Sorry guys but the table posted by Bareges (except for the ISO references) and Pugster is just way off base. What marius claims is more accurate. ISO standards does not require that a watch have the word "Diver's" written on it, anywhere. If you don't believe me feel free to have a read here (ISO charges for a copy of the standards, but Saudi Arabia adopted the 1996 ISO 6425 standard for divers' watches verbatim):
http://www.saso.org.sa/sasod/ProjectFiles/E2891.PDF
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The following is a composite answer based on my own info and those of others:
For the overwhelming majority of people (with the possible exception of hard hat divers), anything above 150 feet (such as 300m, 600m or 1,000M designations) will only be necessary if you're tying your watch to the OUTSIDE of a deep diving submersible. FYI the world depth record for scuba diving on compressed air is only a little over 300 meters. If you know of any scuba diver who regularly dives on air to 200m who is not confined to a mental institute, I would love to shake his hand (assuming he can still move it). 150m rating is far more than adequate for a dive watch, for the far majority of divers, both professional and recreational.
This whole talk about dynamic pressure because of movement is nonsense. The amount of pressure that you could except on a watch face when moving through water is very small. You might add a few extra psi, but not much more than that. You should be more concerned about dynamic pressure exerted from banging your watch into something. Tha said here are a coule of quotes from a SCWF member called spearfish that shed light on dynamic presure:
spearfish said:
Here is something I read on:
http://www.chronocentric.com/watches/wresist.shtml
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What does "Water Resistant" really mean?
Here's the real scoop: Water resistance of watches is rated based on a laboratory pressure tests comparable to a swimmer or diver sitting still at that pressure level. But many water-based activities involve a lot of movement and other environmental changes. These exceptions to how the watch was rated may challenge or defeat the water protection features of a water resistant watch.
In particular, the water resistance rating of a watch does not take in to account:
* Sudden, rapid, and repeated water pressure changes experienced by the wrist of a surface swimmer. The force of plunging your arm into the water while swimming can for a fraction of a second greatly exceed the static pressures the watch was rated for.
* High water temperatures experienced in a hot tub. Normal diving and water activities are done in temperate to very cold waters--not water exceeding body temperature. Such high temperatures can damage the water protection seals of a watch.
* Sudden changes of temperature experienced going from a hot tub to a cold swimming pool. In diving and swimming, temperature changes are usually fairly gradual. A sudden transition from the 100º F of a hot tub to the 70º F of a cold pool causes a contraction of the rubber seals in a watch--which may allow water to leak in.
* The ability of the watch to STAY water resistant as it ages. The seals that prevent water from entering the watch will weaken and fail with age. For use in water, water resistant watches should be pressure checked every year. The seals should be replaced at least every two or three years.
Even taking a shower or bath with your watch on can be bad for it. Besides the hot water issues already mentioned, many people do not realize that bath soap is a fine level abrasive. Soap can build up in the small, precision joints of the watch bracelet links. Over time this can wear down the link joints, ruining the bracelet. This is a greater issue with softer metals, such as gold. But steel can also be worn down this way too.
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similar information, from:
http://www.europastar.com/europastar/watch...sp#anchor653701
"My watch is labeled "water-resistant to 50 meters" but the manufacturer's instructions say I can only wear it swimming, not snorkeling or diving. Why is that?
The different levels of water resistance as expressed in meters are only theoretical. They refer to the depth at which a watch will keep out water if both watch and the water are perfectly motionless, says Scott Chou, technical director at Seiko Corp. of America. These conditions, of course, are never met in the real swimmer's or diver's world. in real life, the movement of the wearer's arm through the water increases the pressure on the watch dramatically; so it can't be worn to the depths indicated by lab testing machines."
Screw-down crowns on most watches do NOTHING to enhance a watch's crown seal properties (there are a few designs in which the stem seal swells a bit when the crown is pushed in). All the screw down crown does is prevent you from accidentally turning the crown while under water. This is crucial because if you accidentally adjust your time (as unlikely as that sounds) you will screw the time calculations you have timed your bezel to. When a watch is pressure tested it is done with the crown unscrewed.
Helium release valves are also bollocks. They only come into play in SATURATION diving. In other words, if you are planning on being underwater in a helium rich environment, such as a diving bell, for a very extended period of time, then and only then will your watch begin to accumulate helium inside the case. The HRV only comes into play during your ascent. Otherwise, HRV's serve no purpose on a dive watch.
Also watch ratings are not absolute amounts. In a professional dive watch, the depth rating is only a fraction of the watch's true depth performance. Don't quote me on it, but IIRC, the depth rating is usually about 2/3 of what the watch can actually do, before it begins to experience seal failure. IOW's if your watch says 200m rated, it should actually withstand closer to 300m worth of pressure before failing.
As for depth ratings here is a well thought out response posted by a commercial diver in and certified dive master:
Mike said:
The recognized maximum sport diving depth is 132 feet, lets say 130 feet for simplicity sake as it's easy to remember. The U.S Navy is more conservative at 100 feet for sport divers. But let's think this through and try to get some perspective. How long do you think your air supply will last from a standard 80 cubic foot aluminum tank at 130 feet, the short answer is not very long, it'll be in the few minutes maybe few breathes range if you're going for no decompression. You will be cold as you will be below a thermal layer, it will be darker, and there will be less wildlife, you will also be experiencing nitrogen narcosis. All in all, it'll be short, you won't see much, you'll risk getting bent, and it'll be awhile before you can make a repetitive dive. So, unless you have a purpose or are trying to be macho I suppose you can do what you want. Me? I'm staying shallow as a sport diver unless someone is paying me to go deep then it won't be on scuba gear. It'll be surface supplied with communications and a decompression chamber waiting for me topside and my tender will time my ascent. Oh, and I won't be wearing a watch then so it won't matter.
Most sport divers would do well at depths much shallower than 100 feet. In fact, you'd probably have a great dive at 40-60 feet. Lot's of wildlife, easy on your air, make a repetive dives sooner than later, no nitrogen narcosis, above the thermal layer so it's a little warmer .... all good stuff.
I guess what I'm trying to get at in a very round about way is ....... your watch can go deeper than you can. If they were only ever rated at 50 meters and had screw down stems most sport divers would be fine.
Enjoy your watches because you like them and don't caught up in "my watch can go deeper than your watch". Buy based on what you want or need and enjoy.
My opinion for what it's worth.
Mike
Lastly here is a quote on depth ratings and scuba from the Open Water Sport Diver Manual:
Beyond 100 feet, nitrogen narcosis can affect your ability to think and make judgments; at 150 feet, you may become somewhat dizzy. Between 200 and 250 feet, you may be unable to communicate or perform simple motor or mental tasks, and below 250 feet, the average diver is more or less useless and becomes a safety menace to himself and others.
So to recap:
- ratings whether in bars, water resist, or otherwise, when listed in a watch produced by a major manufacturer, are designed to have the seals keep out water to a minimum of the stated static presure.
- What keeps water out of your watch are the rubber seals around case-entry points, not anything else. Seals can and do deteriorate over time and should be replaced whenever a watch is serviced. Things such as excessive heat/cold, solvents or detergents can speed the deterioration of rubber seals.
- A proffesional dive watch must be rated to ISO standards, which include dynamic performance as well as static. ISO standards used to be 150m (what do you think all those vintage seiko dive watches were for) but were revised upward in the mid 90's to 200m.
- Humans can only dive on compressed air (scuba), with reasonable safety to about 130 feet (not meters). Much beyond, whle possible, and you face decompression and risk injury or serious complications.
Take care of your watches sure, but for the most part, most modern watches will be able to withstand splashes and the occasional immersion without any ill effect, provided everything is in working order.
