IWC Schaffhausen

Dear friends,

before couple of days I had a disagreement with a friend of mine about the need or not of the helium valve on a diving watch.
He explained to me that without it, an irreparable damage could occur in a watch during decompression procedure.
If this is true, why IWC don't have something like this on AT or DeeptTwo models?

Best regards
Dimitris
dpsaromialos@gmail.com

Last edited: 6 May, 2013 - 13:26

interesting question, as a diver I would like to know too.

Based on what I have found and asked and have answered, there are two situations, whether the watch and diver is inside or outside a helium-saturated environment. a helium-saturated environment contains helium because divers are breathing a gas mix like trimix, which contains helium or hydrogen. at deep depths/under pressure, it is fatal to breathe pure oxygen.

When the diver and watch are inside such an environment - such as a dry dive suit (which covers & seals your watch within the suit), or deep sea exploration made possible with the use of diving bells or other vessels - the helium may seep inside the watch, and when the diving bell or vessel is brought to the surface, the helium may not seep fast enough out of the watch - so the helium release valve is used. The valve releases the helium, hydrogen and/or other gases used in the breathing gas mix trapped inside the watch case.

But for most divers who wear the watch on our wrist and enter the sea without such aids (dry dive suit/vessel), a helium valve is not necessary, as the watch is not in any environment that contains helium or other gases - its in sea water. The casing need only be strong enough to withstand the pressure.

Also, if in a dry dive suit, decompression safety stops are done during your ascent (for me that would mean 3 minutes every 5 metres of ascent), generally the helium would be able to escape sufficiently. But with a dry dive suit alone (without a vessel), you would not be able to spend enough hours underwater long enough for the helium built up to be significant that a release valve is necessary. I don't have the exact numbers but infer from information seen that you would have to descend to depths of 300m (in other words spend a really long time underwater, days perhaps) in order to be breathing enough helium to require a valve - in which case the sensible (perhaps only)thing to do is to use an exploration vessel.

This being the case, I infer that the rarity of any of us using the watch in an exploration vessel would have led to the design decision not to include the helium valve gauge.

That, at least, is my guess and understanding. Please correct me if I am wrong.

Regards, Shing | email iwcforme1976 (at) gmail (dot) com
time does not change us. it just unfolds us. max frisch.
all that really belongs to us is time; even he who has nothing else has that. baltasar gracian.

Last edited: 8 December, 2012 - 16:07

I know also that for all active AT collections save the AT 2000, the maximum depth is 12 bar = 80 metres.

AT 2000 can withstand pressure up to 1333 metres (200 bar). This would be the question mark for me, based on what I have written above, on why the AT 2000 would not require a helium valve - because at this depth you probably would.

Alternatively, it could also mean that the deep diver with the AT 2000 simply needs to ensure that the helium escapes during the ascent.

Regards, Shing | email iwcforme1976 (at) gmail (dot) com
time does not change us. it just unfolds us. max frisch.
all that really belongs to us is time; even he who has nothing else has that. baltasar gracian.

Last edited: 8 December, 2012 - 16:07

Dmitiris,

This issue has been discussed before, and there should be much in the archives.

But if I recall a helium valve is only needed in saturation diving, which involves depths that not amateur would ever attempt. For all recreational diving, a helium valve isn't necessary (which is why only one major Swiss watch company uses one on only one of its models, and not even their most famous diving watch).

Regards, Michael
mfriedberg@iwcforum.com

Last edited: 5 April, 2012 - 19:53

Thanks Michael, yes the archives should have been my first port of call.

Interesting discussions. Many links further from these archived threads are no longer available, although these two discussions are to me very insightful.

Suffice to say:

a) this discussion & issue is for most intents and purposes purely theoretical, as Michael rightly pointed out, the typical IWC collector is unlikely ever to dive to depths so deep as to necessitate long stays in a helium/mixed gas-saturated environment - which is the only reason why a helium release valve would be necessary; and

b) there doesn't seem to be a consensus as to whether the AT 2000 (which can withstand pressure up to 200 bar so really deep diving), could similarly prevent or handle helium/gas buildup within the watch casing even without a helium release valvue. some say it already can, others disagree. if it can, then may I just add my humble opinion that this for me makes the AT 2000 truly a magnificent watch.

I would absolutely love to hear from commercial divers who have used/tested the AT 2000 to such limits, although I know this is not going to make much practical difference to most forum participants - do feel free to email me privately. A very big thank you in advance from me :)

Regards, Shing | email iwcforme1976 (at) gmail (dot) com
time does not change us. it just unfolds us. max frisch.
all that really belongs to us is time; even he who has nothing else has that. baltasar gracian.

Last edited: 8 December, 2012 - 16:07

Shing,

thank you for your valuable informations. ;-)

Best regards
Dimitris
dpsaromialos@gmail.com

Last edited: 6 May, 2013 - 13:26

Gents, Michael nailed this one SPOT ON !

Whilst I agree with most everything that Shing states here - the key to the whole discussion (and also reflected in Shing's posting" is Saturation Diving as mentioned by MF.

In practice, this means days on-end spent at pressure [ not necessarily in water - the commercial divers enter into underwater chambers/housing via airlocks, in order to sleep, eat, warm up etc. - and do so for practical and economical reasons of having to avoid multiple descents/assents (all which require lengthy and costly sessions in a hypobaric decompression chamber after each accent)].

When conducting this type of commercial diving, the divers are exposed to high levels of helium whereby part or all Nitrogen is removed from the breathing air thereby reducing the risks of a decompression (the Bends) accident. The "thinness" and permeability aspects of the Helium ensures that it reduces the risk of bubble formation - yet, it is exactly this quality of the helium, that as Shing correctly states, causes it to 'leak" under pressure past the normal seals and O rings in the watches - which THEORETICALLY could then cause an issue on surfacing.

In practice, and with recreational scuba diving (Sport Diving, there is no reason whatsoever to have Helium seals on the Aquatimers, and given that the recommended maximum depth for scuba is 30m and the absolute depth limit for SCUBA set by most diving organizations is 40m - all IWC Aquatimers depth ratings are more than sufficient for the job.

Have I taken my AT's deeper than 40m? Yes - but not as part of any scuba recreational dive. And neither should any one not properly trained do so.

Mark Levinsohn
Master Scuba Diver Trainer / Tec Deep Instructor # 933271.

Best regards
Mark

Last edited: 16 April, 2013 - 00:36

Thanks, Mark. That's very helpful. I'm afraid I can't offer your expert perspective since my experience is limited to a swimming pool!

Regards, Michael
mfriedberg@iwcforum.com

Last edited: 5 April, 2012 - 19:53

Thanks Mark. Great visual description of the environment and conditions commercial divers go into - these are true professionals.

Regards, Shing | email iwcforme1976 (at) gmail (dot) com
time does not change us. it just unfolds us. max frisch.
all that really belongs to us is time; even he who has nothing else has that. baltasar gracian.

Last edited: 8 December, 2012 - 16:07