Info Why are tables not taught in OW classes anymore?

[tursiops]

He didn't get it in the other thread, either. (See post #21.) He thought your post saying you couldn't do it cofirmed that you could.

Thanks for pointing that out. I went back to that thread and replied to him.

 

[tursiops]

He didn't get it in the other thread, either. (See post #21.) He thought your post saying you couldn't do it cofirmed that you could.

By the way, the incorrect use of tables in this way, for multi-level dives, is a BIG reason that tables are inferior to computers for most recreational diving...which is nearly always multi-level.
It is trivially easy to misuse a table. One has to overtly ignore a computer to misuse it.

 

[lowwall]

By the way, the incorrect use of tables in this way, for multi-level dives, is a BIG reason that tables are inferior to computers for most recreational diving...which is nearly always multi-level.
It is trivially easy to misuse a table. One has to overtly ignore a comnputer to misuse it.

Except for incorrectly setting O2 percentage. Or forgetting to turn it on and doing the dive anyway by following a DM or buddy. Or switching to a backup or rental that hasn't been with you on previous dives.

 

[Vicko]

Deep stops were not created for people whose slow compartments were already saturated at depth. Your use of the word "slow" first of all confuses the issue because you don't define it. With the exception of saturation divers, people don't ever have the slowest tissues saturated at depth. The theory on deep stops was that they protected the fast tissues from bubble expansion. The problem seems to be that 1) maybe they don't need that protection and 2) while you are protecting those fastest tissues, you are dangerously ongasssing in the midrange tissues that are not saturated.

The whole bubble model "movement" (what could we call them?) was based around research done on sat divers, they misinterpreted the results to the point that sat diving schedules were bastardized into bounce diving plans leading to the deepstop ideas, they had to find a reason why their dive plan was spending so much time at depth, so they pretended it was to protect the fast tissues. Deepstops in sat diving do make sense and are used due to slow tissue loading and are part of normal sat decompression schedules.

At the moment I only have a suunto d6i left that runs their version of rbgm and for a dive to 40m with no deco it gives me the first deepstop at 30m lasting 1 minute, decreasing the depth by 6m for further stops and increasing to a maximum length of 3 minutes for the 12m stop. While all of those are technically counted in minutes and do add up to 9 minutes of extra dive time (or only 6 if you use them as travel time too) I personally would not consider them long enough to matter much in the tissue loading department. I did not go into deco using it for a long time, but as I remember the deepstops were ridiculously long and deep, which is why I was referring to them not being a big deal in rec diving, not tec diving.

I call the tissues slow as I don't have a PHD in any form of medicine or physics and don't really feel that using proper terminology would help me or anyone else understand the issue. I do understand that the slow and fast tissue nomenclature is archaic, but I would guess that most divers, were taught using those terms.

 

[tursiops]

Except for incorrectly setting O2 percentage. Or forgetting to turn it on and doing the dive anyway by following a DM or buddy. Or switching to a backup or rental that hasn't been with you on previous dives.

Sure. But the REAL problem is people ignoring a computer that is set up and working properly.

 

[boulderjohn]

Can you do a multi-level dive using just tables? Of course you can, just as you can do a multi-level dive with neither tables or a computer. You might be OK. You might not. The only option to doing it with any guidance is doing it with a computer.

When I was diving in the Philippines, I did some dives on the "house reef" at the resort. The maximum depth might have reached 30 feet. Maybe. So as I moved around the muck looking for critters, it occurred to me that I really didn't need to be wearing a computer for those dives, since I would never be in the water long enough to violate NDLs. Tables were no help. I didn't need a depth gauge, either. There wasn't any point in a pressure gauge, since I would have been bored to tears and surfaced long before I had spent the hours needed to run out of gas.

If that is the kind of diving you are doing, go ahead and do a multi-level dive without a computer. No problem. Deeper dives require more care.

 

[dmaziuk]

I call the tissues slow as I don't have a PHD in any form of medicine or physics and don't really feel that using proper terminology would help me or anyone else understand the issue. I do understand that the slow and fast tissue nomenclature is archaic, but I would guess that most divers, were taught using those terms.

It has nothing to do with physiology or physics, it's purely a math construct. But you are correct in that a 1-minute stop at 30 msw would have no appreciable effect on even the Workman's slowest compartment at 240 minutes, far less: on ZH-L's 635-minute one.

It really wouldn't do much to ZH-L12/RGBM's 2.5-minute one either.

 

[DAJ]

So how does a kid get into scuba diving?

SeaRat

Like many contemporary hobbies, it takes money. Some parents will fund these types of endeavors while others may direct their kids into less-expensive pursuits. I can set up a kid with a complete set of gear for less than it would take to own the latest Iphone but you will be hard pressed to find a teenager without a phone, notebook, and a gaming system. It’s all about choices and priorities. If a kid is really passionate about diving, they will find a way.

 

[scubadada]

Thank you @tursiops

This is an interesting thread, I enjoy reading what others think, even when they are wrong

I enjoyed learning and using tables, 1970 the US Navy tables, 1997 the PADI air tables, 2002 the PADI nitrox tables. I enjoyed working the table questions that @Pedro Burrito gave us in his quizzes in the early part of the pandemic.

However, I have exclusively used dive computers since 2002. I have dived a backup computer for almost as long. I don't carry tables with me anymore, they reside in the scuba drawer.

Some of the questions that have come up are:

• Are my dives gas limited or NDL limited?
• How much gas do I need to do a dive anyway?

A few simple recommendations:

• Use the NDL planner on your computer, it will give you a reasonable idea of the no stop time you have, either on a clean dive or a repetitive dive.
• Learn to calculate your gas usage in volume/time/atm, your RMV (or SAC if it is in those units) and use it to estimate the gas requirement for your dive.

 

[lowwall]

It has nothing to do with physiology or physics, it's purely a math construct. But you are correct in that a 1-minute stop at 30 msw would have no appreciable effect on even the Workman's slowest compartment at 240 minutes, far less: on ZH-L's 635-minute one.

It really wouldn't do much to ZH-L12/RGBM's 2.5-minute one either.

I remember way back when deep stops was first being discussed in an NDL context, the recommendation was usually 1 minute at half depth (OR halfway between deepest and safety stop OR depth of half the pressure differential between deepest and safety stop) plus a 2 or 3 minute safety stop. The first DCs to incorporate optional deep stops used some version of this as well.

I found this 2006 article that reflects my memory: One Minute to Safer Diving

IMO, this version of "deep stop" is completely reasonable in an NDL context. It's not going to add appreciably to the intermediate compartments that appear to cause issues with the full-blown deep stop regimen. It may help reduce overpressure for the fastest tissues, but IMO the greatest benefit would be in helping sloppy ascenders getting their overall ascent rates under control.

Many of the people who advocate deep stops for recreational, NDL dives do indeed call from them to be done in minutes, not seconds.

Any multi-minute and multi-stop NDL safety stops came later as various entities tried to emulate RGBM deco stop theory.