Orient's King Diver Depth Gauge Watch

Incorporating depth gauges into dive watches made a lot of sense, especially before the advent of dive computers, which began to gain popularity in the late 1980s. Before these electronic devices, divers relied on mechanical wristwatches to measure depth and time spent underwater. Mechanical depth gauges provided a convenient, all-in-one tool for divers to stay aware of their limits. However, integrating these mechanisms into watches presented challenges—such as complexity, cost, and reliability issues—which explains why relatively few brands attempted this.

Despite these challenges, a number of notable brands did succeed in producing mechanical depth gauge watches, each using different systems to achieve accurate depth measurement. Some of the earliest examples of this combination popped up in 1968. Such was the Favre-Leuba "Bathy 50", which used a membrane system to translate water pressure into depth readings.

Another example from the same year was Nivada's "Depthomatic". This watch used a different mechanism, called the Bourdon tube. However, whatever the system used the concept is the same – these are different mechanical structures that converted water pressure into a circular movement (of either a needle or a circular tube), and that movement was placed against a scale that converted the pressure into water depth.

Orient did not take long to follow this trend, and in 1970 introduced the King Diver Depth Gauge into the Chronoace line. The new model was seen as a unique response to the growing demand for practical dive tools.

Orient's King Diver Depth Gauge used a capillary tube system, where water entered the watch through an inlet at 3 o’clock, compressing air to display depth on the dial. Its robust 42mm stainless steel case, rated to 100m depth, made it a durable tool for divers. Additionally, its specialized version of the caliber 42 movement – without a quick-set date button – enhanced its water resistance, making it an even more reliable companion for underwater exploration.

Depth gauges eventually fell out of favor as electronic dive computers became the standard, during the 1980s. It is worth noting that dive watches with depth gauges have not completely disappeared, although they now serve more as novelty than practicality. Take, for instance, the highly complicated mechanism embedded in the 1999 IWC "Deep One" – which not only shows you the current depth, but also the deepest you reached.

As a side note, it's worth mentioning another means of "measuring" depth, although measurement is a big word for this crude, yet innovative approach. If you ever wondered what that colorful markings on some old king diver models was intended for – here's the secret: Different wavelengths of visible light get absorbed by the water in different depth. And so, you can tell at what depth you are (very roughly) by noticing when each of the colors on the internal bezel disappears.

Back to the Chronoace King Diver Depth Gauge, this watch is not just a relic of a bygone era but a testament to Orient’s adventurous approach to watchmaking in the late 1960s and early 1970s - taking inspiration from the Swiss watch industry and incorporating it into its own very Japanese watchmaking.

Like many other Orient divers from those years, its size makes it a perfectly wearable watch even by today's standards – although you will need some hard work and luck to find one nowadays, and likely a bit of cash to make it come your way.

The picture of the IWC Deep One was taken from monochrome-watches.com. Pictures of the Orient Depth Gauge King Diver and other models that appear in this post were taken from various sale ads and the 1999 Orient Watch Catalog book.