johndiver999
Contributor
Sorry, I do not understand what your point is. The purpose of carrying the pony is if you lose your gas supply. A 13 will barely suffice, if all goes well. That 13 is not for someone else, it is for me. Yes, you can give it to an OOG diver, but then you have no backup if you lose your gas, or the dip tube clogs, or whatever. So are you saying that if I leave the bottom with 1000, I can be at the surface with 500? But if someone is OOG, I must leave the bottom at 1500 so we each have 500? Or are you saying that you'll use that last 500 to get the OOG diver to the surface and get back on the boat with zero? Or what?
The scenario you describe above involves two simultaneous failures/problems. The buddy looses all gas supply and then the donor with the pony bottle ALSO has a total failure of a scuba unit.
It is my understanding that in recreational diving, we generally will assume ONE failure in a buddy team - and then implement a plan to get the team to the surface. For example, a buddy team without a pony will be in trouble if BOTH divers loose their gas supply. So this simultaneous failure is outside of the recreational emergency planning scenarios that I am familiar with.
If we are talking about recreational diving, I think we need to be somewhat consistent in our assumptions.
Also the statement (by others?) that a 13 cu-ft tank will require a super fast ascent from recreational depth is clearly incorrect. The math proves that point. The assumption that a diver would need to swim horizontally to acquire an ascent line/anchor line and also perform a safety stop seems rather extreme. Recreational divers are assumed to go directly to the surface when an emergency occurs. If that option is not available (in an emergency) then the diving activity should probably not be considered recreational.
It is unclear to me why some people want to diverge from recreational assumptions, when the scenarios involve recreational diving?