I heard that rebreather technology comes to commercial diving industry from 2018. I was preparing to join in a commercial diving school in UK. May I know the truth about above. If like that how it will affect new divers ?
Rebreather in Commercial Diving
- Thread starter Swaroop
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Scuba is scuba. My commercial dive plan makes no distinction as to method of scuba....
The Divex SLS bailout system for saturation divers is basically a rebreather. I doubt Scuba-style rebreathers will ever replace surface-based closed-circuit breathing gas reclaim systems.
And one more thing which I heard is now the catogories are 1.pro divers, 2. Tenders 3.navy divers this also going to change as 1.pro 2.navy 3.tenders, and it will be a difficulty to get a new job for new divers. Please get me out of this. !
Your comment on hot water couldn't be more true and more important than most Scubaboard members can appreciate. In reality, the cost of a rebreather is cheap compared to a surface based recycling system. The limitations are reliability, WOB (Work of Breathing), backup systems, and their back is full of bailout gear.
Larger saturation diving operations have at least two diver's gas recycling systems. Usually one for each bell plus a spare (or more) -- Helium is expensive but the day rate on a DSV (Diving Support Vessel) is even more so reliability is worth a LOT of money. One or more technicians manage the process of separating moisture, scrubbing the CO2, replenishing the O2, and pumping the gas back into tube-trailer size gas banks. That lets the diver(s) keep working even if the system goes down for an hour. It also provides huge time margins for analysis and mix correction in case of system problems.
Divers wear hats like this: Divex Ultrajewel 601 Helium Reclaim Helmet
The system on the surface looks something like this: JFD's Divex Gasmizer diver gas recovery system
6 MILLION hours of safe diver operation. That's crazy awesome!
With a record like that, why bother with anything else..... A bail out rebreather makes sense, but I don't see a reason why you would want to operate full time on a rebreather. Too many cons for seemingly zero pros.
With a record like that, why bother with anything else..... A bail out rebreather makes sense, but I don't see a reason why you would want to operate full time on a rebreather. Too many cons for seemingly zero pros.
True, but it isn't a no-brainer. These guys work in very tight and harsh conditions. Who knows what kind of beating their bailout-rebreather will take before they actually need it? Personally I would take an open-circuit bailout down to the 600'/200M range over an Divex SLS bailout any day. The chances of a gas supply failure and not a simultaneous hot water failure is pretty low. It is questionable how long you can keep conscious without hot water and open circuit is relatively super-reliable. I have never heard of a case where a diver didn't make it back to the bell on bailout.
There was a case of a diver's umbilical being severed and it took 45 minutes to get back to him. He was recovered and, as I understand it, had a nearly full bailout. Apparently he passed out from hypothermia very quickly. The amazing part is he recovered soon after he was brought back to the bell and hot water was poured on him.
Heliumthief
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Rebreathers are almost wholly used in Saturation Diving commercially as a bailout which can provide more in reserve than conventional twin-sets. There was a lot of research done when Statoil collaborated with DOF and Technip on the Skandi Arctic, with a variety of concepts researched, such as a rebreather as primary gas supply with Bell onboard as backup, electric undersuits, and 4 man bellruns to name a few, but none of these were taken forward to the build stage.
I don’t have the numbers to hand, but in certain regions of the world, there are regulations governing minimum gas volume in a bailout at a given depth, excursion umbilical lengths and respiratory rates. In essence, the regs state you must have 3 minutes worth of gas in your bailout. On a relatively shallow. Sat, say 50m, twinsets blown to 300ba would enable you to work safely at the end of a 70m umbilical, but at 200m, say, the umbilical length would have to be restricted severely, the bailout would have to have more gas, or rebreathers have to be used to get the requisite bailout endurance.
In practice, a twin set is considerably cheaper than Rebreathers, and they are only used when regulations, depths and excursion lengths dictate.
The only other current use for rebreathers commercially is media and scientific divers, where the exhaust bubbles of scuba or open circuit SSDE would disturb the work
I don’t have the numbers to hand, but in certain regions of the world, there are regulations governing minimum gas volume in a bailout at a given depth, excursion umbilical lengths and respiratory rates. In essence, the regs state you must have 3 minutes worth of gas in your bailout. On a relatively shallow. Sat, say 50m, twinsets blown to 300ba would enable you to work safely at the end of a 70m umbilical, but at 200m, say, the umbilical length would have to be restricted severely, the bailout would have to have more gas, or rebreathers have to be used to get the requisite bailout endurance.
In practice, a twin set is considerably cheaper than Rebreathers, and they are only used when regulations, depths and excursion lengths dictate.
The only other current use for rebreathers commercially is media and scientific divers, where the exhaust bubbles of scuba or open circuit SSDE would disturb the work
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