Skeeter1097:
I see one out of a hundred divers use a pone. I think that a lot of people have them but never yo-use them.
I have to say there is a time like ship penetration or cave diving.
A pony bottle wouldn't be considered an adequate redundant breathing system for cave diving and I wouldn't consider it adequate for any real wreck penetration either.
Dives in an overhead are planned based on thirds (or more conservative) and you need redundancy on that main supply.
In this country, manifolded doubles are probably the most common but independant doubles and sidemount (which are independant doubles as far as gas management) are also used.
I don't see the discussion as being about whether or not redundancy is needed. The question is when and what training and equipment options might be more useful than a pony.
If one looks at this thread without having their feelings hurt by thinking they are being bashed, I think it's pretty clear that an awful lot of divers who think they need a pony bottle are doing dives beyond their training/experience/comfort, maybe beyond the real capabilities of their other equipment and doing those dives in less than optimal ways. And no, this isn't bashing and I've made my share of diving mistakes which is exactly where this opinion comes from.
I really don't care how someone dives but I do get worried when I see all these newish divers getting in situations that concern them (and rightly so) and their first inclination is to get a pony bottle when there are so many other things they should be looking at. Those things, if not addressed, are likely to cause them trouble whether or not they have a pony bottle.
I don't want to see anyone with hurt feelings but it's better to be hurt here than at 120 on a wreck someplace. When divers are doing hosed up dives with hosed up equipment, adding a pony bottle may just hose it all up more. All else being good and equal, dragging a pony around probably won't do any harm, but all else is not good and it is not equal.