Chronostop Part 3 - Seamaster Fixed & Rotating Bezel Variants

The Seamaster Chronostop is the largest and arguably the most practical and useful of all Chronostop models with a suite of bezel options that bring new functionality, style and purpose to the model line.

A Continuation of the Series

This is part 3 in a 4 part series about the Omega Chronostop line.  For the first and second parts, click the link below:

Chronostop Part 1 - Geneve Chronostop & Special Japanese Variants
This will be the first of four parts in our series on the Omega Chronostop, a model spanning many model lines and even brands with a complication so unusual that there is nothing in Omega’s modern product line that even compares.
Chronostop Part 2 - The Italian Geneve Pentatlon, Lemania Racing & De Ville
Our journey into the Chronostop model lines ventures into Italy with the Chronostop Pentatlon, also known as the Chronostop Fontana, and the little known Lemania & De Ville variants of this case design.

The Seamaster Chronostop Family

The Seamaster Chronostop family are an entirely different case design, aesthetic and direction from the original and Italian Geneve cases.  These watches add additional functionality through both fixed and rotating bezel and carry the references 145.007 and 145.008 respectively.

While the bezel and case designs do vary among Seamasters, there is only a single dial in black for all Seamasters across both references, a stark contrast to the wild variety available in Geneves.

145.008 with 24-Hour bezel - Image by @Baz9614, IG: cediaguy

While the Seamaster Chronostop models were not the most popular model in their own right, they share parts with many other models in Omega's line-up and were influential in future designs.  The dial of the Seamaster including the unique reverse-pie-pan shape and dial furniture was also used on the Geneve Chronostop in a variety of different colors.  In addition, the case design was re-used in the Seamaster Chronograph References 145.016, 145.019 & 145.020 powered by Calibre 861, as were the exact same fixed and rotating bezels.

The closely related Seamaster Chronograph 145.019 - Image by @Shane0Mack

There is some discussion that the Seamaster actually was the original Chronostop design and that the Original Geneve followed after some prototype Seamasters were made.  This makes some degree of sense, and fits with a prototype discussed in the variants section but cannot be confirmed without better sources.

Case & Bracelets

The two cases, 145.007 & 145.008 are identical except for the fact that the 145.008 has an additional crown on the left hand side at the 10 o'clock position for the purpose of rotating the inner bezel.

The Seamaster Chronostop cases are large for the era, at 41 mm in diameter and 12 mm thick, with a C-Case style that wears larger on the wrist than the numbers would indicate.  Compared to the other models of Chronostop, the Seamaster is certainly the most substantial.

The Seamaster case is radially brushed on the top surface, with a thick, pronounced, polished bevel running down the sides before transitioning to brushed sides.  The large 22 mm wide lugs are cut into the case without much room between the spring-bar holes and the case.

The case-back is of a standard, keyed, screw-in style with a Seamaster hippocampus logo in the center.  The pusher and crowns are recessed into the case and partially hidden from the front, yet are exposed from the back to allow easier access.

145.008 Case-back - Image by @Vujen, IG:

On the 145.007, with the single crown, there is a fixed bezel underneath the plexiglass surrounding the dial.  On the 145.008, with dual crowns, the inner bezel under the plexiglass can be rotated by the 10 o'clock crown.

The most commonly fitted, and most suited bracelet is the reference 1117 with 549 end-links.  There are some other choices including the reference 1170 with 604 end-links, the reference 1162 with 172 end-links and even Omega vintage mesh bracelet are also a good option.

1117 Bracelet - Image by @Vujen, IG:

It should be noted that due to the abnormally large lug width of 22 mm, it may be slightly more difficult to find straps that work well with it and looking at custom makers could be the best approach.


The Seamaster Chronostop only comes in one dial, and accordingly only in one movement across both references, the Calibre 865.  

As mentioned in part 1, the Calibre 865 is derived from the highly regarded Calibre 861 movement found in the Speedmaster Professional Moonwatch.  The family has proven over many decades to be highly reliable, accurate and maintainable, with the latest Calibre 3861 Co-Axial movement still based on the original Cal 861 design.

145.008 with Cal 865 - Image by @Kokito, IG: watch_by_pieces

The Calibre 865 is manual wind, beats at 21,600 vph and lacks hacking.  The calibre is not chronometer rated, however when serviced correctly can reach quite good levels of accuracy.  Being derived from the Calibre 861, the chronograph mechanism found in these movements is a cam and lever design. It differs here from the 861 in that there is only a single pusher for all three functions rather than two.

This means that the same pusher will function in the order Start -> Stop -> Reset before starting again on the fourth press.  This also means that once the chronograph has been stopped, there is no re-starting it without resetting first as the sequence is dictated by the position of the cam with a single pusher configuration.

Calibre 865

Parts for these watches are still available and they can be serviced by any qualified watchmaker with access to an Omega parts account.  It is worth keeping in mind that these movements are more expensive than most vintage Omega calibres if needing a whole donor movement.  Also, a watch with many worn parts can add up to a somewhat large bill on these movements. If buying one you are best to have it serviced prior to using it, in order to minimise any wear-induced parts bill.

Bezel Variants

Normally we would discuss the dial variants but in this instance, we will discuss the 4 different fixed bezel options available on the reference 145.007, as well as the three rotating bezel options for the 145.008.  We will also then finish up with an early dial that may be a limited production or prototype early version.

145.007 with Tachymeter bezel - Image by @ICONO

The standard dial used on all models of this Seamaster is very similar to the Geneve Chronostop with a dial that is flat in the center, before angling upwards from the beginning of the dial furniture outwards.  The applied dial furniture is vaguely shaped like a door-stopper for all hour markers except 12 o'clock which is a wider cheese-wedge shape with luminous material on its surface.  All dials are luminous, with dots of lume on the outer edge of hour markers and use sporty styled stick hands with luminous inserts.  All dials are marked T SWISS MADE T at the bottom.

The dial text is all in white against the black dial with the exception of the Omega logo which is in an orange to match the chronograph seconds hand.  At the outer edge of the dial is a racing style sub-seconds track with a white background for contrast.  This appears on both references and all bezel options.

Fixed Bezel

The fixed bezel is the only variant that does not rotate, and accordingly has its own case reference of 145.007 as it does not need the additional crown that the others do.

While the fixed bezel may seem less interesting, it actually offers a lot of variety and practicality with four different types available.

Tachymeter Bezel:  This is the most common option and is used to measure how many times an action, event or process can occur per hour if happening continuously.  As an example, if pouring a beer takes 30 seconds, the tachymeter bezel would indicate 120 beers could be poured per hour.

145.007 With Tachymeter bezel - Image by @Tyrantlizardrex

Pulsimeter Bezel:  This is a far less common bezel intended to be used by a physician to take a patient's pulse.  The user would use the watch to time how long it took for 15 beats, and then the patient's beats per minute can be read off the scale.

145.007 With Pulsimeter bezel - Image by @Stevengrg

Telemeter Bezel:  This is also a far less common bezel, used to measure distance.  As an example, if a lightning strike occurs in the distance, and the chronograph is started, and then stopped when the sound reaches the user, the distance can be read off the bezel.

145.007 With Telemeter bezel - Image by @dantheman3u4i

Decimeter Bezel:  This bezel is also far less common and is used to measure minutes in decimal scale in order to benefit scientific users that require timing for use in equations.  As an example, measuring the time for a chemical reaction in decimal form and plugging that number directly into an equation on a calculator.

145.007 with Decimeter bezel - Image by Fabrice Ribet

These bezels can be swapped out by a watchmaker if you find a suitable replacement with the indices that you prefer and are also shared with the Seamaster Chronograph Reference 145.020 which uses the same bezels.

Elapsed Minutes Bezel

The elapsed minutes bezel is the first of the reference 145.008 rotating bezel models we will look at and tends to be the most common.  This bezel is arguably the most useful of all Chronostop bezel options as it addresses the major shortcoming of the design in the most effective way possible by adding elapsed minutes timing.

145.008 with Elapsed minutes bezel - Image by @Vujen, IG:

The way to use this bezel is fairly simple, to time minutes as well as seconds, you would rotate the bezel until the triangle shaped arrow points to the minute hand, and then press the start button.  As the elapsed seconds hand runs, the minute hand will also continue to run and the minutes can then be read off of the bezel, allowing timing up to 1 hour duration.

The downside to this is that it still remains a two-part process as the timing of minutes and seconds are separately initiated, and the issue of not being able to stop and re-start due to the single pusher remains.

145.008 with Elapsed minutes bezel - Image by @Ewand

While it isn't a perfect solution, it is a unique and novel one, offering very good legibility, far more so than would otherwise be possible from a traditional sub-dial for elapsed minutes so for certain purposes there are genuine benefits to this bezel option.

24-Hour Bezel

The 24-hour bezel is the most famous bezel for the Seamaster Chronostop, especially the highly desirable "roulette" bezel which is so well loved that Omega even brought it back in the 2000s on a Speedmaster model.  

145.008 with Roulette 24-Hour bezel - Image by

This bezel allows you to see a different timezone, or even multiple timezones if you remember the correct offsets by rotating the bezel forward or backward however many hours the second timezone requires.  You can then read that second timezone by observing where the hour hand was pointing to.

The downside to this bezel design is that the Chronostop only has a 12-hour hand, and not a true GMT hand that rotates once every 24 hours.  As a result, the bezel has two hours for every hour marker, and it is up to the wearer to remember which is the correct one to read, and whether it is midnight or noon.  For this reason, it can be a bit confusing for timezones that are significantly different.

Having said that, it is a very cool and interesting idea, which works relatively well and brings a very unique look to the watch.

Regatta Bezel

The regatta bezel for the Seamaster Chronostop is a surprisingly useful design, and arguable better for its intended purpose than many regatta timers on the market before or since.

145.008 Elapsed minutes bezel - Image by @Trevshep2

In essence this bezel is identical to the elapsed minutes bezel, but in reverse, as it counts down to zero rather than counting upwards.  To this end, Omega has marked this bezel with high visibility minute hashes in blue from 10 to 5 and in red from 5 to 0, which is excellent.  You can see the individual minutes far better on the large bezel than on the sub-dials many other regatta watches use.  Additionally, you can start the countdown at 10, 5, or anywhere else on the scale, which is particularly handy if you're in the middle of a complex maneuver on the water when the countdown begins.

The only downside is once again that there is a two-part process to starting the timing. That is also made more difficult when you are trying to fiddle with the crown for the bezel while wearing wet sailing gloves and have a tiller-extension in one hand and a mainsheet in the other.

145.008 Elapsed minutes bezel - Image by @Trevshep2

On balance, it is a better than average approach and more practical than most regatta watches although still not quite as useful as a quartz digital alarm watch like an Omega X-33 Regatta Timer for sailing purposes.

Early Coat-hanger "S" Dial

This is a very unique and interesting dial, which may be an early production version of the Seamaster Chronostop and so far, has only been seen in one example.  

The watch that this dial is fitted to is owned by Dan Henry of and is subtly different from all other Seamaster dials yet looks to be an original example with some rather interesting features.

145.008 Regatta bezel - Image by Dan Henry of

Firstly, the S in Seamaster is a "coat-hanger" S, which was more common in the early to mid-1960's, while all other Seamasters use a rounded S.  Everything about  the font looks correct, as does the weight of the printing, just slightly different and earlier.  Secondly, the outer sub-seconds track of this dial is wider, with a black background as opposed to all other Seamasters which have a narrower sub-seconds track with a white background.

145.008 Regatta bezel - Image by Dan Henry of

The sub-seconds track actually looks very similar to the original Geneve Chronostop models which gives some degree of credence to notion that this Seamaster pre-dates those Geneves but once again it would require some input from Omega or potentially Lemania to confirm this.


Seamaster Chronostop models have among the strongest prices of the Chronostop family, especially among dealer asking prices.  This is partly due to how similar these watches are to the Seamaster Soccer timer chronographs, Ref 145.016, 145.019 & 145.020 which are highly desirable and quite expensive watches.  They don't often sell at those prices however and you will find there are much better deals to be had from private sales and eBay.

Supplies for all models are quite decent, and demand isn't huge so watches on Chrono24 and similar dealer listings will often sit for a very long time at prices of $2,500-3,000 or more.  In contrast, listings on Omegaforums, and on eBay can sell for as low as $800, especially for fixed bezel variants.

145.007 with tachymeter bezel - Image by @Tdn-dk

The prices will step up from fixed bezel models as the cheapest, to elapsed time, black and white 24-hour bezels, and regatta rotating bezel at the mid-point, and roulette bezels at the top end.  The price difference is such that regular rotating bezels are often found around the $1,500-2,500 mark depending on condition, while the much loved roulette bezel models can command $3,500-5,000 depending on condition.  Patience can pay off significantly when these watches do go no-reserve at auction, where some very impressive deals can be had.

It should be noted that there are numerous "New Old Stock" roulette bezels that have been floating around the internet for a long time, some definitely authentic from the WatchCo days, and more that are sometimes suspiciously cheap on eBay. These bezel can be swapped into a cheaper rotating bezel model to increase the value so if there is a significant difference in appearance between the bezel and dial, I would be a little concerned.

The cases on these watches often lose their original brushed finish and this is easily corrected by a skilled watchmaker, however it is important that the case has not been over-polished to the extent that the edges of the side bevels have gone soft.  Water resistance on these watches is generally decent although the multiple points of entry where seals can degrade mean that some watches will have water damage if gotten wet after a period of neglect.  It is best to avoid any watch with signs of water intrusion as the cost to put the movement right will be very high and the dial and bezel will never be the same.

145.008 with Elapsed minutes bezel - Image by @Kokito, IG: watch_by_pieces

These watches typically come on bracelet, and those bracelets will cost several hundred dollars to replace if they are not present on the watch so this must be factored into the purchasing equation.  There are several different options available with some being cheaper than others.

Seamaster Chronostop models were sold widely around the world and are not difficult to find so there are no specific markets to look for them in unless currency or tax reasons lead you in that direction.

As with other chronostop models, it is best to factor the cost of a service into your purchase and have the watch fully serviced prior to wearing it as unlubricated metal-on-metal wear can lead to a costly parts bill.  This can be most cost effectively handled by an independent watchmaker with an Omega parts account.

145.008 with Elapsed minutes bezel - Image by @Kokito, IG: watch_by_pieces

These Seamasters make a very compelling daily wearer, arguably the most useful and practical of all Chronostop variants if not the most elegant on the wrist and the more special models like the roulette and regatta timers stand out even among historically important Omegas.

Discussion thread on Omegaforums can be found here:

Chronostop Part 3 - Seamaster Fixed & Rotating Bezel Variants
[IMG] The Seamaster Chronostop family are an entirely different case design, aesthetic and direction from the original and Italian Geneve cases....