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Dive Watches in Depth: A Dive Watch FAQ | Features

We reply your FAQs about water resistance, dive bezels, depth gauges, and extra about divers’ watches on this function from the Options archives.

How waterproof ought to a dive watch be?
Some producers say that their watches with a water-resistance ranking of 300 meters or extra are appropriate for leisure scuba diving. Others say the watch want have a ranking of simply 200     meters; nonetheless others say it may be 200 meters so long as it’s particularly labeled as a dive watch. The Worldwide Requirements Group (ISO), then again, stipulates {that a} dive watch have to be waterproof to 100 meters.

All these depth scores are considerably increased (or decrease, if you’ll) than the depths to which a non-professional diver can dive. Leisure divers don’t go deeper than 40 meters (130 ft). Past that, they enter the realm of technical diving, which requires in depth coaching, particular combined gases to breathe, lengthy decompression stops and particular tools.

The rationale for the discrepancy: when examined for water resistance within the manufacturing facility, the watch is in a man-made atmosphere that’s a lot totally different from what the watch will face throughout an precise dive. For the take a look at, the watch is completely stationary, the gaskets model new, and the case newly assembled, in order that nothing will compromise its water resistance. The testing equipment doesn’t account for such phenomena as extra strain from the impression of the wearer’s leaping or diving into the water; or for temperature and strain adjustments because the diver ascends and descends, which may trigger the case to shrink or increase. Moreover, a watch’s water resistance will probably be lessened by growing older of the watch’s gaskets. Knocks and different tough remedy may cause the case’s parts to suit collectively much less tightly than they did when the watch was model new. All these imponderables trigger the businesses to supply a slightly massive cushion of security in order that clients won’t maintain them accountable if their watches leak.

Rolex Triplock crown

A screw-in crown is important to a watch’s water resistance.

What options make a watch impermeable sufficient for diving?
A number of options are required to make a watch impermeable sufficient to put on diving. In practically all dive watches, the case has a screw-in again and crown. O-rings are used to seal the crown, caseback and crystal. The case and crystal are thicker than in a non-dive watch. Watches designed for very deep diving usually have extra pressure-defying options corresponding to domed crystals, or a metal ring for reinforcing the case (as on the Rolex Deepsea).

What are the opposite options of a dive watch?
Most dive watches have a rotating bezel for measuring elapsed time. Additionally they have luminous arms and markers that may be learn underwater. ISO customary 6425 requires a dive watch to have a “time-preselecting gadget” (a rotating bezel satisfies this requirement) and a dial that may be learn at the hours of darkness at a distance of 25 cm. The ISO additionally says the watch will need to have an indicator that exhibits at a look if the watch continues to be working. A seconds hand satisfies this requirement. Most dive watches have a metal or titanium bracelet or rubber strap, though some straps are manufactured from nylon or numerous composite supplies. Some dive bracelets and straps are outfitted with an extension gadget that  allows the watch to suit over a dive-suit sleeve. Some dive watches have a helium valve and/or a depth sensor.

Rolex bracelet buckle

A bracelet with a divers’ extension could be lengthened to suit over a wetsuit.

What’s a helium valve?
A tool for equalizing the strain inside and out of doors the watch case when the watch is worn in a diving chamber. Contained in the chamber, divers breathe a gasoline combination that incorporates helium. The helium molecules are extraordinarily small and are therefore in a position to penetrate the watch case, build up inside it. Within the strategy of decompression, the strain contained in the chamber decreases extra quickly than the strain contained in the case. This may trigger the watch crystal to pop off. To stop that, some watches have a valve on the aspect of the case that permits helium to flee from the case throughout decompression, making the strain inside and out of doors the case the identical.

Do many dive watches have helium valves?
Most dive watches wouldn’t have helium valves as a result of they’re of use solely in saturation diving, when a diver spends time in a diving chamber.

Rolex helium valve

A helium valve prevents the watch crystal from popping off when the diver is in a decompression chamber.

Why do the rotating bezels on most dive watches flip in just one path?
Most dive bezels flip in a single path solely, counterclockwise, in order that the bezel can’t be by accident knocked off place within the clockwise path and thus understate the elapsed time (often the whole dive time) being measured. Some watches clear up this drawback through the use of internal rotating bezels that can not be rotated by accident.

Many bezels have solely the primary quarter-hour marked individually. Why?
This can be a dive-watch conference that goes again to the mid-Nineteen Fifties (it in all probability began with the Rolex Submariner). It’s unclear what function the markers have been initially meant to serve. An early Submariner commercial exhibits a diver setting the bezel to measure complete dive time, then utilizing the minutes markers for a exact studying of his descent time. Why this data is beneficial just isn’t defined (and customary diving procedures don’t require it).

An oft-tendered clarification for the markers is that they’re used to time decompression stops, however this clarification is problematic. The diver must reset the bezel firstly of every cease. The bezel couldn’t due to this fact be used to measure complete dive time, the principle function of the bezel.

One attainable clarification for the markers: quarter-hour is the approximate period of time a diver can spend at 130 ft, the utmost depth for leisure diving, with out making decompression stops. The markers might need been meant to alert him to that restrict and assist him learn his remaining backside time exactly. This idea is supported by some variations of the Omega Seamaster, which had gradations for the primary 20 minutes (a diver can spend about 20 minutes at 110 ft, near the depth restrict). On the Seamaster 200, the 20-minute phase was painted fire-engine pink, presumably to warn the diver of the hazard of staying deep for too lengthy.

Tudor Dive Watch

Dive watches have luminous arms and markers that may be learn below water.

How do depth-gauge watches work?
In most, there’s a sensor (sometimes a membrane or diaphragm) on the aspect of the case that’s distorted by water strain. The diploma of distortion is then transformed into ft or meters of depth and displayed by arms on the watch face. Oris, in its Aquis mannequin, makes use of one other sort of depth gauge: it has a tubule across the perimeter of the crystal with a tiny opening to the surface. Roughly water enters the tubule, relying on the depth, and the diver can learn the depth in meters on the size subsequent to the tubule.

What number of mechanical dive watches have depth gauges?
Only a handful. Other than the aforementioned Oris Aquis Depth Gauge, different mechanical watches with depth gauges embrace the Blancpain X Fathoms, the IWC Aquatimer Deep Three, the Jaeger-LeCoultre Grasp Compressor Diving Professional Geographic and the Panerai Luminor 1950 Pangaea Depth Gauge (which  regardless of its mechanical motion has an digital depth gauge).

Some watch depth gauges report the deepest level of a dive. Why?
There are three causes. First, for security’s sake, the dive-time limits prescribed by dive tables assume the diver spends his whole dive time on the deepest level of the dive. To make use of the dive desk, the  diver should due to this fact know his deepest level. Second, it’s a usually accepted rule of diving that the diver ought to do the deepest a part of the dive first. This provides him the utmost period of time to off-gas the comparatively excessive quantity of nitrogen he absorbed on the backside of the dive (the decrease you go, the extra nitrogen dissolves in your blood). Third, many diving specialists advocate that, even in no-decompression diving, which doesn’t require decompression stops, the diver make a so-called “security” cease of 1 minute midway between the bottom level of the dive and the floor in an effort to off-gas nitrogen.

IWC Aquatimer Deep Three

A handful of mechanical dive watches, just like the IWC Aquatimer Deep Three (above) and Blancpain X Fathoms (under), provide a particular additional function: a depth gauge.

Blancpain X Fathoms

Which mechanical watch has the deepest water-resistance ranking?
The CX Swiss Navy 20,000 ft. The watch, manufactured from titanium, is almost 3 cm thick; the crystal alone is 1 cm thick.

On this age of dive computer systems, are dive watches vital?
Probably not. Divers generally take them as backups to their dive computer systems, ought to the computer systems run out of energy throughout a dive, however now that wrist-worn dive computer systems are extensively accessible and fairly priced, some divers use these as backups to their console-style computer systems (or put on two wristwatch-style computer systems). If a diver does use a watch as a backup, he additionally wants different backup tools that provides data  given by a dive laptop: a depth gauge, strain gauge and dive tables.

Then why achieve this many individuals purchase dive watches?
For a number of causes. Many individuals just like the sense of safety {that a} excessive water-resistance ranking offers. If a watch is protected to put on on a deep dive, they purpose, absolutely it’s assured to outlive a swim or a snorkeling tour. Others like a dive watch’s different options, corresponding to a rotating bezel or extremely luminous arms and markers. For a lot of dive-watch wearers, seems to be are the principle draw: sporty, technical-looking watches are all the fashion.

Luminous Dive Watch

Dive watches have luminous arms and markers that may be learn below water.

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