Dive Watches: What to Know Before a Swim
DIVE INTO THE DEEP HISTORY OF AN ICONIC WATCH
Dive watches are among the most hallowed and sought-after niche models in the world of watches. The pursuit of the best dive watch dates back almost a century. Rolex was the groundbreaking watch company: the iconic Swiss watchmaker released its Oyster model in 1927. Horologists acknowledge it as being the world’s first water-resistant watch.
Dive watches have come a long way since then. This article will seek to explore some of the fundamentals and more interesting aspects of this fascinating type of watch. This article won’t incorporate watches made for diving with mixed gas or references to dive computers, which are not technically timepieces.
The Rolex Oyster, the first waterproof watch photo via rolex.com
WHAT IS A DIVE WATCH?
The diving, divers, or dive watch has been one of the most popular wristwatches people buy. It might be safe to say that the vast majority of these watches will never be used for their intended purpose, providing safety to a diver while they are at depth.
What is it that makes a watch a dive watch? The International Organization for Standardization (ISO) has established the criteria for a watch, or timepiece, to be classified as a dive watch, ISO 6425. Compliance is voluntary.
Here are four that you should look for in choosing a dive watch for your collection, not listed in any particular order.
- Water resistance to 100 m (300 feet), as measured using specialized equipment.
- It is equipped with a diving (elapsed) time indicator—commonly a unidirectional rotating bezel with indentations to facilitate operation wearing diving gloves.
- There is adequate readability/visibility in total darkness at 25 cm (9.8 in). Achieved by using lume material on the bezel, watch hands, and watch face.
- Corrosion-resistant case and strap materials; are important, especially for saltwater diving. 316L typically meets the necessary standards here.
More characteristics are outlined in ISO 6425, but making sure your watch has at least these four will meet most casual diving requirements.
WHY A DIVE WATCH?
It may seem like stating the obvious, but diving to the depths of an ocean, sea, or even deep lake can mean submerging into near-darkness. Hence there is value in having a timepiece that is easily viewed in such an environment.
Fundamentally, a dive watch allows a diver to monitor how much time has been spent underwater. Most importantly, a diver can know how much air they should have left in their breathing tank. Durability and construction are the two most important features of a dive watch.
WHAT MAKES A DIVE WATCH A ‘DIVE WATCH?’
Dive watches have some distinctive aesthetic features, making them instantly recognizable to the knowing eye. These include:
- They tend to be larger in diameter (around 42mm or 1.65 inches);
- They have a rotating bezel;
- They have a well-built, solid-looking, and sturdy case; and
- The strap is made of metal or rubber.
Berner’s Illustrated Professional Dictionary of Horology is an excellent starting point for what constitutes a dive watch. It defines a dive watch as “a watch designed to withstand immersion to a depth of at least 100 m and to satisfy requirements specified in ISO standard 6425.”
The ISO 6425 standard for ‘Divers’ watches,’ as formulated by the International Organization for Standardization, was first released in 1982 and last updated in 2018. The current 7-page standard outlines the international requirements for what constitutes a ‘water-resistant watch.’
The ISO standard stipulates that it “specifies requirements and test methods for divers’ watches. Saturation divers’ watches for use in deep diving are addressed in Annex 1 of the standard”.
And therein lies a little problem: very few watches meet all the requirements of the ISO standard.
However, the ISO standard is a good starting point, if only to raise factors you may not have considered. It can also allow you to decide whether you need to invest in a ISO-certified dive watch.
- The time on the watch face must be visible at all times, with the minute’s hand distinguishable from the hour hand.
- The watch must be equipped with a device that the diver can pre-select up to 60 minutes.
- The time set on the pre-selected device must be visible.
- The above can be in the form of a rotating bezel or a digital display.
- Said display must show 60 minutes with markings indicating every 5 minutes.
- The watch-keeping time (i.e., in good running order).
- Battery-powered watches must have a visible low-battery indicator.
- All the above requirements must be visible at a minimum of 10 inches (25 cm) at a depth (i.e. in the dark).
TEST-RELATED REQUIREMENTS:
- Saltwater resistance is tested by placing it in a sodium chloride solution of 1.05 ounces per 0.26 gallons (or 30 grams per liter) for 24 hours at 64 to 77ºF (or roughly 18 to 25ºC). The watch case should thereafter be inspected for adverse changes, such as oxidation and moving parts tested for functionality.
- There must be a test of resistance to thermal shock. In this test, the watch is immersed in hot water (at 104ºF or 40ºC), then placed in cold water (at 41ºC or 5ºC), and then back into hot water. Here too, the focus is on whether moisture has entered the watch.
- There is also a complex ‘reliability underwater’ test, which tests whether the watch can withstand undue leakages.
- A further test is for shock resistance, which is akin to the watch being dropped from a height of one meter onto a hardwood floor. It, too, is quite a complex test in its execution.
Suffice to say that failure of any of these tests means the immediate failure of that watch model being designated as a dive watch. A watch that passes these ISO-mandated tests has earned the right to be marked with the word ‘Divers’ followed by the depth rating in meters. An example would be ‘Divers 300 m.’
LUME & UNDERWATER VISIBILITY
’Lume’ refers to the luminescent material applied to a watch dial (face). The face's hands and indices (or numerals) illuminatein the dark, i.e. at depth. This luminescence used to be made of radioactive materials such as radium and tritium in the past. Fortunately, non-radioactive luminescent paint such as Super Luminova is used today.
The use of radium in watch- and clock-making, and the health risks involved, is detailed in the 2017 book Radium Girls by Kate Moore. The practise ceased in 1968.
As stated before, the primary feature of a dive watch is the ability to check time in the darkness underwater. This is especially relevant when driving at night and for other dives such as a deep-water cave or canyon diving, the exploration of underwater wrecks, and so forth.
Dive lights are needed in such dives, of course. Still, an illuminated watch as a quick reference timing check can be very useful.
An interesting aspect of lume is what colors are preferable. Some watchmakers insist that orange is particularly helpful as lume on dive watches. However, the light spectrum colours fade as a diver descends, rendering bright colors such as orange and red into a dull gray.
Some believe that yellow and blue are the colors that remain most visible at greater depths. However, many divers believe that contrast between the dial and hour and seconds hands is most important. As such, nothing beats thick white hands against a black watch dial for a dive watch for some divers.
KEY COMPONENTS OF A DIVE WATCH
There are two components to any dive watch worth discussing here: the movement and the rotating bezel
THE MOVEMENT
We here at LIV Watches have written in detail regarding watch movements, as can be seen, on our blog. For dive watches, automatic movements are undoubtedly the most popular. There are two main reasons for this:
- Automatic watches are easy ‘wound’ from the sheer movement of arms and hands necessary when swimming underwater.
- An automatic movement negates the need for a battery, which is more susceptible to moisture and damage inside a dive watch.
GX-DIVER'S 44MM SIGNATURE ORANGE
THE ROTATING BEZEL
We, of course, had to include a reverse panda in our list of favorite panda watches, and we decided to go vintage with our choice. Zodiac may not be a watchmaker with the high-end prestige of the likes of Omega or Audemars Piguet. However, it’s still a respectable Swiss watchmaker that has been in business since 1882. We really love its zodiac Sea-Chron, which was released in 1965 at the height of the deep-sea diving craze that swept the world in the 1960s. Being a dive watch also distinguishes it from most panda watches, which are chronographs usually inspired by motor racing.
The Zodiac Sea-Chron was a 200-meter shock-resistant dive watch housing a Valjoux 72 movement with 17 jewels. Its features included three sub-dials (with 1/5 second, 30- minute and 12-hour registers) in white, a tachymeter scale, and a stainless steel bracelet with 17 links and matching end links. The watch was notable for its uncluttered dial and rotating bezel with hash marks and triangles from 0 to 20 minutes, both of which made for easy reading underwater. Two oversized pushers were also welcome for divers.
TAKING A DEEP DIVE INTO WATER RESISTANCE
There is a common misconception that a dive watch that is stated as being water-resistant to 100 meters means that a user can dive to 100 meters below the surface. That is false. That’s why understanding water resistance levels, as outlined below, is so important.
Water-resistance levels are taken seriously by professional divers. According to the Professional Association of Diving Instructors (PADI), the world’s largest professional dive instructor organization, 60 feet (or about 20 meters), is the depth to which basic Open Water certification divers should be allowed to dive. PADI dive masters will take divers to 130 feet (40 meters) if they have Advanced Open Water certification.
Early LIV Watches concept sketches
A SIMPLE GUIDELINE TO WATER RESISTANCE LEVELS
So, ‘Water Resistant 10 m’ does not mean one can safely use a diver’s watch to a depth of 10 m below the surface. Rather, it means that the watch can withstand splashes of water and is protected against accidental exposure to water. It is a watch that is showerproof or splash-proof. It means nothing more than that.
With that in mind, herewith are the internationally-accepted ratings regarding water resistance levels:
- ‘Water Resistant 30 m’: The watch will withstand splashes or brief immersion in water but is still not suitable for swimming.
- ‘Water Resistant 50 m’: The watch is suitable for shorter periods of swimming in shallow water.
- ‘Water Resistant 100 m’: The watch is suitable for recreational surfing or snorkeling - again, no deeper than that.
- ‘Water Resistant 200 m’: The watch is suitable for professional marine activity; most water sports are above-water or in shallow water.
- ‘Water Resistant 300 m’: This watch can be used as a diver’s watch.
- ‘Water Resistant 1000 m’ watch is claimed to be suitable for deep-sea diving.
There are some important water resistance-related factors one must remember to do or not do with your dive watch:
- Never wear a diver’s watch at depths greater than its declared maximum depth;
- A diver’s watch should not be used for deep diving, i.e., diving with a gas mixture;
- The crown should not be operated during the dive;
- To ensure the continued integrity of your dive watch, make sure to use normal water to rinse all salt and dirt from your watch after each use; and
- Continued water resistance requires that you regularly have the gaskets of your watch replaced, i.e., at least once every two years.
