Helium Release?
Discussion
bikemonster said:
So, thanks to the contributors to this thread, I now understand that the helium release valve is only necessary on watches which are used in a DRY submarine environment.
If you mean a regular SUBMARINE, the answer is incorrect. Submarines are at ambient pressure, ie same as where you are sitting now, unless you are in a pressurised chamber of course. But guess you may have gleened that from the other responses on this one.
Vipers, by dry submarine environment, I meant an environment that is beneath the surface of the briny but not in the water.
In a wet submarine environment (as in, within a submarine that was full of water), I don't think anybody would be too fussed about the depth rating of their watch, or whether it had a helium release valve!
In a wet submarine environment (as in, within a submarine that was full of water), I don't think anybody would be too fussed about the depth rating of their watch, or whether it had a helium release valve!
Vipers said:
andy_s said:
In technical sports diving you can go deep if you're breathing mixed gases and not just air. In sport diving you'd go and do the dive and decompress on the way up to the surface rather than live in a bell for 4 weeks. This means although you are breathing mix, the watch is just subjected to the ambient water pressure and not gas under pressure - if that makes sense?
Yes of course Andy, that makes sense, saw some good footage recently on Sky, some fish scientiest swimming around 100 msw on various gas's looking for specises of fish, commercially we are governmed by UK legislation, and restricted to 50 msw max on air, and we have to use a diving bell below this depth. But I still don't know why Rolex bothered with their need for a super dooper watch rated to 3900 msw???? bit like making a road car which will do about 900 mph.Edited by Vipers on Monday 25th May 11:16
When my Father was diving in the 60s most of their group turned commercial. Most of those that did now have joints and bones that are knackered. From what I understand, standards were less rigorous back in the day.
Re the 3900msw, I'm guessing because the ISO is a static pressure test at a constant ambient temp. Commercial diving is dynamic by nature - simply banging your wrist against the leg of a rig or a subsea pipeline will alter the pressure inside the watch case. In addition, prolonged underwater welding can create localised heating which again raises pressure within the casing. Also because they can is a good excuse.
What I find amusing are the oil filled diving watches which are rated to stupid depths like 15000m
bikemonster said:
Vipers, by dry submarine environment, I meant an environment that is beneath the surface of the briny but not in the water.
In a wet submarine environment (as in, within a submarine that was full of water), I don't think anybody would be too fussed about the depth rating of their watch, or whether it had a helium release valve!
Guess we are using different terminology here, sumbarines are long pressurised objects at 1 atmospheric pressure, with men inside them, and nip around the globe underwater.In a wet submarine environment (as in, within a submarine that was full of water), I don't think anybody would be too fussed about the depth rating of their watch, or whether it had a helium release valve!
A wet submarine to which you relate to being a submarine full of water, has obviously sunk? wondering if you mean a "Habitat", which is an enclosure around an underwater object, ie pipe line, and as atmosphere is pumped in, the water gets pushed out, hense a dry environment albeit at the same pressure as the sourounding sea, and no worries, I think we all know what these helium relief valves do not.
rhinochopig said:
Vipers said:
andy_s said:
In technical sports diving
bit like making a road car which will do about 900 mph.What I find amusing are the oil filled diving watches which are rated to stupid depths like 15000m
The oil filled ones can be rated deep as you like - for the case. After 5,000m though the quartz movement is compromised and fails, so keep an eye on your depth gauge...
ETA - the dry submarine example above - in a normal submarine you're protected from the pressures by the hull so it's normal atmospheric pressure (or thereabouts?) so you don't need the valve. In a bell you are pressurized up to the same pressure as the water outside at the depth you are working - you could use the helium valve when you were repressurized back to normal pressure (at the end of your 28days). A wet submarine is called a wreck, and you just need a normal divers watch!
Edited by andy_s on Monday 25th May 15:26
Vipers said:
jshell said:
North Sea divers tend to live in a Helium rich environment (up to 96%) for up to 28 days at up to around 13bar. During that time the very small helium molecules can penetrate the watch seals (where water cannot) and raise the watch internal pressure to ambient (13 bar). Decompression takes a relatively shorter time, so the watch doesn't have time for the Helium to find it's way out past the seals so there is a potential for a 10+ bar overpressure of the watch at the end of the trip. The helium valve allows a quick depressurisation as ambient pressure drops.
At last a sensible response. I couldn't work out the early Sub Mariners (Rolex), rated to 300 msw DIDNT HAVE A HELIUM RELIEF VALVE, and a diver at depths over 50 msw (Commercially) can only be in an Helium environment. Nice to see the latest Rolex is rated to something like 12,000 fsw, maybe no one has told Rolex how deep man can go.Wika post is slightly incorrect, divers dont spend hours in diving bells, a bell run in UK is 8 hours seal to seal, but they do spend up to 28 days in a saturation chamber breathing an O2/He mix. Splitting hairs I know.
For those interested, 13 bars is 130 msw - 426 fsw in old money, and decompression is around 4.8 days.
Edited by Vipers on Monday 25th May 10:11
We've probably been on some of the same vessels working with the same divers..... 
Though I'm all ROV's at 1,500m in warmer climes now!off topic, but is it true that the north sea commercial divers earn probably the highest £/hour of anyone outside maybe professional footballers, the top of the top investors and shieks etc?
My folks used to know one when I was a kid in the 80s, I seem to remember he was only allowed to do about 40 hours work per year by law, and was paid a huge amount of cash.
I guess the downside is the fact that unless you are very careful you end up very dead. And that you spend a lot of time in a decompression chamber looking like the worlds crappest astronaut.
My folks used to know one when I was a kid in the 80s, I seem to remember he was only allowed to do about 40 hours work per year by law, and was paid a huge amount of cash.
I guess the downside is the fact that unless you are very careful you end up very dead. And that you spend a lot of time in a decompression chamber looking like the worlds crappest astronaut.
Wadeski said:
off topic, but is it true that the north sea commercial divers earn probably the highest £/hour of anyone outside maybe professional footballers, the top of the top investors and shieks etc?
My folks used to know one when I was a kid in the 80s, I seem to remember he was only allowed to do about 40 hours work per year by law, and was paid a huge amount of cash.
I guess the downside is the fact that unless you are very careful you end up very dead. And that you spend a lot of time in a decompression chamber looking like the worlds crappest astronaut.
Most are lazy buggers and 40 hours sounds about right, joking aside, god knows where the 40 hours comes from. They work shifts just as same as everyone else offshore. I am not about to flaunt the pay, but they get a daily allowance just the same as everyone else, but are paid extra per hour in saturation. They normally do 28 days in sat, then go home, in Norway its only 21 days offshore.My folks used to know one when I was a kid in the 80s, I seem to remember he was only allowed to do about 40 hours work per year by law, and was paid a huge amount of cash.
I guess the downside is the fact that unless you are very careful you end up very dead. And that you spend a lot of time in a decompression chamber looking like the worlds crappest astronaut.
Its very demanding work, getting qualified means the guy taking an air diving course for £9,000, then find work, after the required surface dives, he can attend a Bell Divers Training Course, paid by him again, around £18,000, and has to hope he can find work to pay it back even before he starts to earn money to keep. Not many jobs around mean the guy paying £30,000 for the priviledge of having a "Chance" to find a good paid job.
Then for all his hard work, he finds himself in the 40% tax bracket, not being content in being away from the family for weeks on end (Overseas, its not unusual to be away for 60 days), and living in a small chamber, the tax man cons him for 40% of what he works. Oh and he has to pay for an offshore survival certificate, almost a grand, plus an offshore medical, plus be trained as a paramedic. And all after this, if he finds a regular slot offshore, he is lucky, most work on a day rate basis, no pension schemes either for them, down to them to arrange it.
On the dead side, no, diving in the UK is probably one of the safest occupations around, we have come along way since the early days of offshore.
At the end of the day, YES they earn good money, and deserve every penny they get, (Unlike the conning barstewards MP's), they don't swan around like footballers, they go to work in a diving bell, get suited up, lock out of the bell at up to 200 msw, and work bloody hard for 6 hours.
One last thing, the medical fraternity still don't know what long term diving under saturation conditions do to your body. But at the end of the day, its good money, but they work hard to get to the position to be able to work for it,.
Edited by Vipers on Tuesday 26th May 09:30
Vipers said:
Wadeski said:
off topic, but is it true that the north sea commercial divers earn probably the highest £/hour of anyone outside maybe professional footballers, the top of the top investors and shieks etc?
My folks used to know one when I was a kid in the 80s, I seem to remember he was only allowed to do about 40 hours work per year by law, and was paid a huge amount of cash.
I guess the downside is the fact that unless you are very careful you end up very dead. And that you spend a lot of time in a decompression chamber looking like the worlds crappest astronaut.
Most are lazy buggers and 40 hours sounds about right, joking aside, god knows where the 40 hours comes from. They work shifts just as same as everyone else offshore. I am not about to flaunt the pay, but they get a daily allowance just the same as everyone else, but are paid extra per hour in saturation. They normally do 28 days in sat, then go home, in Norway its only 21 days offshore.My folks used to know one when I was a kid in the 80s, I seem to remember he was only allowed to do about 40 hours work per year by law, and was paid a huge amount of cash.
I guess the downside is the fact that unless you are very careful you end up very dead. And that you spend a lot of time in a decompression chamber looking like the worlds crappest astronaut.
Its very demanding work, getting qualified means the guy taking an air diving course for £9,000, then find work, after the required surface dives, he can attend a Bell Divers Training Course, paid by him again, around £18,000, and has to hope he can find work to pay it back even before he starts to earn money to keep. Not many jobs around mean the guy paying £30,000 for the priviledge of having a "Chance" to find a good paid job.
Then for all his hard work, he finds himself in the 40% tax bracket, not being content in being away from the family for weeks on end (Overseas, its not unusual to be away for 60 days), and living in a small chamber, the tax man cons him for 40% of what he works. Oh and he has to pay for an offshore survival certificate, almost a grand, plus an offshore medical, plus be trained as a paramedic. And all after this, if he finds a regular slot offshore, he is lucky, most work on a day rate basis, no pension schemes either for them, down to them to arrange it.
On the dead side, no, diving in the UK is probably one of the safest occupations around, we have come along way since the early days of offshore.
At the end of the day, YES they earn good money, and deserve every penny they get, (Unlike the conning barstewards MP's), they don't swan around like footballers, they go to work in a diving bell, get suited up, lock out of the bell at up to 200 msw, and work bloody hard for 6 hours.
One last thing, the medical fraternity still don't know what long term diving under saturation conditions do to your body. But at the end of the day, its good money, but they work hard to get to the position to be able to work for it,.
Edited by Vipers on Tuesday 26th May 09:30
rhinochopig said:
Is bone necrosis still an issue, or have modern decomp regimes largely removed this risk?
As far as I know, bone necrosis was associated with deep AIR dives, and affected some R.N. divers. We used to open water dive on air to 75 msw, and do a weekly chamber air dive to 100 msw, talk about narked up, like a bunch of school girls all giggling and laughing at the slightest thing.Commercially we are governed to 50 msw on air, due to nartrogen narcosis, as pointed out earlier, and to be honest, in the UK, not much air diving takes place on a regular basis much deeper than 30 msw.
I have been in diving business since 1969, (RN days), and commercially since 1975, I personally don't know of anyone having bone necrosis, but I am sure it is still around, albeit in a minority of people.
Vipers said:
rhinochopig said:
Is bone necrosis still an issue, or have modern decomp regimes largely removed this risk?
As far as I know, bone necrosis was associated with deep AIR dives, and affected some R.N. divers. We used to open water dive on air to 75 msw, and do a weekly chamber air dive to 100 msw, talk about narked up, like a bunch of school girls all giggling and laughing at the slightest thing.Commercially we are governed to 50 msw on air, due to nartrogen narcosis, as pointed out earlier, and to be honest, in the UK, not much air diving takes place on a regular basis much deeper than 30 msw.
I have been in diving business since 1969, (RN days), and commercially since 1975, I personally don't know of anyone having bone necrosis, but I am sure it is still around, albeit in a minority of people.
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