A chronograph refers to a watch with a stopwatch function. This function starts, stops, and resets the stopwatch by pressing a button on the watch case.
It was originally invented for tracking celestial bodies, and later, with the need to measure horse racing times accurately, it became mass-produced and found use in various fields. So, you shouldn’t assume it’s just a racing watch.
Some examples include a tachymeter, which measures speed per hour, and a pulsometer, which displays the number of heartbeats per minute when measured during 60 beats. For military use, it was used to measure the speed of artillery or missiles.
Additionally, dive watches with chronograph functions began to be mass-produced, serving to measure work time underwater and assist with various diving missions.
Examples of dive watches with chronographs include the IWC Aquatimer, Omega Seamaster, Tissot Seastar, Citizen Promaster, Doxa Sub 200, Tudor Black Bay, Mido Ocean Star, Oris Divers Sixty-Five, Panerai Submersible, and Blancpain Fifty Fathoms, among others. However, most chronograph dive watches are equipped with screw locks for the chronograph pushers. These locks do not seal the pushers, and it is advised not to use the chronograph underwater. Therefore, even though it’s called a chronograph dive watch, this function can only be used when the watch is out of the water.
I contacted several brands that produce chronograph dive watches to ask if their chronographs can be operated underwater:
- Mido: They responded that the function cannot be used underwater, and the product description states it is a marine tachymeter.
- Oris: They also confirmed that the function cannot be used underwater, as mentioned in the manual.
- Citizen: The answer was that it’s not possible to use the chronograph underwater.
- IWC: They confirmed that the chronograph cannot be used underwater.
- Doxa: The manual officially states it’s not possible.
- Omega: They responded that it is possible to use the chronograph underwater, and this is officially stated in the manual.
- Tudor: There is no official inquiry channel on their website, and different stores had different responses. When I tried to inquire using the “Contact Us” function on various store websites, I kept encountering errors, so I excluded them. Dealers and boutiques have advised never to operate the chronograph underwater.
Some brands even advise against wearing the watch underwater or near the surface. There’s interesting information on this topic in Blancpain’s Lettres Du Brassus 15, which can be found on their website. The Fifty Fathoms chronograph and Bathyscaphe chronograph flyback models are equipped with sealed pushers and have a water resistance rating of 30 bar, allowing them to be used underwater, making them true chronograph dive watches.
I currently own a Bathyscaphe chronograph, so I had the chance to verify this myself. I once posted about a scuba practice session while wearing the chronograph in a diving pool. Since then, I’ve received many DMs asking, “Was it waterproof? Did the chronograph function well?” At the time, I wasn’t planning to record it, so I didn’t capture any footage.
If you’re looking to buy a true dive chronograph, I recommend choosing brands like Blancpain or Omega, which design and manufacture them properly. Personally, I avoid brands that prioritize appearance and marketing over investing in technology.
Finally, always check the water resistance of your watch at the frequency recommended by the manufacturer before using it underwater (and this applies to all water-resistant watches, even those rated for just 1 meter).
