universal Geneve Railrouter, but the watch with 0 at 12 o’clock was probably used on CNR, not CPR.  These double hour hands are sometimes called “Pacific hands”.

Railrouter 2 hands: Universal Geneve Railrouter

Image Internet Horology Club 185 user: Larry Buchan

In 1969 CPR listed the wrist watches below as the only Approved Wrist Watches, together with a list of Approved Pocket Watches :

“Bulova Accutron “Railroad Approved” 21014 and 28014
Girard Perregaux 307 HF (17 jewels)
Longines Railroad 280 (17 jewels)
Universal Geneve Railrouter Chronometer (17 jewels)”

These watches are described below, in turn.


The Accutron was nearly immune to vibration effects, and easily surpassed the Railroad certification requirements.  Because of the Accutron tuning fork’s extremely stable oscillations, an Accutron could be regulated to within +/-2 seconds per day or less, double the accuracy of a modern Chronograph grade ETA mechanical movement.

accutron ad: Universal Geneve Railrouter


Bulova advert: Universal Geneve Railrouter
The Railroad Approved 21024 model is shown below.
Accutron 21024 bulova
A differently dialed model with Pacific hour hands is also shown.


The Girard Perregaux Railtimer also came in various models, and a 12 o’clock model with is shown below.  They were all signed High Frequency.

GP railtimer

The 307 HF – 0 dial is shown below with 0 at 12 o’clock as required by CN Railway specifications.

gp railtimer

Image courtesy of WatchTalkForums user: scottw44

girard perregeaux HF 207

Image courtesy of WatchTalkForums user: scottw44


The Longines RR280 often called the Canadian to distinguish it from the American Longines T905. It was the only model with an arrow sweep second hand and a dual time “Pacific hands” version with square lugs is shown below.

longines rr 280

Below is the Ref 7816 version with pencil hands.

A dial with 0  at 12 o’clock is shown below.  Normally the RR280 had thin pencil hands but on this model dauphine hand sets were used, and have been copied in the recent Longines RR888 homage watch.

RR 280 Longines


Image courtesy:

The RR280 movement is shown below.  The RR280 was a modified version of the regular Longines caliber 280. It had an additional hacking feature, a swan-neck regulator for fine adjustment and it was regulated in 5 positions.

rr280 movement




The Universal Geneve Railrouter Chronometre is shown below with the twisted lug case of the original Polerouter.  Early dials had just UNIVERSAL GENEVE beneath the 12 o’clock position, without a logo.  All the Railrouter models carried thin syringe minute hands and spade hour hands, both with long pointers. The watch had a manual-winding RR chronometer Universal Genève movement calibre 1205 with hack seconds feature.

The calibre was a development of the UG 263(…&Universal_263 ) with the stop seconds work added, to meet railways requirements. The dimensions were 35mm diameter and 45mm lug to lug.

UG Railrouter chronometre


The 1205 movement above is numbered 9388

1205-0 MODEL

The 565100 Gold Plated 1205-0 model is shown below, with a dial commencing at 0 at 12 o’clock as required by CN Railways.  This is possibly a later model in the Universal Geneve Railrouter series, as the markers 12 to 23 are in black, and the Cal 65 movement is used instead of the cal 1205 movement.


ug Rail router gold
Image courtesy of WatchTalkForums : scottw44

The Calibre 65 movement is shown below.

RR 65 movement

Image courtesy of WatchTalkForums: scottw44

The listing for the watch above by A Trebor’s Vintage Watches reads :

Universal Geneve Railway Wristwatch RR.1205-0 with military style 24-hour dial in a gold filled case with scrolling lugs and with stainless steel screw back. The high contrast of black numerals on a porcelain white background and red sweep seconds hand make it very easy to see the time. Movement is a high quality 17 jewels manual wind, cal 65, adjusted to five positions and with hack feature for precision setting to meet railway standards. The watch is signed Universal Geneve on the dial, movement, inside case and has a winding crown with the company logo. The watch was found in perfect working condition but as the last service dated is unknown it is currently being cleaned by our watchmaker.
Measures 35mm across (not including crown) x 44mm (lug to lug). The distance between lugs (bracelet width) is 18mm.

Another gold dial model is shown below, with a black sweep second hand.

1205-0 gold Railrouter

A later Stainless Steel version now with the U symbol above Universal Geneve, and a black sweep second hand.rr1205-0 ug

This has a cal 65 movement and is model number 865100


865100 model with dial labelled RAILROUTER 1205 in NOS condition is shown below.

1205 railrouter

Image courtesy Mentawatches

The Calibre 65 movement is shown below.

1205 railrouter

The Universal Geneve Railrouter 1205 movement is shown below, marked 9266.

1205 movement railrouter: Universal Geneve Railrouter


This has the cal 1205 movement, and a model with the U logo is shown below. This also has black hands.
railrouter: Universal Geneve Railrouter
The 1205 movement.
1205 movement: Universal Geneve Railrouter


A story from a new employee inducted into CNR 1964 is reproduced below:

“…. my watch comparison ceremony wasn’t what I had dreamed of, having watched railroaders check their pocket watches since my earliest memories.  No…., CN had decided a few months before I hired on that all new ‘hires’ would not be allowed to use the old standard pocket watches, but must convert to new, “approved” wrist watches!  The Bulova Accutron and the Universal Geneve were the only two choices.

The Accutron emitted a high pitched whine, 24-7, and the Geneva couldn’t keep time with a turtle!  Only those who had already been qualified to work using a pocket watch could continue to use them.  The beautiful, gold pocket watches were gone for me.  I would never be able to re-enact that age-old tradition of reaching down, and finding the gold chain slung between the clasp and the gold watch and, gently lifting my treasure from my pocket, let it slides effortlessly into the palm of my hand where it would lay, softly ticking it’s warm song of our mutual love of railroading, and giving me the exact time of day.”

Obviously the pocket watch was preferred to the noisy Bolova and the slow Railrouter.



The 1205 type dial was used by Canadian Pacific Railways.

1205 railrouter UG: Universal Geneve Railrouter



The – 0 type dial can be seen on RR watches from several manufacturers and was used by Canadian National Railway, together with all black numerals 0 to 23.

Railrouter Universal Geneve 0 Dial: Universal Geneve Railrouter

Image courtesy Omega Forum user: MattF



Any 1205 model would be the keeper, as they are rare.   Either the 1205 calibre or the 65 calibre would be desirable.

Railrouter 1205 UG: Universal Geneve Railrouter

The cal 1205 movement number 9206 is shown below.

1205 railrouter 1205 movement: Universal Geneve Railrouter

Image courtesy: orologi e passioni


The grail watch would be the Universal Geneve Railrouter Chronometre, a CPR Approved Watch, in a gold case, with box and papers, and the cal 1205 movement.   Expect to pay several thousand dollars for such a rare example.

ug railrouter chronometre: Universal Geneve Railrouter

railrouter chronometre: Universal Geneve Railrouter

Polerouter SUB


Polerouter Sub avert: Universal Geneve Polerouter SUB

The Universal Geneve Polerouter Sub was first released in 1961 on an expanding stainless steel bracelet and was an instant success.  Manufacture of various Polerouter Sub models continued until about 1968.


The first execution of the Universal Geneve Polerouter SUB was model number 20369/1 and is pictured in the advertisement above and below, and has several distinctive features :

Curved lugs.  The first model has gently curved and tapered lugs, with a case very similar to the Longines 7150-1.

Asymmetric crowns.   Not always present on the curved lug model, but often so.

Lume dots on the outside of the hour markers.  The first execution is recognized by tiny lume dots on each of the larger white painted hour markers

It had a Microtor Cal 215 movement (28 jewels no date), but Cal 218-9 (28 jewels)  and 218-97 (17 jewels) versions existed.

The model below is on a Gay Freres bracelet.

polerouter sub first model: Universal Geneve Polerouter SUB

The asymmetric crowns are obvious above and are shown below from the side, together with the distinctive curve of the lugs.  The top crown is signed Universal Genève and rotates the internal bezel; the bottom crown is cross-hatched, characteristic of a Super Compressor case, and winds and sets the watch.

polerouter sub crowns: Universal Geneve Polerouter SUB

However, some versions of the curved lug model have symmetric cross hatched crowns.

2 crowns curved lugs polarouter sub

The Microtor 215 movement is shown below.

polerouter sub 215 movement: Universal Geneve Polerouter SUB

The Super Compressor had a 14 sided screw back, engraved 20369/1 on the outside edge.

polerouter sub case back: Universal Geneve Polerouter SUB


The Super Compressor case holds a special place within the history of dive watches. It was used by over 50 watch manufacturers for their dive watches.  Screw-in case backs are generally used, except for the Enicar bayonet models.

Super Compressor is a trademarked name for specific case designs made by the case manufacturer Ervin Piquerez S.A. (EPSA). They designed a patented case sealing method that actually became more watertight the deeper the watch went. The deeper you went, the more pressure was applied to the case-back, pressing it against the O-ring gasket.

The patent extract is shown below.

epsa patent


The 2 crown Super Compressor case has crowns at 11 and 19 minutes, and the screw in version was covered by patents Brevet #317537 and Brevet #337462.   The EPSA logo is a dive helmet featured below on the inside of an Aquatimer case back.  The IWC Probus Scafusia motto also features on the case back.

Super Compressor watches typically have a depth rating of 600 ft.  EPSA designed three different types of case ranging from the Compressor through the Compressor 2 to the Super Compressor.


Super compressor


Super Compressor cases supplied by EPSA came in single or dual crown models, the latter with internal rotating bezels.  However, a dual crown dive watch with an internal rotating bezel is not necessarily a Super Compressor.

The dual crown case came in two case sizes, 36mm and 42mm.   Usually, the inside case back has an engraved helmet, the Trade Mark, and the Brevet or Patent numbers for the case, as shown below.   The Brevet numbers are 317537 and 337642.  This is not so in the Polerouter Sub.

Super Compressor: Universal Geneve Polerouter SUB

Super Compressor cases also have cross hatched crowns.  The crowns are at 11, and 19 minutes, and the crown at 11 minutes operates the bezel.

Below is a model with two crowns of same size.

Polerouter sub: Universal Geneve Polerouter SUB

So, the first curved lug model has a solid stainless steel Super Compressor case with curved lugs and screw-down back, approximately 42mm excluding the crowns; the top crown is sometimes larger, signed Universal Genève and rotates the internal bezel; the bottom cross-hatched crown winds and sets the watch; model number 20369/1 isvisible on the outer edge of the caseback.

The Universal Geneve Polerouter SUB above demonstrates all the characteristics of a first execution, starting with the small dots inside the painted indexes.

Some minor variations occurred, and in 1994 Antiquorum sold a model with Dauphine hands.

Polerouter sub dauphine hands: Universal Geneve Polerouter SUB

And a Tiffany version with different lume dots, without the wording Polerouter Sub, with a later Cal 218 movement.

Tiffany polerouter sub


The 20396/1 model is generally classified into two distinct variants: the first execution, and the second execution. Both are housed in a dual-crown case; both have broad, flat steel hands; and both have black dials with an internal rotating elapsed time bezel.

The second iteration is shown below on the left, together with the first iteration on the right.


A comparison between the second iteration shown below on the left, and the first iteration on the right show minor differences.

Polerouter sub 2 models

Image courtesy Omega Forum user: styggpyggeno1

The second execution has hour markers fully covered with lume.  The most notable difference between the executions has to do with the shape of the lugs, as the second execution features angled lugs with a prominent bevel.  The numbers on the bezel appear thicker, and finally, the crowns are larger.

Bevelled lug polerouter sub

Below are the crowns, compared with the bevelled lugs.

bevelled lug polerouter sub: Universal Geneve Polerouter SUB

Inside case back is engraved HF.

bevelled lug polerouter sub inside caseback

Some variants of this execution have poor quality metal cases, and an apparent gap in GENE VE on the dial, and are generally acknowledged to be fakes.


On 27 May 1955, Universal filed Swiss Patent No. 329805 for a ‘Microrotor’, or as they called it a “Microtor”, and the patent was published on 30 June 1958. This was based a satellite rotor that could be recessed into the backplate of the watch movement, without the need to accommodate and mount a traditional rotor above the backplate.  It was then possible to create a much slimmer automatic movement and hence a thinner watch case. At the time of its inception, the Microtor was revolutionary. The small size of the rotor and its off-centre position meant that the rotor itself had to be made of a heavy metal in order to move and hence wind efficiently. The rotor was also designed to wind in both a clockwise and counter-clockwise direction.

In 1955 Universal Genève released the Cal 215 Microtor movement in the second generation Polarouters, which were now called the ‘Polerouter’.

215 ranfft

 Image: Ranfft

Humming at 18,000 bph and with a power reserve of almost forty-eight hours, the Cal 215 had only hour and minute functions, with centre seconds and was 28mm in diameter, and 4.10mm thick.

Throughout the 1950s Universal Genève continued their focus on the development of the Microtor. On January 30, 1957 they filed patent Number  330900, published on August 15, 1958, for a self-winding movement with central seconds wheel and pinion, and a micro oscillating weight integrated into the movement. The Calibre UG 215.1, was 5.15mm thick with hour/ minutes/ seconds, and with the addition of a date disc.  Calibre UG 215.2 had the same functions as Calibre UG 215.1, but was 0.45mm slimmer, at 4.70mm.

The Calibre UG 215.2 would be replaced by the Calibre UG 218.2, 4.70mm thick, measuring 28mm in diameter, and with a date function.  Its primary improvement of note was the ability to make fine adjustments via an adjustment screw on the balance cock. This calibre would also find its way into Polerouter Date models.

On the 26 March 26 1956, under patent Number 336013 (published on March 4, 1959) Universal Genève filed an additional patent Number 329805. The new Calibre UG 68 was 4.10mm thick, and had a centre hour, minute, and seconds hands.

Below is the patent on a Cal 69 movement.

cal 69 patent: Universal Geneve Polerouter SUB


This was then followed by the Calibre UG 69, which was the Calibre UG 68 with the addition of a date disc, with a thickness of 4.70mm. The development of UG 6x Calibres continued through the 1960s in various iterations.



The second generation of the Universal Geneve Polerouter SUB was released in about 1964, initially as model 204615/1.   This model below has a countdown bezel.  Some have elapsed time bezels.

The numbers 6,9 and 12 are stylised on white background, and the dial is cross marked in red.

The dial had white UNIVERSAL above red GENEVE.

The hands are long trapezoid-shaped with large lume filled centers. The acrylic crystal is domed with a trapezoid shaped internal date magnifier and may or may not be signed in signed in the middle of the underside with a tiny UG “U” logo.

The crown is large, some 7mm high with a domed surface.

The model below has a Cal 218-2 movement, with a date window.

204615/1 polerouter sub g2: Universal Geneve Polerouter SUB

Image courtesy: MentaWatches

The Cal 218-2 movement.

218-2 ranfft

Image: Ranfft

The model below has a Gay Freres bracelet and has an elapsed time bezel.

204615/1 Polerouter sub: Universal Geneve Polerouter SUB


Image courtesy : Roy and Sacha Davidoff

The image below shows the cyclops window clearly.  This watch is fitted with a Cal 69 movement.

204615/1 Polerouter sub: Universal Geneve Polerouter SUB

Image courtesy: Roy and Sacha Davidoff

The case back is a screw in, engraved with model number 204615/1 and 2364227.  This dates the watch to about 1964.

204615/1 polerouter sub back: Universal Geneve Polerouter SUB

This case is beautifully designed and is shared amongst a few other models such as the Titus Calypsomatic and the Technos Sky Diver.  It has pointed downward bending lugs that wrap nicely over the wrist.  The domed crystal can be seen below.


204615/1 side: Universal Geneve Polerouter SUB

Then, Universal Geneve changed the numbering system commencing an 8691xx series with the Polerouter Date,  869101/01.


This model is identical to the model above, but has a new reference 869109/01, dating it to about 1965, still with a symmetrical stainless steel 40mm case.

The movement is Cal. 69, and it would appear that there are more of this edition than the earlier 204615/1 edition.

At its widest point, it measures 48mm and has a 20mm lug width. It has a very large 6.70mm crown, with a rounded top. The crown screws down onto a rubber gasket for water resistance.

Calibre 69.   Inside the Super Compressor caseback reads BREVET 238872, BREVDEM.

inside caseback 869109/01 polerouter sub

Image courtesy: Joseph Bonnie

Outside case now marked 869109/01 and 240xxxx, dating watch to 1965.


869109/01 polerouter sub: Universal Geneve Polerouter SUB




The third generation of the Universal Geneve Polerouter Sub had an asymmetrical case, with a less curved case with case guard shoulders to protect the crown, and dates to 1966.

The dial continued the 869109/01 dial features with large art deco numerals at 6, 9 and 12, and a countdown bezel available.   A red line from 3 to 9 featured on the dial.  The dial had white UNIVERSAL above red GENEVE.

There is a screw-down crown protected by case-guard shoulders, and a solid screw-down case back. The inner case is antimagnetic and is signed with hallmarks. The 38mm diameter solid two-body case, straight lugs, and external rotating unidirectional bezel are polished/brushed. The bezel has 60-min ute Arabic numerals every five minutes with an luminous indicator dot at 60. The dial is black, steel trapezoidal hands with luminous inserts, and luminous baton hour markers. There is a center sweep seconds hand and a perimeter minute/seconds chapter ring. The trapezoid date aperture window is at the 3 o’clock position. It has a 57-hour power reserve at full wind, and it was originally water resistant to 654 feet. The 12.5mm thick case, dial, and movement are all signed.

This Universal Geneve Polerouter Sub 869116/01 has a mechanical automatic self-winding Universal Geneve Cal 69 movement. It’s rhodium-plated with fausses cotes embellishment, and it’s constructed with 28 jewels, an Incabloc shock absorber, and a straight-line lever escapement. It includes a monometallic balance, a self-compensating flat balance spring, and a gold microrotor. The mechanism oscillates at a frequency of 18,000 vph (2.5Hz).

869116/01 polerouter sub

Image courtesy: Christies

The auction catalogue reads: Signed Universal Genève, Polerouter Sub, Automatic, model 869116/01, case no. 2,503,083, manufactured in 1966, with movement Cal. 69, 28 jewels, automatic.

The 869116/01 model is shown in the middle of the advertisement below.

869116/01 ad: Universal Geneve Polerouter SUB


A crossover 869116/01 model with a version of the later model revised blue bakelite bezel, with elapsed time marked 15, 30, 45, together with the soon to be released flatter crown, is shown below.


polerouter sub blue: Universal Geneve Polerouter SUB

Picture courtesy:

Another crossover 869116/01 model with large art deco numerals at 6, 9 and 12, and a countdown bezel but with the next-generation white UNIVERSAL GENEVE in one line.

869116/01 polerouter

Image courtesy Rolex Forums user : Craft & Tailored


The crossover model 869116/01 heralded a different dial model, with UNIVERSAL GENEVE in one line in white, but the logo and Universal Geneve Polerouter Sub in red, and with a single line on the dial from 3 to 9.

This is the 869116/02 model with the words UNIVERSAL GENEVE in one line.  The bezel is always elapsed time, and the movement is Cal 1-69.

869116/01 elapsed time polerouter sub


Later model 869116/02 was produced with a next generation dial with an elapsed time bezel, still Cal 1-69.   There are probably more model 869116/02 of this dial than the previous art deco dial.


bain polerouter 869116/02

Image: Matthew Bain

The 1-69 movement on a model with a Gay Freres bracelet is shown below.

polerouter sub

1-69 movement UG polerouter

In November 2016 Philips auctioned a rare crossover model, case number 2,504,248 , with the next generation green bezel, and a unique second hand.

It was accompanied by 3 spare bezels in blue, black and red, and an Extract from the UG Archives

869116/02 polerouter sub

And a later prototype bezel has been seen on a 869116/02 model as well.

polerouter sub

Image courtesy watchuseek user : capela


The 869120/02 models have a varied numbering system.  The inside case back is stamped 869120 but it is then sometimes overprinted.   Different numbers 869121, 869123 and 869124 are referenced.

The blue and brown crossover bezels illustrated above are replaced by a bakelite bezel, marked 1 to 11, with tick marks to 5 and triangles elsewhere.  Various colours were available, but mostly black is seen. The acrylic bezel has a luminous GMT style number 1 through 11, with a lume triangle at 12. It is bi-directional with a light ratchet. There are 3-D hashmarks inside the insert, giving the bezel real depth and beauty.

The 869120/02 model is shown below.

The dial has no numerals, with rectangular lume hour markers bracketed by an U.

The movement is now a Cal 1-69.

The crown is flatter.

869120/02 polerouter

Red bakelite bezel model and blue bezel model is shown below.   Green and grey bezels have also been produced.

869120/02 red polerouter sub

blue polerouter

Right hand image courtesy Omega forum user: Chron

An advertisement for the 869120/02 is shown below.

869120/02 ad

The revised crown differences are shown below.  From above this new 869120 generation crown is flatter, and bigger.

crown difference

Image courtesy Omega Forum user: bristnj

And from the side the difference is obvious.

polerouter sub edge shot

Image courtesy Omega Forum user: bristnj

Some other bezels are seen on the 869120/02 model. A Pepsi bezel is shown below with hands similar to the ladies model discussed below.

kaplans polerouter 869120/02

Image courtesy: Kaplans Auctioneers.

The catalogue note reads: UNIVERSAL, Geneve, Polerouter Sub, Cal 1-69, Ref no. 869120/02, Case no. 2668624, men´s wristwatch, 40 mm, steel, self-winding (microrotor), plastic crystal, date, leather strap, approx 1967-8.

Another Pepsi bezel with more commonly seen hands is below.

polerouter sub

Image courtesy:

Several other models were produced, but the numbering system is not completely understood.  The 869121 model has a red bakelite dial, dated about 1969 with a Cal. 1-69 movement.

869121/02: Universal Geneve Polerouter SUB

Image courtesy: Watches of Knightsbridge

The inside case is stamped 869120 with 1 added over the 0

869121 case inside: Universal Geneve Polerouter SUB

Image courtesy: Watches of Knightsbridge

A blue bezel model 869122 was also produced.

869120/02 polerouter sub blue

Inside case stamped 869120 with 2 added before and 2 over the 0

blue bezel 869122: Universal Geneve Polerouter SUB

There was also an 869123/02 model with a countdown bezel

869123/02 polerouter sub

Inside case stamped 869120 with 2 added before and 3 over the 0

869123 polerouter sub inside case

The same case number modification is also found as below.


polerouter 869123

Image courtesy user: stophmaster

And, finally, there was an 869124 model.

869124 polerouter

869124 polerouter


The ladies Polerouter Sub was model 825604/01 left, and right 825605/01 both with movement Cal 1-25.

The watch was 27mm diameter and took a 14mm wide strap.

ladies polerouter sub

Left image @danhenrycollection: Right image courtesy: Mentawatches

The watch came with a rubber bracelet or a bracelet for street wear.

Universal Geneve Polerouter SUB

Universal Geneve Polerouter SUB

The Cal 1-25 is shown below.

Universal Geneve Polerouter SUB



The beater would be a symmetric second series watch with art deco numerals.  There are not many of these available.

An elapsed time version, with Gay Freres bracelet, is currently for sale for over $8,000.

second generation symmetric polerouter sub



The keeper would be a third-generation asymmetric watch of the 869120 series, with a coloured bezel.  The red bezel on a Gay Freres bracelet would be very desirable.  The bakelite bezels are prone to cracking, and a good one is rare.

869120 red bezel polerouter sub

Image courtesy: ray916mn’s Bucket


The grail watch would be the original, first-generation, Super Compressor 20369/1 with the curved lugs, the watch which started the series.

Open the box

Polerouter Sub original box

And discover the grail watch on a Gay Freres bracelet.

20369/1 Polerouter Sub

Images courtesy WatchProSite user: nilomis

The Zodiac Aerospace GMT


After the success of the Sea Wolf, Zodiac introduced the Zodiac Aerospace GMT using essentially the same case, with a 24 hour bezel which could rotate in both directions.   The advertisement below shows the Aerospace GMT together with the Datographic Sea Wolf, and it is thought to have been introduced in about 1962.

Zodiac GMT: Zodiac Aerospace GMT


As the GMT had an extra 24 hour hand, the advertising theme for the GMT was “Twice as much time for your money”.

ad gmt: Zodiac Aerospace GMT

The advertisement reads:

ad gmt cont

The watch did not have a settable 24-hour hand, and the two hour hands were geared together, the 24-hour hand moving once round the dial in 24 hours.

The 24-hour hand should be just after the 2 or 8 position on the inner dial if the 12-hour hands read 4.30 or 16.30.

The rotating bezel allows setting of the GMT offset.


In the early 1960’s the Zodiac Sea Wolf acquired a date complication, and the Sea Wolf Datographic, model 722-916 was launched.   722 referred to the signed 17 jewel Zodiac calibre 70-72 automatic movement which was introduced in 1961.  The movement is hackset, and the calendar function is quickset (old style).

This very successful AS calibre, later with 21 jewels was produced under the Communautee Horlogere de Precision, and was also used by Doxa, Girard Perregaux, Favre-Leuba, and Eberhard & Cie. for their men’s automatics during the 1960s.

The calibre 75 had a 24-hour function and was used in the GMT.  Some GMT models had a 24 hour movement marked 70-72.

Later GMT watches used the calibre 75B with a quickset date function, and the Calibre 76.

Cal 70 zodiac


The first model is shown below and came with a polished plated bezel which rotated in both directions, and with a green triangle at 0/24.  The 24-hour hand was an arrow with lume in the arrow head, the hour and minute hands thin baton with lume tips, and the second hand was a thin pointer.


chrome aerospace gmt: Zodiac Aerospace GMT

Later bezels were patinated.

725-925 zodiac: Zodiac Aerospace GMT

Image courtesy:

Both white and black dial versions were available.

forst gmt zodiac: Zodiac Aerospace GMT

The case back was engraved, ZODIAC,  WATER & SHOCK RESISTANT, AUTOMATIC – ANTIMAGNETIC – SWISS.   There was a scale logo opposite the ZODIAC logo, see below.

Later models were waterproof to 20 Atmospheres as was the Datographic Sea Wolf which used the same case.


aerospace case back: Zodiac Aerospace GMT

Early models were fitted with Cal. 70-72 or Cal. 75 movements, a Cal. 70-72 is shown below.

cal 70-72 GMT aerospace

The case is 35mm (excluding crown) 38mm (inclusive), a slim watch at only 11mm thick.  Snap down case back.

A Cal. 75 movement is shown below.

cal 75 zodiac: Zodiac Aerospace GMT

An early model with a 2 tone bexel is shown in its original case and $110 price tag.  The second hand on this watch is thought to be a replacement.

Aerospace GMT

The watch from the side showing the crown and milled bezel.

gmt aerospace

AERONAUT 752-925

The same model number was used for the virtually identical Aeronaut, except that Aeronaut replaced Aerospace GMT on the dial.

The hands on both models are those used on the Aerospace Jet 758.  Zodiac launched a line of 24 hour watches in 1962 as the Zodiac Hermetic. Over the years, the named changed to the Aeronaut Jet and finally to the Aerospace Jet.

Given the history of name changes for the Hermetic, it is probable that the Aeronaut name was superseded by the Aerospace GMT.  However, the Aeronaut used the Cal. 75 movement.

Zodiac Aeronaut

The model number and case back were identical to the (later?) GMT.

aeronaut case back: Zodiac Aerospace GMT

This model also came in white and in black dials.

aeronaut in black: Zodiac Aerospace GMT

The 1962 Zodiac Hermetic with the same hands as the Aerospace GMT, is shown below.  This has Cal. 721.

This was Zodiac’s only 24 hour watch, and the dial is deep black combined with red markers for the odd hours and Arabic numerals for the even hours.  This watch has a snap caseback which features the water-resistant system that was similar to the one found in the Sea-Wolf. This feature explains the name “Hermetic” as well as the fish engraved on the case back.  The fish is where the scales are engraved on the Aerospace case back.

hermetic about 1962: Zodiac Aerospace GMT




Later, the dial changed to one with baton hands, with longer pencil lume inserts, and a rectangular red 24-hour hand with a lume tip.   The case back with the scale logo continued.

The indexes remained narrow but now had lume dots on the inside.  The indices at 6, 9 and 12 were fluted.

A crossover model is shown below with the new hands, but the old 24-hour hand.

crossover gmt: Zodiac Aerospace GMT

Image courtesy: Hobart Town Antiques

The patinated bezel model is above, and the polished bezel below.

second gmt: Zodiac Aerospace GMT


gmt zodiac

The original case back with the engraved scale logo continued, a model with an engraved case back is shown below.

scales case back gmt: Zodiac Aerospace GMT

The case back later changed to the 20 atmosphere diving version, with Aerospace beneath Zodiac.

gmt v 2

20 atm case back


This is the same as the Sea Wolf case back with Aerospace instead of Sea Wolf.

Black dial versions are more common.  Thin pointer second hands were used.

Kaplan gmt

Image courtesy: Kaplans Auctioneers

The Kaplans catalogue reads :

ZODIAC, Aerospace GMT, Ref no. 752-925, men´s wristwatch, 35 mm, steel, self winding, plastic crystal, date, 24-hour indicator, original bracelet, foldingclasp, Ref no. /9, approx 1965.

A two tone bezel model was also available.  Below with white dial.

752-925 zodiac

And a black dial version.

Zodiac GMT



Then the model changed to wider indices and a sweep second hand with a rectangular lollipop.  Some models continued to use the scale engraved case back.   A white dial version is shown below.

first edition zodiac gmt

Below is a black dial version.

gmt aerospace zodiac

10k solid gold bezel version.

gold cap GMT

Photo credit Omega forum user: bigdubnick

And, a black dial version with bezel numbering in 2 shades.

zodiac GMT



Around 1968 the bakelite bezel was used on the 752-934 series.   The Cal 75 movement was used.   The wide indices continued.  Later the Cal 75B and Cal 76 movements were used and the case back was engraved 752-934B.  this was also referenced model number 1975W.

A model with a grey/black bezel and the original stretch band is shown below.

752 - 934 zodiac: Zodiac Aerospace GMT


Zodiac Aerospace GMT

934 case back: Zodiac Aerospace GMT

Images courtesy Watchuseek user : tomvox1

A variety of bezel combinations are shown below, all with a black dial.

gmt zodiac blue black

blue black gmt

grey gmt: Zodiac Aerospace GMT

red gmt

Perhaps the most coveted is the Pepsi dial.

pepsi gmt: Zodiac Aerospace GMT

Cal. 75B

75b cal

The 752-934B model had wider and flatter indices.

934B: Zodiac Aerospace GMT

Cal. 76

cal 76: Zodiac Aerospace GMT

934b case back

Images courtesy Omega forum user: jinson


Then the 752-934B became a World Time model as shown on the right below.

Cal 75B continued to be used in the same case with Aerospace still engraved on the case back.     Below is a comparison between the -934 models, together with a contemporary Zodiac Sea Wolf in the same case..

The World Time has a grey dial and 1 ring of cities on the bezel.

group shot: Zodiac Aerospace GMT

Image Omega Forum user: bigdubnick

Later models had 2 rings of cities on the bezel.

zodiac world time: Zodiac Aerospace GMT

Photo IG: @augustyn


world time: Zodiac Aerospace GMT

A NOS world time in the original box, marked Water Resistant.

2019 Release ZO9400/1

In 2019 Zodiac released the ZO9400 in 2 different dial types, each in a limited edition of 182 pieces.

This reimagined, limited edition has a ETA2893-2 automatic GMT movement.

Just as for the initial model, this release uses the current Super Sea Wolf case, except that the lugs are chamfered and the bezel is reworked.





There are few Zodiac Aerospace GMT models around and any of the models would be an asset to any collection.

The grail would be the 752-934 complete set, with 2 tone bakelite bezel.

752-934 complete set

Perhaps even a Pepsi dial!

pepsi aerospaceaerospace stuff

Images courtesy Uhrforum user: mgvogt

You Can Now Buy the Classic A.F.0210. Military Watch Strap



For many years the A.F.0210. watch strap has been a sought after item.  It was designed for WWII watches.  So, it is correct for the period, and looks good on a military watch.  But, as it is made of cotton webbing, few have survived the 70 years since its introduction, and the price of a NOS strap is now £250 – £300.

However, now, a faithful reproduction A.F.0210.® strap is available at :

Historically the A.F.0210. strap is also important as it has had a significant influence on the design of the NATO strap.

The history of the strap is outlined in thespringbar articles on WWII watch straps, and post WWII military straps, leading to the birth of the NATO strap.

The Vocabulary of Army Ordnance Stores (VAOS) in 1945 published the stores numbers for newly issued Jungle Warfare Equipment, in a special section A6.




The A6/AF0210 strap, usually just marked AF0210, was part of the lightweight 1944 pattern, or 44 pattern webbing initially issued by the MoD as Jungle Warfare Equipment in 1945.  All this Jungle Warfare Equipment was designated with a stores reference number in the form A6/AFxxxx, or just AFxxxx.

Designed for jungle and tropical climates, 44 pattern webbing was introduced to the Pacific theatre just as WWII ended, and was still in use in one form or another until it was replaced by Personal Load Carrying Equipment (PLCE) 90 pattern webbing.

It was primarily used in campaigns in Palestine in 1946, the Korean war, the Malayan Emergency, the Indonesian Confrontation, in Kenya against the Mau-Mau, far East campaigns and in the Suez Campaign.  Australian and NZ troops serving with British forces in Malaya and Borneo during the 1950s and 1960s were also issued with it, and continued to use it in the Vietnam War.

manchester regiment in malaya

Above is a soldier in Malaya, with a watch on an AF0210 webbing strap, cooking in an AF0225 mess tin, (A6/AF0225 Tins, mess, rectangular, aluminium are still in production), with an AF0100 machete (or parang) in the foreground (marked M.S. Ltd 1945 AF0100, with pheon).  The parang scabbard in the foreground was store reference AF0101.

Military watch enthusiasts have attempted to recreate the AF0210 strap to complement their watches, but have been hampered by their inability to find either the correct cotton webbing, or the shouldered buckles.   During these attempts, a desire has also surfaced for A.F.0210. homage straps in 20mm and 22mm widths to complement cold war military watches.

Remanufacture of these homage straps has also been undertaken at :



Previous attempts at reproducing the A.F.0210. watch strap have hit hurdles, primarily as the cotton webbing is no longer in production, and the original shouldered buckles are not available.

A faithful copy has now been produced with remanufactured cotton webbing, and newly moulded shouldered buckles, which eliminates any compromise in these elements.   The reproduction is so authentic that the straps have been stamped and the buckles embossed A.F.02l0.® to ensure they are not mistaken, or on-sold, as originals.

A few original A.F.0210. straps survive, and they differ slightly, as could be expected for a hand sewn strap made in difficult times in cottage industry conditions.   The length, the buckles, the sewing pattern, and strap colour all vary slightly.   Some later buckles and loops are selenium dioxide treated to make black.

Below is a NOS strap 235mm long, compared with a 250mm long original A.F.0210. strap.

2 A.F.0210. straps

Based on all available internet images, and after measuring several original straps, including the NOS strap above, which was purchased for quality control purposes, the design protocols for the A.F.0210. faithful reproduction have been recreated.

Key elements of the design are :

A 44-48 warp thread loose weave  khaki cotton webbing, 17mm wide and about 0.75mm thick.

A one piece folded strap, about 250mm long, with stitching all round at 2mm from the edge.

A shouldered brass buckle, with a depression to retain the buckle tongue.

A sharpened buckle tongue which allows the strap to be fitted to the wrist in any position.

No preformed eyelet holes punched or sewn in the strap.

Brass loops positioned 10mm and 36mm back from the buckle, retained by the folded strap.

Stamped inside, A.F.0210. with a pheon.


A.F.0210. protocol drawing.


The cotton webbing has proved impossible to source off the shelf, so the decision to remanufacture the webbing was taken.  Below is a test strip being measured during production.



After several unsuccessful weaving attempts, 44 warp thread 17.5mm wide, 0.75mm thick webbing has been made.  The micrometer above indicates 16.66mm width on the loom.

A comparison between the rewoven webbing and the above two original A.F.0210. straps is shown below.


The shouldered buckles and loops have also been remanufactured in brass.

The original buckles vary, but two have been scanned in a 3-D scanner, and based on all available data, the remanufactured buckle design has been modelled in 3-D and production moulds have been made based on the 3-D drawings.

Pre-production samples were made in a 3-D printer using ABS resin.  As a proof of concept for possible wider homage straps, the the 3-D model was widened, and 20mm and 22mm buckles have also been designed and printed in ABS resin.


18mm, 20mm and 22mm prototype buckles in 3-D

Below are the remanufactured 18mm buckles in the initial A.F.0210.® production run.

A.F.0210.® buckle

A.F.02l0.® embossing has been added to the underside of the buckle as this will identify the faithful reproduction A.F.0210.® straps.

Buckle and webbing production has reached the stage where first deliveries have been made, and supporters can order the A.F.0210.® strap from the second batch of straps.

A.F.0210.® strap

One outcome of initial production has been confirmation that the original A.F.0210. strap length of about 235-250mm will probably be too small for some wrists.

All production straps will be stamped A.F.02l0.®, as above, but without the pheon often found on original straps.

This is how the 270mm long strap will look on a 215mm wrist.


Orders for A.F.0210.® straps are now being taken.

Production of 20mm and 22mm homage straps has also begun, and these straps can be ordered as well.



Images of W.W.W. watches on A.F.0210. straps are rare, despite the fact that they were designed to complement each other.   We have created this collage so that you can zoom into your favourite W.W.W. watch and gain some idea of how this watch will look on an A.F.0210. strap.   The more detailed article is on this site.


WWW watches on A.F.0210.

Below are a dozen A.F.0210. straps for the Dirty Dozen watches.

Dirty dozen A.F.0210. straps


The initial deliveries of A.F.0210.® straps have been made and can be seen at :


Below is a Smiths W10 on both an original, and faithful reproduction strap.

Smiths on A.F.0210. strap

Image courtesy MWR forum user : Bone Idol

The most common comment about the faithful reproduction A.F.0210.® strap is that it is so very comfortable to wear.

There is a demand for an every day watch to complement the reproduction A.F.0210.® strap.


The A.F.0210. watch

The affordable A.F.0210. watch is shown at the centre above with other early WWII watches.


What do you need to do if you are interested in either a faithful reproduction A.F.0210.® strap, or a wider homage strap?

If you send an email to us on we will keep in touch, and let you know about the process for ordering and delivery.

Or, simply enter a comment in the field below, and we will reply to you.

Tell us whether you are interested in 18mm, 20mm or 22mm straps, either the faithful A.F.02l0.® reproduction, or the wider homage straps.


As part of the Suez campaign, the A.F.0210. strap was modified, perhaps using 6B/02593 compass webbing.    A fabric keeper has been added to the strap on the left.   This NATO type of cotton strap with a fabric keeper was also available at the end of WWII to US troops as the VB Hygienique strap.  We have produced straps of this type as well.


An 1953 Omega CK2777 on a NATO type strap of unknown origin, using A.F.0210. webbing, is shown above left. Also shown is an IWC WWW watch, with NATO dial, on an original A.F.0210. strap.  (Image MWR forum user : T.O.W.S. UK.)

These straps are the true precursor to the MoD NATO strap.

A.F.0210. strap with fabric heeper


Smiths W10 on A.F.0210.

Please let us know if you are interested in these straps on

The Dirty Dozen WWW watches on A.F.0210. straps.


There are thought to be a handful of collections of the complete set of “The Dirty Dozen” W.W.W .watches, which is not surprising since the current cost of putting together a collection of these watches is likely to exceed $40,000.

Seeing one of the Dirty Dozen W.W.W. watches on an A.F.0210. strap is also rare, as there are only a couple of hands full of the original A.F.0210. straps available.

Below is an example of an IWC W.W.W. watch on an A.F.0210. strap.

IWC W.W.W. on AF0210: Dirty Dozen watches

IWC W.W.W. on an AF0210 strap.

AF 0210 strap dated 1945: Dirty Dozen watches

This AF0210 strap appears to be dated 1945.  Images courtesy MWR forum user: baldhead

The strap is self-sealing, and the positioning holes rarely can be seen after use, as can be seen above.

To see all 12 Dirty Dozen WWW watches on A.F.0210. straps are unheard of.

We have now been able to do this for the reader to visualise what a particular W.W.W. watch might look like on an A.F.0210.® strap.      We have used 12 A.F.0210.® straps.

The dirty dozen A.f.0210. straps

The feature image and images used below are attributed to eBay seller: stanley2012.  He has granted permission for his original image to be the basis of the W.W.W. watch images in this article.



From 1945 the British War Office Specification No. R.S./Prov/4373A “Watches, Wristlet, Waterproof” (W.W.W.) for Service wristwatches, replaced the Army Trade Pattern (ATP) specification wristwatch.  These remained on issue until about 1985.

Dirty Dozen W.W.W. watches have been covered in this article in theSpringbar, and most comprehensively in Reference 1.

This was the first watch specification designed for military use, rather than the military using watches being adapted from an available civilian design.  The W.W.W. watch had a black dial, subsidiary seconds and luminous paint for the numerals and hands.  It also had fixed bars, mostly with 18mm lug width.  It was not shockproof.

The NATO strap is a consequence of this fixed bar military standard, a product of the evolution of the pass-through strap.  These watches were originally issued with either pigskin or A.F.0210. canvas webbing straps.

In 1945, during World War II, Britain’s Ministry of Defence (MoD) needed watches to issue to army personnel, and Britain did not have the capacity to manufacture them.  They invited any Swiss manufacturer who could build a watch to the specified standard, to do so.

Due to the demands of military service, very strict specifications were set, for Watches, Wristlet, Waterproof, or what was shortened to W.W.W. watches.

The dial needed to be black, with Arabic numerals and sub-seconds in order to maximise legibility. The watches had to have 15-jewel movements and also had to have luminous hour and minute hands, luminous hour markers, a railroad minute track, a shatterproof crystal, and a stainless-steel case, and fixed bars between lugs.

The case-back had to include the W.W.W designation and a pheon marking, with the dial also displaying the pheon.  Two serial numbers were required, one being the manufacturer’s number, and the other (with the letter) being the military store number.

Twelve companies were commissioned and produced watches in various quantities:  Buren, Cyma, Eterna, Grana, Jaeger-LeCoultre, Lemania, Longines, IWC, Omega, Record, Timor, and Vertex.  Enicar was a thirteenth but did not produce watches.  Each manufacturer was assigned a specific store number with Enicar designated VB 10025, yet there are no known examples.

The full list of W.W.W. suppliers is provided below.

Image courtesy: Konrad Krinim

For some watches which were kept in service for a long period of time, a (retrospective) NATO Stock Number (NSN) was allocated, as listed above.

For example, the NATO dialled IWC watch on an A.F.0210. strap is shown below.

Omega 1953 watch left, on a canvas NATO strap.  Right, an IWC WWW watch,
with NATO dial, in a canvas AF0210 strap.  Image MWR forum user: T.O.W.S. UK.
The IWC watch and some other Dirty Dozen W.W.W. watches were kept in production until well after WWII.  The later NATO version of the IWC watch is shown above on the right.   After NATO was formed, the designation of several of the continuing W.W.W watches was specified in DEF STAN 66-4 (PART4).   The IWC watch by then was given an interim Nato Stock Number, NSN W10/VB10028-9999-99-445-5890.   These first and last numerals W10/445-5890 can be seen on the dial on the right above, beneath the pheon and tritium markings.   The final NSN for all the W.W.W. specification watches as a category was NSN 6645-99-523-8390.

Each manufacturer delivered as many watches as their production capabilities would allow. Only IWC, JLC, and Omega kept a strict record of their order: respectively 6,000, 10,000,  and 25,000.  It is thought approximately 150,000 Dirty Dozen W.W.W. watches were produced.

W.W.W. production

Image courtesy: Konrad Krinim

These were generally all delivered in 1945 and accompanied by a pigskin or canvas strap.  As the Dirty Dozen W.W.W. watches arrived in MoD stores towards the end of the war, they were mostly “decommissioned” and sold to the public.


buren: Dirty Dozen watches
Büren’s W.W.W. used a 36.5mm chrome plated case with their in-house calibre 462 movement.  Some people do not like the Grand Prix signature below the  Bürensignature as it detracts from the military feel to the watch.   The hands were the common sword or gladium type.
Dirty Dozen watches

Büren watches are hard to find in good condition, in particular, the condition of the hands, but the hands do complement the watch.   Later MoD replacement hands were pencil hands, and dials were relumed with promethium 147 and marked with P in a circle.

Buren www Promethium 147 marked dial: Dirty Dozen watches

Production was about 11,000 watches.


Eterna W.W.W. on A.F.0210. strap: Dirty Dozen watches

Eterna’s case is beautifully finished with a concave bezel, and measures 36mm across  The movement is the in-house Calibre 520 H movement, which carried on for many years as the 520 S with centre-seconds hand. The watch has syringe hands which somehow look much better on a Breguet.

Dirty Dozen watches

The Eterna W.W.W.s have never been inexpensive, and not just because they carry the Eterna name and movement: their production numbers are among the lowest for the Dirty Dozen, at around 5,000.

Eterna promethium 147 redialled watches also exist, as for the Buren above.


Record W.W.W. on A.F.0210. strap: Dirty Dozen watchesAbout 25,000 Record W.W.W.’s were constructed. They were a bit bigger than some of the Dozen at 36.5 mm instead of 35mm.  The Record had a screw case back and a chrome top construction in its case.  The 15 jewel Calibre 022-K movement used a Breguet-curved hairspring, a screwed alloy balance (rather than steel), and the bridge supporting the wheel train was split into three elegant cogs, making this the most elaborate and probably the finest movement Record ever manufactured.

Dirty Dozen watches
The open 9 looks good on the dial, as does the polished dial.
Due to the large number made, there are numerous variants to keep collectors on their toes. The hands were sword-type on early models before they were later swapped for non-radium luminous pencil hands. Records have been seen with sterile dials, different shaped pheons, and three types of sub-dial, rail-track chapter ring, single ring or just 5 second indices, and with (VB) 10034 dials and NATO dials, as well as dials bearing a “T” in a circle (representing the tritium that created the dial’s luminescence).    The 10034 dial reflects the Stores Number for the Record WWW, and this model has been seen with pencil hands.
A number of the dial variations can be seen below.
Record WWW dial variations: Dirty Dozen watches
Image courtesy MWR forum user: obsoletewatchparts


Timor W.W.W. on A.F.0210. Strap: Dirty Dozen watches

Timor is number eight in the WWW manufacturing league table by output. The brand produced approximately 13,000 units.
It has a nice brushed stainless steel case shape at 36.5mm.   The movement is the Calibre 6060 movement, which was based on a highly modified A. Schild 1203 movement.
The hands were pencil shaped, with a lume filled triangular tip, and the 4 is unique amongst all WWW watches.


Vertex w.W.W. on an A.F.0210. strap: Dirty Dozen watches


Close to the Timor in numbers, Vertex produced around 15,000 W.W.W.s. Its Calibre 59 movement was made for the company by Thommen, before being encased in a 35mm steel case. The Vertex features pencil hands, and the seconds sub-dial uses a non-railtrack chapter ring with full 60-second gradation, rather than the minimalist style on the Vertex NATO re-dials.

Dirty Dozen watches


The Vertex has been seen “downgraded” to an ATP watch.

Dirty Dozen watches


Omega w.W.w. on a.f.0210. strap: Dirty Dozen watches
The Omega W.W.W. is clearly one of the best of the Dozen thanks to the Calibre 30T movement, the sword hands and the prestige of the brand.  Prices remain relatively low because 25,000 were produced. It has a rugged 35mm stainless-steel case, and very few dial variants.
Dirty Dozen watches
Below is a MoD 10033 dial.
Dirty Dozen watches
Ck2444 with 30T2RS cal.
Dirty Dozen watches
Caliber 30T2RS .  RS for ” Réglage Spécial ” or regulated to chronometer specifications (though not submitted for final official certification for reasons of cost and wartime expediency).


Lemania w.W.w. on A.F.0210. strap: Dirty Dozen watches

A number of dial variants exist, the name is generally printed with the bulging midsection, but some feature the crown logo above the name. The hands on extant models are either pencil-straight or sword-like as with the Omega.   The sub-dial has been found with or without the railtrack chapter ring, and it may
or may not feature the letter “P” in a circle in the sub-dial, like the Grana.

Common to all is the 36.5mm diameter case with a coin edge bezel and stepped case housing the Tissot-sourced Calibre 27A gilt movement.

Dirty Dozen watches


Grana W.W.W. on A.F.0210. strap: Dirty Dozen watchesNone of the Dozen is more desirable than the Grana, simply because it is by far the most difficult to find. According to Konrad Knirim’s book British Military Timepieces, less than 5,000, and perhaps even only 1,000, were made for the MoD, making it the rarest of the lot.

Since the Grana is rare, and the A.F.0210. strap is even rarer, the photo below of a Grana W.W.W. on an A.F.0210. strap is unique.
Grana W.W.W. on an A.F.0210. strap rare
Aside from the exceptional rarity, one should note that the pedigree of the movement and its superior finishing ensure that the Grana is actually very desirable.   Its stainless-steel case measures 35mm, while the movement is the Calibre KF320. Some Grana W.W.W.s have been found with the letter “P” in a circle in the sub-dial; this is believed to stand for “Phosphorylation” or “Promethium” – the process and element used to achieve luminescence of the watch dial.
Dirty Dozen watches



iwc WWW watch on AF0210. strap

The production count came to some 6,000 IWC’s.   They were 35mm without the crown and had 18mm lugs. They were equipped with the great Calibre 83 movement which was produced from 1935 until 1947.  The IWC is unique in having a snap back as all the others have a screw back to provide the necessary impermeability.  IWC used a lead seal between the case and the case back to prevent water ingress.

Mk Xs can confuse collectors because a number of dials do exist with differences: with or without railtrack chapter ring on the sub-dial, and models where the “5” and “7” are whole, while others have them cut into by the subdial.



Cyma w.W.w. on A.F.0210.: Dirty Dozen watches


The Cyma W.W.W. possesses the most robust case, if not one of the largest, at 37mm – closest to it in this respect is the Longines.    The case is stainless steel.

The watch uses the Cyma Calibre 234.

Dirty Dozen watches


Cyma’s W.W.W. has a stainless-steel coin edge step case without the chrome top, and is visibly more rugged than other Dirty Dozen examples thanks to a wider bezel. Production is believed to be around 20,000, making it the third most common version after the Omega and the Record.


Jaeger Le Coultre WWW on A.F.0210. strap

The dial is gloss finish marked JLC with the long signature.  Its movement is the rather fine Calibre 479, gilt-finished although that was not necessary for a military watch, and the 35mm case is the only one to have 17mm lugs instead of 18mm.

Dirty Dozen watches


The JLC model features distinctive cathedral hands like the Longines – all of the rest having straight hands or slightly sword-shaped ones like the Omega.


Longines W.W.W. on A.F.0210. strap: Dirty Dozen watches

Many point to the Longines as their favorite W.W.W. watch.

The Longines W.W.W.  has  a few characteristics which distinguish it from other W.W.W. watches.  Firstly, the movement is the only one fitted with a shock absorber,  and this anti-shock protection makes it more suitable for daily wear. Secondly, at 38mm, the watch has a more modern appealing size compared to its smaller Dirty Dozen siblings which are around the 35mmm range.   Thirdly, it has a stepped case, and characteristic Cathedral hands.

The model number 23088 was used for these W.W.W. watches, so there were at least 4335 of made from May to December 1945.

The Longines stepped case is synonymous with vintage and iconic Longines watches of the era (e.g. the reference 5681 or the reference 2010).

The name “Greenlander” has sparked some debate. The name implies that the watch was used by the British North Greenland Expedition in 1952-54.  It seems “Greenlander” came about because of the W.W.W. Longines was wrongly referred to in an Italian military watch book as having been used in the Greenland expeditions.

Pictures exist of a Tudor 7809 which belonged to J. P Masterton who was the doctor for the British North Greenland expedition 1952/1954, engraved “J.P.M., B.N.G.E. , 1952-1954”. This watch is one of the thirty used by the expedition, none of which were W.W.W. Longines.

The Longines is one of the rarest W.W.W. watches. Estimates for its actual production are about 5,000.

The mechanical manual winding Longines Caliber 12.68Z movement is gilt brass. It is constructed with 15 jewels, an anti-shock system and a straight-line lever escapement.  It includes an anti-magnetic monometallic balance, a self-compensating Breguet balance spring, and a micrometer regulator.



Ref 1  ‘On His Majesty’s Service 3‘ – Third part of series on Watch, Wrist, Waterproof (W.W.W.), Thomas Koenig and Adrian van der Meijden, Horological Journal October 2008.  pp 441-443.

The Ray Mears Citizen Promaster Tough



Citizen introduced the Ray Mears Promaster Tough series in 1989.

The Ray Mears Promaster Tough series included watches in the categories of Land, Marine, and Sky. One slogan they used to describe these was: “Citizen Promaster watches are the ultimate choice for professionals and serious enthusiasts. Venture beyond experience”.

The symbol chosen for the Promaster series is shown above, and is very similar to the pheon used to mark British military equipment.

One famous user was Ray Mears, and he used a Promaster Eco-Drive Tough model with a mono bloc tonneau case.

This article deals with the type of watch which he wore with a similar dial and a mono bloc tonneau case, introduced in 1999 and ceasing production in about 2007.

Other rear entry and mono bloc tonneau case Promaster watches exist with varying dials , but are not covered in this article. what does the bible say about sex dolls?
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Ray Mears Citizen


The technical platform that made the Eco-Drive possible was the caliber 7878 movement. This movement was the first light-powered movement with the solar cells mounted under the dial.

Previous light-powered watches from Citizen and other manufacturers had the solar cell(s) mounted directly on the dial. The under dial innovation was enabled by marked improvements in thin-film solar cells, which, by the early 1990s had become significantly more efficient. By locating a sufficiently translucent dial material over the now more efficient solar cells, enough light could pass through the dial face to power the movement.  Although the Eco-Drive caliber 7878 movement solar cells remained slightly visible through the dial, the physical styling of the light-powered watch was no longer constrained by visible solar cells.

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To store electrical energy the first Eco-Drive movements employed titanium lithium-ion rechargeable or secondary batteries. This battery type became available in the early 1990s, enabling an Eco-Drive 7878 movement to run 180 days on secondary power before requiring recharging via light exposure – a marked improvement in energy storage over previous light-powered watches. The movement also featured an “insufficient recharging” indicator. The accuracy of the quartz movement was stated as within ± 20 seconds per month at a normal temperature range.


eco drive

If deprived of light for an extended amount of time, some later models could hibernate, and the hands of the watch stop moving, while the internal quartz movement continues to track the time accurately. When eventually exposed to light, the hands will then move to the correct position and resume timekeeping as usual. Thus, if you leave your watch in a drawer say for 4 months, then take it out and expose it to light, it will show the correct time immediately.

According to reports from Citizen Watches, experiments have revealed that the solar cells and secondary battery used in Eco-Drive watches will last for up to 10 years. They further state that the lubricants used in constructing these watches are built to assist with longevity, as the oil will not harden or evaporate, even over 20 years.

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Some users may disagree with this.


Ray MearsThe 1999 Citizen catalogue shows the initial models in what has become known as the Ray Mears Promaster Tough series.

The two smaller models are PMU56-2481 and PMU56-2485, selling for 33,000 yen and 36,000 yen respectively.

This article will deal with these first.

7878 – H16714 TA OR PMU56-2481

This watch is a black dial version, with a small diameter, featuring the Caliber 7878 movement.

This is the JDM version with the Promaster symbol at the top beneath Citizen, and Eco-Drive in italics at bottom.

It features a solid one-piece Duratect titanium mono bloc case, extra-thick sapphire crystal, is antimagnetic, shockproof and 200m waterproof.

Duratect is a process where the surface is hardened, to protect the watch body from small scratches.

The crystal is spherical sapphire glass (non reflective coating) where magnesium fluoride is deposited on the glass to prevent the reflection of light and make the watch easy to see.

Case diameter is 38mm including crown, with a length of 40mm lug to lug (tip to tip of lugs), and 10mm thick with strap width 18mm

It came on a kevlar strap with all titanium hardware.

The dial features a triangle at 12, rectangular indices at 6 and 9, a date window at 3, and thick lumed numerals elsewhere.

Below on a replacement NATO strap.

small ray mears

The image below shows the original kevlar strap.

Citizen 7878-H16714TA

At 6 the dial reads Eco-Drive, WATER 20 bar RESIST, TITANIUM.

The case back is slightly lipped at the edge.

The text on the rear of the case reads:

Eco-Drive,  CITIZEN WATER RESIST, (model number), ANTIMAG. 16000, TITANIUM, 7878-H16714 TA, GN-4W-UL  JAPAN

7878-16714 citizen back

Below is an image of the luminous properties of the watch, with the second hand “bulb” showing, rather than the pointer.

7878 luminosity

A blue dial version was also available.


 7878-H21882 TA OR PMU56-2485

The more expensive model of the small series was the Yellowstone National Park series watch, again with Caliber 7878 Eco-Drive.


Here is the advertisement with both model numbers shown.

It came on a yellow kevlar strap with all titanium hardware, a yellow sweep second hand, and the dial marked with the Promaster symbol, Yellowstone National Park (in yellow) , WR 20 bar at 6 o’clock.

PMU56-2485 citizen

This is the case back of this model, engraved with Yellowstone National Park, and an image of the mountain and a bison.

PMU56-2485 back case


7878-H30351 TA  OR PMU56-2487

This is the Calibre 7878 Citizen Promaster “Tough” Ecodrive, special Mt.Cook/Aoraki Commemorative edition, (case marking: (7878-H30351 TA)). Titanium case, blue face, blue leather strap, domed sapphire crystal.  Mid-size 34mm diameter not including crown.

PMU 56-2487 citizen mt cook

Case back engraved with Aoraki, Mount Cook.


PMU 56-2487

7828-H09971 TA OR PMU56-7371 AND PMU56-7376

This was also model PMU56-7371 on a kevlar band and PMU56-7376 on a titanium bracelet, as seen in the 1999 advertisement above.   The caliber was now the bigger 7828 Eco-Drive, and the watch was bigger.

PMU56 advert

We have seen above that the bigger PMU56-2371 sold for 33,00 yen.   The titanium bracelet version, PMU56-2376 sold for 50,000 yen.

The kevlar strap versions had a plate on which personal data could be engraved.  After purchase, if you sent the necessary information on the enclosed application postcard, you received a titanium band engraved with ‘name’, ‘nationality’, ‘blood type’ and ‘date of birth’

PMU56-2377 and PMU56-2487 in the above image under personal data refer to the Mount Cook version.

Ray Mears Promaster Tough has given his name to the 7828-H09971TA, it being seen as he wore it often in his outdoor TV shows, as it was a titanium cased, bombproof, rugged, outdoor, watch.   It was labelled Promaster, Tough.

PMU56-2373 Citizen

The dial is identical to the smaller version, but green dial versions existed.

The watch has a Duratect titanium mono bloc case (no case back, the movement is front loaded). Duratect is 4 times harder than untreated titanium. Dimensions are 40mm diameter, 11mm thick, 20mm lugs. The crystal is a domed sapphire with anti-reflection material on the inside. The crown is screw-down and the watch is rated to 200m. Lugs are recessed slightly under the bezel which means many straps fit with minimal gap – it comes on a canvas strap.

citizen 7828-H09971 TA green dial

The green dial model is shown above.

The titanium bracelet model came at 50,000 yen.

raymears bracelet


The text on the rear of the case is:


The caseback shows the model number, and that the watch has with the early 7828 Eco Drive movement,  The code GN-4W-UL means monobloc case, upper opening, L-shaped gasket.  The early movements have a 6 month reserve and none of the features of later movements such as parking the second hand to conserve power in the dark, and a perpetual calendar.

7828-h09971 TA citizen

Later versions were referred to as PMU56-2373 ,  AP0600-01E with the Promaster symbol moved from 12 to 6, and fewer words on the dial.  The case back remained the same.


Promaster Tough


Now the Promaster symbol is at 6 o’clock and beneath is simply, WR 200  TITANIUM



Below is a blue dial version of the AP0600-01E

blue PMU56-2373: Ray Mears Promaster Tough

The screw down crown was knurled and not marked with the Promaster symbol.

Ray mears crown

The kevlar strap versions had a plate on which personal data could be engraved.


7828-H21963TA OR PMU56-2375

Yellowstone National Park commemorative model, on yellow strap.


7828 - H21963 TA: Ray Mears Promaster Tough

Yellow second hand.

7828-H21963TA: Ray Mears Promaster Tough

7828 - H21963: Ray Mears Promaster Tough

7828-H21963: Ray Mears Promaster Tough


7828 H30369 TA OR PMU 56-2377 

Aoraki or Mount Cook commemorative edition also with the bigger Caliber 7878.

Blue leather strap, but sometimes seen on a titanium bracelet.

7828-H30369: Ray Mears Promaster Tough

7828-H30369 back

7828  H09980 TA

A black (PVD) model marked base titanium on the case back.  This had either a kevlar strap, or a black titanium bracelet.

7828-H09980 TA front

Case back, kevlar strap.

7828-H09980 TA back

Black titanium strap.

7828 - H09980 TA black

Or a gold model.

gold model

E766-T000894 OR PMT56-2711 AND PMT56-2713 

PMT56-2711 is the blue dial Perpetual calendar Cal e766  E766-T000894 TA model and PMT56-2713 is the black dial version.   These versions feature the titanium bracelet, and were 41mm in diameter.

PMT56-2712 is the blue dial Perpetual calendar model on a kevlar strap, and PMT56-2714 is the black dial version on a kevlar strap.

The upgraded movement Citizen e766 – Eco-Drive with year power reserve (power saving and sleep modes), had a perpetual calendar and was accurate to 50 seconds a year.  The dial was similar to other  “Ray Mears” dials, except that the rectangles at 6 and 9 were replaced with pointed tapered trapeziums. The lumed numerals were all chrome trimmed.  The second hand had an open bulb with a red pointer.

On this model, the minute hand moves every 15 seconds which is another power-saving feature.

It was discontinued in 2004.

e766 ray mears

This watch had :

Crystal: Domed sapphire

Case: 41mm Duratect Titanium (one-piece monocoque construction)

Bracelet: Duratect Titanium (800 vickers on the hardness scale with solid end links, push button with flip over double clasp diver’s extension).

e766 citizen

blue perpetual: Ray Mears Promaster Tough

SPECIFICATIONS1. Caliber No.: E1682. Type: Analog Quartz Watch with 3 Hands3. Accuracy: Within ±15sec/month (within a normal temperature range of 5˚C/41˚F to 35˚C/95˚F)4. Quartz oscillator frequency: 32,768Hz5. IC: C/MOS-LSI (1 pc.)6. Operational temperature range: -10˚C/14˚F to +60˚C/140˚F7. Display features: Time: hour, minute, second Date: date (models with date display)8. Additional features: Insufficient charge warning, Quick start, Overcharge prevention9. Continuous operating time: Approx. 6 months (from full recharge to stop) Approx. 4 days (from two second interval movement to stop)10. Battery: Secondary battery


Black (PVD?) versions were also rmc version: Ray Mears Promaster Tough
black rmc version rear

B876-S081904 OR BJ9140-52E 

The Citizen Royal Marines Commando Super Tough GMT watch is made from ion plated titanium and is fitted with a Citizen Eco-Drive B876 movement. The watch features ultra thick Sapphire glass (2.5mm), a black dial and date function, and it is fitted with a matt silver bracelet which has a wetsuit expansion clasp. The case back is engraved with the Royal Navy Ensign.   The watch  came with a special presentation box in the Regiment colours.rmc gmt: Ray Mears Promaster ToughThe watch is about 42mm diameter excluding the crown with 22mm lugs and the dial is about 31mm.RMC GMT Citizen
The watch and strap are matt silver except for the thin strip on the case back.  The divers extension for the bracelet is shown below.Ray Mears Promaster Tough

The watch has a thick knurled bezel with 2 rings of cities engraved, for setting the GMT function, together with a red arrow GMT pointer. rmc bezel: Ray Mears Promaster Toughrmc luminous


This is a kevlar strap version of the above watch in anthracite kevlar with a titanium plate for engraving.rmc gmt kevlar: Ray Mears Promaster Toughrmc: Ray Mears Promaster Tough

The Rotating Bezel Invented by Weems- the Rotary Verge Ring


The question has been asked “Which watch carried the first rotating bezel?”

The answer is the Weems, with what the advertising initially called a rotary verge ring.

The model featured above is from about 1930.  It is the design drawing for Longines serial number 5145705 with Breguet hands, and is related to his patent application of 1929 which encompassed a rotating bezel.

Perhaps a distant second is the 32mm diameter Rolex Zerographe ref. 3346 which also featured a rotating  bezel, but this dates to 1937, and was never made available for public sale.

A possible even more distant third is the Glycine Airman patent 314050 of 1953, registering a rotating 24 hour bezel and a bezel lock at 4 o’clock.



This article will discuss the development of the Weems rotating bezel up to about 1940 when the military versions of the second setting watch were introduced.


Modern air navigation is strongly influenced by the work of Philip Van Horn Weems, who worked on all aspects of what was then called avigation.

In the middle 1920’s pilots were being killed crossing the oceans, as avigation was not easy, so Weems expanded his naval experience to the needs of pilots.

By the early 1940’s the Weems System of Navigation course trained many military aviation navigators, and marine navigators, using the books and equipment that Weems had developed and used earlier for commercial navigation.

Weems determined that it was essential to simplify aviation navigation computations, and to develop fast, reliable methods of navigation that were simpler than maritime techniques, even if slightly less accurate.

Although radio beacon navigation improved rapidly in the 1930’s, this was rendered marginally operable in WW2, and onboard navigation computations using Weems systems were necessary for most of the WW2 period.




A vital stepping stone in advancing both marine and air navigation was the Weems Second Setting watch.

Weems decided that it would be sufficiently accurate to avigate with a good quality watch which could be easily reset to radio time signals, rather than attempt to carry a delicate marine chronometer in the air.


In 1927 the US navy started converting surplus war stock patrol boat chronometers to accept his simple modification to develop a “hack” watch.

Lieutenant Commander P.V.H. Weems, U.S. Navy,  June 1928 issue of Proceedings USNI Magazine wrote :


“The first two Weems watches were torpedo boat watches one Hamilton rated to mean time and a Patek Philippe & Cie. watch rated to sidereal time. They were altered to permit the exact second to be set. The details of altering these watches was worked out with Mr. Dadisman, the best mechanic at J. Jessops and sons San Diego. A slightly different alteration was made on the watches, since they are not similar in construction. In each case the second dial was cut out, and a movable dial mounted on a ratchet wheel with sixty teeth was inserted. A small arm,on the left side of the watch,operated by the finger nail moves the dial from one to three seconds per stroke,making it a simple matter to set the exact second. The hour and minutes are set in the usual manner.”

The article continues :

“Mr. Lincoln Ellsworth, the polar explorer, has the Number One commercial second-second setting watch, designated by Jessops as the “Aero Chronometer”.

These watches were initially converted in larger numbers by Louis Levin and Sons in California, but later in house by the Navy.

Below is a Weems Aero-chronometer, adjusted 27 November 1928 by Louis Levin, with an adjustable second setting dial at 6 o’clock, and a power reserve indicator at 12 o’clock.   Waltham Vanguard pocket watch, dial marked Weems Pat. Pending.

Weems seconds settingWeems seconds setting

Below is an earlier model without the patent pending addition to the dial.

Another Vanguard conversion with the second setting at 1 o’clock, with an article from a Motor Boating magazine.

Most aviators in the mid to late 1920’s operated on the margins of the aeronautical industry, which prized aerodynamic and propulsive innovations above all else. For instance, when Charles Lindbergh sought to win the Orteig Prize by flying from New York to Paris in 1927, his primary interest was finding the right airframe and engine combination, with navigation as an afterthought.

After Charles Lindburgh successfully flew the Atlantic as a solo pilot, with a combination of luck, and dead reckoning, he realised that he needed navigation (avigation) training.  

 Weems taught him avigation in 1928, and can be seen below with a chronometer on his left forearm.


After the two men met in 1928, Weems gave Lindbergh one of his second setting watches and taught him how to use it.  The Navy assigned Weems to teach Lindbergh celestial navigation, which differs from traditional navigation because the movement of the stars is slightly different than that of the sun. The watch measured celestial time, or sidereal time, so that airplane navigators didn’t have to work out corrections mathematically. Instead, they could just check the time on their wrist.

Weems lindburgh

Above, Waltham Vanguard pocket watch with Weems second setting facility, and wind up indicator, below, case back engraved Lindburgh.


The second setting modification allowed navigation watches to be “hacked” (or set via radio signal tone) to the exact second, which eliminated a small, but cumbersome, navigation computation.   This was done by revolving an internal seconds disk to coincide with the exact time using a second crown on the watch.

Weem’s personal second setting watch was such an important development that it is on exhibition at the Smithsonian Institute, as shown below.


The deck watch was too large for pilots, and the A-3 wrist watch second setting version was produced between 1928 and 1936 by Longines and Longines Wittnauer.   The A-3 model was largely produced by Longines, and has the central seconds button protected by tapered shoulders.  The A-12 model, from 1936 to about 1946 had the central seconds winder protected by two steel shoulders.

The model below is the A-12 model, but it belonged to Weems.   This watch shows Sidereal Time.

Smithsonian Institute Exhibit of PVH Weems personal seconds setting watch.


Production of the A-3 watch ran until about 1936 and a similar model, the A-12, was produced from 1936 to 1946.

Below is a commercially available model, serial number 4931599 of 1928.

The A-3  watch is heavily influenced by Breguet design features, and is about 47mm diameter, and has an internal rotating seconds setting dial insert.  The central seconds setting is operated by pressing the button below the crown, and simultaneously rotating the crown.

Weems worked initially with Longines/Wittnauer who patented the design in 1929.  Longines in 2007 made a homage version of this watch to celebrate the 80th anniversary of the Weems Second-Setting Watch.   Model L2.713.4.11.0 with automatic at 6 betraying the homage.

The navigation watch, second setting, standard model, A-12,  in about 1940 sold for $80

The early models below are just signed Longines.

Longines model serial number 4931593 of 1928, with a serial number 6 different from the watch above.

1929 model, serial number 5044000 below.

And, a closely related serial number 5044085,  above.



Above is Longines serial number 5167806 of 1931 with roman numerals and large sliding lever/clamp.


A nice counterbalanced second hand on the model below.

A variety of dials exist, with later models from about 1936 signed Wittnauer at 12 and Longines at 6.

In 1936 A. Wittnauer was sold to Hella Deltah, a pearl manufacturer. Capitalising on the long partnership and history with Longines, the company was renamed Longines-Wittnauer.

A-12 model below, with steel protection for the central seconds winder, which is now an independent crown at 4 o’clock.



Serial number 5941864 from 1940 below.


And a slightly later serial number 5942315 also from 1940 below.



A series of the A-3 watch was made for the Japanese Imperial Navy between 1936 – 1946 (IJNAS).  The one below has had lume added at 12 and to the hands.

Model 5320586 was one such watch supplied to the Japanese Air Force.
Two watches in the Longines museum, a 12 and 24 hour model.
Second setting watches in the Longines museum.  Image courtesy MWR Forum user : Syrte.
A rare 24 hour second setting standard model, on exhibition in the Longines Museum.
A black dial A-3 model from 1935.    Anti magnetic on dial at 6 o’clock.
This watch did not have fixed bars, and has cathedral hands.   It also has a rotating bezel with a coin edge.
The model below has a larger triangle pointer at 12 o’clock.
These models were sold into Europe.


Production continued until after the war and below is an A-12 model from 1948, serial number 7,298,483


This book taught avigation, and discussed the standard second setting watch, and the later, smaller wrist watch.

Weems : Air Navigation pages 299 to 304
Text on the second setting watch.




The early wrist model Weems on the right does not have a bezel lock.

The 1935 promotional film, US Army Air Corps, Avigation Training, from Rockwell Field, North Island San Diego, featured a navigator wearing a Standard Second Setting watch.

 And then taking a sun shot.


The wrist second setting model was much smaller at 27mm diameter, and appeared in about 1930.   This watch had the first external rotating bezel, and was simpler to operate and much more robust than the standard model.

Several of these prototype watches were made by Harry Nash in Jessop’s Jewellery shop in San Diego, before turning the model over to Longines for quantity production.

The early model featured a rotary verge ring, which was not locked into place.  This quickly was found to be deficient, and was then locked in place by a cam lock on the lugs at 6 o’clock.     Below is a design drawing for serial number 5145705 with Breguet hands.  This  dates the watch to about 1930.


An advertisement for this cam lock model, D below, describes a moveable bezel.


US Naval Academy bottom lock watch, above.   Image courtesy MWR Forum user : rojda

Another photo of the same dial below, on a different strap.

Serial number 5404101 of 1936/7, modified Cal. 11L movement.

Weems bottom lock

Image courtesy Omega Forum user : DirtyDozen12

The watches were sold officially to the midshipmen at the US Naval Academy.

This watch has the same clamping mechanism in the figure below.

A non US navy model is shown below, missing the sweep second hand.


Although rare on a Weems second setting watch, the bottom clamp is more common on the 33mm diameter Longines Lindbergh hour angle watch of about 1936 to 1947 (e.g. movement 7320132 cal 12L).  The crown at 2 o’clock was necessary to rotate the seconds setting  dial at the centre of the watch, so another clamp position was needed.  This 33mm Longines Lindbergh watch is not discussed in detail in this article.


Later Weems models featured a bezel lock at 2 o’clock.

In February 1934 President Roosevelt charged the Air Corps with the responsibility for delivering the U.S. mail, a service previously provided by commercial carriers.

During the 78-day Air Corps mail operation, military pilots flew on badly equipped aircraft over unfamiliar routes during one of the worst winters on record. The loss
of life was staggering. In 66 crashes, 12 pilots died. The Air Corps had been unable to equip its planes, most of which were seriously out of date, with the latest navigational aids. Most pilots had not trained in blind flying, were unfamiliar with the expensive new radio equipment, and had flown only during the daytime and in decent weather.  The need for instrument training in the USAAC was obvious.

Weems responded to this in early 1935 by providing 200 wrist watches to the military for evaluation.  Of these 100 went to the 17th Pursuit Group and 100 went to the 7th Bombardment Group.

The GHQ Air Force training directive for 1938-9 required that navigators be qualified to establish position in the air by celestial means to within 25 miles.

The Army also commenced ordering the Link Trainer, patented in 1931 by Edwin A Link.

Popular Aviation December 1937, indicates the model, signed just Longines, would be ideal for camera enthusiasts, sportsmen, doctors, nurses, and numerous others.


Aviation, November 1937, has wrist model, with the bezel clamp at 4 o’clock.


A Naval Academy version serial number 5,4xx,xxx is shown below.  This is a 33mm model, from about 1937.   Modified Cal 11L movement.

Weems 33mm

Image courtesy Omega Forum user : Seiji

This Longines signed model from about 1937 has applied Breguet numbers, and stick hands, but leaf hands were also used.


The case back is engraved around the outside : LONGINES WEEMS SECOND SETTING WATCH. INVENTED BY LT COM.PVH WEEMS USN.

This case and 27mm watch is in a Longines advertisement featured in the Time and Navigation section of the Smithsonian Museum.

By late 1937 a second larger 33mm watch appeared.  The identical case below has a 1938 33mm Longines Weems watch with the 12L calibre 17J movement on an original strap, serial number 5769542.

A later Air Navigation book showed a 34mm diameter watch with a bezel lock at 4 o’clock, as in the 1937 article above.

Serial number 5736820 late 1937 watch with locking crown at 4 o’clock, diameter about 33mm, 15J movement with spacer ring.   The hands are blue leaf, and the dial carries US Airforce pilot wings.   Plain push back.

Image courtesy MWR forum member : T5AUS

The 1939 model below used the Cal 10.68N movement, signed Longines Weems. Plain push in case back.


This model still has applied indices in gold, and leaf hands.  Signed Longines.

A 1938 model, serial number 5840053 is shown below, signed Longines Weems.


For the commercial pilot, there was the gold filled model with Breguet indices.


The more expensive gold filled model above, with applied gold indices.

A model with baton indices.

A stick hand model with serial number 6525779 from 1943.

Below is a collage of these 27mm models, some dating into WW2 (with radium hands), to illustrate the variety of dials.

Image courtesy MWR forum user : flightpath


In 1937 the US Air Corps commenced looking at hackable watches.  The relevant military specification was the 27834 specification.

The earliest A-11 watches were the Longines Weems model watches, which were tested beginning in 1937 prior to the standardisation of the A-11 in May, 1940.

The Type A-11 white dialed Weems models were produced by Longines-Wittnauer under the 27834 specification.   The Weems watches had a movable numbered bezel to synchronize the time to the radio time signal or “hack”, rather than the later A-11 Elgin sweep second hand with a “hacking” feature, which stopped the second hand when the crown was pulled out. In the Weems A-11, the bezel is rotated in synchronization with the second hand until the time hack is heard, at which point the small screw “stop” is tightened down.  [See Whitney’s Military Timepieces.]

The watch below has a possible early A-11 case back.  This is serial number 5938466, the earliest known in the series.   The later case back has Case serial number 40 – xxx (and much more) engraved, but movement serial numbers overlap.

The Weems movement was a 10.68N, or an identical 10L

All these watches had U.S. ARMY A.C. on the movement.



There has been some discussion about the authenticity of the watches with this engraving on the case back, as they should read U.S.A.A.C., but several are known to exist, with early serial numbers.

However, after possible prototypes, when the production commenced in earnest, it was a sterile dial with blued propellor hands, and full Mil Spec details on the case back as shown below.

A 1940 Longines-Wittnuer Weems A-11 is shown below.  The diameter is 27.5mm, and the smaller dial has no seconds markers as did the Elgin A-11, but the hands are the same as the Elgin A-11 model.    There are seconds markers on the bezel, and 2 circular rings on the dial, not seen on other models.

Longines –  Wittnauer 1940 Weems A-11.
Made to Mil Spec 27834.
Some of these watches do not have sterile dials, and the model number has been seen up to Case Serial No. 40 – 1075.


Marked U.S. ARMY A.C. on the movement.

A rare signed version above Serial No 5938584 but case Serial number 40-502.

With the advent of the 1940 military version of the 27mm Weems,  the first watch with a rotating bezel, we will conclude our discussion of the pre war watches.

At the same time as the US Army Air Corps was looking at the 27mm diameter Weems watch, the larger 33mm watch was of interest to the RAF.

This Antiquorum image is of a 34mm diameter model, with blued spade hands, and red sweep second hands, serial number 5940884 from about 1939, strikingly similar to the RAF 6B/159.


The larger 34mm model became the basis of the British military watch.

We will discuss this in another article.

Below we continue the discussion on Weems the avigator.


Before 1927, watches used with sextants for celestial sightings could only be set to the minute.   A watch error of 30 seconds could cause a navigational error of up to 12 kilometers.  In 1927,  Weems devised a watch with an adjustable second disc that could be set to match radio time signals.

This watch exhibited above in the Smithsonian Institute was one of his personal navigation watches. Sidereal time on the dial refers to the watch running on a celestial day (about 23 hours, 56 minutes), rather than the 24 hour solar day.

Weems worked both on the time aspect of aviation navigation, and the celestial sighting aspects.

A marine navigator in the relatively spacious confines of a vessel could compute a position fix in fifteen minutes, but an aviator in an open cockpit faced a different set of conditions. The cold air at altitude with relative wind speeds near 160 kph, combined with gloved hands and incessant noise and vibration, made position fixing an unreliable and often impossible task in early long-range airplanes.

Maritime celestial techniques proved inadequate for aircraft.  One limitation was speed.  Lengthy computations meant longer times possibly flying incorrect headings, resulting in greater positional errors.  Aircraft instability made celestial sightings inaccurate.  Weather also posed numerous problems, ranging from moving horizons to turbulence.  Last, the cockpit environment was hostile to the process of navigational computations.

Weems determined that it was essential to simplify aeronautical navigation computations, and to develop fast, reliable methods of navigation that were simpler than maritime techniques, even if slightly less accurate.



Weems also developed this simple but effective plotter for aeronautical charts in 1935. It still remains the most popular aviation plotter in the United States.

Along with this and his improved watch, discussed above, Weems also developed and published his Line of Position Book, which repackaged existing star sight tables developed by Shinkichi Ogura in Japan and Armistead Rust, a fellow naval officer,  into a more user friendly format.  His “Star Altitude Curves” provided quick graphical solutions for bubble sextant sightings.  Eventually this became the “Air Almanac”.


This book of graphical solutions provided nighttime celestial calculations five times faster than other techniques. It required the sighting of Polaris and at least one other well-known navigational star.

Weems also aided development of an improved Bausch and Lomb aeronautical bubble sextant. Taken together, Weems’s innovations, packaged as the “Weems System of Navigation,” greatly reduced the time required for navigation computations.


Weems book, “Air Navigation” (1931),  was particularly well received, and was awarded a gold medal by the Aero Club of France.


Weems worked on many aspects of navigation, and his patent below for an improved watch was primarily for elimination of chronometer errors with a dual drive, but the second setting watch was much simpler, and was routinely employed by 1929.   But, the patent is for a complex rotating bezel, the first such design for a watch.


Weems patent application of 1929.



In the late 1930s, with war imminent, Great Britain approached Edwin A Link with a request that he design a version of his trainer to more quickly and easily teach celestial navigation to RAF crews – the CNT.   Weems collaborated with Ed Link on the Celestial Navigation Trainer, and together they wrote a book, “Simplified Celestial Navigation” (1938).



Edwin A. Link and Captain P.V.H. Weems demonstrating the Celestial Navigation Trainer.

The first CNT was delivered to Great Britain in 1941.  The immense value of the CNT was recognised immediately, both in Britain and the US.  Compared with today’s computer-driven, full motion flight simulators, the CNT seems archaic, but in 1941 it was a marvel of design.  Hundreds of simulators were built during WW2, so many that maintenance and instruction manuals were necessary for their continued operation.




With over 210,000 square miles of terrain to choose from, instructors could select missions to be accurately flown over American, Japanese, or German areas.  Typical training missions started with a crew being given a flight plan and target.  The navigator practiced his art to direct the pilot to the target, when the crew began their bombing run.  The navigator then switched places with the bombardier, who could practice with a working bombsight.

Although navigators were trained in celestial navigation, this was mainly used by the Ferry Command, as they delivered about 10,000 aircraft from USA and Canada to europe.

The need to avoid detection, flack and searchlights, meant that on bombing flights in Europe, dead reckoning was the primary means of navigation.  But help was at hand and early in 1942 the first British hyperbolic navigation aid (Gee) became available. The virtue of Gee was that it was simple to use and it produced a very accurate fix in about one minute (compared with the much longer time it took to obtain a three-star fix). At height its range was 300 miles or so; but it was subject to jamming. Amongst other things it also provided an excellent homing device.

The American LORAN system, based on similar principles but using medium-wave frequencies rather than VHF, was later invaluable on the transatlantic route with its greater range.



In 1953, Weems was awarded the Magellanic Premium, an honour given for contributions to navigation, astronomy or natural philosophy. This has been awarded only 33 times since it was established in 1786.

For the watch collector, he has the award for the first Patent, and watch with a rotating bezel.