Stage Diving: What are you doing?

[rjack]

has anyone ever had a doubled burst disk blow during a dive? ever?

The real salient questions are,
Has anyone ever screwed with a dropped bottle: yes
Has anyone ever forgetten to shut off a stage: yes
AND it has all the failure modes of backgas except the manifold crossbar/orings.

Gas in dropped stages is IMHO alot more subject to loss than backgas. Thus, I would not sprinkle my reserves around the cave in stages, 1000psi here and 1000psi there. Since I don't solo dive I don't need for buddy bottles and I'm not to the point of needing safeties.

The net conclusion for me is that I'll keep reserves with me and at least have the potential to shut down a leaking reg, burst disk, or valve.

[LiteHedded]

The real salient questions are,
Has anyone ever screwed with a dropped bottle: yes
Has anyone ever forgetten to shut off a stage: yes
AND it has all the failure modes of backgas except the manifold crossbar/orings.

Gas in dropped stages is IMHO alot more subject to loss than backgas. Thus, I would not sprinkle my reserves around the cave in stages, 1000psi here and 1000psi there. Since I don't solo dive I don't need for buddy bottles and I'm not to the point of needing safeties.

The net conclusion for me is that I'll keep reserves with me and at least have the potential to shut down a leaking reg, burst disk, or valve.

agreed. I've had issues with stage bottles more than once

[aainslie]

Fair enough. It is indeed feasible to swim past a stage in zero vis (I posted elsewhere about a dumb thing I did that resulted in me doing this), so I buy that argument, IN situations like high traffic or low vis where a tank might "go missing". I've also once had a problem with a tank that decided not to repressurize nicely - it blew an O ring. So I'm beginning to buy into the "on your back" strategy more.

[HappyHacker]

..I haven't done a dive where I haven't had enough air.

lol. Well that's good to know Hence, the reason you're able to make this post.

[LiteHedded]

Fair enough. It is indeed feasible to swim past a stage in zero vis (I posted elsewhere about a dumb thing I did that resulted in me doing this), so I buy that argument, IN situations like high traffic or low vis where a tank might "go missing". I've also once had a problem with a tank that decided not to repressurize nicely - it blew an O ring. So I'm beginning to buy into the "on your back" strategy more.

mine always seem to go at the SPG

[rjack]

mine always seem to go at the SPG

The only ones I've seen "lost" (outside of a class) were orings on lp hoses that came loose, extruded and then were useless.

[rchrds]

Gary posted a while back a thought that most people should try before you are satisfied that you can make a "low-stress" air share out of the cave. Try making a dive at Ginnie with 100 PSI in your doubles (use stages for gas.) I think most underestimate the difficulties involved in overly light tanks- particularly the sidemounters who cannot add a v-weight.

Jason

[Swede]

... I think most underestimate the difficulties involved in overly light tanks- particularly the sidemounters who cannot add a v-weight.

yes, thats right... During one dive I hade to stay down for a bit longer... and I discovered that LP 85's will get positiv when thay get under ~40 bars (and around 50~60 bar they get neutral), so don't count for the tanks to get you enough ballast. I did the dive in SM. A god thing was that the dive was in a iron ore mine so I could just fill the pockets with iron ore rocks...

[aainslie]

Gary posted a while back a thought that most people should try before you are satisfied that you can make a "low-stress" air share out of the cave. Try making a dive at Ginnie with 100 PSI in your doubles (use stages for gas.) I think most underestimate the difficulties involved in overly light tanks- particularly the sidemounters who cannot add a v-weight.

Jason

It's yet another reason to drain stages first, and then dump them, in an emergency. You're leaving positive buoyancy behind you.

Also, partially flooding your drysuit would probably help a bit with excess + buoyancy.

[Gary]

Also, partially flooding your drysuit would probably help a bit with excess + buoyancy.

Would that actually save gas though? If you got cold enough you could double your gas use - it could be as bad as being bouyant.