Freeflow at 140'

[lamont]

Lamont
And your advice to me was to switch to the pony, shut off my primary, wait five minutes of a seven minute dive for it to melt, go back to the primary and not abort the dive?

No, my advice is to dive doubles or sling at least an Al40. And carry enough gas and run your dive plan so that you know what to do in a contingency where you go over by +5 mins at depth.

 

[rjack321]

I suggest:

Limiting your narcotic depth to something more reasonable, like 100-110'.

Get more training so you can pick the best gas for the dive.

Carry all the gas (including contingency gas) needed to complete the dive with you.

Lastly stay with your buddy, this incident could have been disasterous if he'd had a small problem at depth after you started heading up on the pony. Dive as a team or plan the dive as a solo dive (if you're into that sort of thing). Don't plan a dive with a buddy and then split up.

 

[jeckyll]

Addendum:

By the design of doubles with an isolation manifold, you can turn off one valve (regulator) and still have access to the air in both tanks with the other regulator. However, shutting down a valve for an unfixable freeflow is a major failure and should drive you to thumb the dive.

Really? How do you have access to the air in _both_ thanks if you've isolated one? I thought the point of an isolation manifold was that if you have a catastrophic failure you can save the air in _one_ tank and have access to it via one reg, thereby being able to make it back....

 

[rjack321]

If the failure is a reg you need not close the isolator only the failed post. You can access all the gas through the other reg.

If a burst disk, tank neck o-ring, or part of the manifold itself fails you close the isolator and access the gas in the remaining tank.

 

[TheRedHead]

Really? How do you have access to the air in _both_ thanks if you've isolated one? I thought the point of an isolation manifold was that if you have a catastrophic failure you can save the air in _one_ tank and have access to it via one reg, thereby being able to make it back....

Turning off the isolator, isolates the tanks. Turning off a valve, disables the regulator for that tank but you can still access the gas in both tanks through the bar in the manifold.

 

[jeckyll]

Turning off the isolator, isolates the tanks. Turning off a valve, disables the regulator for that tank but you can still access the gas in both tanks through the bar in the manifold.

Thanks for the clarification

So if you had a tank o-ring failure you'd use the isolator but if you had a freeflow on the reg you'd shut down the post only.

Not to get this thread offtrack, but don't have double (obviously) and have wondered about how that worked

 

[GulfCoastdiver]

In typical Padi AKA 'wrong' fashion, I'll bet they were hung on the line @ 15ft.

This is standard DIY (dumb-a*$$) gas planning, the kind that is typically taught in Padi Deep specialties....no doubt other rec deep diving classes of other agencies do this too, I do not know, but we know who the leader is here......

Maybe you can tell me why I shouldn't hang a tank at 15', I have a reg in the shop how getting O2 cleaned for just that reason.

 

[TheRedHead]

Maybe you can tell me why I shouldn't hang a tank at 15', I have a reg in the shop how getting O2 cleaned for just that reason.

You should have a back up plan in case it is not there. You can't count on it without planning for its loss.

 

[GulfCoastdiver]

You should have a back up plan in case it is not there. You can't count on it without planning for its loss.

I see, My plan is not to include it in the plan

 

[rainman_02]

Thanks for the clarification

So if you had a tank o-ring failure you'd use the isolator but if you had a freeflow on the reg you'd shut down the post only.

Reg failure (1st stage, 2nd stage, hose burst, o-ring extruded, etc): You'd shut down that post only. The bubbles would stop.

Manifold failure (tank neck o-ring, manifold o-ring, etc): You'd shut down that post and close the isolator. The bubbles would continue until the tank with the failure was empty.