Back in the early 90s, when I was still in my teens, I took a diving course during a visit to Curaçao. In a few weeks time I managed to earn my PADI Open Water Diver qualification with the help of the Wederfoort diving school, which is still active today. Half of the course was completed in the water, diving to various depths. The other half was theory learned from the books, something I’ve never excelled at. Yet once again it turned out to be very important.
A Matter of Life and Death
One of the first things we learned was the effect of compressed air underwater. The air we breathe in daily life consists of roughly 21% oxygen and 79% nitrogen. The same goes for the compressed air you take along when diving. While diving underwater, however, the pressure impacts the way our bodies absorb these gasses. The deeper you dive, the more nitrogen your body absorbs. During daily life this doesn’t affect you, yet while diving, the pressure makes your body consume the nitrogen; consuming too much can cause significant harm.
To prevent this, there are guidelines and tables for safe diving practices. These can help you determine how long it is safe to stay underwater, including for multiple dives. One of the things you learn is how to read the diving tables. For specialty dives, special gas mixes are used to prevent the body from consuming too much nitrogen.
So when you go diving, it’s very important to be able to measure the depth and length of your dive. This will help prevent decompression sickness, where the nitrogen absorbed by your body is released too fast, causing bubbles to form in your tissues and blood. While you will probably have proper diving equipment, it’s pretty cool to have these important functions on your wrist as well, even if you just use them as a backup.
We’ve selected three mechanical watches with fully functional depth gauges that you should consider for your next diving adventure.
IWC Aquatimer Deep Three
Made of lightweight titanium, the IWC Aquatimer Deep Three is the third generation of IWC diving watches featuring mechanical depth gauges with multiple functions, i.e. actual depth, maximum depth, and elapsed diving time. These are all necessary for a safe dive. IWC developed a special mechanism for these functions that works via a set of levers controlled by a membrane that is influenced by the pressure of the water. The maximum depth indicator can be reset at the push of a button.
Like the other dive watches, the IWC’s case measures 46 mm in diameter and has a depth indicator that goes up to a maximum of 50 m. Its waterproofness to 100 m should be enough for the enthusiastic recreational diver even though it’s not enough for a professional diver’s watch. The IWC has a mechanical self-winding movement with a power reserve of 42 hours.
Jaeger-LeCoultre Master Compressor Diving Pro Geographic
The Jaeger-LeCoultre Master Compressor diver is also made of titanium. Waterproof to 300 m, it sits between the Oris and IWC in terms of depth capacity, but wins for power reserve, lasting 48 hours on a fully wound movement.
The depth gauge is mechanical, similar to the IWC, and functions to 80 m below the surface. A hand indicates the actual depth. In addition to the time and depth rating, you also get a GMT-function with this diving watch; convenient for those who travel the globe to dive. At nearly 20 mm, the Jaeger-LeCoultre is the thickest of the three.
Oris Aquis Depth Gauge
The Oris Aquis Depth Gauge has an interesting construction and unique way to measure pressure. There is a cavity in the sapphire crystal along the edge of the dial that allows water to enter. The deeper you go, the higher the water pressure. Thus, more and more water enters the crystal, compressing the available air and indicating how deep you are on the depth gauge. This is a unique construction, which is seemingly quite accurate according to online reviews.
The stainless steel case on this Oris diver measures 46 mm in total and is waterproof to 50 bar (500 m). The watch comes on on stainless steel braceelt or a rubber bracelet with folding clasp featuring a diving extension. The automatic movement has a 38-hour power reserve.
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