Depth: 95 ft, In Deco, 500 psi, No Buddy

[dumpsterDiver]

Yeah it was a j valve and we didn't have big LP steels... I got a spg when I bought my first reg at 13 yrs old, even though the regs we were trained on had only ONE hose. I remember that one guy ran out of air on our check out dive in April in a NJ quarry with 40 degree water and no pressure gauges - it made an impression on me and I washed a lot of dishes (at $1.80 per hr) to save up for the reg and pressure guage.

Put into the context of that old type of diving, the whole scenario is embarrassing trivial.

 

[barth]

And let's not forget that this is a computer saying your in deco... There is wiggle room for a reason built into them...

And, Having 500psi is far from running out of gas.. Because PADI and all the others have brainwashed the masses, Does not mean that what most of us old time divers did or does is dangerous..

I don't see a thing wrong with that dive.

Jim

I also don't see a thing wrong with that DD did.
I would make other choices, but he knows what he's doing.

I think that padi haven't brainwashed the masses, they didn't teach gasmanagement. I don't understand why they didn't teach gasmanagement, it is important...

I guess it's all about your risk acceptance. Me, I don't feel comfortable with 35 bar in an 11L tank. My personal safety stop limit is 50 bar in a 10L tank, or 35 bar in a 15L tank. Given my RMV, that's about 15 minutes at 5m depth. So, about ten minutes' margin at the safety stop provided I don't have to share air and aren't stressed due to some unanticipated situation. Me, I prefer to plan my dive to allow for realistic unforeseen situations, and if you don't see any reason to do that, that's all up to you. Me, I prefer a safety margin, but then I might well be a brainwashed sissy.

What do you mean with safety stop limit? When I do gas management I calculate how much gas I need for me and my buddy. This calculation starts from the deepest point of the dive. It starts with a few minutes to solve problems, then the ascent and safety/decostops. For open water my minimum gas will be 1200 liter at 30 meter or 600 liter at 18 meter. I don't care how much presure there is in my tank at the safetystop. It should always be enough to do the safetystop and get back to the surface.

How much gas is your minimum at 30 meter/100 feet?

 

[scubadada]

Yeah it was a j valve and we didn't have big LP steels... I got a spg when I bought my first reg at 13 yrs old, even though the regs we were trained on had only ONE hose. I remember that one guy ran out of air on our check out dive in April in a NJ quarry with 40 degree water and no pressure gauges - it made an impression on me and I washed a lot of dishes (at $1.80 per hr) to save up for the reg and pressure guage.

Put into the context of that old type of diving, the whole scenario is embarrassing trivial.

Was certified in Southern California by LA County in 1970, steel 72 with J valve, horse collar, single reg, no SPG. Bought my 1st gear in 1972, upgraded to a SPG, early version of BC, and a good 1/4 inch wetsuit. Did not have a 2nd reg until sometime later. Did mostly shore dives in LA and San Diego Counties, occasional trips on the ferry to Catalina.

Sometimes it does seem like diving these days is pretty cush.

 

[Storker]

How much gas is your minimum at 30 meter/100 feet?

A little more than 1000 liters.

 

[beester]

So now all the old dino's start yadayadayada about how they be ol' school and training was soooooo hard and we were so fit and handsome and could handle anything. 3l33t

YEAH RIGHT! pass me some of that rum and coke please. I'm not buying it.

First in the days when T-rex still roamed the earth, you would dive USN tables (or a variant of them). If you were diving multilevel dives you would be well above NDL in any case because of 2 reasons. Smaller tanks and no SPG, so people were more conservative on gas management. Second, because of dive table limits combined with multilevel diving (most general diving).

Typically you would take max depth as your depth, but you would not stay that long at max depth (unless diving wrecks). So your average would be much shallower and you would not really have any deco obligation. Next you would be diving a smaller low pressure tank (or if you were really LEET you would have a small double set) with a J valve. So most dives you would already be way up when you pulled that valve. So in the end most dives were more conservative.

On the J valve, it could be risky if the tank was filled and the J valve was in the wrong position, If you then pulled you would have no reserve. Luckily your regulators were "unbalanced" so the breathing got harder and if you pulled the J valve and nothing came out, maybe... by not doing the dumpster ascend but ascending like a bat out of hell, you might still get a few squeezing breaths out of your tank.

What I'm trying to say is... I bought the t-shirt, I've done those dives (first 50 or so with a Jvalved tank and a single stage reg) and frankly being old school doesn't mean you can't do proper gas management and dive accordingly. Specifically with all the tools available now (computer, spg, bcd, etc).

Like I already said... encouraging people to try to stay calm when the doodoo hits the fan is a nice idea. And I enjoyed the video. But to be honest, it's not much use IMHO. Better to put some time and effort in pointing out how easy it is to plan a dive with good gas management and to show them that the risk of ever having to do what dumpster this if you abide by this is very very very minimal.

 

[dumpsterDiver]

So now all the old dino's start yadayadayada about how they be ol' school and training was soooooo hard and we were so fit and handsome and could handle anything. 3l33t

YEAH RIGHT! pass me some of that rum and coke please. I'm not buying it.

First in the days when T-rex still roamed the earth, you would dive USN tables (or a variant of them). If you were diving multilevel dives you would be well above NDL in any case because of 2 reasons. Smaller tanks and no SPG, so people were more conservative on gas management. Second, because of dive table limits combined with multilevel diving (most general diving).

Typically you would take max depth as your depth, but you would not stay that long at max depth (unless diving wrecks). So your average would be much shallower and you would not really have any deco obligation. Next you would be diving a smaller low pressure tank (or if you were really LEET you would have a small double set) with a J valve. So most dives you would already be way up when you pulled that valve. So in the end most dives were more conservative.

On the J valve, it could be risky if the tank was filled and the J valve was in the wrong position, If you then pulled you would have no reserve. Luckily your regulators were "unbalanced" so the breathing got harder and if you pulled the J valve and nothing came out, maybe... by not doing the dumpster ascend but ascending like a bat out of hell, you might still get a few squeezing breaths out of your tank.

What I'm trying to say is... I bought the t-shirt, I've done those dives (first 50 or so with a Jvalved tank and a single stage reg) and frankly being old school doesn't mean you can't do proper gas management and dive accordingly. Specifically with all the tools available now (computer, spg, bcd, etc).

Like I already said... encouraging people to try to stay calm when the doodoo hits the fan is a nice idea. And I enjoyed the video. But to be honest, it's not much use IMHO. Better to put some time and effort in pointing out how easy it is to plan a dive with good gas management and to show them that the risk of ever having to do what dumpster this if you abide by this is very very very minimal.

I think your understanding of the functioning of a j-valve is "incomplete". Also, the dinosaurs were commenting that when diving with a j-valve, when it got hard to inhale, you pulled a little rod down and it released the last 350 psi or so of the remaining air supply.

Without a gage to monitor air pressure in the tank, the diver either came up when it seemed like the right time, or they waited until it got hard to breathe and then ascended, with less air than I ascended with (500 psi) - not to mention the tanks back then were considerably smaller than the one i was using. So back then, the system (a j-valve) was intentionally set up to preserve less air than I did ( a lot less really).

I'm not saying that things were better then, but my point was simply that.. compared to the old school way to dive, my scent was trivial.. it would have to be considered more conservative than the way things were done back then. It simply provides a frame of reference, not advocacy for any type of diving.

 

[scubadada]

I'm not saying that things were better then, but my point was simply that.. compared to the old school way to dive, my scent was trivial..

Your ascent was not very risky, not sure about smell, will take your word for it

 

[scubadada]

I think your understanding of the functioning of a j-valve is "incomplete". Also, the dinosaurs were commenting that when diving with a j-valve, when it got hard to inhale, you pulled a little rod down and it released the last 350 psi or so of the remaining air supply.

Without a gage to monitor air pressure in the tank, the diver either came up when it seemed like the right time, or they waited until it got hard to breathe and then ascended, with less air than I ascended with (500 psi) - not to mention the tanks back then were considerably smaller than the one i was using. So back then, the system (a j-valve) was intentionally set up to preserve less air than I did ( a lot less really).

I'm not saying that things were better then, but my point was simply that.. compared to the old school way to dive, my scent was trivial.. it would have to be considered more conservative than the way things were done back then. It simply provides a frame of reference, not advocacy for any type of diving.

Correct, with a steel 72, one had less than 10 cu ft of air after activating the J valve. Of course, there were no safety stops either

 

[Rhone Man]

I think your understanding of the functioning of a j-valve is "incomplete". Also, the dinosaurs were commenting that when diving with a j-valve, when it got hard to inhale, you pulled a little rod down and it released the last 350 psi or so of the remaining air supply.

Without a gage to monitor air pressure in the tank, the diver either came up when it seemed like the right time, or they waited until it got hard to breathe and then ascended, with less air than I ascended with (500 psi) - not to mention the tanks back then were considerably smaller than the one i was using. So back then, the system (a j-valve) was intentionally set up to preserve less air than I did ( a lot less really).

I'm not saying that things were better then, but my point was simply that.. compared to the old school way to dive, my scent was trivial.. it would have to be considered more conservative than the way things were done back then. It simply provides a frame of reference, not advocacy for any type of diving.

I just had an amusing mental image of a T-Rex trying to deploy a J-valve with his stubby arms...

 

[Steve_C]

I just had an amusing mental image of a T-Rex trying to deploy a J-valve with his stubby arms...

Hmm. It is much larger, but reptiles, or reptile like, can reduce their metabolism. How much air does a T-Rex need for a safe ascent? Also, given the length of a T-Rex does it risk DCS if it quickly goes from horizontal to vertical?