Solo diving pony size/primary red vs octopus

[Kaveman]

Hello everyone,
I have a few questions for the professionals out there.
1)What's your take on the size of pony bottle for solo diving? 19 cu ft vs 30 cu ft.
2)I am going to use LP 130 cu ft steel cylinder, and if I will follow the rule of thirds, it will leave me with 43 cu ft of air for my assent. On the other hand, when I'm diving AL 80, I will have 26 cu ft left using the same rule. Can I leave 26 cu ft instead of 43 cu ft for my assent when diving steel 130?
3)I am currently using scubapro knighthawk bcd with air 2 as octo and my setup is scubapro mk20/s600. I want to add scubapro R190 as second octo so I can use my other BCD. Was wondering if R190 will serve as octopus.
4)I have another set of regs(Tusa RS-350)that I want to use for my pony bottle. The problem with TUSA that it is not serviced by my diving shop. I can by used Oceanic alpha 8 with dx4 for $90 and service it at my shop. What's your take on TUSA RS-350 vs Oceanic Alpha8/DX4?

 

[northernone]

Hello everyone,
I have a few questions for the professionals out there.
1)What's your take on the size of pony bottle for solo diving? 19 cu ft vs 30 cu ft.

Welcome!

In answering here's a few thoughts to consider:

Planning your redundant air supply needs to allow safe ascent in case of complete loss of your primary air source. This figure, and stress factor appropriate, varies from person to person and is covered in a solo diving training. For a solo pony least I've use is al13 and the most so far is a lp131 cave filled. It's whatever is needed for the dive profile. Diving to 130ft I'll need a bigger pony to safely ascent than if I'm in 10ft of water. Which one is suitable for your dive depends on the plan.

2)I am going to use LP 130 cu ft steel cylinder, and if I will follow the rule of thirds, it will leave me with 43 cu ft of air for my assent. On the other hand, when I'm diving AL 80, I will have 26 cu ft left using the same rule. Can I leave 26 cu ft instead of 43 cu ft for my assent when diving steel 130?

The reasonable amount of gas needed for a safe ascent isn't dependant on the tank size. When you need to get to the surface, you want enough "spare" gas to match level of conservative you feel comfortable with. The rules of thirds is sometimes useful, sometimes it has proved fatally insufficient. Other times it is overkill. Myself I prefer calculating what I need for a safe ascent from maximum depth under distress. Remembering too I have a redundant airsource of equal capacity in case there are cascading failures.

3)I am currently using scubapro knighthawk bcd with air 2 as octo and my setup is scubapro mk20/s600. I want to add scubapro R190 as second octo so I can use my other BCD. Was wondering if R190 will serve as octopus.

It's a fine octo, no issue. It breathes nicely and I'd be happy to use it if my buddy offered it to me.

4)I have another set of regs(Tusa RS-350)that I want to use for my pony bottle. The problem with TUSA that it is not serviced by my diving shop. I can by used Oceanic alpha 8 with dx4 for $90 and service it at my shop. What's your take on TUSA RS-350 vs Oceanic Alpha8/DX4?

I'm not familiar with the dx4. For local service I suppose you'll need to switch regs. Might another option be to find another shop?

Hope you find this helpful.

Welcome,
Cameron

 

[swimlikethefish]

To answer your questions related to solo diving and tank sizes you would need to know a few things.

1. What is your surface air consumption rate? SAC
2. What is your Respiratory Minute Volume? Rmv (based off sac rate)
3. What is your planned depth for diving?
4. What safety factor do you plan on building into your air calculations?

The bailout tank you carry (pony) could range from 30, 40, 72, 80, 85.... You get where I'm going with that. The tank size is based upon you air consumption, depth, safety factor, and mod. The later of which shouldn't be an issue if you are solo.

If you hesitate to answer these questions it is best to seek training, diving solo is inherently more risky than diving with a buddy. You must plan for failures and have multiple redundancies. It is more than just planning to have enough air.

 

[swimlikethefish]

On a lighter note, welcome to "the board" you will find a wealth of information. You will also find varying opinions on every subject known to man. Do not be discouraged if you do not get the exact answer your were hoping for in your questions immediately. Most members see safety as the #1 priority. You came to the right place for answers. But, crawl before you walk, and walk before you run.

A pony is a great addition to your diving as far as safety is concerned. People will just get a little touchy if you mention solo diving without the appropriate training. Search around in the forum and you will likely see your questions already answered.

Safe diving.

 

[Kaveman]

Thank you for all the answers. Let me clarify few things that I forgot to mention.
As a solo dives I’m planing to do max 50ft probably way less on the average. At that depth I can swim to the surface with one or two breaths of air. I’m not panning to do it all the time especially on deep dives. I want to do shore dives near by my house. I like spending time under water, I find it very relaxing. I am limited for boat dives to Sundays only and I rarely can make it. So I just want to go and do more dives when I can, given that I live next to redondo beach and have my own equipment.

 

[northernone]

Thank you for all the answers. Let me clarify few things that I forgot to mention.
As a solo dives I’m planing to do max 50ft probably way less on the average. At that depth I can swim to the surface with one or two breaths of air. I’m not panning to do it all the time especially on deep dives. I want to do shore dives near by my house. I like spending time under water, I find it very relaxing. I am limited for boat dives to Sundays only and I rarely can make it. So I just want to go and do more dives when I can, given that I live next to redondo beach and have my own equipment.

Perfect. I love the peace of solo diving too. And it's always easier to fit my own schedule.

Any entanglement hazards or changing currents?