How to Know When To Start Heading Up

[D_B]

just a note .. Doc was talking about the decent on a crowded moring line using up gas , not on assent

If you're on a cattle boat with bunch of idiots who don't know what they're doing, you may get stuck behind a bunch of slow pokes who are descending the mooring line very slowly. You may get to the bottom of the mooring line on the wreck with only 2,300 psi remaining. You've got to completely change your turn pressure and game plan underwater. Do you have a contingency plan for this?

Edit: Oh, I see that Doc has it covered already

 

[Buoyant1]

just a note .. Doc was talking about the decent on a crowded moring line using up gas , not on assent

Even on an empty line in a stiff current! A dive I did on the Duane two years ago was pretty gnarly getting down to the wreck. I think both of us wasted about 500psi each (Me using a 119, buddy using a 100) getting down.

 

[Doc Harry]

Even on an empty line in a stiff current! A dive I did on the Duane two years ago was pretty gnarly getting down to the wreck. I think both of us wasted about 500psi each (Me using a 119, buddy using a 100) getting down.

That's what I'm talking about. If you dive a deep wreck on a single AL80, then you really don't have much time or gas to explore. If you are forced to blow 700 psi just getting down to the wreck because of crowds on the mooring line, your whole dive plan is shot to hell. If you don't reasses your plan, then trouble is not far away.

 

[idocsteve]

That's what I'm talking about. If you dive a deep wreck on a single AL80, then you really don't have much time or gas to explore. If you are forced to blow 700 psi just getting down to the wreck because of crowds on the mooring line, your whole dive plan is shot to hell. If you don't reasses your plan, then trouble is not far away.

I didn't understand your point the first time, and I understand it even less now...the part about having to change your thirds calculations because of time getting down to the wreck.

If a diver has figured to turn at 2000 lbs because that's 2/3 of his original tank volume, why change that amount to 2300 just because it took him longer to get down the line?

If it was me I'd stay at the 2000 psi turn around pressure.

 

[ScubaInChicago]

I didn't understand your point the first time, and I understand it even less now...the part about having to change your thirds calculations because of time getting down to the wreck.

If a diver has figured to turn at 2000 lbs because that's 2/3 of his original tank volume, why change that amount to 2300 just because it took him longer to get down the line?

If it was me I'd stay at the 2000 psi turn around pressure.

Because if your plan was to penetrate and use the rule of thirds it's almost pointless....Reasses and do 1/2 use, stay out of the wreck and maintain RB at the upline.....

 

[Buoyant1]

That's what I'm talking about. If you dive a deep wreck on a single AL80, then you really don't have much time or gas to explore. If you are forced to blow 700 psi just getting down to the wreck because of crowds on the mooring line, your whole dive plan is shot to hell. If you don't reasses your plan, then trouble is not far away.

Which is why I question the use of 80's for those types of dives

Thankfully I've been driving down and taking my 119's and my 40 (pony) for a little peace of mind! Sometimes it appears that larger cylinders are tough to find depending upon which area you go.

But a little dialogue BEFORE you hit the down line is always a good thing, that way you can get your point across if there is a need to modify your plan. I don't like being given the option of a "trust me" dive while I'm at 100 fsw unless it's with a buddy I know and can actually trust!

 

[RonFrank]

...actually most dive ops DO enforce depth limits, de facto 'scuba police'.

And how exactly do they do that?

 

[TSandM]

They do it by having the guide go only so deep and no deeper. Most divers follow the guide.

 

[RonFrank]

The majority of the diving I have done has been in the states! No guides are provided. :blinking: When diving in other places that did provide guides they were effective only if you made a point of staying close.

One comment I have is that this is in basic discussions, and the conversation turned advanced a while back.

I enjoy the gas management discussion, but we may want to focus on the OPS original question without going into discussions on rules of thirds, and complex dive planning.

 

[Buoyant1]

The majority of the diving I have done has been in the states! No guides are provided. :blinking: When diving in other places that did provide guides they were effective only if you made a point of staying close.

One comment I have is that this is in basic discussions, and the conversation turned advanced a while back.

I enjoy the gas management discussion, but we may want to focus on the OPS original question without going into discussions on rules of thirds, and complex dive planning.

The OP pretty much bailed on it 10 days ago...

But yeah...