Hi Guys,
Interesting article : Out of Air at 40 Meters by Christian Gerzner.
The BCD being an emergency air supply has been done by a few people I personaly know. There is one article, can't remember when or who but it was so interesting, I remember the detail as such :
He was a commercial diver who was organizing of piling up some big steel pipe underwater. Somehow he got into an accident where his leg was trapped under one of the pipe. Simply he can't move, unless he cut his foot. So the story goes that he knew he needed to conserve air because the search and rescue will not take place for sometime untill which he will be out of air by then. So he started breathing from his BCD till the air get sour, dump & fill it up again. Just like a re-breather. He managed to extend his "suffering" for a great deal of time and was about to be out of air and decided to cut his foot and fortunately his team found him. Lucky guy, live to tell the tale.
However the idea of cutting a high pressure hose if the tank still contain decent amount of air ( first stage broke down ) and writer assuming that the air hole size of the HP port in first stage is pin hole and thus we will likely to have less air than more instead of tons of bubble..................is not correct. The pin hole is correct but the amount of air delivered is massive, but breathable. I seen SPG console flew like small rocket when the rotating swivel joint broke and the amount of air released from this "pin-hole" is definitely not small, very much like a second stage full-blown free flow but much worse.
Scuba diving alone is definitely not as safe as when you have a buddy, but on the condition that the buddy is not going to be the person who will introduce any sort of danger to you. Two person doesn't guarantee safety, two person double the risk of whatever danger or bad luck one person could instead have. The best is to have a buddy at least with a similiar skill level as you are or better, this include not being easily panic and so on.
It will be best you equip urself with enough back up, especially rebundant air source like Spare Air, just be prepared and think that you will dive independent even if you have a buddy.
I dive in groups but since we all spearfish, no one wants to be with no one. We descent together but when u hit the bottom, everyone go on their own way to the "secret spot". If bottom time is 45 minutes, I see them only like the first 3 minutes, sometime more if we deco together at 5 meters, if there is a decent line used. Since visibility is normaly bad in my area, you hardly can "see" them in the hunt area at the bottom. Technicaly I been solo diving for so long. However, there was a case that I blessed the presence of a buddy next to me. I was at 120 feet and out of air. This is purely my dumb fault that I did not realize that the boat crew forgot to change a new tank for me, unlike for the other 5 divers who got new tanks. First case and last case. In the excitement of the hunt I too simply forgot to check my air pressure (first time ever ) before jumping in the water and my regular second check half-way down. The desire to be the first diver down the small FAD was simply too overwhelming. Two mistakes all heading my way...........what a bad luck !!
I think the danger is about diving either solo or buddy is that when you think you dove so often you take everything for granted. You either forgot this and that or start thingking ...well I have a buddy, if anything happens I can rely on him/her.
Don't ever be as dumb as me...remember that.
IYA