Big Mistake

[Spectre]

SeaJay once bubbled...
No. My buddy pointed to his bottom timer and did the "open hands" signal, saying to me that we'd hit our turn time. I signaled okay, checked my 'puter, and signaled, "four minutes," if I remember correctly. He signaled back, "okay."

I'm not really intending to hijack or steer this thread off on a tangent, but ...well... I'm gonna.

I feel an important part in the choice of dive buddies is someone that is going to step up and question you if they don't believe you are making the best decision. I've done it, and I've had it done to me, and I expect that my buddies in the future will see fit to continue to do it. If they disagree with a decision, there is one easy, unquestionable, solution... the thumb.

Actually just yesterday we were out diving... two groups of two doing skills training. Yes, we were only in 10 feet of water. Yes, the request I received was a reasonable request; however given the fact that we were training, I felt obligated to overrule their suggestion.

Situation: My team [dive team #1] went to pull the reel while dive team #2 waited at the flag. We returned to the flag and one of the members of team #2 signaled his buddy was cold and heading to the surface. He wanted to group up with my buddy and I for our tour dive. I shook my head no, I pointed at him and his buddy and I told them to ascend. He looked a little confused, and repeated his 'him cold, him surfacing, me with you'. I repeated my "no, you him surface'. They did. I looked a my buddy, pointed to the flag and asked him to grab it while I finished dealing with my reel. When that was done, I looked at him, and thumbed so we could deal with the change in plan.

I explained after the dive exactly why. #1. Sure, leaving your buddy to ascend alone in 10 feet of water when the air temp is in the high 60s is probably fine... but the dive was a training dive, and that means in my eyes it's a training dive from start to finish. #2 my buddy was close enough to see us, but not close enough in my opinion to see the communication between myself and team #2; he needs to be present for any dive plan change decisions so he can reserve the right to overrule. #3 I've not been in the water with the guy requesting to join the group before. I'm not sure he knows how to correctly execute in a 3 member group. I don't feel it worthy to write out a tome on how to dive in a group of 3 in my wetnotes while his buddy waits shivering.

So even though I couldn't thumb 'our' dive, because we weren't together, I felt it appropriate to thumb their dive for them. And if the situation were reversed, and they had reasons to not go with my suggestion; then I have every expectation that they would overrule me and thumb my dive as well.

Not that I ever really have a point, but my point here is simply... Make sure you dive with a plan that everyone involved understands, and that everyone involved is assertive enough to enforce it when you don't.

 

[Uncle Pug]

SeaJay once bubbled...
My low SAC, which is something that I've worked on very hard for the past hundred dives.

what did you figure your SAC to be for this dive? Some where around .7 or so?

 

[SeaJay]

.58.

I'm gettin' better.

I've had dives in the low 40's. That's been my personal best. .43, to be exact, even with a little current.

I think it was a little elevated for that dive because of all of the swimming we did around that big boat.

It wouldn't have surprised me to have been in the 60's, but the meditation at the end during the stop probably improved the overall rate a little.

 

[SeaJay]

Yesterday's fossil dive was .40. ...And there was current there, too.

Wow. I'm happy with that.

Hey, I just turned 800 posts, too!

Why do you ask, anyway?

 

[Uncle Pug]

SeaJay once bubbled...
Why do you ask, anyway?

...your critical mistake was not over staying your time but over staying your gas.

That might be attributed to thinking your SAC is better than it actually is.

You would be better off planning the working portion of your dive at .7 SAC.

That said... there really was nothing wrong in taking plenty of time shallow and using the gas you had. Probably something you should actually include in your plan anyway... BTW your SAC for that 15 minutes at 10' was something like .53.

 

[Se7en]

I'm reading all the trolling and flaming, and have to admit I don't get it.
A few minutes of deco, more or less, won't kill you. Drowning will.

For rec dives like this, I'd dive my computer or my plan, or anything I felt like. BUT I'd make damm sure that I had enough gas to get me and my buddy back to the surface, with lots to spare.

Seajay - you're a big guy. Stop putzing around with small singles and take enough gas so it's not a problem anymore. If you had been wearing double 80s, then the dive profile would not have been a concern at all.

Se7en

 

[SeaJay]

Uncle Pug once bubbled...

BTW your SAC for that 15 minutes at 10' was something like .53.

Interesting. That's 400 psi in 15 minutes at 10'? Does it improve if we say that I actually hung at 11 or 12 feet, to stay under ceiling? What about the fact that 400 psi in an empty tank is actually less volume than 400 psi in a full tank?

Sorry; Just trying to improve the numbers.

Very interesting point on overstaying the gas. Planning for a working SAC of .7 should have meant that I should have planned for an even shorter dive than my NDL would have allowed.

On both dives.

 

[Uncle Pug]

SeaJay once bubbled...
Sorry; Just trying to improve the numbers.

Don't try to fudge the numbers down.

Fudge them up.

Improve your actual rate of consumption but still take plenty of gas.

 

[budgy]

Plan your first dive max btm time within the naval no deco stop zone, do your 2nd dive in the no limit zone.
When you reach half pressure in your cylinder (100 bar) head for around 5m in the no limit zone and enjoy your diving until you reach reserve.
When ascending go slower than your slowest bubble. (50bar)
Do short 30 sec stops when ascending every 10m. Give yourself a 3min stop at 5m.
Maybe its just over cautious nonsense

 

[Diver0001]

SeaJay once bubbled...
Okay, I'm keeping a good attitude about this.

<snip><snip>

Got it. Don't take this personally, but it seems like what you're actually saying in essence is that you didn't use your computer the way it was intended and you got yourself in trouble.

Which begs the question. When you saw it was going to go into deco didn't it occur to you to find your way to 18 metres at the "normal" speed and then slow your ascent from 10 metres to the surface to like a metre per min? I'm assuming you choose to ascend so slowly for a reason but it seems to me in that situtation you would have been better off getting off the bottom and slowing your ascent to a crawl in shallow water..... just thinking out loud.

Obviously there are better ways to plan (I won't go there) but given the circumstances--namely, not being sure if you had enough air to work off what was becoming an unknown deco obligation--surely a little faster ascent would have been preferable. Why did you stick to your guns when you saw it was going pear-shaped?

R..