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. Above 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.
Philip Van Horn Weems
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.
The Weems Second Setting Watch
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.
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.
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.
Weems Second Setting Standard Model
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.
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 watch above is heavily influenced by Breguet design features, and is about 47mm diameter, and has an internal rotating seconds setting dial insert.
Weems worked initially with Longines/Wittnauer who patented the design in 1929. Longines have since made a homage version of this watch.
The early models below are just signed Longines.
The central seconds setting is operated by pressing the button below the crown, and simultaneously rotating the crown.
The navigation watch, second setting, standard model, A-12, in about 1940 sold for $80
Longines model serial number 4931593 of 1928, with a serial number 6 different from the watch above.
1929 model, serial number 5044000 below.
Longines serial number 5167806 of 1931 with roman numerals and large sliding lever/clamp.
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 nice second hand on the model below.
A-12 model below.
Serial number 5941864 from 1940.
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.
Air Navigation - the book by Weems
This book taught avigation, and discussed the standard second setting watch, and the later, smaller wrist 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.
Wrist model special bezel - rotary verge ring.
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.
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.
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
The A-11 watch
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.
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.
Air Navigation and Weems
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".
Star Altitude Curves
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.
The Weems Patent
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.
Celestial Navigation Simulators
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.