Buddying an mCCR diver

Noel

Good morning all,

I'm an OC diver but one of my regular buddies has just gone over to a mCCR rebreather. The last time we dived together (Dosthill a few weeks ago) we got down to 20 where there seemed to be a internal battle inside her, then a ascent to 10 metres and round the quarry at breakneck speed. Not once did she stop and ask if I was OK - this was the first sign that something may have been amiss as she's very good at that sort of thing - until we got half way round. At which point she did ask but didn't seem to register that I weanted to slow down and she set off again at breakneck speed. The ascent then was up to 6M - still going hell for leather, but not rapid - and out at the platforms.

Apparently she was close to hyperventilating throughout the dive, confessed to some perceptual narrowing and didn't enjoy it at all.

What do I need to look out for next time to try and be more aware of what's going on? I presume this is not a common occurence.

Cheers all,

Noel.

__________________
Team Bunny. Depth before dishonour.

whaam68

Hi Noel
If this was one of her first post course dives on the Rebreather (doesn't really matter what type) she was probably "pretty nervous" as I know I was. On the KISS (assuming that's what it is) it takes quite a few dives before you get into the groove & start to really dive the RB rather than it diving you...takes a while before the dawning realization that you won't instantly die if you take your eyes of the displays for a moment or two or if setpoint drifts a little...that does tend to lead to some "perceptual narrowing" at the Buddy's expense but this should improve with time. Hyperventilating is another thing & not good on an RB as it can indicate or lead to problems with CO2 buildup , the breathing rythm should be natural & relaxed. Your buddy may want to check they have enough loop volume & that the bags aren't restricted but hyperventilation should mean stopping & getting it under control or bailing out to O/C rather than carrying on.
Mike

decoweenie

Another possible thing about the fast swimming is...

As new Rebreather divers are still learning to control the buoyancy of their units, they often find it easier to swim when dealing with it/other issues than to stay stationary.

It is not the correct way to learn, but that's what I often observed. And one of the bad habits I concentrate to break during the course.

One of the best things you could do is making sure to signal that you want a slower pace. You might need to grab her fins to stop her, and insist on your message.

Or even offer to lead, and dictate a slower pace while keeping an eye on your buddy.

Make sure she is checking her PO2 displays often!

__________________
"...after a while you get bored offering advice to a bull that like to keep butting the fence with its head rather than walking through the open gate..."

- Rebreather World PM

onetime

Sounds like communication might be an issue as well. Working out beforehand precise definitions of signals (like slow down, speed up, etc) is always a good idea.

I agree with others that she'll likely get better with time but to speed the learning curve, have a serious discussion about your perceived differences between what she was like as a buddy while on OC versus CC. She may not realize all that she's doing.