Issues with DIR gear configuration

[RichLockyer]

Buoyancy control can be difficult when using an Air2, and yes, there is a certain issue of reliability. Failure of the LPI would leave you having to disconnect, eliminating your backup air source.

Moving further into tech diving, with a set of doubles, your backup reg is on a different 1st stage from your primary... the LPI is on the same one as the primary. Yes, the Air2 could be moved to the secondary 1st stage, but then a loss of that reg robs you of both your backup air source and your BC inflator.

Also, you technically do have three air sources. If your buddy is on your primary and your backup fails, you can use the LPI as a reg. This is a last-resort type thing, as you will swallow water, but it does work and will get you to the surface.

The name of the game to surviving under water is reliability and redundancy.

 

[idratherbediving]

that makes sense, i guess i took my air for granted. but how is bouyancy easier with a lpi?

 

[mer]

that makes sense, i guess i took my air for granted. but how is bouyancy easier with a lpi?

Ditto what Rich said. The DIR answer is that you want these devices to be separate to have a "third-last-resort" reg and so that a failure of your inflator or your backup does not automatically yield two pieces of equipment unusable.

How is buoyancy easier with a low pressure inflator vs. an integrated "Air 2" type inflator? Go to your favorite, protected site... go to 30'... switch to your AIR2... now make a controlled ascent including a safety stop. You'll find adding and venting air from your BC through the AIR2 is rather difficult when breathing off it.

 

[idratherbediving]

gotcha, again, thanks to this site and the information available, my horizons have been widened and i am a smarter, safer diver. thank you all very much.

 

[detroit diver]

that makes sense, i guess i took my air for granted. but how is bouyancy easier with a lpi?

To just add to what Mer posted, the problem of the AIR2 (and it's cousins) will magnify itself during the worst possible of situations- a real OOA when the heat gets turned up big time. You're already at a high stress level, and adding the AIR2 complexity is just not where you want to be.

 

[idratherbediving]

ok, now that you have me reconsidering my rig.... the backup 2nd stage, is the hose routed over my left or right shoulder?

 

[detroit diver]

ok, now that you have me reconsidering my rig.... the backup 2nd stage, is the hose routed over my left or right shoulder?

It always comes over your right shoulder. On a singles rig, there is usually only one source for it to come from. On a doubles rig, the backup source comes from your left post.

 

[idratherbediving]

im sure if i was setting up my rig, i would have seen how going over my left shoulder wouldnt really work. thanks again

 

[RichLockyer]

[edit]

Oops... already answered

 

[cornfed]

Fin-wise, consider full length tubular webbing. It's dirt cheap from outdoor shops like REI & you could cover the entire spring.

Some people use plastic tubing but I think that tubular webbing is much better. The reason being that it bunchs up. You can get a piece which will cover the entire spring when it is stretched and it will just bunch up when you take your fins off. With plastic tubing you're limited to the unstretched length of your straps which can leave a portion of the springs uncovered when you put them on.