7L Pony?

[Juz]

No.1 In an emergency your SAC goes ballistic, 80 - 100l/min is not unheard of and 40l/min is common.

40l/min SAC at 30m would drain the 3l in approx 4 mins, but of course you're not going to stay there, you're going to be on your way up.

When you realistically do the numbers, a 3l is only just good enough for 30m no deco diving and certainly not comfortable.

I think you should try different mounting methods for the 7l, but I suspect you'll end up at the 'side slung is best' option.

Another option might be to sell the 7l and get an ally side sling, it will hang more nicely when in water.

As always, borrow a few tanks and try them out. If you're ever further south you're welcome to try anything that I have - AL80, 7l Steel, twin 12's, 3l Steel.

Juz

[Mal Bridgeman]

Originally Posted by MATTBIN

Just after I started diving there was a post on Divernet by Vic (remember him, I bet Chasey does ), anyway he posted they had documentry proof that a diver drained a 3l as his sac hit 100lpm (surface rated, so he hit 400l/min at 30m), drained a 3l in moments, well 1 1/2 minutes actually. It is more than possible, rare, one would hope, but possible.

Matt

Mmmm that is an extreme case and I wouldn't have thought that everyone would want to plan based on an extreme case.

The point I was trying to make was that you can get yourself into more trouble with overdoing the contingency and sometimes it would be better to address the root cause....like staying close enough to your buddy, not getting into deco obligations till you are ready to deal with them and if you are that uncomfortable at that depth .... then don't be at that depth.

Mal

[Nick Kay]

Stage rig it - far more flexible and allows you to hand off the cylinder if you're ok and your buddy needs it

Properly rigged it should be more balanced than attaching it to your twins plus you get to dive with it turned off - presuming you'd attach it at the centre of twins to stop roll