If you prefer watches for diving because of their big dials and water resistance you can enjoy them without studying the essence of this “beast”. But if you are a true diver, so you should know enough about your future “mate”.
Water resistance is a feature requiring special certification. While diving into great depths, the diver trusts his safety and even life to this measuring instrument. Therefore, the reliability of the watches for diving must be in 100% compliance with established standards.
The first standard for water resistant watches ISO 2281 was introduced by the International Organization for Standardization (ISO) in 1990. Its objective was to put things on the watch market right, for many manufacturers presented their models as "waterproof", although the extent and reliability of this "water resistance" varied strongly. For this purpose there were introduced and described quality criteria and testing system that determined the compliance of the watch with these criteria. In order to obtain a certificate of quality, every watch goes through a series of tests. And the presence of such a certificate guarantees the buyer reliability of the watch regardless of its manufacturer. In 2010 a new standard ISO 22810 was introduced. It was improved in accordance with the development of technology and increased customers’ requirements. However, both of these standards relate to watches with water resistance up to depths of 30 meters. For true watches for diving there is a special standard ISO 6425, introduced in 1996. It guarantees reliability of watches with water resistance up to a depth of 100 meters, and contains stricter requirements.
In accordance with this standard, every diving watch goes through individual and versatile tests. Besides the obvious water resistance of the case, shock resistance, convenience and reliability of the bracelet and clasp, antimagnetic properties, resistance to salty environment and drastic temperature drops, resistance to water pressure and atmospheric pressure are also tested. The last parameter is tested under a pressure of at least 10 atmospheres.
Watches for diving must be not only reliable but also the most adapted to work under water. Therefore, the standard of quality establishes a number of additional requirements to the watches. The dial must be large and have a clear layout with intervals by 5 minutes, luminescent hands and indication readable in the dark from a distance of 25 centimetres.
In the process of diving it is important to track the beginning of the dive, the remaining time to spend under water and stages of surfacing. The surfacing should be gradual and phased, otherwise, the pressure drop may affect the condition and health of the diver. To track these vital indications the watch for diving has a rotating bezel. Having turned it, the diver records the time of immersion and can calculate the remaining time. The bezel rotates only in one direction to avoid accidental time shifting to the longer duration.
When diving to a depth of more than 60 meters it is not normal compressed air used (at this depth it’s harmful), but the mixture with high helium concentration. Helium molecules are so small that they can percolate even through the waterproof case, if the immersion lasts a few hours. And during surfacing as a result of pressure difference helium expands and can push the glass of the dial. So most diving watches have special helium escape valves which release excess of helium outside.
Considering so many details you may wonder: why are professional divers bothered with mechanical watches, if specially for them wrist computers for diving have been invented? The answer is simple: reliability and power supply. Electronics is a complex and intricate thing. If your computer’s battery discharges under water, true self-sufficient mechanical watch will continue ticking, accompanying your way to the top. It’s a high old movement.
Top-3 of watches for diving by version of GQ.
Calibre de Cartier Diver
This is the first model for diving watches by Cartier, proudly presented in 2014. It’s a model for 100% meeting all the requirements of ISO 6425. This watch differs from other diving watches by the classic Cartier style, owing to which it is good not only for diving but also for everyday wear.
Blancpain Fifty Fathoms
Model Bathyscaphe appeared in the late 1950's. It was developed for the French military divers and has military-like clear dial and reliable bezel. In 2003 Fifty Fathoms collection was released, it presented updated versions of the Bathyscaphe.
Thanks to the legendary Rolex Submariner created in the early 1950's we have the watch that has become the image and the prototype for almost all modern watches for diving. The Rolex Company equipped the winding crown with a rubber gasket, having protected this most vulnerable part of the case against water. Models Submariner and Sea Dweller possess clear black-and-white dials with rotating bezel that is easy to operate even in massive gloves.