And, just to make sure it is clear what DIR-Atlanta is saying. Steel bottles are only every DIR appropriate as an oxygen bottle for cave dives where the bottle is being immediately dropped at 20' and not carried on any portion of the dive. In this application, they work great. Particularly on dives with lengthy portions of the deco on oxygen. Having said that, for the vast majority of cave dives, an AL40 is all that is needed for O2 and is much easier to deal with.
DIR/GUE - No steel stage bottles
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DIR-Atlanta
Contributor
Thanks for the clarification - as I have stated in the past, I don't do any ocean deco diving to speak of, and my comments were directed specifically at cave diving, where the deco bottles would be dropped early.
When I first started cave diving, I was using a steel 72 as an O2 bottle because I could fill it once and use it for a whole weekend. Carrying it underwater was a nightmare though (a cinder block would have been more manageable!), and I was always glad to get rid of it at 20 feet on the way in. I find the 40s to be much easier to handle for most recreational cave profiles. Even with unboosted O2, a single 40 will provide enough deco gas for a decent bottom time, and you can always bring extra bottles if you are planning multiple dives.
So yeh - what RTodd said.
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Since the cave angle has been answered...
In the ocean you "could" use 2x lp45s for up to ~220ft dives/60mins total deco. But beyond that, with 3 bottles, rotating them would really suck since they are heavy. Regarding the weight, we don't weight ourselves including heavy bottles (in case we need to remove or rotate a bottle). So wearing steel deco bottles with enough weight to stay down with empty doubles starts to be ALOT of weight. Like 80+lb wing and that's a large bubble to shrink and swell with depth. Even in salt water they hang below the plane of the body and can snag stuff. Basically it comes down to steel stages creating some (perhaps not insurmountable) problems but solving none.
In the ocean you "could" use 2x lp45s for up to ~220ft dives/60mins total deco. But beyond that, with 3 bottles, rotating them would really suck since they are heavy. Regarding the weight, we don't weight ourselves including heavy bottles (in case we need to remove or rotate a bottle). So wearing steel deco bottles with enough weight to stay down with empty doubles starts to be ALOT of weight. Like 80+lb wing and that's a large bubble to shrink and swell with depth. Even in salt water they hang below the plane of the body and can snag stuff. Basically it comes down to steel stages creating some (perhaps not insurmountable) problems but solving none.
Everyone:
Thanks for the insights. Right now I'm using a single Steel 40 for deco in the open ocean. I couple it close to my body and have never noticed it hanging or impeding movement. But I'll start watching more carefully.
I clearly understand the weight problem with multiple bottles. I'm just not there yet.
Thanks to everyone.
PS> Great forum-Although I haven't (and probably will not) adopt a strict DIR approach, I've gained a lot of insight in this forum to use in my rig/diving and I appreciate it.
Thanks for the insights. Right now I'm using a single Steel 40 for deco in the open ocean. I couple it close to my body and have never noticed it hanging or impeding movement. But I'll start watching more carefully.
I clearly understand the weight problem with multiple bottles. I'm just not there yet.
Thanks to everyone.
PS> Great forum-Although I haven't (and probably will not) adopt a strict DIR approach, I've gained a lot of insight in this forum to use in my rig/diving and I appreciate it.
rainman_02
Contributor
Just remember...the system is a whole approach to diving. Just taking bits and pieces you like generally invalidates the reasons behind a lot of the choices.
Yup, I know of at least one set of cave fatalities that was the direct result of people trying to use the portion of DIR/WKPP procedures they liked without actually understanding/ using the whole system. While DIR divers do tend to quibble over the little details, the philosphy and the reason behind doing things the DIR way is really an all or nothing proposition.
While it is possible only using bits and pieces of the DIR approach might make a diver safer, they are more likely to actually create a situation that is less safe. For example, diving multiple steel stages but using a wing designed for a balanced rig.
orange_diver
Contributor
DIR-Atlanta
Contributor
There was fatality at Jackson Blue several years ago where a team of scooter divers silted out the cave and became separated, resulting in one of the divers becoming lost off the main line and running out of air.
My recollection is that one of the contributing factors in that particular incident was that the divers were trying to apply some of the WKPP safety bottle and scootering procedures that they had read about on the Internet, without necessarily having a complete understanding of what to do or how. They had the right idea in that they were actually trying to make their diving "safer" - just did not have the experience to think things all the way through.
I am not sure if RTodd is referring to that one - his response seems to imply a multiple fatality, so I don't know for certain. Perhaps he will elaborate.
Understand. But from my POV much of the DIR is based on doing cave diving. I'm purely open water, so I adapt what makes sense for me (after talking with folks much more experienced that I).
For example, and I know this is heresy in this forum, I choose to put my long hose on my octo. In an emergency, I don't want to have to take my primary out of my mouth. That's just one more step that could go wrong. If the distressed diver pulls it out of my mouth, I'll deal with it and just go to my octo. But I don't see a reason that I need to add another step in a crisis. Hopefully if I'm doing my job as a buddy, I'll see it coming and be ready to shove the octo into his/her mouth as I'm approached.
Many of the gear concepts are great along with the minimalist approach and the general philosophy of safety first and forement. These I buy into completely. I believe that an open ocean diver can learn a lot from DIR, but it takes a filter. If I were diving in overhead, I'd look at it differently.
Thanks again for the insights.
PS> I've driven nuclear submarines for a living so I understand the value of redundacy, safety and training.
I said almost the exact same thing several years ago. Once I started really trying to understand it, it made more and more sense, and I become more and more aligned with what their standard approaches.
Just focus on understanding the WHYs of the decisions, and you can find ways of applying them to the type of diving you do in a safe manner.
Tom
BTW, a long hose on the backup is definitely _NOT_ DIR. In fact, I would highly question the need/wisdom for a 7' octo in an OW rig. Between two properly trained divers with good buoyancy, a long hose makes air shares easier, especially while swimming. Between those with poor control, it can just give you more room to accelerate before the reg is pulled from the OOA Diver's mouth.
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