Spare Air

[ItsBruce]

The problem I am trying to work out is this: what depth limit should I set for myself for using the Spare Air as opposed to my pony?

There is no good answer. Some very good divers will say not to use the Spare Air ever and to always use a pony. Some will even tell you having a Spare Air is worse than having nothing.

The answer to your question, however, is dependent on how risk adverse you are.

I can calculate that assuming an SAC of 1.0 (it assumes a degree of stress and makes calculations easier) and an ascent rate of 30 feet per minute, the Spare Air will give you 30 seconds to sort things out or attempt to reach an errant buddy at 30 fsw.

If you are willing to rush the assent to 60 feet per minute, you can take 1 minute to sort things out at 30 fsw.

If you are willing to do the assent at 60 feet per minute and head for the surface within a few seconds, you can make it from 60 fsw.

Basicallly, a Spare Air is a supplement for a "blow and go." You may not need to go quite as quickly. You may not need to go quite as far on your fiinal breath. And, that's good enough for me.

However, all of the foregoing requires the skill of going to the Spare Air to have been practiced adequately. ... But so, to does going to a pony.

 

[Scuba_Steve]

I personally am not concerned with the comparable cost. I have BOTH a 3 cu ft Spare Air AND a 13 cu ft pony, along with an Atomic Z1 to put on the pony and a button gauge for it. But for shallow dives < 60 feet, I find it easier to use the Spare Air. It's alot less fussing around between tanks and you are carrying less weight when you are trying to get up the ladder -- a significant consideration for a middle-aged lady who has had a partial knee replacement, even though I do work out with weights and cardio. I can swim nearly the length of a 25 meter pool underwater on one breath, so I figure I could make an emergency ascent from 60 feet even without a spare air. Back in the 60's, my Dad had an out of air situation when he came to the end of his air, went to flip his J-valve and found it was already flipped. He made an emergency ascent breathing out the whole way up from 90 feet!

For sure, last time I did Punta Sur/ Devil's throat in Coz (where, for those of you who don't know, you go in the 30' coral tunnel at 80 fsw and come out at 130' fsw), I used my pony. There would have been no way I could have breathed from my buddy's alternate unless he had a 7' hose like the DIR people use, but it would have been easy to get to my pony bottle reg.

I am not a tech diver. I dive Nitrox and recreational limits, and watch my computer, staying on the conservative side of it -- so there is never a question of missing a deco obligation -- just of missing a safety stop, which is not essential -- just for extra safety.

The problem I am trying to work out is this: what depth limit should I set for myself for using the Spare Air as opposed to my pony? Of course, most of my diving trips have 2 morning dives each day (and maybe an afternoon or a night dive later -- both at the shallower depth)-- the first is usually 80-100 feet and the second 50-60 feet. It's much easier to have the same set-up for both dives, and yet my above argument would suggest I use my pony for dive 1 and my spare air for dive 2. That pony set-up is so darned inconvenient and heavy though -- I really hate it.

BTW, I am going to Little Caymen in October -- does anyone know what the usual depths are for dives there? I guess it's wall dving, so it's whatever you plan, right? Just trying to decide whether to bring my pony and extra reg. along.

Sounds like you got your monies worth out of that Padi Master Diver program........... :shakehead

 

[DivingDoc]

SCUBA-Steve:
I can't tell if you're being sarcastic or genuine in your above comment. If you dive in CA, I would gues you're mostly doing dry suits?

 

[Scuba_Steve]

A bit of both I guess.

The main point being after how much money on how many specialties, it seems to me that a Master Diver knows nothing about basic dive planning, and just how convoluted your set-up and mindset is from this perspective.

In your defense however, it's not at all your fault. I'm sorry you had to waste that much money and time on that clearly useless path.

I don't know what you're driving at with respect to dry-suits. All I see is a lot of pony/spare air questions, trying to decide what depth for each yada yada. I may be missing something however.

Also didn't note anywhere were you had a buddy entering into the plan at all. I'm pretty sure the training gave lip-service about it, but again, this proves how well that novel idea is truly enforced....

The unfortunate thing here is you paid good money for what you truly believed would be decent training, of which you would know these answers, and what is wrong with all of this. You've been taken (IMO) and don't even yet know it.

sorry.

regards

EDIT: spelling, grammar, the usual.

 

[rexman24]

Can someone explain to me how its not a good idea to have more air, even if its only 3 CF, when you dont have any?

yes you always plan not to get in a no gas situation and to have backups and buddies, but sometimes a diver gets there, plan or not.

sorry but this line of thinking makes no sense to me.

 

[TheRedHead]

Can someone explain to me how its not a good idea to have more air, even if its only 3 CF, when you dont have any?

Because 3 CF is not enough air to factor in a sensible gas plan. Because on a deep dive 3 CF might get you to the surface, but bent, and bent is not an acceptable state when more gas would allow you to make a slow ascent with all the planned stops.

 

[rexman24]

Ok so if your debating its better to have a pony bottle or EAS I agree, but not that its better to have no independent air source at all.

 

[Scuba_Steve]

Your highly competant,attentive, well skilled, thinking buddy has your reserve gas. He is cost-free and is more fun to dive with than your spare-air.

He also promotes a sense of team work, whereas the scare-air or pony actually does the opposite and leaves you with less options in the event of any mishaps, (not limitted to just low/out of air) that may occur.

Ya know, all that real slick stuff that should be part of basic scuba training but evidently isn't.

regards

Please explain to me how a diver 'gets there' when they have a reasonable plan because I'd like to know.

From there we'll show you a long list of screw-ups en route to that point in the dive, any of which if they had been addressed correctly would have sorted this non-existant problem out.

 

[redacted]

Can someone explain to me how its not a good idea to have more air, even if its only 3 CF, when you dont have any?

yes you always plan not to get in a no gas situation and to have backups and buddies, but sometimes a diver gets there, plan or not.

sorry but this line of thinking makes no sense to me.

Unfortunately, there are some divers who would look at their (primary) SPG and see they are "low" but decide to continue the dive because they "have a redundant air source". A spare air or pony can make some folks stupid to the point where they continue a dive that they would have otherwise ended.

 

[rexman24]

yeah, unfortunately I travel alone and dive with "insta buddies". Who is to say if they will be close like they are supposed to be, that I would be able to get their attention, trained to help out and capable of thinking clearly in an emergency, and even willing to hand over their air source if it came to that.

For these reasons I am looking to put my survival in my hands not that of a stranger of unknown training, intentions, or ability to act under fire.

I think I will get an EAS but I would rather have a spare air than nothing at all.

"whereas the scare-air or pony actually does the opposite and leaves you with less options in the event of any mishaps, (not limitted to just low/out of air) that may occur."

how does having gas leave me with less options as opposed to not having any again?
your assuming none of the listed options when it comes to buddies I mentioned above happens right?