gas switch: backgas? move bottles?

[HIGHwing]

Depends. I can create scenarios that work for the BOV and those that don't. If you're making no-stop or very limited deco 80ft-130ft dives using Air Dil and plumbing the BOV to an offboard AL80 of air the BOV is a smart choice. But if you're going to use CCRs with helium that changes the equation enough (for me) that the BOV becomes less attractive.

As I stated previously, I really think BOVs are a mixed bag.

 

[Garth]

I don't know. You dive the RB80, I don't.

The risk vs reward is perfect with the Hammerhead because it's a dream to dive. It's built like a tank but not the size of a tank. The massive bailout would be the only thing that I would consider as reason not to dive the RB80 on a 60ft dive. With the hammerhead and the smaller tanks on the back I can sling a 40ft3 tank on a shallow open water dive for bailout.



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[PfcAJ]

You can put baby tanks on an rb80. Its neato. I've seen it flanked by al40s, a pretty compact package.

 

[Makhno]

switching to backgas between deco gases helps minimize the potential confusion and tangled up hoses. I think the biggest reason though is the o2 break.

Thanks for clearing that up for me.

I dont see any reason to move the 6m bottle on top. Top or bottom, it
doesnt matter at all and gas switching based on position of tanks is bad news.

Yeah, I don't see any reason for it either. Some divers do it, and I have never really understood why.

 

[jadairiii]

....why don't you research the cases of OxTox and what pO2 they occurred at. Anyone diving at 1.6 has a greater risk of OxTox, ....

Most people I know hit their 80% at 30’ for deco, so their PpO2 is 1.51, Use 100% at 20’ your PpO2 is actually 1.59. So your fear of toxing at rest in deco is based on an increased PpO2 of .08?

And if you don’t have solid buoyancy skills and drop below 30’ on your 80% you are above a 1.6 anyway. So what is the fear? Do people really believe that the “trigger point” is .08? Is that it, that's the "greater risk"?

Having researched and followed OxTox incidents, they are rarely (if ever) during deco at rest. It is usually improper gas switch deeper (or a CCR malfunction). And you guys solved that problem of improper gas switches by using different colored 2^nd stages and poodle jackets.

 

[Garth]

You can put baby tanks on an rb80. Its neato. I've seen it flanked by al40s, a pretty compact package.

I was thinking 3 liter tanks.

With 100% used in a 3 liter I can easily get 8hrs oxygen required to run the rebreather or more.

40's are definitely smaller than the steel 85's I've seen on some..


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[PfcAJ]

ive got a set of 85s and a set of lp120s. its big.

 

[Dr. Lecter]

I've read enough reports of folks who are so borked mentally that they can't even take the DSV out of their mouth to switch.

No thanks, chief. I'd rather not drown.

You and me both, but open loop breathing seems like a better solution to me. Then again, I'm not diving an SCR with a set of doubles stuck to the sides.

Most people I know hit their 80% at 30’ for deco, so their PpO2 is 1.51, Use 100% at 20’ your PpO2 is actually 1.59. So your fear of toxing at rest in deco is based on an increased PpO2 of .08?

I guess all my tables lied to me when they showed a whopping CNS difference for the same deco on 80 vs 100.

 

[PfcAJ]

I'm curious as to why you feel that a DSV is a better solution (if I'm interpreting your post correctly) over a BOV?

 

[Dr. Lecter]

I'm curious as to why you feel that a DSV is a better solution (if I'm interpreting your post correctly) over a BOV?

It's less complicated, has fewer failure points, and doesn't weigh a frigging ton hanging out of my mouth for hours on end. if I'm so out of control on my breathing that I know I can't transition from the DSV to my BO without involuntarily sucking in a lungful of water, all I have to do is go to open loop breathing.

At that point I've effectively turned the DSV into a diver controlled 2nd stage and will be reducing my CO2 levels regardless of whether the scrubbers are broken through. After I'm under control in terms of breathing, BO normally.