Is a Pony Bottle too complicated for a beginner?

[Hartattack]

I agree. The UK comes to mind as a place where it is not uncommon for newer divers (though maybe not total beginners like the OP) to dive doubles and no deco obligation.

I'd like to make that a norm here in the states. It makes complete sense in the Midwest, and we like to get our community members to hop on doubles as soon as they feel comfortable. It also helps a ton in the balanced rig realm as we are all in dry suits most of the season, lol.

 

[wetb4igetinthewater]

@Hartattack

What's easier when traveling and wanting redundancy?

Pony bottles or doubles?

While it was a PITA, I did travel with a 19 cu ft pony before I got into sidemount. Sometimes but not always I could rent a pony bottle. Of course slinging an extra AL80 is my solution if sidemount is verboten.

Kosta, I haven't said anything about GUE. If new divers are looking for a redundant air source on a single AL80, They have not been taught how to 1. Calculate the gas it would take them and their buddy to get the surface safely in an emergency. 2. How to calculate their surface consumption rate. 3. How to calculate usable gas, and 4. How to determine how long their gas supply will last at depth.
These are examples of fundamental dive math that should be taught at the open water level, and IMHO, it lacks in today's instruction.

By using the SCR acronym you appear to be talking about GUE. Your other assertions indicate the same.

I can only try to lead a horse to water. While a number of instructors and divers have used my dive planning doc as reference, I don't know how many open water classes perform SAC swims and timed distance swims and to calculate swim rate for an incredibly detailed dive plan.

But doing what I describe in my doc is no fun. It's purpose is to give new divers a method for overcoming nervousness and becoming confident to dive and enjoy their dives. Just adhere to min gas for safety.

If min gas with a high RMV is used, then that's good enough. If they have some sort of redundancy, even better to account for possible separation due to unexpected circumstances.

 

[Hartattack]

@Hartattack

What's easier when traveling and wanting redundancy?

Pony bottles or doubles?

While it was a PITA, I did travel with a 19 cu ft pony before I got into sidemount. Sometimes but not always I could rent a pony bottle. Of course slinging an extra AL80 is my solution if sidemount is verboten.


By using the SCR acronym you appear to be talking about GUE. Your other assertions indicate the same.

I can only try to lead a horse to water. While a number of instructors and divers have used my dive planning doc as reference, I don't know how many open water classes perform SAC swims and timed distance swims and to calculate swim rate for an incredibly detailed dive plan.

But doing what I describe in my doc is no fun. It's purpose is to give new divers a method for overcoming nervousness and becoming confident to dive and enjoy their dives. Just adhere to min gas for safety.

If min gas with a high RMV is used, then that's good enough. If they have some sort of redundancy, even better to account for possible separation due to unexpected circumstances.

No need to perform swims, use an SCR of .75ft/min for each diver for calculation; experience demonstrates this is a useful guesstimate that can be adjusted over time with experience. 1.5ft/min considers the needs of both divers. For a novice diver or a diver entering a new environment this value should be adjusted to a higher volume. However, once they get the basics and learn how to calculate these interchangeable terms correctly, It is a diver’s responsibility to evaluate their realistic stress consumption rate over several dives in various environments and adjust their Minimum Gas calculations.

As always, we want to create thinking divers in our students. Plus, it makes the sport more fun and nerdy, lol

 

[tursiops]

SCR of .75ft/min

0.75 cuft/min

 

[Hartattack]

0.75 cuft/min

 

[wetb4igetinthewater]

No need to perform swims, use an SCR of .75ft/min for each diver for calculation; experience demonstrates this is a useful guesstimate that can be adjusted over time with experience. 1.5ft/min considers the needs of both divers. For a novice diver or a diver entering a new environment this value should be adjusted to a higher volume. However, once they get the basics and learn how to calculate these interchangeable terms correctly, It is a diver’s responsibility to evaluate their realistic stress consumption rate over several dives in various environments and adjust their Minimum Gas calculations.

As always, we want to create thinking divers in our students. Plus, it makes the sport more fun and nerdy, lol

I have found that when students use their own RMV and based on time it takes to go from waypoint to waypoint and they see that what they calculated is close to actual gas remaining, it does a lot for their confidence.

Unless they have large lungs (Hoovers) an RMV of 0.75 cu ft/min or 20 L/min works well for min gas calculations.

 

[Hartattack]

I have found that when students use their own RMV and based on time it takes to go from waypoint to waypoint and they see that what they calculated is close to actual gas remaining, it does a lot for their confidence.

Unless they have large lungs (Hoovers) an RMV of 0.75 cu ft/min or 20 L/min works well for min gas calculations.

I might give that a go next class if I have time.

 

[tursiops]

Unless they have large lungs (Hoovers) an RMV of 0.75 cu ft/min or 20 L/min works well for min gas calculations.

As more and more people use computers like Terics that provide pressure/min but not vol/min, some useful (approximate) equivalences for all those folks diving AL80s are 75 cuft/min, or 20 L/min, or 30 psi/min, or 2 bar/min.

 

[Hartattack]

As more and more people use computers like Terics that provide pressure/min but not vol/min, some useful (approximate) equivalences for all those folks diving AL80s are 75 cuft/min, or 20 L/min, or 30 psi/min, or 2 bar/min.

Yeah, I agree; they will make things easier as technology continues to advance in our sport. I use that tech like anything else in my kit, a tool in the toolbox—but I do like to use the old noggin now and then to keep me sharp. It's better than sudoku, I suppose.

 

[rick00001967]

I am SDI Solo now, a yr ago, I was a brand new OW diver, slnging a 13cu pony.

am i just misunderstanding? SDI requires 100 dives before you can do their solo course