hi!

daviddem

Hi,

New on this board. I am from Belgium, but live in Dubai. I've been diving for 5 years only, and am through my IANTD trimix training and proceeding with the GUE one. I don't dive a rebreather, and do not intend to in the near future (but most probably will one day).

I am here to learn, because I do not know very much about Rebreather's. I understand the principles, but not the details, such as the differences (some subtle) between the various units.

So I will just poke around, and probably not post very much, maybe time to time to ask a question if I think it is not too silly.

See ya,
David

jepuskar

Hi David and welcome.

Don't worry about posting silly stuff...I do it all the time and am still welcomed here..although a few members may disagree with that.

Jason

Fun Under Pressure

Welcome and a lot of fun here on Rebreather World. Ask us all your questions !!!
Greetings from germany.

Cheers Markku

bcdiverdennis

Welcome to the board.

Why is it that you do not plan to dive an Rebreather in the near future ?

daviddem

First, I feel that I still have a lot to learn and experience to gain on OC. Second, I already spent a lot of money on my gear recently (scooter, dry suit, etc). Third, for the dives I do at the moment, I don't need a Rebreather as a tool to achieve them.

When the time comes and I feel the limits are closing on me, I will consider to start training on a Rebreather. Maybe SCR, maybe CCR, I have not decided yet, I need to learn more about the various units and their potential problems. From what I have read so far, looks like the Megalodon is a top notch CCR.

Now, could somebody enlighten me here? When you dive a Rebreather, should one not plan for a worst case scenario where one has to bailout to OC at the end of the bottom time or at the furthest penetration point. Does that not involve that:

- in open water, you would have to carry just as much deco gas as you would on OC (and be sure that your diluent on OC gets you to the first switch point, or have to take an extra bailout bottom gas bottle).

- in an overhead (cave), you not only have to stage as much deco gas you would on OC, but you also have to stage bailout bottom gas to reach your first deco gas.

So at the end of the day, do you really need much less gas on a Rebreather?

daviddem

See? That's what I meant... with my stupid questions, nobody talks to me anymore already

No kidding, I searched the forum and I see that bailout is a hotly debated topic. Seems to me though that if you are being reasonably conservative... hell, you still need to carry a lot of gas... Granted, you don't have to re-blend it every week (hopefully!), but you still have to carry it around...

Solitude Diver

Hi David (and welcome).

As no one else has posted, I will give it a shot. (Although mind you I am just about as green as anyone as I do not have a lot of hours in yet).

Yes you do need to carry enough bail out to get you “home” but there are other things to consider.

1. As you are diving per PPO2 vs set O2, you get credit for the least amount of nitrogen as possible at any depth, so you reduce you deco obligation considerably. (Think ultimate nitrox mix which remixes for each depth). Therefore, you would have less required deco obligation and therefore less required gas in a bailout.

2. It seems some divers plan with the thought of splitting the bailout deco between them, and/or keep just enough bailout to get them to a stage area where there is enough “extra” to cover one them until they can get to a better stage. As they are all carrying back-up and it is not likely they will all need it, you don’t necessarily need to carry larger amounts of surplus for situations. I.e extra 1/3’s each. You can assume your buddy will give you a little if need be. (If he likes you).So depending on depth, you don’t need a huge amount carried with you.

3. The main thing is you do not carry large twins on your back with extra 1/3, and side mounts for each diver all carrying extra 1/3’s too, and have the longer obligations which require extra gas too.

4. And in an emergency (that does not involve a failed unit) you have much more gas to solve the emergency than you would on OC. Especially at depth. Think 3 hours at 200 feet vs 20 minutes.