Dive buddy for air? No thanks.

[LeadTurn_SD]

This is one of those moments that I find my thinking in flux, a bunch of new things all at the same time, and I'm playing with some interesting syntheses. Thanks for the help, you've been instrumental in supplying some critical components.

I'm poking about at the intersection of diver experience levels, equipment vs skill solutions, risk compensation with respect to gear changes and skill changes ... I can't wait to see how if comes out.

Thal, if you arrive at an answer you are comfortable with, please let us know ( I'm assuming your talking about where to draw the line, below which an auxiliary air source is needed).

I've tried to wrap my brain around that exact question, and failed badly because I just don't have enough dive experience to arrive at a solid answer.

I know some divers are not comfortable at any depth without some form of redundancy (pony, doubles).

Others using a single steel 72 or Al80 will dive right to the edge (or beyond) what most people consider "recreational depths". I was one of them in the '70's.

I've always relied on my buddy for redundancy, especially once I cross the 50-60' threshold. Maybe this is completely adequate, but maybe it is not.

I'm not talking about gas planning for a given dive profile (which would determine the amount of gas needed), I'm referring to true gas/equipment redundancy in addition to carrying enough gas for the planned dive.

At what point should each diver in a team be 100% self-reliant and have a redundant air supply? Only on dives with an overhead (physical or deco), or on dives beyond reasonable CESA depth (for that diver)?

Where is the line where the additional complexity, bulk, drag, etc., become necessary for safety? What failure modes (equipment or training) are possible that would create the need for redundancy?

How much risk, if any, does the additional equipment required for redundancy create (extra weight, drag, failure points, etc.)?

Here in Hawaii with generally excellent viz (less chance of buddy separation), and warm water (less chance of free flows) I see the "line" for redundancy as being a bit deeper than in the NE or NW United States. But I may be overlooking something or not thinking about all the factors correctly.

Anyway, thanks!

 

[Web Monkey]

Research suggests 17 repetitions of air sharing are required to have 90% confidence that students will actually be able to do it.

That's interesting. We do way more than that, but it's nice to have a number.

Any idea how long it takes to forget almost everything?

Terry

 

[Thalassamania]

No, that was purely rhetorical. What I'm playing with the the qualification definitions I posted a while back, the concept of risk compensation, how those two concepts interact with each other as well as help to define the intersection space with failure mode analysis of equipment mediated solutions optimized against the investment in training (and maintenance of gained skills) that alternatively present solutions for the same issue(s).

Way too much jargon ... cough, hack ... that's what I need to wend my way though and chop out.

That's interesting. We do way more than that, but it's nice to have a number.

Any idea how long it takes to forget almost everything?

Terry

I can do that in a flash, can you still ride a bike?

 

[tna9001]

Great thought-provoking thread.. thanks everyone.
How many breaths can you get from a 3.0 Spare Air unit if you are OOA at 100 feet and begin a safe ascent (at or slower than 60 ft/min) ?

(Just curious... I would always swim towards a buddy first)

Don't know about the breath thing but Spare Air 3.0 fully charged = an 80 cft tank at 112.5 psi.:shocked2:

According to their web site Spare Air 3.0 gives you 57 breaths sitting on your couch watching TV. An adult male during strenuous exercise breathes 34-45 breaths per minute that equals 1.3 minutes of air at the gym on the elliptical machine. (Spare Air bases that on 1.6 liters per breath, normal tidal volume is .5 liters per breath)

At 100ft that air is worth 25% what it's "worth" at sea level. Of course as you ascend the air in the tank is "worth" more.

Please correct as needed.


Tank Volume

 

[LeadTurn_SD]

No, that was purely rhetorical. What I'm playing with the the qualification definitions I posted a while back, the concept of risk compensation, how those two concepts interact with each other as well as help to define the intersection space with failure mode analysis of equipment mediated solutions optimized against the investment in training (and maintenance of gained skills) that alternatively present solutions for the same issue(s).

Way too much jargon ... cough, hack ... that's what I need to wend my way though and chop out.

Oh ok, thanks, I wasn't reading carefully enough (plus I'm easily confused ). Great definitions by the way (followed the link you provided).

 

[Peter Guy]

<Hijack>
LeadTurn wrote

Here in Hawaii with generally excellent viz (less chance of buddy separation)

I would argue the opposite. That BECAUSE of the "excellent viz" there is MORE chance of EFFECTIVE buddy separation. I contend that "excellent viz" is a double-edged sword -- yes, you can see your buddy from 100 feet away -- BUT, that means you might BE 100 feet away and that is a LONG way if you need your buddy or she needs you!

I've found there is more "effective separation" in tropical diving than in the muck here in Puget Sound.

 

[NudeDiver]

I contend that "excellent viz" is a double-edged sword -- yes, you can see your buddy from 100 feet away -- BUT, that means you might BE 100 feet away and that is a LONG way if you need your buddy or she needs you!

Anyone who is 100' away from you is not your buddy. He or she is merely a person you are diving with.

 

[Thalassamania]

Hm ... risk compensation as a result of visibility.

 

[TSandM]

I'm not talking about gas planning for a given dive profile (which would determine the amount of gas needed), I'm referring to true gas/equipment redundancy in addition to carrying enough gas for the planned dive.

At what point should each diver in a team be 100% self-reliant and have a redundant air supply? Only on dives with an overhead (physical or deco), or on dives beyond reasonable CESA depth (for that diver)?

Where is the line where the additional complexity, bulk, drag, etc., become necessary for safety? What failure modes (equipment or training) are possible that would create the need for redundancy?

How much risk, if any, does the additional equipment required for redundancy create (extra weight, drag, failure points, etc.)?

I think these are superb questions, and I don't think anybody can give you a hard and fast answer. Some of it has to do with risk aversion in the individual diver, some of it has to do with how easily additional resources are available at hand.

I decided a long time ago that dives in the deeper recreational ranges (say 90 - 130 ft) were sufficiently different from dives in the shallow ranges (<60 ft) that they require additional training and frequently additional equipment. Whenever possible, if I am going deep, I am diving doubles. But then, I own them, and I know how to use them. I do sometimes dive in the 100 ft range in a single tank, as well. Most often, that's with very well known buddies, where the equation shifts a little in the direction of my ability to count on them if I have equipment issues.

This type of thought is why Peter and I use the term "techreational" diving, to indicate that the dives in question have components that make them higher risk or more complex than the standard "recreational" dive.

 

[FritzCat66]

...Peter and I use the term "techreational" diving, to indicate that the dives in question have components that make them higher risk or more complex than the standard "recreational" dive.

Love it! That term has now instantly become part of my diver vocabulary.

It's not without precedent, either... I know in the camera industry (video and still) manufacturers will target some products at the "prosumer" market, in between professional-level gear and consumer-grade equipment.

Of course, here we're not talking about a specific piece of equipment, but a general category of diving. At the edge of recreational limits, but not necessarily as involved as full tech diving.

Techreational. Great term!


Oh, and regarding the topic, my inclination is to be prepped and ready for solo, regardless of whether or not I have a buddy. When I do have a buddy, I expect them to be pretty independent and tolerant of me getting involved with my photos or whatnot while they are wrestling lobster or whatever. I am not interested in being part of an integrated team, even a buddy team.

I mean, just look at the avatars: On the one end you have your Borglike beings where the individual is completely absorbed into the collective team. I'm a cat, at the opposite end of the spectrum, wired and adapted for solitary existence. You can put a few of us together, but the term "herding cats" means what it does for a reason: we're still just a collection of autonomous individuals.

Neither is more right than the other, it just depends on what your goals and expectations are underwater.

Ironically, however, some of my best dive buddies on the recreational dives I do are techies with their doubles or rebreathers, BP/W rigs, and cave training. Why? Because they are supremely competent divers so I don't have to worry about them, and they know they don't have to worry about me either.

>*< Fritz