Posted by seahunt on March 08, 2004 at 05:56:47:
In Reply to: Calculations? posted by Ross-O on March 07, 2004 at 23:47:48:
For a .45 you need iodine as well as a bandage.
Uh... it's a matter of perspective. I didn't mention 30 fpm.
Maybe I shouldn't comment on the subject because I'm different than most divers and have different experiences, but I know that I can come up pretty fast from depth without getting 'noticably' bent. I used to do it all the time. I dove for 20 years before anyone said anything about safety stops or going up less than 60 fpm. That was before SPG's also. I used to suck my tank dry as a habit. There is a lot of variation between how people respond to surfacing. While I'm not in that kind of shape now, that guy sounds like he is. Admittedly, I would come up faster than I should with the small bottle, but experience never showed that to be a problem and since the pony is strictly for emergencies, I'll take my chances. I don't plan to use it anyhow. In 34 years of diving, I never needed it and still don't expect to, but I do expect it to get me to the surface. Strategy is a fast ascent to 15 feet and then empty the tank before surfacing.
As for scared, that's an issue perhaps, but I don't get scared in the water. It has been tested. Repeatedly. I said I have used less than the best gear. That is putting it mildly. Years back, I got more experience with gear failure than most people. My motto is that panic is fine, after you are dead. North Coast diving teaches you that too. I've done a lot of soloing where diving would be more appropriate for a team.
Another difference for me is my experience freediving. It gives you more options.
Related to that, have you ever read my essay on breathing? I have trained my body a bit more than most people and have pretty good control.
Truth is, I was amazed at how long the tank lasted in the shop. Calculations said it should have been empty way before I quit breathing on it. I never did empty it all the way.
Calculations of air consumption are fine, but based on experience, I calculate that my small pony should get me up safely, usually without bending, in the event that I need it.
Of course, I really should use it for a real ascent, but I just haven't got to it.
One caution of a pony bottle like that is that if you don't have an SPG on it, you have to make sure it is full. A little regulator flow and it might be 10% down.
Enjoy the diving, seahunt