Diving watches are rarely used for diving in today’s age of dive computers (at most as a backup instrument), but certified diving watches must have certain characteristics. Which features these are and why diving watches are mainly sporty everyday companions today, that’s what this article is about.

DIN 8306 or ISO 6425: The characteristics of a diver’s watch

A diving watch certified for diving must meet certain requirements. These are specified in the diver’s watch standard DIN 8306 and the international standard ISO 6425:

  • Pressure-resistant up to 20 ATM (≈ 200 m) (the diver’s watch must remain in this water depth for two hours and then another three hours at three meters – the diver’s watch must still work during and after 20 minutes of water pressure at the specified depth)
  • Rotating bezel, which for safety reasons can only be rotated counterclockwise and which can still be operated in 30 centimeters of water
  • Continuous minute markings and every 5 minutes a clearly legible, offset line marking as well as a luminous triangular mark on the bezel (or, depending on the design, on the dial) with which the immersion time is marked
  • Clear readability of the diver’s watch from a distance of 25 cm in the dark, which is why the markings on the bezel, hands and indices are provided with light sources
  • Luminous second hand, which shows that the watch is running
  • Antimagnetic according to DIN 8309 (accuracy of ± 30 seconds per day in three positions under a direct current magnetic field of 4,800 amps per meter)
  • Shockproof according to DIN 8308 (the deviation may not exceed ± 60 seconds per day after an impact at 4.43 m/s)
  • Rust-resistant in sea water (the diver’s watch must withstand 24 hours in warm salt water without damage)
  • Fixed strap (nothing should come loose or bend if the bracelet is loaded with 40 kilograms for one minute)
  • The average rate variation may only be between -4 and +6 seconds per day (only applies to DIN 8306)
  • Pressure-resistant crown (this is 25 percent above the specified pressure resistance (at 20 ATM this is 25 ATM) for ten minutes with 0.5 kilograms)
  • Resistant to temperature fluctuations (the watch is first brought to 40 degrees Celsius for ten minutes, then ten minutes to five degrees Celsius, then ten minutes to 40 degrees Celsius in a water depth of 30 centimeters)
  • Resistant to pressure (the diver’s watch must withstand 25 percent above the specified depth for one hour, then one hour at 0.3 bar negative pressure)

In the case of a type test, all tests must be completed; in the case of the individual test, only the test for tightness must be carried out at 25 percent above the specified depth.

With the exception of the anti-magnetic feature, the new Circula diving watch Aquasport as a chronometer fulfills all the characteristics of these diving watch standards.

Taucheruhr mit Lünette und Dreiecksmarkierung

Condensation test on watches

The pressure resistance of the crown as well as the resistance to temperature fluctuations and pressure is checked by means of a condensation test. This test determines whether the case is still tight after a pressure test. For this purpose, the case is heated to 40 ° C and then a drop of water is placed on the watch glass. If no condensation has formed on the inside of the glass after wiping off the water droplet, then the case has passed the test.

Further features and special features of a diving watch

In order for a diver’s watch to be easy to read under water from the side and in the event of reflections, the cover glass should have an anti-reflective coating, at least on the inside. Diving watches usually also have a screw-down crown so that it cannot be accidentally pulled out while diving, preventing water to penetrate the watch and to damage the movement.

Rubber straps have also proven themselves in diving practice, as they adapt perfectly to the changing pressure conditions under water. But metal watch straps and textile straps are also very popular on diving watches.

A helium valve, on the other hand, is only necessary if the watch is to be taken on dives to several hundred meters and the diver is in a pressure chamber during the decompression phase. This usually only applies to professional divers.

A helium valve is not necessary for amateur divers. On the contrary: a helium valve is then just an additional opening with a risk of leaks.

How does the rotating bezel of a diving watch work?

Even if modern dive computers have largely replaced diving watches, the function of the rotating bezel should be briefly discussed here.

The bezel is used to mark the submerge time by the diver marking the current position of the minute hand with the triangle on the bezel just before diving. This means that for the next 60 minutes he knows exactly when he submerged and how long the breathing gas will last from the bottle. Depending on the model, diving bezels have 60 or 120 clicks, so that the immersion time can be set to the minute or half a minute.

Circula Vintage Taucheruhr

As already mentioned above, the bezels on diving watches can only be rotated in one direction (unidirectional) – this ensures that if the bezel is unintentionally adjusted, the displayed diving time is only shortened and not extended. In contrast to shortening the diving time, an unintentional extension of the diving time is life-threatening, since the diver can run out of breathing gas.

The diver’s watch as a robust and sporty watch for everyday life

Since diving watches are no longer mainly used for diving, they have blossomed into robust everyday companions. Diving watches can therefore be kept on for swimming, mountain biking or jogging, for example, since they can withstand high water pressure and are relatively insensitive to vibrations.

But diving watches not only cut a good figure in sports. Thanks to their classic design, they can also be worn in the office and on festive occasions and give the outfit a sporty touch.

Incidentally, the rotating bezel can be used not only to mark the time of diving, but also to measure the duration of various activities to the second in everyday life. This is e.g. practical for cooking and baking times or when you want to find out how much time you need from A to B. To measure the time, turn the bezel until its zero point is at the position of the minute hand. As soon as the second hand hits the minute hand and the zero point of the bezel, the activity starts.

The time can be read on diving watches at any time of the day or night thanks to the fluorescent hands and indices (today: Super-Luminova) – and also from many different angles thanks to the at least inside anti-reflective coating.

The new automatic diving watch in retro design by Circula

As early as the 1970s, there was an automatic diving watch from Circula (see above). Inspired by the design of this vintage watch, we have launched a new edition.

The special thing about it: Instead of a scratch-prone aluminum bezel, we use an inlay with a scratch-resistant sapphire glass coating, which underlines the retro character of the new edition.

Circula Taucheruhr

The specifications of the automatic diving watch:

  • Made in Germany
  • 39 mm diameter
  • 46 mm lug to lug
  • 13 mm high
  • Domed, single anti-reflective coated sapphire crystal
  • Bezel covered with sapphire crystal
  • 20 ATM (200 m) waterproof
  • Screw-down crown
  • Different watch straps available, e.g. beads of rice, rubber or mesh
  • Three different automatic movements to choose from (STP, ETA or officially certified chronometer movement)
  • Five different colors.

The new Circula diving watches can be ordered from September and will be delivered on time before Christmas 2020.

The best thing to do is to register directly for the Circula newsletter to secure an introductory discount for the new automatic diver’s watch and to be informed about the start of orders!