Should all divers have a redundant air source on every dive?
- Thread starter Thalassamania
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I may only hurt you once, but the pain placed on your family and friends continues for a long time.
I do agree that diving with some sort of redundancy, be it a buddy or additional gear, is a divers choice and responsibility.
If you care one bit for those who care about you, you take that responsibility more seriously.
Buoyant1
Contributor
I agree as well: As long as no one tells me I need to do it! (although my local quarry has it that any dive over 70' you need a pony, but no one is there to enforce it)
I don't think EVERY dive needs a redundant air supply (other than a trusted buddy) Locally? I dive with the same bunch of guys, and we hit anywhere from 30-120ffw, being that it's COLD water, I take the pony with me for those scenarios. So technically I have two options, and seeing that the majority of the guys I dive with are switching over to doubles, it's even better.
In the Keys, (which is where I usually am if I'm not diving at home...well so far) I don't take it on any dives above 50 ft. I figure I can either get to the surface or to my "insta-buddy" in a decent amount of time, most of the dives other than some of the wrecks, have been 40 feet or shallower.
I feel it has it's uses, and it's not that intrusive when I do use it and not that much of a change when I don't. But there are times where it's not necessary.
I don't think EVERY dive needs a redundant air supply (other than a trusted buddy) Locally? I dive with the same bunch of guys, and we hit anywhere from 30-120ffw, being that it's COLD water, I take the pony with me for those scenarios. So technically I have two options, and seeing that the majority of the guys I dive with are switching over to doubles, it's even better.
In the Keys, (which is where I usually am if I'm not diving at home...well so far) I don't take it on any dives above 50 ft. I figure I can either get to the surface or to my "insta-buddy" in a decent amount of time, most of the dives other than some of the wrecks, have been 40 feet or shallower.
I feel it has it's uses, and it's not that intrusive when I do use it and not that much of a change when I don't. But there are times where it's not necessary.
Blackwood
Contributor
Every diver should dive with enough gas (primary and redundant) that they have a warm and fuzzy feeling that they can safely complete the dive within their own personal risk tolerance.
If your choice is to 'bolt and pray', then the redundant gas is unnecessary. If your choice is to solve whatever issues you have underwater and complete your ascent as planned, then redundant gas may be necessary. That gas could be in a tank on your side, in your buddy's tanks, hanging on a rope, etc..
Generally speaking, I prefer to solve problems underwater and complete the ascent which I believe my depth/time exposure requires. I choose to do so by diving with buddies who maintain reserve for me (and I in turn maintain reserve for them).
As Captain suggested, this reserve is arbitrary. But it can be no other way. It is impossible to know what an emergency will entail, and thus impossible to know with precision how much gas will be needed to solve it. So you make a best guess. You plan your ascent, figure out how much gas is needed nominally, double it (for your buddy), and add some padding to taste.
This is no different than anything which has been engineered. Things are designed for nominal maximum loading, and some arbitrary factor on top of that nominal maximum, leaving you with a margin of safety above the loads which you expect to see.
If your choice is to 'bolt and pray', then the redundant gas is unnecessary. If your choice is to solve whatever issues you have underwater and complete your ascent as planned, then redundant gas may be necessary. That gas could be in a tank on your side, in your buddy's tanks, hanging on a rope, etc..
Generally speaking, I prefer to solve problems underwater and complete the ascent which I believe my depth/time exposure requires. I choose to do so by diving with buddies who maintain reserve for me (and I in turn maintain reserve for them).
As Captain suggested, this reserve is arbitrary. But it can be no other way. It is impossible to know what an emergency will entail, and thus impossible to know with precision how much gas will be needed to solve it. So you make a best guess. You plan your ascent, figure out how much gas is needed nominally, double it (for your buddy), and add some padding to taste.
This is no different than anything which has been engineered. Things are designed for nominal maximum loading, and some arbitrary factor on top of that nominal maximum, leaving you with a margin of safety above the loads which you expect to see.
Does redundant gas supply include your buddy's back gas?
Blackwood
Contributor
Only if said buddy saves some for you.
For me the answer is I don't know. I can't say whether all divers should have a redundant air source. All I can answer is for myself. I want a redundant air source on all (or a least most) of my dives.
A buddy is great if they have enough air to share and are available exactly where I need them when I need them but I'd also like to just sling a bottle so as to be as self-reliant as possible.
I think most of the answers to this question depend on where the respondent lives and dives. Many mention not carrying a bottle on 40 fsw dives in warm water. Most dives here that I do seem to be down to 100 fsw or so with limited viz in water in the 40's.
If I had a lot of 40 fsw dives in warmer water, no entanglement hazards, good viz I might answer slightly differently.
It's like insurance though, how do you know when you don't need it and what's the point in finding out!
A buddy is great if they have enough air to share and are available exactly where I need them when I need them but I'd also like to just sling a bottle so as to be as self-reliant as possible.
I think most of the answers to this question depend on where the respondent lives and dives. Many mention not carrying a bottle on 40 fsw dives in warm water. Most dives here that I do seem to be down to 100 fsw or so with limited viz in water in the 40's.
If I had a lot of 40 fsw dives in warmer water, no entanglement hazards, good viz I might answer slightly differently.
It's like insurance though, how do you know when you don't need it and what's the point in finding out!
captain
Contributor
This is very different than engineering. In engineering strength and stress can be accurately calculated and an appropriate saftey factor applied. There is no way in diving to calculate what might the needed safety factor be. It is just a shot in the dark.
Blackwood
Contributor
The stress and strength can be accurately calculated for a nominal loading, just like the necessary gas required can be calculated for a nominal ascent.
The safety factor is arbitrary, regardless of whether it's labeled as "appropriate" or not. Some suit says "I want at least 1.25." Papers are signed and you are off to the races. But that 25% is just some number pulled out of nowhere meant to give a warm and fuzzy feeling that if the unexpected happens you should still be okay. Same with whatever pad we give to solve problems such as entanglement or increased consumption rates, etc..
captain
Contributor
But in engineering you have a known strength and a known stress and you add a safety factor to those knowns
In diving you have only one known, the amount of gas you are carrying. The stress is the chance of something happening and the unknown amount of gas needed to deal with the happening. That's why what ever safety factor you add is just shot in the dark
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