H2Odyssey Extra Air Source

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Your adding a level of safety to your diving and that is certainly a good thing. I really like the fact that you have taken the time to test it out in your pool and know how long it last, and what it feels like when it is getting down to the last breaths. Very good on you for testing your new gear out and understanding it before just jumping into the water. Any additional safety is always a good thing.

I do not know a lot about the Odyseey but I see it appears that it can be put on a larger bottle, which you may want to consider.

I find it interesting the comments about the "real diver" that are telling you the bad things about it. If you mean by real diver, those that may have more training, experience, and have possibly dealt with emergencies, then you may not want to be so quick to disregard what they may have to say.

That being said, here are the potential draw backs of a system like this, or a spare air that is more limited as you cannot put on a bigger bottle.

You tested the system in your pool to understand how it works, how long it will last, and what it feels like in the last breaths. You now need to factor in depth, and stress factor. As noted you have an RMV of 0.60 based on your practice in the pool. Figure in a high stress, OOA, that doubles, add in you are at 60 feet or almost 3 ATA, your volume has now been reduced by almost a third.

That tank now is going to be much less than you might expect or need, and you are making a very rapid accent which also has a great potent to harm you. This is why "real diver" who carry pony's tend to carry something like an AL40.

I would personally consider up sizing the bottle a bit, yup bigger bottles can be a pain, but not having enough gas is a bigger pain.
 
Thanks for the post, I've been looking into getting myself a 13cft pony setup. What gauge did you add to your setup?

A typical dive for me has a bottom at about 75' and an average depth of 55'-65', so a 13cft with slightly elevated breathing would give me around 6 minutes of emergency air; that's much better than a 75' CESA!
 
If you mean by real diver, those that may have more training, experience, and have possibly dealt with emergencies, then you may not want to be so quick to disregard what they may have to say.

Nope. I'm talking about those that think they have more training, experience, and have possibly dealt with more emergencies and think that their opinion is the be all and end all. Guess what - it's not one size fits all - or even one size fits most.

As far as more training & experience - neither guarantees a great or even good diver. Neither guarantees they even know what they are doing.

Also, if they are dealing with emergencies do I really think they are a good source of information? Are they getting in situations by pushing limits that they should not be going beyond. Or maybe these parameters they so dogmatically state come from imagined situations and other smoke and mirrors.

With all due respect (which is probably less than you imagine) I'll keep my own counsel. Sorry, but I do not need an 80, 60, 50, 40, 30, 27, 19, or even 13 cubic foot pony for my skill set, equipment, and diving parameters. Some may - I don't.
 
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The gauge I added is the Storm Pony Bottle Pressure Gauge.

It isn't quite ideal...there's a slight rub between it and the swivel tube between the 1st and 2nd stages when it swivels. It works and the rub is probably OK, but if it were 1mm smaller in diameter it'd be better.

As for depth and size of bottle and "real divers," I hope you notice I haven't commented anything on the subject. That is all commentary from other posters and I value their input. I made my decision looking at a very conservative ascent profile. The DiveNerd profile.

To determine the time needed for the ascent, we base the calculations on the following profile:

  • 1 minute at depth to assess the problem and donate regulator to the OOA diver.
  • Ascend at 30 ft/min to half of the max depth.
  • Ascend at 10 ft/min for remainder of dive to surface.

That profile and a 0.6 RMV is what a 6 cft bottle will just barely get you to the surface on from 60 ft. In an OOA situation, where, as Ierpy said, you'll be running a much higher RMV, but also, you won't be ascending as slowly as that profile either. I can't seem to find the calculator again, but I used one to see how long a 6 cft would last ascending from 100 ft at 60 ft/min with an RMV more like 1. As I recall, it was enough to get to the surface. Now, do I ever want to ascend from 100 ft. at 60 ft/min? <bleep> no! But I'd rather do it with a little bottle than no bottle. Maybe it's time for me to make my own calculator...time to dust off the old calculus skills...

Would a bigger bottle be better. Of course. Would I travel with a bigger bottle? At this point, no...and all my diving is going to be travel. So, for me, the 6 cft is a good option. Others may very well want to go bigger. Fortunately, with this setup, it can be done if I eventually go bigger too.

Finally, this is a backup to a backup (dive buddy sharing air...I'm not planning on solo diving with this) to a backup (proper dive plan/execution and equipment checks). If I ever am in a situation where I have to use this thing, I have pretty seriously messed up. My main concern is that the thing works...even if all it does it get me to a reasonable CESA depth...and it does work.

I am not recommending 6 cft for anyone...I probably shouldn't have even mentioned the size pony I'm using, it's not really meant to be the point here. The info I was hoping would be helpful to some is the info on how the H2Odyssey setup works as a bailout.

Anyway, as I get more experience...who knows...maybe I'll be diving sidemount with an AL80 as my bailout. :)
 
[[Edit...the there was a mistake in this post...see later post re: gas consumption]]
 
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40m/120ft (4 ATA) deep - Min bailout size required = 1/2 [16 + 4] = 10 cft

You are not taking into account the rate that you ascend 30 feet per min

so =1*2.82*(120/30) = 11.28

:) You need to be a true nerd... Excel is your friend...
 
[[Edit: Mistake in this post...see later post re: gas consumption]]
 
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My bag of popcorn is ready...!

Tip: Put on a flame-retardant suit. You'll need it especially after buying that junk.

This is the type of 'real diver' comments I was referring to. Not helpful or informative in the least.

I'll sling a pony when the conditions call for it. 90% of my dives are warm water, less than 60' deep, no overhead. I prefer to dive solo, an am comfortable with a al80 in these conditions. If I'm flying to a destination where the dive operator will require a redundant air supply to dive solo, the h2odessy is a perfect fit. Another nice thing about the 6 cft is you can fill off your first tank. Some of the charters I prefer do not have compressors on board, so filling a 19 or bigger won't be as convenient. More air is definitely better. When used as intended the 6 is a perfect fit.
 
Bah, I'm dumb...I missed a factor of 2 in there that actually makes the numbers I posted first way too conservative. Fail.

More correct now...I think. Assuming:

- SAC of 1 cft/min
- Ascent of 60 ft/min (or, more specifically, 2 ATA/min)

Bailout size = 1/2 [ (1/2 Depth(in ATA)^2) + Depth(in ATA)]

10m/30ft (1 ATA) deep - Min bailout size required = 1/2 [0.5 + 1] = 0.75 cft
20m/60ft (2 ATA) deep - Min bailout size required = 1/2 [2 + 2] = 2 cft
30m/90ft (3 ATA) deep - Min bailout size required = 1/2 [4.5 + 3] = 3.75 cft
40m/120ft (4 ATA) deep - Min bailout size required = 1/2 [8 + 4] = 6 cft

That's what I get for scratching this out quickly while at work. I am ashamed...I'm glad nobody here knows me. :)

I just took a little time to be more careful now...here's a graphical way of viewing it. The factor of 2 I missed originally is the 1/2 in the area inside a triangle. My elementary school math teacher would be horrified. My PhD prof would probably make me give back my degree.

Anyway...I think this is more right now. And yes, it still scales linearly with ascent rate and SAC. As I said, don't use my numbers or you will die.
Untitled.jpg
 
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My bag of popcorn is ready...!

Tip: Put on a flame-retardant suit. You'll need it especially after buying that junk.

This is the type of 'real diver' comments I was referring to. Not helpful or informative in the least.

I'll sling a pony when the conditions call for it. 90% of my dives are warm water, less than 60' deep, no overhead. I prefer to dive solo, an am comfortable with a al80 in these conditions. If I'm flying to a destination where the dive operator will require a redundant air supply to dive solo, the h2odessy is a perfect fit. Another nice thing about the 6 cft is you can fill off your first tank. Some of the charters I prefer do not have compressors on board, so filling a 19 or bigger won't be as convenient. More air is definitely better. When used as intended the 6 is a perfect fit.
 
https://www.shearwater.com/products/teric/

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