The Sinn 903 Navigation Chronograph

Sinn 903


The Sinn 903 St B E Navigation Chronograph

The birth of the Sinn 903 is actually quite an interesting one. During the quartz crisis in the late 1970’s, Mr Helmut Sinn, the founder of Sinn watches was able to secure the rights, at an undisclosed price, from Breitling to be able to produce a timepiece with a slide rule, logarithmic bezel that also functions as a chronograph too! This is why you may see some quite obvious similarities between the Sinn 903 St and the Breitling Navitimer!

The 903 St has been consistently updated through the years, and now the latest version is here, and has a lot to appreciate. In addition to the fascinating variety of different features that this model holds, the 903 St BE Navigation Chronograph has been characterized by the feature-rich, deep blue dial, with hands and indexes that have been coloured with an ivory imitation tone. Any watch enthusiast will be able to appreciate the attention to detail and the the convincing clarity in the assignment of functions.

sinn 903

A chronograph targeted at those interested in analog calculations, with a classic slide rule. In order to perform the mathematical operations on the Sinn 903, there is a second crown at the 10 o’clock position. This is used for the slide rule turning ring where the logarithmic scale graduation is served.

With its help, for example, multiplication, division and rule of three can be performed as well as other useful calculations such as fuel consumption or speed, distance and time. In addition, this watch has a chronograph function, with which time periods can be measured and recorded.

Mechanical Specifications

  • SW 500
  • self-winding
  • 25 ruby ​​bearing stones
  • 28,800 vibrations per hour
  • stop second
  • Antimagnetic according to DIN 8309

Case Dimensions

Measurements and Weight

  • Case diameter: 41.0 mm
  • Strap width: 22 mm
  • Total height in the middle of the clock: 14.5 mm
  • Weight without band: 88 grams

Another fantastic timepiece from the Sinn range is the 104 collection, a classic pilots watch that is available in a number of different colours and strap combinations, check it out here!

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