What air level indicates your dive is done?

[got4boyz]

Bob3 once bubbled...
Dang, you left out the whole range below 500 psi.

for this reason!

(Need to add another catergory or two below 500 psi!)

 

[FredT]

I want to know where the boat is and be close enough to the upline (if any) to do an ascent at ~1/6 my start pressure unless deco requirements requires more.

I want to be on the boat with more than ~50 psi. but I don't always make it with that much. The mix between deco and dive of where that delta is used depends on conditions and dissolved gas loading. The bubbles are in that tank to blow so I'd rater blow them and decrease a DCS hit risk more often than not. Air I bring back on the boat will do me NO good in that regard!

FT

 

[Dryglove]

My smartcom is set so that i arrive at the surface with 500psi remaining.

 

[weight_for_me]

Butch103 once bubbled...
it depends on the dive and whom I am diving with......I try to plan to be at the ascent line (if using one) with the first diver I am with hits 1000 lbs.

.....that would be me.....or Bottomsucker....

 

[landlocked]

mchiapetto once bubbled...
So hence the poll. At what volume of air do you end your dive and start heading to the surface?

I have been back on the shore with as much as 2000 pounds and as little as 250 pounds. The 250 is unusual but we had been following the shore back to the dock at about 15 feet for the past 7 or 8 minutes and prefered underwater to surface swimming. The 2000 was also unusual. I called the dive early because it became obvious that my dive buddy wasn't comfortable. (Later we had a little discussion about not diving unless you are comfortable on a dive.)

There have been some excellent discussions on the board about gas management. However, I think that for the brand new diver, until our skills become a little better refined, a good rule is (assuming an AL80 tank) 500 pounds plus 100 pounds for each ten feet in depth. So if I were diving at 70 feet, I would begin my ascent at 1200 pounds. That gives me plenty of time to get me, and my buddy if necessary, to the surface in a slow and controlled manner. I will usually breath any extra (down to about 500 pounds) while playing around at a depth of 15 feet.

Hope that helps.

 

[tombiowami]

Let's say you are at 70', OOA. Boom! Stress, deep breathing, getting everyone synced up and figuring what to do.

Let's assume everything goes perfect from there though.
70' @ 2 seconds/foot= 140 seconds
3 minute stop= 180 seconds
320 seconds to surface
round up for conservativeness, 6 minutes
round up for conservativenss, 2 ATAs
SAC rate, at best will be 1 cuft/min per diver
2 divers x 2cuft/min x 6 minutes=
24 cuft of gas needed
at the very least, or rock bottom

I think you could probably double your typical SAC rate for an OOA emergency if you have not practiced them over and over, which new divers have not.

Of course this also presupposes you go OOA right at the anchorline, if you need to get both back to the anchor line and then go up.....

Otherwise you are OOA and drifting with the current away from the boat, SAC soars.

This could push it to 50 cuft needed. Think about this next time you are with a dive boat given buddy at 100' and you both are breathing down to 500psi or so and then going up the line.

The "500psi" has nothing to do with anything, getting back to the boat or beach safely is the deal.

T

 

[notabob]

On a typical shore dive I plan on turning around when I use up half of the air I got after subtracting ~400PSI from my starting pressure. I.e. I start with 2640 PSI in my LP95. 2640-((2640-400)/2)=1,520. So I plan on turning around when I reach 1,500 or so. That is, of course, assuming that I reach the turn-around pressure before my buddy. If my buddy reaches his/her turn-around pressure first, that's fine, I'd rather end the dive with a few hundred psi more than I originally planned than have to surface early. Realistically, of course, that doesn't always hold up. Oftentimes, at least with my regular dive buddies, the swim back to shore ends up taking less time than the swim out, so I may plan my turn-around for 1300-1400PSI instead, and still get out of the water with 500-700PSI left

-Roman.

 

[jepuskar]

I wait till when I inhale and there is no air. Then I will do a controlled emergency swimming ascent if above 50ft.

If I'm below 50feet, I will inflate my BC fully and swimming upwards like a mad man. However, after 8 hours in the deco-chamber this gets old.

I feel sorry that I have to mention that I am joking, but some people on this board dont have a sense of humor so this sentence is for them.

 

[got4boyz]

jepuskar once bubbled...
I feel sorry that I have to mention that I am joking, but some people on this board dont have a sense of humor so this sentence is for them.

I was getting a great laugh out of your post knowing you were going to get someone griping at you who didn't figure out it was a joke. Then ya went and ruined it by telling 'em you were really joking! LOL

 

[landlocked]

I think that you both have a morbid sense of humor. You probably enjoy old Three Stoges movies.