-hh
Contributor
- Messages
- 1,020
- Reaction score
- 245
A pony is merely one means of several alternatives to manage risk. Specifically, its to provide air supply redundency.
Another way to have air supply redundency is to have a good buddy. But this doesn't apply if you're going to go dive solo, or if you're serious about UW photography.
Some people will argue that if you think you need a pony, that you really need doubles. There's some merit to this line of thought, but it generally assumes that the dive plan needs a significant air supply, and that the pony will be included as part of it.
Recommendations for doubles also assumes that you're strong enough to carry doubles without injury. Unfortunately, most "former serious divers" I personally know had to give up the sport due to back injuries from the weight of doubles. Similarly, the Military Specification (MILSPEC) for Human Engineering product design places the upper safe limit for repetitive lifting of heavy objects as significantly less than the weight of most doubles systems...in fact, its right around the weight of a single tank system. If you want to be able to enjoy diving for decades, the health implications are IMO clear: avoid doubles.
In some areas, local custom and/or policy is to require some form of redundency. NJ diveboats are one example. Sure, a "Spare Air" technically qualifies, but from a capability standpoint, that's a very poor value...the only realistic choices are a pony or doubles.
If and when you decide to go with a pony, there's another philisophical debate on how best to mount it. In short, the choices are between a slug tank (like a stage) or attaching it somehow to your primary tank. Both systems have their advantages and disadvantages, and both draw some criticism that is incorrect. Some examples of bad advice are:
a) that a bottle behind your shoulder will throw you further "off balance" more than the same bottle off your hip (they're both the same distance off of your center of mass)
b) that 2-3 of pounds of mass that's offset by adjusting your weightbelt's lead in the opposite direction causes a tortuous torque on your body (better watch out for that console!)
c) that one location "Never" gets in your way no matter what you're doing and the other location "Always" does.
d) how cheap a stage rig can be put together for overrides all other performance considerations.
FWIW, if its not obvious, I'm slightly biased against stage rigging - - I tried it a decade ago because they're cheap, but I found that its location/configuration interfered with my UW camera.
FYI, a nice non-stage-mount pony rig that's very compatible with rental equipment and/or rental tanks is a "PonEase" by SeaLutions.
In closing, if you have a good buddy, good equipment and you're doing rec profiles, you probably don't have a pressing need for a pony or doubles.
-hh
Another way to have air supply redundency is to have a good buddy. But this doesn't apply if you're going to go dive solo, or if you're serious about UW photography.
Some people will argue that if you think you need a pony, that you really need doubles. There's some merit to this line of thought, but it generally assumes that the dive plan needs a significant air supply, and that the pony will be included as part of it.
Recommendations for doubles also assumes that you're strong enough to carry doubles without injury. Unfortunately, most "former serious divers" I personally know had to give up the sport due to back injuries from the weight of doubles. Similarly, the Military Specification (MILSPEC) for Human Engineering product design places the upper safe limit for repetitive lifting of heavy objects as significantly less than the weight of most doubles systems...in fact, its right around the weight of a single tank system. If you want to be able to enjoy diving for decades, the health implications are IMO clear: avoid doubles.
In some areas, local custom and/or policy is to require some form of redundency. NJ diveboats are one example. Sure, a "Spare Air" technically qualifies, but from a capability standpoint, that's a very poor value...the only realistic choices are a pony or doubles.
If and when you decide to go with a pony, there's another philisophical debate on how best to mount it. In short, the choices are between a slug tank (like a stage) or attaching it somehow to your primary tank. Both systems have their advantages and disadvantages, and both draw some criticism that is incorrect. Some examples of bad advice are:
a) that a bottle behind your shoulder will throw you further "off balance" more than the same bottle off your hip (they're both the same distance off of your center of mass)
b) that 2-3 of pounds of mass that's offset by adjusting your weightbelt's lead in the opposite direction causes a tortuous torque on your body (better watch out for that console!)
c) that one location "Never" gets in your way no matter what you're doing and the other location "Always" does.
d) how cheap a stage rig can be put together for overrides all other performance considerations.
FWIW, if its not obvious, I'm slightly biased against stage rigging - - I tried it a decade ago because they're cheap, but I found that its location/configuration interfered with my UW camera.
FYI, a nice non-stage-mount pony rig that's very compatible with rental equipment and/or rental tanks is a "PonEase" by SeaLutions.
In closing, if you have a good buddy, good equipment and you're doing rec profiles, you probably don't have a pressing need for a pony or doubles.
-hh
