Deep Diving - Safe bottom air pressures

[bwerb]

I'd suggest this as a minimum workup schedule for deep air dives. With a buddy who is quite experienced on air at the depth you are going to, make a minimum of 12 dives in each depth bracket, completing each bracket before progressing to the next:
0 - 30
30 - 60
60 - 100
100 - 130
130 - 150
150 - 190

But that would mean I'd, like have to do, like almost 100 dives :depressed:

 

[Thalassamania]

Yep - that's the standard progression in the science community. Don't forger, each and every dive has an experienced mentor as a buddy. We do not take this stuff lightly.

 

[Blackwood]

But that would mean I'd, like have to do, like almost 100 dives :depressed:

Correction:


That would mean I [-]get[/-] to do like almost 100 dives

(note, I know your post was in jest)

 

[bwerb]

Yep - that's the standard progression in the science community. Don't forger, each and every dive has an experienced mentor as a buddy. We do not take this stuff lightly.

but, but, but...I have a buddy who's at the same level as me and we have a trip planned and we want to do it now, you've already run the numbers for us and that spear fishing guy would have had like 7 cubic feet left after his dive if he was using an AL80, and we could always bribe the tank monkey for an extra few PSI...what could possibly go wrong?

 

[Thalassamania]

but, but, but...I have a buddy who's at the same level as me and we have a trip planned and we want to do it now, you've already run the numbers for us and that spear fishing guy would have had like 7 cubic feet left after his dive if he was using an AL80, and we could always bribe the tank monkey for an extra few PSI...what could possibly go wrong?

I know nothing about the spear fishing guy ... he sounds, to me, like an accident waiting to happen. The numbers are the numbers, if you're ready for it, a bounce to 197 should not be a big deal. But it does not sound like the diver that you appear to be pretending to be is anywhere near ready and lacks the required items to ever et themselves ready ... but that's a separate issue.

 

[bwerb]

But it does not sound like the diver that you appear to be pretending to be is anywhere near ready and lacks the required items to even get themselves ready ... but that's a separate issue.

Bingo! We have a winner :banana:

 

[SharkDiver36]

+1

Yeohcheeweng,

1. You're trying to learn deep air diving on the internet. Not smart.

2. The guys above have outlined why, unless you're doing some bounce dive (which still has potential issues involving air that deep), at which you have zero experience, trying to do a dive to those depths on a single 80 is ill advised.

3. You have zero margin for error. Slinging another single 80 (assuming from your post that single 80s are your only option at this specific site) gives you at least some total volume that provides you with adequate gas for planning. But only if you understand how to plan the dive.

4. See #1 above.

Before you and your buddy head down to 60m - 197 fsw - on a single 80, please consider getting some additional training.

You really are gambling with your life trying to do air dives to that depth going off "what some guys told me on the internet".



Doc

I couldn't agree more.

Based on your questions and responses to some of the thread's I'm guessing you don't have the training or experience to make this dive.

Never dive beyond your training. Go get the training. We're both saying this because the dive can be done and done safely, but it's obvious you just don't have the training to make these calculations and appreciate how fast your air can go at deeper depths.

Be safe, err on the side of caution and be able to dive tomorrow.

Words to live by.

 

[dumpsterDiver]

Incidentally, how did you know your depths (140, 160, 190, 25) without a working depth gauge? General knowledge of the dive site?

General knowledge and 100 ft visibility helps too. I would not have continued the dive with no depth guage and no computer if I didn't have a pretty good feel for what I could pull off on that dive with just a watch.

I had the opportunity to shoot another fish on that dive, which I probably would have done if I had a buddy and/or worling computer and a safe way to start doing a drifting deco in a 2 kt current(i.e., hadn't forgot my reel). As it was, I knew I had to hurry to the surface to make it more likely that the boat would find me.

As for the non-dIR comment: I thought NOT using a computer would make me at least a little DIR.

 

[TSandM]

We had a group of young men decide to do a 200 foot dive on Al80's about two years ago. One got narced into near-unconsciousness; another rescued him but ending up dying because he ran out of gas on ascent.

Just for your information . . .

 

[yeohcheeweng]

Thanks guys for all the informative replies. I consider myself an experienced diver, having logged over 200 dives. However, I have only dived twice to over 40m. and that inadvertently because I drifted down once to 41m. and the other time to 43m. on wall dives.
But these were just bounce dives, I ascended on hearing my dive computer beeping. I am taking the prudent advice of not making the attempt to 60m. until I have more experience with deeper dives. The idea was mooted by a buddy who wanted to explore the bottom of a canyon which was known to be 60m. and he asked me whether I could accompany him. I am glad that I asked ScubaBoard and you guys certainly helped to convince me that it would be a foolhardy attempt.