Deadly Down Current

[Geoff_H]

. The regs they are breathing from will probably start breathing pretty hard by 350psi, and stop completely at 250psi, so the team starting their ascent with 715psi will be about 400psi short of making it to the surface, and will have to make an abbreviated ascent.

Not sure what kind of regulator you have, but that statement is flat out wrong for the type I dive with. I sometimes breath it right down to the last 100 psi or so if I'm messing around taking photo's in the shallows on a shore dive with no surge or waves. I've never had it start "breathing hard" or stop completely so far.

 

[Age]

I also felt a down current at the Canyons PG, but it was at nearby Verde Island where I felt I was being sucked down the plug hole. Keeping reference to depth was very hard as the bubbles did not seem to obey the laws of Physics and I couldn't believe what my computer was doing with my BC full of air. Launching the SMB, though difficult in itself in those conditions was the solution and I never dive without one now.

 

[z3r0c00l]

AGE what was the computer reporting? Do you have a dive profile from this dive? I would love to see what kind of depths it made you hit...

 

[Mike Juren]

I had the same experience , but we carried lift bags. for just such a possibility. The divers should have asked local experienced divers about the sites in PG before diving them. It is pretty scary, especially if you are ill equipped and aren't expecting it..
Mike

 

[Mike Juren]

I did a similar dive in the Canyons (ame place in PG). The current dragged us to 165'. But we were expecting it, and were prepared for it. So we had twin tanks, and lift bags (which one has to carry along with reels) to help nad maintain proper buyoncy. If course our deco time was staged, and took 20 minutes, hanging on the lines with liftbags on the surface (so the boat can follow us) first at 80' then 60' then 20', then 15'. With single tanks tanks and just BCD's this dive should not be attempted. Mike

 

[Mike Juren]

Absolutely correct. Lift bags (not just safety sausages) and reels with sufficient lines MUSt be carried on any dive where a downwelling might occur, and the diver MUSt be proficient in it's use. Mike

 

[Mike Juren]

absolutely right. always ask local divers /divemaster about a site you are about to dive so that you can carry the appropriate safety gear and the correct 'air'.

 

[Mike Juren]

Hi Tom, you are absolutely right. Twins would have been the way to go instead of the deco bottle, but at least we had an extra regulator, and were prepared for the possibility of a downwelling. The deco we did was a real overkill, so we wouln't have 'run out' of air really. But I was trying to get across the point of 'preparing and asking' about any dive site. Mike

 

[DandyDon]

Hi Mike, try the new M-Quote feature for quoting multiple posts.

 

[Mike Juren]

don't know how it works, I am not really all that good in using computers. Mike