NDL diving with onboard DIL-OUT? Smaller than 40/50's

[Pavao]

I've never seen nor heard anything like this ever. This happened or is this being facetious?

Yeah, some of the wrecks here in SFL, 165’, 175’.

Last I saw this was on a 150’ where one diver carried an AL40 with air and the other carried an AL40 with either 50% or 100%, don’t remember.

 

[PEDiver]

Last I saw this was on a 150’ where one diver carried an AL40 with air and the other carried an AL40 with either 50% or 100%, don’t remember.

Probably just practicing team bailout…

 

[inquis]

What's so complex about it? Is a 40AL bailout an issue?

No, an AL40 is not an issue, but in this particular case (recreational/NDL dives to a max of 60 ft), it seems at odds with the underlying principle of, "bring only what is necessary."

Again, I'm thinking of a 60 ft NDL dive where the BO is calculated at 40 L/min per atm. Not just to the surface, but enough to sit at 15 ft for another 3 minutes, huffing at 40 L/min/atm as well.

It takes at least 2 major failures before you have to depend on your buddy for assistance. If carrying a 40 as BO, you are still 2 failures away from needing the buddy. As such, the only significant difference I see between the two approaches is the amount of gas to ascend 60 ft. Is a surface consumption of 40 L/min just not conservative enough?

Is this just a general disagreement against dilout (combined diluent/BO)?

Many of you are quite adamant, so I'd love to hear a simple, objective statement of just what you feel the issue is regarding this specific scenario.

 

[kensuf]

I've never seen nor heard anything like this ever. This happened or is this being facetious?

There were some youtube videos posted of something very similar, I think the depths were closer to 130' though. But it was OK, the person was a p2 instructor.

 

[mr_v]

It takes at least 2 major failures before you have to depend on your buddy for assistance. If carrying a 40 as BO, you are still 2 failures away from needing the buddy. As such, the only significant difference I see between the two approaches is the amount of gas to ascend 60 ft. Is a surface consumption of 40 L/min just not conservative enough?

40L/min is cutting it too close for my liking. I consider two breathing rates in bailout cases. The first breathing rate is what you experience the moment you bail out. In my gas calculations, I assume that in the minute following a bailout, I'll consume 5 mins worth of gas. Then my RMV will decrease while still being quite elevated. But I am a conservative diver, and other divers' preferences may vary.

Is this just a general disagreement against dilout (combined diluent/BO)?

No, not at all. Dilout works well in some configuration, e.g., cave Fathom setup.

 

[inquis]

In my gas calculations, I assume that in the minute following a bailout, I'll consume 5 mins worth of gas. Then my RMV will decrease while still being quite elevated.

Thanks for that. I do something similar in that I assume 1.5 cf/min averaged over 10 mins, then down to an average of 0.6 cf/min thereafter.

 

[LFMarm]

Is a surface consumption of 40 L/min just not conservative enough?

Would be interesting to hear what others are using for bailout SAC. I use 45 L/min at the bottom and all the way to first stop, 30 L/min for rest of deco.

 

[211ratsbud]

Doing some basic math, AL30's (~4.16l ea) gives you a total supply of about 8.32 l @ 230 bar ( you could use 208). Subtract some DIL usage, and you get somewhere around 7-8 minutes at depth. Not counting or doing any ascent averaging for SAC rate.

This seems to be fine for the sub 100' dives I would suggest particularly in my setting here in the river. and would appear of similar value to dives where an al40 would be ok for a bailout.

ive been reading the other thread lol

 

[justinthedeeps]

My rig - two 6.7l, 300 bar, carbon cylinders and soft Lola manifold, backmouted as DIL-out and a 3l 200 bar, alu for O2.
Always plenty of air for BOV, suit, wing and DIL, and the weight is at a minimum. why take the chances with “just enough” air for bailout? I only to off my dilout when i hit 200 bar = every 3-4 dive….

What is the 'ready to dive' weight of this configuration?

Do you need to add any other weight to sink those carbon cylinders, versus steel ones? Or is just the manifold/lola assembly alone heavy enough?

Even with a 'heavy' JJ-CCR and 3L steel cylinders, I'm putting lead rods in the handle tubes to get neutral in Santi+BZ400 etc for ~7-12°C dives. ~38 kg, ready to dive.

Being not a hulk, I prefer to hike my bailout to the water separately. Might do the onboard full BO if it was mostly boat diving though.

 

[justinthedeeps]

For years I have been diving my rEvo with on board 3L dil as bailout for NDL open water dives to a max depth of 20m. I really enjoy jumping with that configuration going on long shallow dives.

Is this with a BOV?

The maths kind of work, but do you have backup buoyancy? Is there at least a drysuit fill bottle involved?

Are you not really an eligible dive buddy anymore, because can't donate gas?

For similar shallowish rec dive I have the BOV QC6'ed to the onboard air dil, but also clip on something small with a reg and LPI whip on it (S30, S40, S19, 3L etc). Is that extra little cylinder and reg slowing me down? Idk, maybe slightly. Not much though?