Posted by Kendall Raine on March 16, 2001 at 13:06:06:
In Reply to: Re: Getting a second chance......Totally wrong posted by kelphead on March 15, 2001 at 18:03:08:
Well, I guess we'll just have to disagree on what DIR is and how it functions.
The irony is you seem to have a definite opinion on how and when the concept works without really understanding it or practicing it. I'm the opposite. I understand it, practice it, and so see the nuances. To me, it's not binary. It's asymptotic. DIR is a philosophy and set of principles for which to strive. The striving is more important than the arriving at the end point.
Your remark about eating and sleeping with your team mates highlights this distinction. Here again, I think you've got it backwards. For example, if my team mates are committed to DIR philosophically and gear wise, there is much less I need to discuss before the dive. I can show up, and have, and confidently dive with people I've never met before if they dive DIR. I know how they're rigged, their commitment to the team concept and how they'll deal, at least theoretically, with a problem. If they don't, I need to familiarize myself with their gear, their attitude, procedures, etc. If any of these are screwed up, it could become an issue for me on the dive. Hence, I'm actually less dependent on having a fixed group of people to dive with since, under DIR, they're somewhat interchangeable.
As for not diving with a pony, you're right. I didn't explain why DIR excludes pony's. Let me take a crack at this. First, though, I'm not telling you how you should dive or do anything else. I don't care. I'm simply trying to explain the logic. Let's agree on terms. A pony is an extra cylinder secured to your primary tank and has it's own first and second stage.
A pony as a redundant gas source has no real value if you're diving a set of doubles with an isolator manifold.
If you're diving a single, a pony offers certain things but costs you in other ways. Yes, you get the advantage of another first stage and another bottle so that if you lose the primary first stage or blow a neck o ring, you've got a bail out. You also have more gas. You also have the ability to use two different mixes. Those are all good things. However, a small pony, 6 cu. ft. has so little in it that you may create a false sense of security from having it. It definitely won't do for OE and it may not do much if you offer it to an OOA who is already slightly hypoxic other than offord the opportunity for the OOA diver to run out of gas twice. A bigger pony, like a 13, 14 or 19, creates a possible entanglement hazard and creates drag. Also, attached to your tank, you probably can't tell if you've got a first stage leak unless your buddy, remember him/her?, tells you. That in turn could lead you to rely on the pony and find it's empty when you really need it. Finally, if you have to rely on the pony for the extra gas-that is you plan to use it for anything other than a higher PO2 gas for safety stops, you should simply carry a bigger primary.
A better way, it seems to me, is to carry an extra cylinder as a stage bottle rigged to your harness. Done properly, it's highly streamlined. You can take it off if you need to-like if it's caught on something or you're climbing a boat ladder. You can see the first stage and SPG without the need to have a long SPG hose. You can hand it off to an OOA and so ascend at arms length and unattached. Finally, if you carry it this way, you can have a useful size, like a 30, or even 40. With the bigger bottle, you can help an OOA out of a problem at 100 fsw without fear of them burning the tank in five minutes or skipping safety stops. Remember, a diver close to panic can suck down 2 cu. ft per minute at the surface, that's 8 cu ft. per minute at 100 fsw! Also, if you're using it for a higher PO2 mix for stops, it'll last you all day.