Curious how bail out procedure works at great depth

[211ratsbud]

Hi , I am currently not a rb diver. I was wondering how a bail out procedure would work at greater than standard air 21%o2 po2 1.4 equivalent depth.. An example situation would be perfect as I'm only curious ..

Thanks!

 

[Superlyte27]

I'm not sure I understand completely... But I'll try to answer your question.

Imagine you are on a dive to 300'. Your rebreather has 10/65 Trimix in it. Your PPO2 is set at 1.0 on the unit. Suddenly (and because you're diving a piece of crap Titan) you notice that your rebreather is hopelessly flooded, BAD. Because it's a piece of crap Titan, your sorb looks like a frothy milkshake of Caustic Cocktail, and even if you could clear the water (which you can't because it's a piece of crap Titan) the sorb is trashed. You've got to bail out.

Thankfully, you knew going into this dive what your max depth would be... (bah my phone is in the other room, so I'll guess at the math) so your bailout gases are 15/50 Trimix (sidemounted), 50% Oxygen (staged at 70') and 100% Oxygen (staged at 20'). You immediately close the DSV on your Rebreather (that's the mouthpeice assuming you don't have a BoV, you're not a pansy diver after-all). You yank the DSV out of your mouth while simultaneously putting the 2nd stage regulator of your 15/50 bailout in your mouth. You've checked the operation before, but you ensure the valve is open, pressure is good, and it is breathing clean and dry. You change your computer from CC to OC (if your diving good electronics like Shearwater) You end your dive. Upon reaching 70' you grab your bottle, charge it, switch to breathing it, and change your computer. Wash, Rinse Repeat....

This is pretty basic, and a lot more motions and thought goes into planning your bailout, but hopefully this answers your question. And oh yeah, ditch that Titan and buy an Optima. We don't have no stinkin issues on those things.

 

[211ratsbud]

Excellent thanks . I was wondering how you bailed out beyond safe limits of air. You understood me and that helped a ton.( I wasn't sure how you'd carry the extra bottles even if practical. But you established you drop one, carry one, and could possibly carry both if needed

 

[Superlyte27]

I don't even put air in my tires.

 

[211ratsbud]

Hah, edited my last response to clarify my thoughts a little.


. I'm doing a lot of homework on rb stuff trying to weigh it's viability vs oc trimix etc.. and looking out for my best options when the time comes. I wanted to get a clearer picture of the process too..

 

[Superlyte27]

Well Dana, let me help...

OC Trimix is the most expensive class I teach. I almost never teach it because I feel like the student is getting ripped off.

A few years ago I co-taught a class with a buddy of mine. We spent a week diving Eagle's Nest Cave (300' deep). At the end of the week the two students had spent $1700 on gas fills. Had they been on a rebreather, they'd have spent less than 10% of that.

I guess if cost is the deciding factor, it would depend on how many deep dives you plan on doing. For me, the last 10 dives I did were all 5+ hour long and 300' deep. So, it adds up quickly. But even if everything were equal, and cost didn't play into it at all, it'd still be worth it to fork out the cash and dive a CCR.

So when you are trying to talk your wife into it... here's the bullet points. While they may or may not be 100% factual. They are close, and they make a good argument.

Diving a Rebreather is safer. Especially if you area a cave diver doing deep dives. Imagine, between the rebreather, dive buddy, and your multiple options for bailout, you literally have 3 or 4 completely independent options for survival.

Diving a rebreather is lighter, considerably. My 104's weighed 140lbs fully rigged. My rebreather (on the heavy side is 70lbs). Some rebreathers are under 50. This means your back is going to last longer. Your ankles and knees too. That means you can do yard work well into your 70's.

Diving a rebreather is cheaper. If someone calls me up tomorrow and says, "Hey, you wanna go dive Eagle's Nest?" I don't have to fret. I've already got the bailout, and it costs just $26 to fill the sorb, o2 and diluent to make a 5 hour dive. That's a no brainer. I don't have to cough up $300 anymore in open circuit gas. Woohoo.

If you are into wreck penetration or cave diving, a rebreather is safer because you have virtually unlimited time to get yourself out. My rebreather is good for 10+ hours. Make a wrong turn, get lost, silt out. Lights die, tangled, collapse.... I've got time to fix it.

And between me and you, if all of the above were equal, from OC to CCR. It'd still be worth it just by the fact that I don't have to look at a pressure gauge ever again during a dive.

Once you get used to diving the right rebreather, there's nothing better for diving enjoyment. And you just won't understand until you buy one and hit about 25 hours on it.

---------- Post added October 18th, 2015 at 12:13 AM ----------

Also I should say (back to your original question) that if you have a BoV (Bail Out Valve) on your rebreather, which is just a DSV that doubles as a second stage regulator (plumbed to bailout gas usually), you need only flip a lever to bailout. This switches your gas from the loop to a fresh supply. It's quicker, and ultimately, probably safer, but does cost a butt ton (metric not imperial butt ton) and sacrifices some Work of Breathing.

 

[211ratsbud]

Again thank you for the help, I'm in the 1000 islands and there's some deep ones 250ish, the roy a jodrey is one, but I'm looking to explore some for sure.

I'd really like to see more hands on of some types of units and set ups most of what I see is on the web. I get a couple on the boat each year.. just had a prism2 diver and I was quite fond of her descriptions of that unit and reading about the kiss stuff lights up my inner minimalist tendencies.. ie evo ix rs no radio...5 speed and manual windows no ac lol

 

[macado]

Excellent thanks . I was wondering how you bailed out beyond safe limits of air. You understood me and that helped a ton.( I wasn't sure how you'd carry the extra bottles even if practical. But you established you drop one, carry one, and could possibly carry both if needed

Superlyte27 already explained it better than myself but on a rebreather you should always be carrying a breathable gas that you can bailout to. The bailout gas you carry is usually based on depth with a max ppO2 not to exceed 1-4-1.6 and equivalent narcotic depth (END) you've determined is acceptable. You would also carry one or more rich gases for a deco mixes.

One thing I will add since Superlyte27 is diving in caves. I prefer to carry all my gas with me and I don't drop or leave bottles anywhere. However usually in a cave you can reasonably assume you're going to exit the same way you came in so you can clip bottles off lines or at pre-staged areas. (Note: This is an over simplified but using it as an example).

I don't like leaving bottles anywhere, especially on a wreck. I prefer to be self sufficient and carry all the gas that I might require if I have to bail out. What if you get lost and lose the up line? You can't always assume that you can get back to where you stowed your bottles. Mooring could break or perhaps you have to do an emergency ascent before you get to up line.

I'll use the Jodery (240') as an example as I just dove it last month. My diluent was 10/50 and I was carrying two AL80s, 18/45 for deep bailout and 50% for rich bailout/deco gas. You could also carry a third bottle of Oxygen but my profile and runtimes didn't dictate or require it.

There is also an alternative approach called team bailout where divers carry 1.5 times the bailout gas required to get one team member to surface. I don't like this approach. What if you lose your buddy or even worse, both units fail (unlikely but you never know..). Team Bailout requires a lot of discipline and good familiarity with others in your team.