Big Boy Exotics serves exotic-car buyers across the United States. Tell us about your car search.
Cover: Breitling Navitimer slide rule, Torsten Bolten; Commons crop by Zenith El Primero; shadow adjustment by Soerfm; CC BY-SA 3.0. Existing Commons crop and shadow adjustment, resized by Wikimedia Commons; no further changes by BBE. Compact-delivery image resized and JPEG-compressed; no cropping or content edits.
The Breitling Navitimer’s crowded perimeter becomes much more inviting when you know what two of its scales are doing. One moves with the bezel; the other stays on the dial. Together they form a circular slide rule, a calculating instrument that gives the watch a particular kind of mechanical appeal.
For an enthusiast considering a pre-owned example, learning one calculation is a useful first step. It turns an admired design into something you can actually operate and helps you decide whether the small markings are enjoyable to read on your wrist.
Start with the two scales
Breitling’s Navitimer history places its origins in 1952 and explains the relationship between the bezel and dial scales. Moving one against the other allows multiplication and division. This is established model history, rather than a new feature arriving for 2026.
The photograph here shows a historic Navitimer chronograph and its calculating scales. It illustrates the operating principle without identifying the watch as a particular current reference. Before buying, establish the reference separately and obtain its correct instructions; the Navitimer name now covers a broad collection.
Try a calculation with an obvious answer
Breitling’s slide-rule instructions use seven multiplied by twelve as an introductory example. Set twelve on the outer scale against the inner scale’s ten index. At the inner graduation representing seven, read eighty-four on the outer scale. The scale wraps the calculation around the dial instead of displaying it as digits on a screen.
Decimal placement still requires judgment. The same positions can represent numbers of different magnitudes, so estimate the answer before reading the result. Seven times twelve must be a little below ninety, which gives you a simple reason to reject an interpretation of 8.4 or 840.
For division, the manual reverses the relationship: align the outer-scale dividend with the inner-scale divisor, then read the result at the inner ten index. Practice with a calculation you already understand before exploring speed, time or unit conversions.
Keep the chronograph separate
The slide rule and stopwatch invite different actions. Breitling’s explanation of the chronograph describes pushers that start, stop and reset elapsed-time measurement. Rotating the calculating bezel serves another purpose. You can practice an arithmetic problem without starting the chronograph.
Ask a seller to demonstrate both functions independently. Then repeat the bezel exercise yourself, checking whether you can align the fine graduations comfortably and read them under ordinary room lighting. Try it with your usual glasses, if applicable. A photograph enlarged on a laptop is a poor substitute for that small, physical interaction.
Choose an example you enjoy reading
During a viewing, look at the printed scales as carefully as the main hands. Ask about any declared replacement dial or bezel, and include those parts in an independent authentication and condition assessment. A successful calculation demonstrates operation; originality still needs its own evidence.
Spend a few minutes looking at the time after the arithmetic exercise. Consider whether the busy perimeter remains attractive during an ordinary workday, and whether the watch fits beneath your usual cuff. Those are personal choices worth making before comparing dial colors.
Treat this exercise as watch appreciation, not flight planning. Aviation decisions require the pilot’s approved procedures and equipment. The pleasure for a collector is simpler: learning why the Navitimer looks the way it does, then choosing a watch whose details reward that attention.
From the Journal
Rolex GMT-Master II: Learn the Local-Hour Hand Before Choosing a Bezel
Looking for a particular exotic car? Start your private search with Big Boy Exotics or send your car-sourcing brief to info@bigboyexotics.com.