How deep can you theoretically go on single tank?

[lamont]

here's bottom time (actual time @ 200 fsw, travel and deco time included in gas calc, but not here) vs. gas requirements. its surprisingly linear, with each additional minute requiring about 10 cu ft more gas. that's with a SAC rate of 0.75 deep and 0.60 at deco. divers with better SAC rates might be able to slow down the clock to 6-7 cu ft / min, but they're betting on not having an event which gets them excited...

0:40 35.3
1:40 41.4
2:40 49.7
3:40 59.3
4:40 70.3
5:40 79.7
6:40 89.3
7:40 100.7
8:40 112.2
9:40 123.6
10:40 135.1
11:40 145.1
12:40 155.6

 

[Diver Dennis]

Why?

To see part of a wreck but it was down a lot further so we stopped. It was on a wall that has a ledge at about 210' but we had agreed in our dive plan to turn around about 200' if we didn't find anything sooner. We saw a bit of wreckage on the ledge but it was only about 5' wide and as in our plan we didn't stop to look closer. The rest must have gone over the edge.

 

[MikeFerrara]

On June 12th I did a bounce dive to 207' with a commercial diver friend. The dive duration was 47 minutes during which I used 1740 PSI. At that depth I was just starting to feel the heavy breathing symptom that signals the onset of narcosis. We were there for only about 10 seconds and acended to 70' for a 4 minute stop whch we spent checking out the wall we were on. The rest of the dive was as usual as we had left 2 divers at 60' and they just followed our bubbles. The computer I was using only called for a 3 minute safety stop although we both did 5 minutes.
The dive profile showed us start the decent at the 14 minute mark and we were back up at 70' after about 7 minutes.

Where do I start?

If you drop a rock or even a box of them over the side of the boat it'll go all the way to the bottom. People have followed the example of rocks many times on a single al 80 and to much deeper than 207 ft. But why?

You said it was to see part of the wreck? ok but what if I told you that other divers could drop down and look for that part of the wreck till they found it, video it, map it and enjoy the dive with time and gas to spare in case something doesn't go perfect? You could do it that way to...or you could continue to follow the example of the rock and hope that commercial diver has some kind of a trick up his sleeve (like an extra bottle of gas maybe).

Your computer said you only owed a 3 minute stop? You believe it? Why? What kind of computer was it and what does the owners manual say about using it at 200+ ft for staged decompression dives? What is your own experience with 200 ft dives that make you feel comfortable wqith the decompression that the computer is going to call for? Did you know what it was going to call for ahead of time? Did you know that you would have enough gas to get your single tank buddy up with you if he had an equipment failure?

We go a little deeper for a little longer and see how it goes, how we feel and adjust our schedules if needed before going deeper or longer. You could just believe a table or a computer but you might also spend the rest of your life in a weel chair.

What the heck...it works for the rocks.

 

[Diver Dennis]

Where do I start?

If you drop a rock or even a box of them over the side of the boat it'll go all the way to the bottom. People have followed the example of rocks many times on a single al 80 and to much deeper than 207 ft. But why?

You said it was to see part of the wreck? ok but what if I told you that other divers could drop down and look for that part of the wreck till they found it, video it, map it and enjoy the dive with time and gas to spare in case something doesn't go perfect? You could do it that way to...or you could continue to follow the example of the rock and hope that commercial diver has some kind of a trick up his sleeve (like an extra bottle of gas maybe).

Your computer said you only owed a 3 minute stop? You believe it? Why? What kind of computer was it and what does the owners manual say about using it at 200+ ft for staged decompression dives? What is your own experience with 200 ft dives that make you feel comfortable wqith the decompression that the computer is going to call for? Did you know what it was going to call for ahead of time? Did you know that you would have enough gas to get your single tank buddy up with you if he had an equipment failure?

We go a little deeper for a little longer and see how it goes, how we feel and adjust our schedules if needed before going deeper or longer. You could just believe a table or a computer but you might also spend the rest of your life in a weel chair.

What the heck...it works for the rocks.

First of all, to follow the example of the rock would mean that we would have just kept going and ignored our dive plan. I understood that I was not "one of those other divers" who could stay down and search. The 3 minute stop was the "safety stop" at 15'. We did a deco stop at 70' for 4 minutes. My buddy consumed less air than I did and I used 1740 PSI. My buddy was also a Mexican who worked the oil rigs and did deeper dives. Yes I do trust dive tables as well as computers, we used both. You don't? I had done 9 other dives to between 170' and 180'.
Look, I'm not saying this is for everyone but like so many solo divers out there, some who won't admit it, I am responsible for my own safety and although you obviously think this is reckless you were right when you said people have gone much deeper than 207'. Perhaps you should talk to the agencies who give out dep divers certs.

 

[Diver Dennis]

By the way, I like your sig...

 

[Rick Murchison]

Well..... once upon a time in the bad old days, 200' on a single 72 was a "rite of passage."
'Course I only heard tell about that.
Rick

 

[Diver Dennis]

Well..... once upon a time in the bad old days, 200' on a single 72 was a "rite of passage."
'Course I only heard tell about that.
Rick

Good point Rick. I' glad you only "heard tell". I remember when it was OK to eat red meat and eggs too.

 

[Spoon]

Mike is right on.. you might be able to take a single tank to 200 feet and back to the surface, doing your deco stops, without incident, but then you'd be totally screwed if your first stage blew an O-ring on the way up.. and your buddy would certainly not have enough for both of you to do your complete ascent sharing air.

However, it sounds like you went past 130' on your past couple of dives... did you leave enough gas for both you and your buddy to surface from that depth if one of your regs freeflowed? Were you too narced to be able to effectively manage an emergency situation? At 140', are your buoyancy skills good enough to keep you from sinking to 160' if your mask got kicked off?

me and my bud had just gotten previously certified for the deep dive course and wanted to go deep. we were with our Instructor of course and he explained if we could go deeper than our previous depth. he agreed only if we adhered to the dive plan and monitored our air supply the entire time. i have to admit at 140 i was trying my best to stay focused and concentrate. we stayed in the 130-140ish depth for less than 30 sec before making our ascent. i would have gone deeper if my instructor dint signal us to head up. after that we leveled at around 100 and took our time to enjoy the sights. total dive time was 44mins including the 3min deco stop. we had more than enough air to spare and plenty leftover.

 

[mxracer19]

Why would you want to go to 200 feet on air? You'd be so narced out of your mind that although fun, would you really remember anything that you saw, or would you recognize it when you were seeing it? I would love to do a dive on a b-29, and the whole fun would be to dive down and be like..."wow that is an amazing part of history look at this and look at that". But if I was narced like a sailor on easter...would I enjoy it for the reasons that I went? Or would I just be retarded?(in the literal sence, no harm ment)


-Matt

 

[Spoon]

Why would you want to go to 200 feet on air? You'd be so narced out of your mind that although fun, would you really remember anything that you saw, or would you recognize it when you were seeing it? I would love to do a dive on a b-29, and the whole fun would be to dive down and be like..."wow that is an amazing part of history look at this and look at that". But if I was narced like a sailor on easter...would I enjoy it for the reasons that I went? Or would I just be retarded?(in the literal sence, no harm ment)


-Matt

i may be weird but the actual thrill for me is going deep. i dont care if i see sand and rocks but what gets my adrenaline pumping is going into the black abyss. strange as it seems this has been my inclination ever since i started diving.