Today Oris has updated one of its more technically advanced mechanical dive watches, the “watch with a hole”, the Aquis Depth Gauge. The second generation of the impressive tool watch features three critical improvements over its predecessor.

Mechanical depth gauges are not that commonplace in most modern divers’ equipment bag. Partly because the advanced digital dive computers monitor this for them and because they’re just so few and far between. That said, many divers like to take a mechanical backup watch with them, so having a mechanical depth gauge to boot is certainly a helpful addition.

Oris Aquis Depth Gauge

Into the deep

The mechanical depth gauge mechanism is actually quite simple in its science, but the execution is quite clever, too; it relies on the scientific principles of the Boyle-Mariotte Law to measure depth during a dive. In case you’ve forgotten your high-school science lessons, the Boyle-Mariotte Law states for gases that “pressure × volume = constant”.

I can’t help but love the color choice…

So, Oris’s engineers calculated that air volume in a channel milled into the sapphire crystal would reduce during a dive, compressed under the atmospheric pressure. So during a dive, the volume of air in the channel compresses, thus allowing water to enter the channel. This creates a watermark that corresponds to the gauge indicated in yellow around the outer edge of the dial. The air then decompresses during an ascent, forcing the water out of the hole. As a man who loves yellow on a watch, I can’t help but love the color choice.

Oris Aquis Depth Gauge

No, your Aquis Depth Gauge won’t get flooded…

For those of you worrying about the idea of actively letting water into your watch, fear not. The Aquis Depth Gauge allows water into the crystal, but it doesn’t allow water into the watch itself. Oris designed the depth gauge mechanism so that water can only enter the channel through the hole in the crystal. In addition, a gasket around the crystal seals the watch. Oris is so confident in the ability of its seals and gasket that it has certified the watch as water-resistant to 50 bar (500 meters). That speaks volumes to me.

Oris Aquis Depth Gauge

Updated water ingress channel

I mentioned above that there are three key improvements to this second-generation Aquis Depth Gauge from its predecessor. The first update is regarding the depth gauge system itself. Oris has tweaked and slightly redesigned the process used to mill the channel into the outer edge of the sapphire crystal. This refinement allows for greater accuracy and legibility of the gauge reading. But, of course, this is only positive when minute discrepancies can have a detrimental effect under the water.

Oris Aquis Depth Gauge

A properly aligned case back

The case back has been subtly re-engineered so that the meters-to-feet conversion chart is always set at 90 degrees to the 12 o’clock position. For divers who regularly rely on the chart, this will significantly enhance their experience of the watch. In addition, knowing exactly how the chart is orientated when taking the watch off can be a godsend. In low lighting conditions, every little helps!

Oris Aquis Depth Gauge clasp

Quick-change strap system

Finally, the new Aquis Depth Gauge benefits from Oris’s new patented Quick Strap Change system. Owners can now switch the stainless steel metal bracelet and rubber strap quickly, safely, and securely without needing a tool or a visit to a jeweler. No more scratched or damaged lugs! Hooray! That said, I’ve not seen this new system in the metal, so I can’t accurately comment on its execution in the real world. It looks pretty straightforward, but if it could be a deal-breaker for you, I’d advise seeing it for yourself before taking the plunge to purchase. The strap also features a very nice-looking folding clasp.

For those interested, you can read more on the Oris website. It can be yours for the sum of just £3,000. Not a bad price for an unusual complication! What do you think of it? Be sure to let me know in the comments!

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Watch specifications

Aquis Depth Gauge (2nd Generation)
01 733 7755 4154-Set MB
Black with yellow depth gauge scale
Case Material
Stainless steel
Case Dimensions
45.8mm case diameter, with 24mm lug width
Double-domed sapphire with AR coating on both sides
Case Back
Stainless steel, special engraving, screwed
Oris 733, base SW 200-1
Water Resistance
Stainless steel bracelet
Hours, minutes and central second hands from the center, window date, instant change of date, date corrector, fine adjustment and second stop