903 St BE II – The story behind the Sinn Navitimer

The Sinn 903 St BE II is a watch I've been eagerly awaiting to add to my personal collection. It was released in May 2024, about a year ago, but it's out of stock and waiting lists can last weeks, even months.

In this article, we will explore all aspects of this watch, from its design and functions to its history, offering a comprehensive look at this Sinn masterpiece.

The relationship with Breitling's Navitimer

Many will say that the Sinn 903 is a clear copy of the Breitling Navitimer. And, to be honest, the resemblance is obvious. This is due to the fact that in 1979, during the quartz watch crisis, Breitling was in serious trouble, like many other Swiss brands. In that critical period, the German company Sinn came to the rescue, buying the rights to the design, cases and dials of this watch.

This means that the Sinn 903 St BE II is based on a design that has its roots in the Breitling Navitimer, but with a unique evolution and improvements that make it stand out. For over four decades, Sinn has been producing this model, keeping tradition and quality alive, while offering significant advantages that differentiate it from the original Navitimer.

One of the most notable advantages of the Sinn 903 St BE II is its price. At €3,550.00, it is about a third of the price of the Breitling Navitimer, making it a great alternative for those looking for quality and tradition without digging deep into their pockets.

Technical characteristics and design

The Sinn 903 series includes three different versions, all with a diameter of 41 mm, the same as a vintage Breitling Navitimer. This size offers the ideal balance between classic aesthetics and everyday comfort.

The design of the 903 is faithful to the traditional Navitimer, with 3 sub-dials (three-register) and the characteristic layout at 3, 6 and 9. The hands are stick hands with a red tip on the chronograph, while the scales on the dial retain the classic slide rule functionality. The crown and pushers have the familiar piston pusher style, giving a sense of classicity.

One of the most impressive technical features of the Sinn 903 St BE II is its water resistance: 20 bar or 200 meters deep. This is six times more than the usual Navitimer, which is usually only 3 bar (30 meters). This increased resistance makes the Sinn 903 St BE II ideal for everyday use, even in conditions that require water resistance, such as swimming, without the wearer worrying about damage.

The watch is approximately 14.12 mm thick, which is typical for mechanical chronographs, while its weight is 88 grams, quite light for the quality of construction and materials used. The crystal is domed sapphire, offering excellent scratch resistance and a beautiful visual presence.

Mechanism

The heart of the Sinn 903 St BE II is the LJP L110 automatic movement, based on the reliable and proven Valjoux 7750. It has 26 jewels and offers 60 hours of power reserve, ensuring stable and precise operation.

In a timegrapher test, the watch performed impressively with a deviation of just -1 second, demonstrating Sinn's excellent adjustment and build quality.

Additionally, the movement features a column wheel mechanism, which offers smoother and more reliable chronograph pusher operation, something rarely found in watches of this class. This is a small but significant indication of technical excellence and craftsmanship.

Conclusion

The Sinn 903 St BE II is a watch that combines tradition with innovation, offering an alternative to the Breitling Navitimer with excellent build quality and a much better price-performance ratio.

The water resistance, the clarity of the dial, the functionality of the slide rule, as well as the comfort of the bracelet, make the Sinn 903 St BE II an excellent proposition for those looking for a watch that combines tradition, technology and elegance.

The satisfaction it offers to the wrist and its detailed construction will make you love it, as it did to me!