18 replies to this topic

[PerroneFord]

No, you would need to carry all the gas you need to complete DECO should you have a rebreather failure.

In Howard's example, He'd probably sling an 80 of 50%. That is another thing about SCR. You can use the tanks OFF the rebreather during the dive if desired. The drawback is that you don't get the same level of gas extension from them, nor do you get the deco efficiency.

[ScubaDadMiami]

Dec to 170ft (0) Diluent 15/30 0.40 SetPoint, 300ft/min descent.

That's just a little bit of added conservatism on my part. I basically want to calculate that I am on the bottom the minute I start my descent. I prefer that over putting a slower descent rate, and then exceeding that. I know I am not going to hit 300 per minute. So, it gives me a little margin for error/conservatism.

[ScubaDadMiami]

Then in essense to dive a rebreather you have to carry all the gas that you would need for OC in addition to the rebreather? If you rebreather failed at the deepest part of the dive and at the max deco obligation?

The standard is for a team to carry 1.5 times the required gas to get a single diver back to the surface (or the first staged gas) from the farthest point of penetration in the dive. If you dive solo, you would want to have at least enough gas to get you there (don't forget some chance, though small, of your bailout not working).

So, on a dive like this, I would carry one 40 tank of 15/30, and another 40 tank of EANx 70. This is just enough to get me back to the surface on open circuit from that point in the dive. I could carry less so that I would have the 1.5 times requirement between me and my buddy. However, I don't own 30 tanks, and I am so light and so nimble now that I really don't need to be so minimalist.

[ScubaDadMiami]

No, you would need to carry all the gas you need to complete DECO should you have a rebreather failure.

In Howard's example, He'd probably sling an 80 of 50%. That is another thing about SCR. You can use the tanks OFF the rebreather during the dive if desired. The drawback is that you don't get the same level of gas extension from them, nor do you get the deco efficiency.

You have many choices. I can simply plug in one of my bailout bottles to the CCR, which would allow me to use that bottle for hours. I can use the diluent bottle on my back as open circuit (though I won't get much out of it since it is only a 27 cubic foot tank). There are lots of combinations. So, it gives lots of alternatives should there be an emergency.