OOA after only a few minutes with a full tank at 17m

[Magnus Lundstedt]

FWIW, A valve all the off or all the on feel exactly the same.

A fully closed valve dont give any air when i do my test breath, a fully opened valve does.

Everything inbetween is scetchy. If i have the valve against one end, and can breath, it is open.

 

[The Chairman]

A fully closed valve dont give any air when i do my test breath, a fully opened valve does.

Not if the DM/Deckhand turns it off. You'll have at least two good breaths. Well, at least I do.

I get the fact that much of what we learn from instructors and even other divers is the "yer gonna die if'n you don't do it exactly my way!" mentality. There's a lot of grey out there. If it works for you: great. It might not work for me. If it works for me: great. But then it might not work for you. Dive and let dive!!!

 

[Storker]

Dive and let dive!!!

That's of course a good slogan, but if you overuse it it might kill a good discussion which might give one of us some damned good insight.

 

[Dan]

I have lately tried to tap into that muscle memory by explaining that you turn the valve knob the same way as loosening or tightening a water bottle cap. May be more intuitive than "left loosey righty tighty."

Jury is still out on whether that helps or not...

I think this is the best explanation. Everybody drinks from water bottle at some point in his or her daily life. We don't twist the cap all the way counter clockwise and quarter turn clockwise to take the cap off, do we?

The tank valve knob does not come off like water bottle cap, but if we can't turn it to the left any more that means it is completely open. Likewise, if we can't turn it to the right, it is completely closed.

 

[divinh]

I think the confusion comes from the diver's orientation to the valve knob when setting up. Even if the diver knows "lefty loosey, righty tighty", he/she is looking at the knob from the side, where turning away is loosey and turning towards is tighty. And then there's the opposite orientation for those checking from behind...

 

[johndiver999]

The tank valve knob does not come off like water bottle cap, but if we can't turn it to the left any more that means it is completely open. Likewise, if we can't turn it to the right, it is completely closed.

. Are you sure??

 

[Dan]

. Are you sure??

I mean by hand.

 

[Roy_W]

I went diving on Sunday, then Tuesday and discussed many of the points that have been made, I would have done just as well to talk to a brick wall. Many of my instructors have a minimum of 30 years diving experience and as far as they are concerned they will not change their teaching methods even after I explained and provided proof that CMAS no longer teaches the 1/2 turn back... Who knows maybe I have given them food for thought and they will silently read up on the subject...

Some of these older divers have some excellent advice and techniques so I certainly don't want to knock them.. ( I still think that we can teach and old dog new tricks though :)

I was happy to learn that after speaking with some of my others club members I now know that several of them already use the fully open/closed technique, it's just that they don't discuss the method openly.

Since the incident I now spend a few more minutes preparing, no rush, just a little more method which finally relates to a more comfortable dive..

 

[NAUI Wowie]

Question:

A recurring theme in this thread appears to be that either the DM or crew are physically 'checking' cylinder valves are open prior to entry. Is this a common procedure? maybe more prevalent in certain regions?

The reason I ask is that I've never seen this on any liveaboard, day or charter boat I've been on.

We are talking about certified divers after all. Surely as a minimum they should all be able to assemble and test their own kit and carry out an effective pre-dive check by this point. Even by the end of confined water training, students are expected to have completed this exercise 5 times, with gradually less input from staff. By OW certifying dives I'm only monitoring checks and not expecting to actively intervene to the point of turning a divers air on!

Just sayin'

last year, truth aquatics, channel islands california. The Conception. I just finished readying my tank etc and stood up to go to bag and get defog and turned around and saw a crewmember fiddling with my knob. went back and sure enough i had opened it fully he had closed it completely. I was still relatively new at less than 25 dives and if id not seen him do it I may have walked off the deck into the water. its about an 8 foot drop id guess.

this happens all the time all over the world. people are dumb and they think they are being smart or helpful. I had only been gone a few seconds. Thats all it takes. Would I have checked again if I hadnt seen it? Id like to think so but I was also new....

 

[NAUI Wowie]

In the spirit of SB, I'll invent some statistics to make my point: it is 94% more likely that a DM on a dive boat will prevent someone from entering the water with their gas turned off than it is that the DM will mistakenly turn off the gas.

Im in the 6 percent where some idiot crewmember turned off my tank likely thinking I had just finished a dive where I was actually about to jump in. Ship Conception, location channel islands CA, time a year ago maybe closer to a year and a half as it was april.