I run a similar rig, except I use a single E8-130 with H-valve. Having dove with numerous buddies, I have run into a number of buddy's having equipment failure and running out of air. My experience is about half of the timethe first you know about the problem is when they yank your regulator out of your mouth. Nice to have the back-up nicely located under your chin.
Doug
You don't check your buddies pressure during the dive? Even with my most trusted buddies, we check each other's pressures at least 3 times during the dive. Once after the surface briefing, once when we hit depth, once about halfway through the intended bottom time, and once just before ascent or during the deeper part of the ascent.
This accomplishes a couple of things:
1. We know our tank pressures in the water after the tanks have cooled. This allows us to match gas for the dives.
2. We check pressure after descent to make sure we haven't "lostt gas" somewhere. Either by a leak, or by a particularly stressful descent, or some other issue. When diving with new buddies, this also shows me if they can handle basic taskloading such as hovering and checking gas and communicating clearly at the same time. If they cannot handle this, I might modify the dive or end it, depending on the plan.
3. If we intend to do an hour long bottom time, I'll check with everyone around half an hour in to make sure that we are breathing at a rate that I think we should. If someone is overbreathing badly, half the bottom time should allow enough reserve to turn the dive immediately and ascend.
4. Checking the gas on ascent gets me, and my buddies into good habits of making sure we understand what we are breathing and how much of it we have. In the move to decompression, this is critical.
I'm not trying to say you should be checking your buddies as often as we do, but a quick glance at their SPG, or a question to them mid-way through the dive is basic safety. Not doing this can easily put you both at risk.
Edited by PerroneFord, 25 April 2007 - 08:23 PM.