I have a few chronographs that are somewhat linked to diving (either the line or the case maker). As an example, let's use this Squale. I am wondering if these are really made for diving? If so, (i) why do you need a chronograph in the water? (ii) How is it possible that water doesn't enter via the pushers? I know back then they don't have screw down crowns but the pusher seems very loose. Sorry for the stupid question!

Thanks,
H

 

Good question. I never understood chrono divers.

 

Well I believe the Chrono Seamasters have a secondary gasket system inside the pushers so that they can be depressed under water. Not sure about Squale.

 

This one you mean? I was originally thinking of posting this one as an example but it doesn't have the standard 60min ring/bezel...

 

There are a very different varieties of Seamaster chronos, but yes that's the idea I had in mind.

 

Any chronograph that's really made to be submerged will have screw down safeties on the pushers so you can't operate them while screwed down and flood the watch.

 

So, a Daytona? Don't shoot me or hit me with a bat.

 

Except the Seamaster 300m diver chronos, which have pushers designed to be used underwater.

 

Not a diver. Diving watches should be marked as such on the case back.

Diving chronos should have screw down pushers and a diving bezel. No bezel no 300meter Iso dive rating. A 300m diver rating is not the same as a 300m water resist rating.

Afaik the only diver chrono without screw down pushers is the PO.


In any case if you use a watch for diving it should be tested and gaskets checked every 2 years.

 

I always ruminate on the line between "dive watch" and "dive style watch"

The quintessential diver is such a staple of the watch world that even some watches that look like divers have no business being underwater.

 

Thanks! Yep I didn't expect this is a diver but just curious in general when I see these type of watches.

Actually what does 300m water resistance rating really mean? If you can't submerge it, why bother 300m?

 

Correct which is why a watch that specifically states Diver on it is an internationally legally binding statement. Watches conforming to ISO 6425 are marked with the word DIVER'S to distinguish ISO 6425 conformant diving watches from watches that might not be suitable for actual scuba diving.

ISO 6425 standard for diving watches
The standards and features for diver's watches are regulated by the International Organization for Standardization in the ISO 6425 standard. Besides water resistance standards to a minimum of 100 m depth rating ISO 6425 also provides minimum requirements for mechanical diver's watches (quartz and digital watches have slightly differing readability requirements) such as:[18]

• The presence of a unidirectional bezel with at least at every 5 minutes elapsed minute markings and a pre-select marker to mark a specific minute marking.
• The presence of clearly distinguishable minute markings on the watch face.
• Adequate readability/visibility at 25 cm (9.8 in) in total darkness.
• The presence of an indication that the watch is running in total darkness. This is usually indicated by a running second hand with a luminous tip or tail.
• Magnetic resistance. This is tested by 3 expositions to a direct current magnetic field of 4,800 A/m. The watch must keep its accuracy to ± 30 seconds/day as measured before the test despite the magnetic field.
• Shock resistance. This is tested by two shocks (one on the 9 o'clock side, and one to the crystal and perpendicular to the face). The shock is usually delivered by a hard plastic hammer mounted as a pendulum, so as to deliver a measured amount of energy, specifically, a 3 kg hammer with an impact velocity of 4.43 m/s. The change in rate allowed is ± 60 seconds/day.
• Chemical resistance. This is tested by immersion in a 30 g/l NaCl solution for 24 hours to test its rust resistance. This test water solution has a salinity comparable to normal seawater.
• Strap/band solidity. This is tested by applying a force of 200 N (45 lbf) to each spring bar (or attaching point) in opposite directions with no damage to the watch or attachment point.
• The presence of an End Of Life (EOL) indicator on battery powered watches.

Testing diving watches for ISO 6425 compliance is voluntary and involves costs, so not every manufacturer present their watches for certification according to this standard.

and

The International Organization for Standardization issued a standard for water resistant watches which also prohibits the term waterproof to be used with watches, which many countries have adopted.

Water resistance is achieved by the gaskets which forms a watertight seal, used in conjunction with a sealant applied on the case to help keep water out. The material of the case must also be tested in order to pass as water resistant.[28]

None of the tests defined by ISO 2281 for the Water Resistant mark are suitable to qualify a watch for scuba diving. Such watches are designed for everyday life and must be water resistant during exercises such as swimming. They can be worn in different temperature and pressure conditions but are under no circumstances designed for scuba diving.

The standards for diving watches are regulated by the ISO 6425 international standard. The watches are tested in static or still water under 125% of the rated (water) pressure, thus a watch with a 200 m rating will be water resistant if it is stationary and under 250 m of static water. The testing of the water resistance is fundamentally different from non-dive watches, because every watch has to be fully tested.

ISO 6425 water resistance testing of a diver's watch consists of:

• Immersion of the watch in 30 cm of water for 50 hours.
• Immersion of the watch in water under 125% of the rated pressure with a force of 5 N perpendicular to the crown and pusher buttons (if any) for 10 minutes.
• Immersion of the watch in 30 cm of water at the following temperatures for 5 minutes each, 40 °C, 5 °C and 40 °C again, with the transition between temperatures not to exceed 1 minute. No evidence of water intrusion or condensation is allowed.
• Immersion of the watch in a suitable pressure vessel and subjecting it to 125% of the rated pressure for 2 hours. The pressure must be applied within 1 minute. Subsequently the overpressure shall be reduced to 0.3 bar within 1 minute and maintained at this pressure for 1 hour. No evidence of water intrusion or condensation is allowed.

• For mixed-gas diving the watch has to be immersed in a suitable pressure vessel and subjecting it to 125% of the rated pressure for 15 days in a (helium enriched) breathing gas mix. Subsequently the overpressure shall be reduced to normal pressure within 3 minutes. No evidence of water intrusion, condensation or problems caused by internal overpressure are allowed.
• An optional test originating from the ISO 2281 tests (but not required for obtaining ISO 6425 approval) is exposing the watch to an overpressure of 2 bar, no more than 50 µg/min of air is allowed to get inside the case.

Except the thermal shock resistance test all further ISO 6425 testing should be conducted at 18 °C to 25 °C temperature. The required 125% test pressure provides a safety margin against dynamic pressure increase events, water density variations (seawater is 2 to 5% denser than freshwater) and degradation of the seals.

Movement induced dynamic pressure increase is sometimes the subject of urban myths and marketing arguments for diver's watches with high water resistance ratings. When a diver makes a fast swimming movement of 10 m/s (32.8 ft/s) (the best competitive swimmers and finswimmers can not swim nearly that fast) physics dictates that the diver generates a dynamic pressure of 0.5 bars (50 kPa) or the equivalent of 5 meters of additional water depth.

and

Water resistance classification
Watches are classified by their degree of water resistance, which roughly translates to the following (1 meter ≈ 3.28 feet):[29]

Water resistance rating Suitability Remarks
Water Resistant or 50 m Suitable for swimming, no snorkeling water related work, and fishing. NOT suitable for diving.
Water Resistant 100 m Suitable for recreational surfing, swimming, snorkeling, sailing and water sports. NOT suitable for diving.
Water Resistant 200 m Suitable for professional marine activity and serious surface water sports. Suitable for skin diving only. NOT suitable for scuba diving.
Diver's 100 m Minimum ISO standard (ISO 6425) for scuba diving at depths NOT suitable for saturation diving. Diver's 100 m and 150 m watches are generally old(er) watches.
Diver's 200 m or 300 m Suitable for scuba diving at depths NOT suitable for saturation diving. Typical ratings for contemporary diver's watches.
Diver's 300+ m for mixed-gas diving Suitable for saturation diving (helium enriched environment). Watches designed for mixed-gas diving will have the DIVER’S WATCH L M FOR MIXED-GAS DIVING additional marking to point this out.
Note: The depth specified on the watch dial or case represents the results of tests done in the lab, not in the ocean.[28]

Some watches are rated in bars instead of meters. Since 1 bar is the approximately the pressure exerted by 10 m of water, a rating in bars may be multiplied by 10 to be approximately equal to that based on meters. Therefore, a 20 bar watch is equivalent to a 200-meter watch. Some watches are rated in atmospheres (atm), which are about 1% greater than bars. In the United Kingdom, scuba divers and others often use the word atmosphere interchangeably with bar (1 atm = 1.01325 bar, or 101,325 Pa).

 

Thanks for the informative post!

 

Ya mean like this?

I don't dive, but it times a cook pretty dern good and is a beast at the sink while I do the dishes

 

Great write up about what a diver is. Thank you!

 

Just took the important parts out of the convenient wiki page.

 

Thanks for the writeup guys! Always learning!

 

I don't dive, but it doesn't stop me having three dive watches capable of 300m, 500m and 4000'.
But how many still dive with just a dive watch rather than a dive computer( that costs a fraction of the cost)?
And of those, who regularly dives more than 40m let alone 300m?

 

Common sense says that if you are a diver of any sort, and you use the watch to dive with, and it performs its functions properly, it is a DIVER's watch. The rest of this is silliness unless your profession requires certain specifications. It is a rare individual who does saturation diving. It is a rare individual who requires an all wheel drive Porsche SUV to do the Pike's Peak Hill Climb. Some people just like a Porsche but can only own one at a time and need to go to Lowe's and the grocery store for stuff. Some people (like me) just like the implied toughness of a watch made for some unusually extreme conditions. Who cares what ISO, LMNOP stuff has been written as a standard? My Longines Hydroconquest will see MUCH more water of all varieties than my Seamaster Pro DIVER's Chronograph. The Omega costs too much to beat up and the Longines is my tough little tank (submarine? ;-)). BTW the 300m Chronograph comes with pushers that work underwater and don't screw down. See manual.