Running low on air and failed safety stop

[scubadada]

I probably would have done the same thing, take care of the panicked, perhaps out of air or having a medical emergency, diver. I may or may not have gone back down to clear my more conservative computer, not really needed in this case without lock out. The risk of DCS following the DSAT algorithm is negligible.

The Pro Plus predates dual algorithm and runs DSAT. Though I owned one, I don't remember if it as a conservative setting. I don't know how easy it would be to match the Petrel with an Oceanic computer running DSAT. In recreational mode, the Petrel surfacing GF is already 95 in the low conservatism setting and has more conservative NDLs than DSAT. Perhaps DSAT with conservative setting and/or an adjustment of the Petrel in the regular OC mode would allow matching. Has anyone done this? How did you do it?

Personally, I dive two computers running the same algorithm. They are sometimes minimally different, I clear them both before surfacing.

---------- Post added December 31st, 2014 at 10:49 AM ----------

The Pro Plus does not appear to have a conservative setting, manual is available on the Oceanic website. I'm skeptical that the Petrel can be adjusted to match the DSAT decompression algorithm.

 

[rongoodman]

Petrel's don't lock out violations - not even sure they have a violation screen/alert/notice post-dive.

They will complain if they think you've surfaced with a missed a stop, but you just have to acknowledge it, you're not locked out.

 

[Peter69_56]

I probably would have done the same thing, take care of the panicked, perhaps out of air or having a medical emergency, diver. I may or may not have gone back down to clear my more conservative computer, not really needed in this case without lock out. The risk of DCS following the DSAT algorithm is negligible.

The Pro Plus predates dual algorithm and runs DSAT. Though I owned one, I don't remember if it as a conservative setting. I don't know how easy it would be to match the Petrel with an Oceanic computer running DSAT. In recreational mode, the Petrel surfacing GF is already 95 in the low conservatism setting and has more conservative NDLs than DSAT. Perhaps DSAT with conservative setting and/or an adjustment of the Petrel in the regular OC mode would allow matching. Has anyone done this? How did you do it?

Personally, I dive two computers running the same algorithm. They are sometimes minimally different, I clear them both before surfacing.

---------- Post added December 31st, 2014 at 10:49 AM ----------

The Pro Plus does not appear to have a conservative setting, manual is available on the Oceanic website. I'm skeptical that the Petrel can be adjusted to match the DSAT decompression algorithm.

I agree I am thinking it's not possible to get them exactly the same, with 0 setting in the petrel it's close but not the same.
You are right there are no settings to tweek in the pro plus, you have what you have.

i had to go back down in any case as my wife was still on the line doing her deco and was watching the whole thing unfold (although there were others on the line as well as her)

 

[Dr. Lecter]

They will complain if they think you've surfaced with a missed a stop, but you just have to acknowledge it, you're not locked out.

Right, but compare that to something like the Cobalt that will also not lock you out but will display a deco violation warning after the dive is over/if you start a new dive.

As far as I know, the Petrel doesn't display anything of the kind if you bend it on dive #1. It might be logged somewhere in the dive log, but otherwise it won't look any different from an unbent Petrel during the SI or on subsequent dives (though the deco calculations will obviously be different than if you hadn't bent it).

 

[rongoodman]

It will display "Missed Deco Stop" as I recall the wording, which will continue to be displayed until you clear it with a right button press. My Petrel, which isn't connected to my Prism 2 but runs more or less in parallel with it, has gotten confused a couple of times and thought I had missed a stop, even though the Predator on the Prism was happy.

 

[Dr. Lecter]

Yes, it will do that as soon as you're above the stop depth for the requisite time. Not after the dive is over (unless, maybe, you fail to acknowledge the alert with the right button press).

 

[Frosty]

Ya know what guys I just don't know if I would be as "nice" as you folks in that situation.Maybee the danger of getting bent was fairly slight for the OP but I would have been a LOT more "firm" with the panicked diver. Basicly -"Im on my safely stop.Either you stop here with me or go to the surface on your own"
My reasoning being that
1) I sure don't want to get bent-for my sake and because I'm diddly use to the panicked diver bent and just add to the workload of chamber --if available.
2) I would like to avoid the 'panicked" diver from getting bent( which sounds like a more likely scenario)
3)the panicked diver wasn't actually OOA -they were still breathing their tank.
4)IF the panicked diver was OOA they had just grabbed a couple of decent slugs of air from my tank so 18 feet/6m is a fairly easy freedive. even when panicked. -its equal to diving to the bottom of a 10 foot/3.0m swimming pool with no gear.
5)the panicked diver THOUGHT they were OOA so they ain't leaving me if I stick to my guns.

Afterwards I'd be questioning the panicked diver and his buddy as to how an OOA came to happen.--I wouldn't be roasting them until I'd heard their explaination.-if it was bad buddy skills and bad gas management then yep they get a burn.

BUT--this is all in the comfort of my lounge room -I wasn't there in the situation

 

[TSandM]

I think it is fraught with hazard to try to insist that a panic-stricken diver stay underwater. I think the OP did precisely the right thing, under the circumstances, although I probably wouldn't have bothered with the missed decompression in-water, given the information that one computer felt the obligation had been satisfied. Decompression is not an exact science -- as Rick Murchison would put it, it's "measuring with a micrometer, marking with chalk, and cutting with an axe".

 

[Frosty]

TS and M-maybe I misread but it sounds like the panicked diver had done no offgassing at all and had rocketed up from in fairness an unknown depth. forgive my stupidity if Ive missed something but I see not slowing matters down as just asking for trouble.

 

[Peter69_56]

TS and M-maybe I misread but it sounds like the panicked diver had done no offgassing at all and had rocketed up from in fairness an unknown depth. forgive my stupidity if Ive missed something but I see not slowing matters down as just asking for trouble.

Yes I think that's how it was (finding this out after the fact from the other dive boats DM). Apparently they brought him to the mooring line and told him to ascend, he shot up to me, indicated OOA and as soon as I passed over my Occy (before I could do anything) took off for the surface and was pulling on my hose. so I indicated to my wife I was going up to deal with him. Afterwards the DM fro his boat came over and asked me if the diver did a safety stop. My wife saw him come up the line and I saw him from there and clearly he did not do a safety stop, however he kept stating that he had. From my point of view, he wanted to go to the surface from 5 m and I went with him, not aware of his missed safety stop or his ascent rate.

---------- Post added January 3rd, 2015 at 04:27 PM ----------

I think it is fraught with hazard to try to insist that a panic-stricken diver stay underwater. I think the OP did precisely the right thing, under the circumstances, although I probably wouldn't have bothered with the missed decompression in-water, given the information that one computer felt the obligation had been satisfied. Decompression is not an exact science -- as Rick Murchison would put it, it's "measuring with a micrometer, marking with chalk, and cutting with an axe".

As I said before, the main reason I wanted to go back to 5m was my wife was still decompressing and although there were others with her, I prefer to do my diving with her, and that means finishing the dive with her and not just assuming she will be OK. The secondary reason was to clear my Petrel, more out of what I like to do, rather than concern about a possible bend.

---------- Post added January 3rd, 2015 at 04:32 PM ----------

If I had of been a little quicker off the mark and grabbed him, I possibly could have held him at 5m but I had my hands full, one on the mooring rope and one with an occy, thus he grabbed it and was off before I could react.
He wasn't out of air, just low.
I don't think I could have stopped him without a struggle given he was pulling hard on my occy line and was at about 2m
I would have questioned him had he been on my boat, but didn't get the opportunity.