Do all rebreathers require a bailout bottle on board ?

[happy-diver]

A bailout is required when you want to get off the loop because you want to

 

[ScubaWithTurk]

A bailout is required when you want to get off the loop because you have to

FIFY...I don't any diver who WANTS to get off the loop but I know plenty who have had to get off the loop

 

[211ratsbud]

"on board"? No. I would say it's most common to plumb BOV into the onboard 3l but, just as common to plug the BOV into off board. After that initial switch if using onboard plumbing to 3l the diver would work to switch to off board. This a sort of old tyme status quo, that I'd surmise in the last 10 years has subsided in favor of BOV plumbed into larger offboard cylinder, or dil-out solutions both on and off board. This topic is a tough one to describe all the options, prescriptions, and configurations. If you demo a CCR, or take a class they will get you started with a reasonable option.

DSV solutions start to narrow the field of options and configurations down some. Usually a necklaced or immediately accessible second stage is off board, and on board when using dil-out configuration.

 

[MidOH]

I could have swore that I talked to a guy where his onboard dill tank, and his offboard slung dillout tank, fed the same MAV valve? In the same spot.

I might have misunderstood him.


Is it normal/ok to have two regs basically connected to eachother at the MAV, working in parallel?

 

[kissonerga.ccr]

I could have swore that I talked to a guy where his onboard dill tank, and his offboard slung dillout tank, fed the same MAV valve? In the same spot.

I might have misunderstood him.


Is it normal/ok to have two regs basically connected to eachother at the MAV, working in parallel?

APD sells this to allow simultaneous feed from two dil sources, via separate MAV buttons: Dual Diluent Inflator with ADV Shutoff Valve (for BMCL)

As to whether it‘s OK… it does increase the risk of operator error.

For full disclosure, I have one installed (as well as a dual O2 MAV from the same manufacturer). Personally, when I plug offboard dil, I unplug the onboard connection, although it remains easily accessible in my configuration. Safer that way

 

[Wibble]

APD sells this to allow simultaneous feed from two dil sources, via separate MAV buttons: Dual Diluent Inflator with ADV Shutoff Valve (for BMCL)

As to whether it‘s OK… it does increase the risk of operator error.

For full disclosure, I have one installed (as well as a dual O2 MAV from the same manufacturer). Personally, when I plug offboard dil, I unplug the onboard connection, although it remains easily accessible in my configuration. Safer that way

Or the Revo equivalent, fitted to every Revo

https://www.revo-rebreathers.com/product/r217b-triple-diloxydil-offboard-block-mav/

 

[AJ]

So why do you need a bailout bottle if you have a diluent bottle full of air? Why can't you just flip a switch on your mouthpiece and go to your diluent bottle and use that as an emergency gas to get you to the surface? The bottle line is if i am not diving too deep and have enough diluent gas on board. Maybe this is a dumb question but i can't seem to find an answer. P.S. i am not rebreather certified, but going to very soon.

If you're not deep diving you could get to the surface with a 3 ltr. But there are some considerations:
- It is an best practice to always dive with the same config, even for training purposes;
- As already metioned, you don't have a lot of gas in a 3 ltr. Time to get to the surface is very limited, even shallow;
- When diving deeper it's not always possible to use your diluent gas shallower. Therefore is it good practice to dive always the same way as if you're diving deep. This creates muscle memory.

So, yes you could dive without bailout but why would you want to do that? If the weight of a relatively small bailout is too much, then the rebreather itself will almost certainly weigh too much.

 

[fsardone]

I would definitely advice against diving with a single source of gas.
If you lose the onboard diluent for a blown whip or a free flow overpressure valve or second stage, you would lose also buoyancy (dry suit or bcd and diluent).
So for your sake have a second bottle or at least a dry suit independent inflation source.
There had been an incident in which the diver separated from bailout after surfacing and while climbing the ladder, fell back, tore the loop and died plunging to the bottom.
He was using bailout to inflate BCD and suit while onboard dil for loop.
He lost all of buoyancy sources ….

When I dive shallow, I have a s40 of ean50.
Otherwise a S80 of ea32. I always have an air cyl for dry suit and the onboard dil inflates the BCD.

In making configuration decision suggest you look at failure modes and decide what level of risk you are wishing to accept.

Cheers
Fabio

 

[ND5342]

So the Poseidon philosophy in its initial offering was to make it a very friendly Recreational Rebreather that could be later configured to a more technical unit. With that, PADI along with rebreather manufactures from Poseidon, Hollis and APD set out to create a recreational rebreather training program for a recreational type of rebreather. Without going into too much detail about what makes a recreational rebreather, the first level of training allows the rebreather diver to dive the rebreather to 60 FSW without an external/additional bailout cylinder. However, a bailout valve in addition to an octopus/safe second regulator is required. The Poseidon is unique in that the computer is monitoring the gas supplies and will let the diver know via the display if they need to move shallower or abort the dive based on the amount remaining of diluent supply. In fact, during the precheck tests you need to test the BOV and the computer then monitors the diluent supply being utilized to pass the test. If you are plumbing your BOV to an offboard bailout cylinder I am not sure how one would pass this test. Perhaps in the configuration settings with a tech type battery. Perhaps @RainPilot could fill us in as I know he has been taking his on deep dives.

 

[ND5342]

Poseidon seven sport

I think the Sport is a great option and you can even add the M28 computer and backmounted counterlungs and still come out less than the REC version with the same options and especially the TEC version. You can find your own pieces and parts to invert the cylinders if you want to but if you can reach the cylinder valves in the normal way, why bother. Until you are ready to tech dive the unit you do not need to any add valves either. There are a few different options in that department as well.

The Poseidon is not a bad first rebreather, but it does get expensive to maintain. It is a Poseidon!