Bail Out Breather options?

[stuartv]

And here it is on a boat before I jump in for a 200' dive.

For that dive, you also carry one additional OC cylinder of some kind of deco gas? Like, an 80 of 50% or something?

 

[JohnnyC]

Running bailout/dil on a rack doesn’t absolve you of carrying sufficient bailout, it just moves a portion of the required volume to your back. However, if that volume is sufficient for the depth and profile, it can be your sole source of bailout gas.

For a 200 foot dive, I would personally carry a bottle of 50 as a minimum, and if my drive gas was offboard, use a 40 of O2 as drive/deco bailout.

 

[Dsix36]

When I finally got to the point that I was entering a cave with my back mount RB, 6 BO tanks, 2 scooters, and a camera; it was time to think about a BOB.

I talked to everybody that was willing and got a lot of good advice and suggestions. I spent over 2 years doing the research on a BOB and figuring out exactly what I wanted. I quickly discovered that there was nothing out there that fit the bill for me and I was forced to make my own, which I am still diving to this day.

The number one thing, is that it must have a perfectly simple and reliable ADV. This one thing will completely negate the functionality of the BOB quicker than anything else.

I decided that BOB should be completely self contained and not reliant on any shared resources. It should be as reasonably simply built as it is to operate. It should be able to plug in offboard gasses. It should be able to sidemount and remain streamlined. It should be quick and easy to monitor po2. It should be dewaterable. It should be neutral in the water.

Some of the particulars I decided on were as follows:
1 - It is a full manual unit with no leaky valve or needle valve. O2 is only added when I use the MAV. This way the O2 is turned on and ready to use without me having to remember to turn anything on. At depth it takes so little effort to maintain SP that it is not a concern even when task loaded. It does take a bit more attention as I get shallow but by then I am more relaxed and it is easily managed.
2 - The ADV also serves as the dil MAV, and the O2 MAV is secured near it so each are there when I want them.
3 - I monitor with a rEvo dream. Yes I hate them with a passion, but it works perfect for this project. All I have to do is glance down to see if the green light is on and the loop is breathable. I like to verify this all during the dive to maintain that warm and fuzzy feeling that I am not going to die this dive.
4 - It has an OPV on the bottom of the scrubber that allows dewatering. I used one of the original lower OPVs from a rEvo 2 since they have more tension than a wing opv but still vent before blowing the counterlungs apart.
5 - I carry one alum 80 on the opposite side with deep mix. I also stage 40cf of oxygen. I will carry the oxygen if in the ocean.
6 - the DSV is clipped to my lower shoulder d-ring

This works fine for dives of 300' for 6 hours or less. If I am going deeper then I change it up a bit and fill both onboard tanks with O2 and plumb in the offboard for dil. This gives me redundant O2 on the BOB itself if needed.

This is obviously a very simplified short story of my life with BOB.

 

[kensuf]

Yes, I carried deco gas. Yes on redundancy on the bailout and DIL -- there's even a 7' hose to give to someone in need of gas.

 

[tbone1004]

This one was made by DSS for UTD. Designed for 50's and I have brackets from Piranha for the 3l's. Big, but works really well. The 50's now have a manifold on them. You shouldn't need more bailout or inflation gas than this while ocean diving so the only other bottles you'll carry are your deco bottles. Underfill 80's and put them on a leash behind you if not doing penetration and happy days or put bungee loops on the harness and sidemount them. Either way they effectively disappear.

The regs are standard doubles regulators with the exception of a 40" hose with a QC6 coming off of the right post to feed the breather. I leave it on when diving doubles now, but it's obviously easy to remove. With a BOV, the left post second stage becomes the BOV for some people

 

[rjack321]

This is not for me. I am a long way from needing a BOB.

A buddy of mine just got home from a couple of weeks of very deep wreck diving. He dives an X. For his deepest dives, he was carrying 2 x 3L steels, 2 additional 3L steels - one backup of O2 and a second 3L just for gas for his wing and drysuit. Then he also had 4 x AL80 of actual BO gas.

I told him it sounds like he should really think about ditching all that and starting to use a BOB. His response boiled down to "I'm not sure how the plumbing would look" and "I have never seen any wreck divers using them."

I suggested he have a look at the KISS Sidekick mCCR. It seems like an obvious choice for use as a BOB. Is it?

What other CCRs would be good to look at as a BOB to go with an X as a primary (for deep wreck diving)?

What are the deepest dives? How deep is deep? I am not a fan of wing and drysuit coming from a single source in the ocean at all (cant confirm this is the case but sounds like it)

Changing up the BOs and the gases carried could make a difference depending on the dive. For instance why have a second 3L of O2 when he's carrying BO O2, just add a whip to that offboard bottle to be able to plug it in.
Lp85s carry quite nicely with high fHe in them 12/65 or 10/70 basically makes them float even nicer than an al80 - if you need more volume than a single 80 of bottom gas. Or the dual 50s as mentioned.

 

[Heat Miser]

Thailand Cave Diving - The Wetmules
Ben diving a rEVO with the very sexy new front mounted Triton as his bailout rebreather.

Thailand Cave Diving - The Wetmules

 

[cathal]

Setting aside the potential impossibility of bailing out to another loop while on a wicked CO2 hit, you still may have the problem of overbreathing the scrubber on the BOB. If there's not enough dwell time, because you're pushing so much volume, so quickly through the scrubber, essentially makes it ineffectual. Putting the brakes on a hypercapnia event means controlling your breathing rate, and removing the CO2 from your body. If you're just rebreathing a loop full of CO2 because your scrubber physically can't bind the CO2 fast enough, you're not solving the problem. Hence the need for real OC volume in the first place.

It will go fast, but it may just fix the problem enough to enable going onto the BOB. Even if he just accepts the fact that he's cutting his margins close by only carrying one big bailout, at least it gives him a chance to solve the CO2 problem before accepting that he's screwed. I'm a big fan of BOV's for exactly this reason. Nothing is gonna put the brakes on a CO2 hit faster than fresh gas and getting the CO2 out of your body.

This, this is the issue I have yet to see bar one person solve when diving with a BOB. How do you plan on reliably swicthing to your BOB during a CO2 hit without a BOV????.

 

[stuartv]

This, this is the issue I have yet to see bar one person solve when diving with a BOB. How do you plan on reliably swicthing to your BOB during a CO2 hit without a BOV????.

The same way you would switch to OC if you were not using a BOV at all?

Or, my choice (I think):

The one video I watched where the Wet Mules were diving the Pearse Resurgence, they each had a BOB and they each had a custom BOV that had both loops plumbed into it.

I believe the BOV was made from putting 2 Shrimp BOVs together. The top switch switched from breathing on one loop to breathing on the other loop. The bottom switch switched from breathing the BOB to breathing OC.

I am curious, though, why you would want 2 switches and OC connected. With a BOB, it seems like you'd just want one switch, that switched from one loop to the other, and that's it. Maybe theirs was just that way because of the parts they were working with to build it in the first place? Or is there a reason to still have the OC option when you're diving with a BOB and redundant cylinders of everything?

 

[tbone1004]

This, this is the issue I have yet to see bar one person solve when diving with a BOB. How do you plan on reliably swicthing to your BOB during a CO2 hit without a BOV????.

you can't functionally overbreathe a scrubber, so there is that.
That said, most people either have a BoB that is tied into a custom BOV where they can go back and forth, or at least carry enough dilout/bailuent to deal with that and then switch over to the BoB

@Dsix36 will hopefully weigh in though as he's got a lot of hours on them