pony bottle options

[scoobert]

Woah. Ok, guess I need to be exact when talking about diving.
Right now I dive solo. I clean the bottoms of boats.
Visibility is between 3' and 0. Diving to 12' means everything is going dark, and I am on the bottom.
A good day lets me go to 12', most days my stage2 depth is at 10'. I work purely by touch.
I would consider a deep dive right now 65', I have not been beyond 35' in devils den, FL.

When planning my dive I would start to ascend at about 1500PSI from 65'. leaving me a big safety for a safety deco stop, or a very slow accent with a dive computer. If worst case happened (out of air at 65') I believe I could safely ascend slowly to the surface, checking my pressure, and seeing if a safety stop could be done. If not, its less of a deal then doing the ascent with no pony, or with just a 6CF spare air. I believe a 6CF is far too small for the 65' goal. After this, when I am ready to go deeper yet, I will be rocking a 120CF main, a 40 pony, and my 13 pony. triple redundancy. Its not going to be for at least 6 months or so, and will not be solo. I am looking at the vandenburgh for my very deep dives, most likely with my local dive shop.

---------- Post added August 4th, 2014 at 09:30 PM ----------

As for the pony, I will be looking to side mount after all the research I did here.

 

[jboneng]

Why so many redundant air sources when you are not going to dive solo? wouldn't your buddy be your main alternative air source? wouldn't dragging 3 bottles down create more drag and weight, making your air consumption be higher than normal, making a OOA situation more likely in the first place? (those are genuine questions)

I can see the need for a pony if you are diving solo. But on a 100 feet OW dive with a competent buddy and good communication, checking your pressure gauge often and following the dive-by-thirds rule, I don't see much use for a quadrupedal redundant air setup.

I have no experience with pony bottles though, so take this with a grain of salt. and do whatever makes you safer and gives you a peace of mind.

 

[EFX]

I dive solo occasionally and have used a 30 mounted diagonally across my chest and on the tank. There is advantages to each position. A front or side mount allows you to shut off the valve if you have a malfunction (free flow or 1st stage leak). You can also put your SPG on a short hose and bungee it to the valve. This is best for boat dives as a tank mounted pony won't fit in most tank holding devices. A tank mount gets it out of the way if you prefer a clean front side. You can mount a pony high on the tank or upside down if you need to reach the valve. Just be sure to mount it so that the reg is above the bottom of your tank to prevent damage.

I would suggest taking some formal training. There are other skills you need to know. One important skill is gas management. You can calculate your SAC (surface air consumption) rate using your main tank (AL80?). SAC is volume dependent and must be calculated for each size cylinder. You can calculate a new SAC by first calculating your RMV (respitory minute volume). Using the RMV you can calculate the SAC for the pony. Based on a SAC of 40 psi/min (PPM) the RMV is 1.07 ft3/min. The SAC for a 13 and 19 ft3 tank becomes respectively: 230 and 158 PPM. Calculating the time on both tanks starting with 3000 psi and ending with 500 psi at 66 and 99 feet becomes: 13: 66 = 5.4, 99 = 3.6; 19: 66 = 7.9, 99 = 5.3 minutes. These are near maximum times. In distress the rates go up and you'll have less time. I would not dive below 60 ft on a 13 ft3 tank.

 

[nimoh]

If the Wright brothers were as cautious and self rightous as some people here, they would still be looking for a flight instructor...

If the Wright Brothers had flight instructors available, they would have been foolish not to take advantage of them.

 

[scoobert]

Why so many redundant air sources when you are not going to dive solo? wouldn't your buddy be your main alternative air source? wouldn't dragging 3 bottles down create more drag and weight, making your air consumption be higher than normal, making a OOA situation more likely in the first place? (those are genuine questions)

I can see the need for a pony if you are diving solo. But on a 100 feet OW dive with a competent buddy and good communication, checking your pressure gauge often and following the dive-by-thirds rule, I don't see much use for a quadrupedal redundant air setup.

I have no experience with pony bottles though, so take this with a grain of salt. and do whatever makes you safer and gives you a peace of mind.

I take it from light spelunking I did as a teen. Triple redundancy is very unlikely to fail. eventually I will solo to, and past, 100'. just not initially.
Its hard to find a dive buddy off Henderson island. My wife is prone to freak out, so I impose a limit for her of 33'. Thou her SAC makes me green with envy.
On the last dive we did together (our check out dive) I had 500psi, she had 1600psi left.