How not to dive a Dolphin.

[Freeflow]

This featured in a trip report from this time last year, but a second posting on here doesn't hurt.

"As we were still on stop time as we neared the slip we carried on to the step, where I took my fins off as Barry climbed out and managed to drop one of them. I then suffered from a brief overdose of competency deficiency syndrome, with stupidity to follow. I decided to recover my fin but I had already turned the Dolphin cylinder off, and partially drained the loop. Dropping down 2 metres the pO2 alarm kicked off, but I ignored it while I got my fin back. I was feeling a bit ‘heady’ after I surfaced after 20 seconds or so and saw my pO2 was 0.13 bar. Stupid, stupid, stupid. I know better than that, and it shows how a little complacency can have the ability to ruin your whole day. If I was down any longer or deeper the consequences could have been bad. The stupid thing is that I could have used the OC bailout and been fine."

[David Parker]

I wondered what a co2 hit would feel like so on my bed I emptied my scrubber turned the flow off to see how long I could breath off it. it took arround 45 seconds or so until I was off my face & the reg fell out. What a buzz mind you but a seriously dumb thing to do & I dont recomend it..

Live & learn (well just about)

D..

[narked at 90]

Hello david, i as many others have done, I gave my self a CO2 hit in the dry,
and i thought i would see the onset of a hit before going under water but i can tell you from the two real hits i've had that what i had in the dry was very differant from those i had under water and each hit has been differant from each other. both have already been put in words so i dont want to go into them, ask yipee diver about the first!!
but david from what you right, you gave your self more than just a co2 hit but turned off your gas as well putting your self hypoxic at the same time...
i just hope you were not on your own at the time because thats a fine way to render your self brain dead!
dive safe every one.
kindest regards john routley
Welcome Page

Originally Posted by David Parker

I wondered what a co2 hit would feel like so on my bed I emptied my scrubber turned the flow off to see how long I could breath off it. it took arround 45 seconds or so until I was off my face & the reg fell out. What a buzz mind you but a seriously dumb thing to do & I dont recomend it..

Live & learn (well just about)

D..

[Freeflow]

Gents,

It wasn't a CO2 that got me but O2. The scrubber was fine and I was diving it again after the break, but as I had turned off the gas in preparation to getting out the fO2 was probably about .21 before I partially drained the loop. Exhaling into the loop would have lowered it further when I went in to get my fins, and that is what caused the problem.

I gave myself both a CO2 and hypoxic O2 hit to see the difference. On the CO2 [all loop bits in place except scrubber material] my breathing rate went up, a bit of tunnel vision occoured, I started to sweat and the gas in the loop felt thick. The headache that kicked in later lasted a good while.

CO2 of 4-10% will cause the increase in respiration, which exacerbates the problem, and above 10% the breathing rate slows until you eventually die.

The O2 symptoms were different. Breathing stayed the same, I felt tired and thinking was an effort [more so than usual]. I didin't have the O2 meter on as I didn't ever want to be tempted into thinking 'I was alright on a loop pO2 of .16 on the surface, so I'm all right now'.

If you are going to try this at home, have someone else there with you because if you get immobilised by the hit you will be deaded and the newspaper reports into your death will make very interesting reading, right up there with a bin liner and orange.