rEvo - O2 at more than 100 m ?

[J-Vo]

Find that as long as I am on the loop, the NERD is way easier to change settings or scroll menus than the Petrel. I can keep my eyes on what I'm doing/referencing and reach up without obscuring my vision to press the buttons. The Petrel requires me to completely change my focus to my arm, and I find the buttons more difficult to reliably press with them berried in my dry suit folds with dry gloves.

As for bail out, once you change the NERD to bailout, you just need to reference it periodically to make sure it agrees with your Petrel and stand alone. Not a big deal.

 

[Brad_Horn]

You going to go replace the non replaceable, pressed in orfice inside the seal-beating-sized Revo triple MAV when they do?

Why?

Logic and FMECA requirements indicates that the plumbing downstream of any OXYGEN 1st stage has been engineered to survive a HP seat failure and 300bar... This was a rebreather design lesson learnt back in the 70's by GE and Biomarine et al with the Mk15.
FYSA the Apoc Type IV CMF injector/MAV just fails safe and injects O2 at a constant 10L/min that you can feather via the cylinder valve, vs normal ~0.7L/min CMF and constant 20L/min manually.

 

[Superlyte27]

Hi
Just a needle valve with a normal reg. Still don't get the idea of needle valve with a blocked reg... it is not that much to do adjustments on the fly...
Or just use your DIL as it should have a good enough ppo2...how long are you going to stay that down anyway?

Who is going to tell him? Lol

We watched Nathan S. try this two weeks in a row at the back of Indian on rEvo at 300+ feet. Both times he emptied his DIL in a matter of minutes. We were HOURS from the surface.

FYI, don’t do this. Just get the right rebreather for the job.

 

[jale]

Who is going to tell him? Lol

We watched Nathan S. try this two weeks in a row at the back of Indian on rEvo at 300+ feet. Both times he emptied his DIL in a matter of minutes. We were HOURS from the surface.

FYI, don’t do this. Just get the right rebreather for the job.

Of course, in a cave (Indian is a cave, isn't?), far away from the exit, you don't do that.
But for a touch and go in ow...
Different tricks for different situations

 

[cathal]

Of course, in a cave (Indian is a cave, isn't?), far away from the exit, you don't do that.
But for a touch and go in ow...
Different tricks for different situations

This is my thought as well, for OW wreck dives Bottom Times past 100M are usually in around 30mins including the descent. Of course there will be longer Bottom Times, but just trying to take into account the O2requirements for the average bottom time in Open Water when deeper than 100M.

 

[Wibble]

Another dumb question...

How about taking -- attaching to the unit -- another "O2" cylinder with a normal regulator. If this is filled with 100% then you have to be extremely fast and careful on the injection as (just use 140m/15ATA for example) a 1.2PPO2 at that depth is 1.2/15 which is 8% of the loop gas).

So why not use a special "O2" mix of, say, 50/50? This would mean that manual injection is less sensitive.

 

[grantctobin]

Another dumb question...

How about taking -- attaching to the unit -- another "O2" cylinder with a normal regulator. If this is filled with 100% then you have to be extremely fast and careful on the injection as (just use 140m/15ATA for example) a 1.2PPO2 at that depth is 1.2/15 which is 8% of the loop gas).

So why not use a special "O2" mix of, say, 50/50? This would mean that manual injection is less sensitive.

Works and decreases the spike should you need to add oxygen. I think Don Six was using that method (offboard injection of 50%) during his sub 120M stuff.

 

[broncobowsher]

I remember hearing something about using one of the deco bailouts as a bottom O2 plugged into the off board.

 

[Wibble]

I remember hearing something about using one of the deco bailouts as a bottom O2 plugged into the off board.

Would that mean diluting your helium though? Was thinking that 50/50 (O2/He) would mean the helium's not compromised? Maybe 50/35 would be better to match the He/N2 ratio?

 

[lermontov]

To keep things very simple (which is what you want below 100M) I just use a Dil that will give me a 1.2 SP, while I am at the bottom as 90% of the run time will be well above 100M.

with no o2 supply a po2 of 1.2 will take around 13 minutes to drop to .7 - a dil flush that brings it back to 1.2 seems the simplest solution before adding extra bottles or manually adding and cacluating your off board gasses to bring it back up