46 replies to this topic

[jholley309]

And scenarios like that are exactly why I now own a 19CF pony bottle.

The girl at my LDS asked why I was getting a pony bottle when I went shopping, and I had to think for a minute to organize the "What If's" and "Why For's" that flashed through my mind. I managed to distill it down to a single, compact thought (rare for me, I know...):

It gives you time. Time for you and your buddy to assess the situation and come up with a plan to either solve the problem or make a graceful exit (if you consider a rushing torrent of bubbles coming from your side or behind your head graceful), particularly if it happens at depth, towards the end of the dive when your buddy's tank might not have enough gas to handle the suddenly doubled demand.

I for one am willing to accept the extra drag, bulk, and weight; the gift of time far outweighs the cost, IMHO.

Cheers!

Jim

Edited by jholley309, 19 October 2005 - 04:08 PM.

[casematic]

Just bought a little 6 cf h2odessy set up... You can fill it from your tank yourself... anxious to give it a try... Hopefully I'll never need it, but it will be nice to have it just in case

[jholley309]

Just bought a little 6 cf h2odessy set up... You can fill it from your tank yourself... anxious to give it a try... Hopefully I'll never need it, but it will be nice to have it just in case

I thought about that one, but decided on the pony; the reg on the H2Odyssey is attached to the bottle, which means it occupies one hand while you're going up. The neat thing about the H2Odyssey is that the regulator threads into standard valve threads on a tank: you can "upgrade" to a bigger tank if you want.

As a personal preference, I prefer to have both hands free just in case I need 'em both. I got a 19 CF pony with a basic regulator for about the same price as the H2Odyssey, and it leaves my hands free once I switch to the pony reg (bungeed around my neck, like a real diver! ). It also gives me just enough air to make an emergency deco stop if I have to, once I start getting down to depths where I hit an NDL before I run out of air. The downside is that it required some weight re-arrangement so I don't have a tendency to roll towards the pony bottle, and it's a little tougher to haul the scuba unit back onboard the DiveYak now; relatively minor inconveniences compared to the extra peace of mind, though.

Cheers!

Jim

[Cold_H2O]

it leaves my hands free once I switch to the pony reg (bungeed around my neck, like a real diver! ).

Technically your OCTO should be bungeed around your neck.. not your pony bottle reg.
I did see your smiley but some "Real divers"...(me) don't do the bungee..

[WillDiveForBeer]

Losing a HP hose is no reason to panic. Simply ascend normally, make a stop if you have enough air. If you lose a LP hose, you have very little time to get to the surface, it will go quickly. Sharing air or using a pony bottle are excellent ways to ascend when the LP hose goes.

Your friend injured himself needlessly. I'm glad he wasn't hurt more.

Can someone explain why a LP hose will drain a tank faster than a HP hose? It is just a function of the 1st stage which allows the full pressure of the tank but limits volume, or are all HP hoses low volume hoses, therefore limiting gas loss if it fails?

-Mike-

[WillDiveForBeer]

(I'll bet he will be carrying a pony bottle from now on).

A pony bottle would have been a more dependable buddy here for sure ....

That's why I got mine. I depended on it too much for a while, but still nice to have.

I also like my analog SPG seperate from my computer. I like electronics, but don't trust them. Carry two computers so when one fails, I have the other. And they will fail.

Maybe he could have ascended a little slower, but getting to the surface IS better than not getting there.

Oddly enough, I've had 2 SPGs fail on me while diving, my computer still transmitting my pressure wirelessly . I'm on a 3rd SPG now, different make and model, hopefully this will stop the leaks. I guess Dacor musta had a bad batch.

-Mike-

[Cold_H2O]

Can someone explain why a LP hose will drain a tank faster than a HP hose? It is just a function of the 1st stage which allows the full pressure of the tank but limits volume, or are all HP hoses low volume hoses, therefore limiting gas loss if it fails?

-Mike-

Mike ~ I think I read some where it has to do with the ID of the HP hose being smaller than the ID of the LP hose.
Anyone else want to chime in?

[scubafanatic]

Can someone explain why a LP hose will drain a tank faster than a HP hose? It is just a function of the 1st stage which allows the full pressure of the tank but limits volume, or are all HP hoses low volume hoses, therefore limiting gas loss if it fails?

-Mike-

Mike ~ I think I read some where it has to do with the ID of the HP hose being smaller than the ID of the LP hose.
Anyone else want to chime in?

....unscrew a LP hose from your 1st stage.......do the same thing for a HP hose....now look at the orfice / opening of each hose and compare the two, it's very difficult to even see the opening of the HP hose, isn't it ? ...that's the reason the HP hose vents relatively little gas compared the the LP hose.

Karl

[Capn Jack]

Losing a HP hose is no reason to panic.  Simply ascend normally, make a stop if you have enough air.  If you lose a LP hose, you have very little time to get to the surface, it will go quickly.  Sharing air or using a pony bottle are excellent ways to ascend when the LP hose goes. 

Your friend injured himself needlessly.  I'm glad he wasn't hurt more.

Can someone explain why a LP hose will drain a tank faster than a HP hose? It is just a function of the 1st stage which allows the full pressure of the tank but limits volume, or are all HP hoses low volume hoses, therefore limiting gas loss if it fails?

-Mike-

Basically, gas flow is limited by pressure differential. Once it drops to a differential of 1/2 inlet to outlet - the velocity is fixed - it can not exceed the speed of sound. Thus, an LP outlet, having a much larger orifice, will drain your tank faster, since the velocity will be the same.

Proof is left to the reader.

[scubafanatic]

....by the way, I just picked up / installed my new 30 cu. ft. Catalina pony tank / Quick Draw bracket system on my DeepOutDoors Matrix BC/ Dive Rite Dual Rec Wing harness today, had a local dive shop tech/cave instructor help me set it up....getting it ready for my next weekend's week-long dive trip aboard the DON JOSE live-aboard (Sea-of-Cortez)....and while I've dove 'doubles' before, I've never used a tank-mounted pony before.....so it was great to have a professional orient / clip off everything in a logical/streamlined manner......too bad I won't have a chance to lake-dive it first, that's why it was so critical to me to dry-run it at the shop today......since my first dive with the new configuration will be the 'real-deal' !

....it will be a bit more of a travel hassel than usual, but I feel the level of increased safety is well worth it.........guess after a couple dozen dives out there I'll certainly know, one way or the other.

Karl

[PerroneFord]

I have a couple of questions on the "pony bottle" deal.

1. If you are turning your dive at appropriate times, why wouldn't your buddy have enough gas to get you both to the surface?

2. If you are exceeding deco limits, wouldn't it make more sense to be diving doubles? It's a far cleaner solution to the "redundant gas" issue.

3. When you dive a pony, is the tank turned on for the entire dive, or dou you only pressurize the tank when you run out of air on the other one.

4. How do you monitor the pony bottle to make sure it's not leaking? Either from the regulator if it's on, or from the hoses if it's charged.

6. At 80ft how long would a 6cuft h2odyssey last?

7. Do you test breathing off the pony at the beginning of each dive to make certain it's working normally?


Just some things I've always wondered and since several of you here say you use them. They are frowned upon in the technical community for a number of reasons, but seem quite popular for open water divers.

Thanks,

-P

[scubafanatic]

I have a couple of questions on the "pony bottle" deal.

1.  If you are turning your dive at appropriate times, why wouldn't your buddy have enough gas to get you both to the surface?

2.  If you are exceeding deco limits, wouldn't it make more sense to be diving doubles?  It's a far cleaner solution to the "redundant gas" issue.

3.  When you dive a pony, is the tank turned on for the entire dive, or dou you only pressurize the tank when you run out of air on the other one.

4.  How do you monitor the pony bottle to make sure it's not leaking?  Either from the regulator if it's on, or from the hoses if it's charged.

6.  At 80ft how long would a 6cuft h2odyssey last?

7.  Do you test breathing off the pony at the beginning of each dive to make certain it's working normally?


Just some things I've always wondered and since several of you here say you use them.  They are frowned upon in the technical community for a number of reasons, but seem quite popular for open water divers.

Thanks,

-P

6. At 80ft how long would a 6cuft h2odyssey last?

......to me, that's a 'toy' back-up system, not at all interested in that 'solution', but, hey' it's a free country....whatever floats one's boat.

2. If you are exceeding deco limits, wouldn't it make more sense to be diving doubles? It's a far cleaner solution to the "redundant gas" issue.

.........the vast majority of my dive trips are done on single AL80's........ sometimes I'm fortunate enough to be able to request AL100's, LP 95's, or HP 120's (singles) but the majority of the time I'm stuck with single AL80's.........doubles ??? ...that's a laugh.....for example, can you show me how many SD.com trips offered 'doubles' as an option ? ....only rarely are single 'large' tanks available, much less 'doubles'.

7. Do you test breathing off the pony at the beginning of each dive to make certain it's working normally?

Yes.

4. How do you monitor the pony bottle to make sure it's not leaking? Either from the regulator if it's on, or from the hoses if it's charged.

...I have the pony 2nd-stage and SPG clipped off my lower left D-ring, so I can watch the 2nd stage for any leakage/free-flow, the 2nd-stage has a break-away clip in the event a panicked diver grabs it before I unclip it. I can check the pony SPG to monitor gas pressure.

3. When you dive a pony, is the tank turned on for the entire dive, or dou you only pressurize the tank when you run out of air on the other one.

I'll dive it 'on', ready for instant deployment.

1. If you are turning your dive at appropriate times, why wouldn't your buddy have enough gas to get you both to the surface?

Dive planning in a recreational setting is rather 'informal'.......especially when faced with randomly assigned dive buddies.......recreational divers aren't trained to turn-on-thirds or on any of the other niceities of technical diving....... I dive in the 'real-world' which is very imperfect........the other choice is to rarely dive at all, so a higher level of self-sufficiency is the band-aid I use to cope with the 'imperfect' world of recreational diving.

Karl

[PerroneFord]

Thank you for the very quick and frank response. I haven't been on a dive boat in 11 years. And quite honestly, I see more doubles than single tanks here (not speaking of boats).

I have a feeling I am in for a RUDE awakening when I get on a boat again!

[TraceMalin]

There are solutions for those times when you are traveling and you want double tanks.

1) Make arrangements with the dive operator you are using and tell them that you need to configure double tanks. Buy a manifold and tank bands for AL 80's and put these off to the side for travel. Once you arrive at your destination, just break down two single 80's remove the valve's replace them with the double isolator manifold and your bands and you're good to go. You might have to pay more for the hassle it will cause them, but money does talk. The work involved will be to drain the tanks, unscrew the single valves, screw in the isolator manifold valves, screw in the isolator bar, add the double bands and measure them for your backplate, fill the tanks and you're good to go. If the boat can accommodate the doubles, I'm sure they'll go for it if the boat can hold doubles. We dive pros will do anything for money.

2) There are double tank cam band systems that you can buy. These will allow you to double up your scuba tanks on your back. You can either use them as independent doubles or add a crossbar that will connect K valves together. Check with the operator as to whether they will allow this in advance.

3) Ship your double tanks by air freight to your destination well in advance & assemble them there. You may have to pay additional charges at dive centers for visual inspections on empty tanks. Again, make arrangements with the operator.

4) Another travel solution for double tanks would be to run a sidemount system. You just need your sidemount BCD, your regs and attachment hardware and you're good to go. The tanks will fit into whatever tank holding system the boat has in place since they'll ride as singles & you can just clip them in and have the redundant gas. Again get permission in advance.

5) Go to destinations with operators that teach tech and trimix diving. They'll have the doubles ready to go. But... ask in advance.

Note: Many divers do not realize that extra money and tips will open up many doors. It never hurts to contact operators well in advance and inquire about gear rental for unusual requests. With enough time and monetary influence you could get almost anything to make your dream dive trip exactly that. The worst thing to do is show up with 30 minutes to go before the boat is going to leave the dock and then ask for unsual things that may be "outside the box" as your dive staff is scrambling to load tanks, check people in and deal with that sputter coming from the deisel engine.

Trace

[gcbryan]

I have a couple of questions on the "pony bottle" deal.

1.  If you are turning your dive at appropriate times, why wouldn't your buddy have enough gas to get you both to the surface?

2.  If you are exceeding deco limits, wouldn't it make more sense to be diving doubles?  It's a far cleaner solution to the "redundant gas" issue.

3.  When you dive a pony, is the tank turned on for the entire dive, or dou you only pressurize the tank when you run out of air on the other one.

4.  How do you monitor the pony bottle to make sure it's not leaking?  Either from the regulator if it's on, or from the hoses if it's charged.

6.  At 80ft how long would a 6cuft h2odyssey last?

7.  Do you test breathing off the pony at the beginning of each dive to make certain it's working normally?


Just some things I've always wondered and since several of you here say you use them.  They are frowned upon in the technical community for a number of reasons, but seem quite popular for open water divers.

Thanks,

-P

#1 Buddies like equipment can fail

#2 For my dives the cleaner solution is single tank with pony. I have a 119 cu ft main tank and a 30 cu ft pony. If I planned on substantial deco (wrecks) I would go with doubles. I like looking at sea life including some deep walls but the time I need to spend at depth is more limited than would be the case for wreck diving. Therefore I prefer the simplicity of singles. I also do a lot of shore dives with long approaches to the water which gets heavy with doubles.

#3-4 My tank is back mounted, always turned on, monitored with a SPG just like my main tank. The 2nd stage is bungeed around my neck. I don't use an octo on my main tank. If my buddy needs air I give him my main reg and now I'm limited to the 30 cu ft in my pony. I could have 3 regs but I opted for simplicity having weighed the pros and cons.

#5 There is no #5. What's up with that

#6 6 cu ft at 80 fsw would not last long, maybe 3 minutes if you are being calm. For me 30 cu ft is the least I would consider if you dive below 100 fsw often.

#7 It's tested at the beginning of every dive, sometimes during a dive, and monitored several times during the dive.

Some tech divers say you don't need a pony since your buddy is your redundant air supply. Then again they say they use doubles so that they have a redundant air supply. I like to think for myself and the pony works well for me. If I were seriously tech diving as opposed to just diving deep for short periods of time I would be using doubles as well. As you know tech diving is a lot more than doubles and it's those complications that I'm trying to avoid. If I lived on the east coast with it's more numerous wrecks at doable depths I would be a tech diver. On the west coast the shelf drops off much sooner and the wrecks for the most part are not doable.