OW class question

[Diver0001]

So what are they to do when they are on that ultimate trip...and their computer fails?

Say they're done for the day and get a beer? It's a disservice to the student to not teach them the manual backup way. I know, I know, the industry lowered the standard.

You still how to unhook the inflator from the LP line, right? How often has an inflator failed to function? Probably far less than a computer failing.

It's not lowering standards to teach students to use the tools that they will, in practice *actually* be using.

Since there is no way to map your actual tissue loading from a computer dive to a table then falling back from computers to tables is done the same way as falling back from a gimped computer to one you rented to replace it. You make a long SIT and start diving again.

R..

 

[Pavao]

But what good will the tables be if they don't know how to use it?

We see it over and over again, the students will score perfect on the understanding and using of the tables during class, but soon enough, they will forget it all and have no idea how to use it.

 

[NAM001]

BZ to the OP. I applaud you for wanting to know about tables. I dont use them however i can recognise if my puter is putting out something abnormal. I can only do this because i have a foundation in how the tables work. Let me give you an example. I was diving and found my puter had the wrong time in it. I surfaced at the end of the dive and corrected the tme. (turned it back 2 hours. What a cluster. The Puter goes nuts when you do a dive when there is one in the puters archived history that is now (in the eyes of the puter) from the future. NOw had i changed the time forward. All previoius dives would be in the past where they belong EXCEPT it computed that instead of 1 hour si i had 3 hr si. so when the puter would say i had 50 in dive time left i wuold know that was not possible with the prior dive and a 1 hr si. Unfortunately tables are based on profiles that are archaic,. Expecting them to work is like expecting your child not to ask for candy in the store checkout line. Both of these situations happened on that dive. But wait it gets better. I attempted to correct for that so i would hav a functional puter adn moved the clock back till the end ofthe day. Did n ot like that either. was doing now 2 dives at the same time. Some things just can not be taught in class.

 

[T.C.]

It's not lowering standards to teach students to use the tools that they will, in practice *actually* be using.

Since there is no way to map your actual tissue loading from a computer dive to a table then falling back from computers to tables is done the same way as falling back from a gimped computer to one you rented to replace it. You make a long SIT and start diving again.

R..

BS- to both statements.

You figure out the time you were in the water and the depth from the previous dive. If you don’t know this from YOUR watch, you can compare the time from a diver who dove before you (the start time of their dive), and the end time from a diver who exited after you (thus giving you a longer dive for computing, then look at your depth gauge and get your max depth. Figure out your SI (using a diver who exited after you if needed) and you now have your dive time, max depth, and SI.

You can run the tables, and figure out the pressure group you finished your last dive at, and use the SI to figure out the NDL for your next dive. Set it in your watch and you can make the next dive safely. No need to compromise your trip. It is a pretty grave disservice to set a diver up for failure so they miss a part of a trip that they were anticipating and paid a lot of hard-earned money for. I have actually done this in Bonaire.

It IS lowering the standard to not teach them tables. The standard used to be that a diver could compute their own dive profiles, and use this to plan their next dive. Now, the standard is, as the OP stated: “listen to your computer.” That IS a lower standard.

That is setting them up for failure in the future. I know; you’re not required to teach it. But it IS a lower standard. Teaching them tables IN NO WAY diminishes teaching them to use a computer. You can even teach them both on the same dive. In fact, a savvy instructor can use the comparison of the two, and the extra time a computer gives you to encourage sales.

The OP is to be commended for wanting to know more.

 

[Diver0001]

But what good will the tables be if they don't know how to use it?

I don't want to derail this thread but this is a good point. Worse than just blindly falling back from a computer to tables is falling back from a computer to tables that they may not have used in years, if ever.

Since the question was about the "ultimate trip" I assume T.C. meant "heavy repetitive diving" and in all honestly I wouldn't want anyone I know to be using a tool they had learned about but probably never used "for real" in a "fall-back" scenario. The potential for making costly mistakes is too great, IMO.

I think we need to face the fact that the generation of divers being taught now will by-and-large never need and never use a table. I'm not against learning about them but I think for most recreational divers it's quickly becoming an historical curiosity, like the double hose regulator or the J-valve. You could still use them, but most people will never do so.

R..

---------- Post added March 16th, 2014 at 02:54 AM ----------

BS- to both statements.

If you would like to discuss it, then please start another thread. I think we owe it to the OP to not make this thread into yet another flogging of a dead horse.

R..

 

[T.C.]

I don't want to derail this thread but this is a good point. Worse than just blindly falling back from a computer to tables is falling back from a computer to tables that they may not have used in years, if ever.

Not staying current and proficient in your skills is the fault of the diver, not the instructor. Not teaching them a skill IS the fault of the instructor.

Since the question was about the "ultimate trip" I assume T.C. meant "heavy repetitive diving" and in all honestly I wouldn't want anyone I know to be using a tool they had learned about but probably never used "for real" in a "fall-back" scenario. The potential for making costly mistakes is too great, IMO.

Not necessarily. My computer failed the second dive of the second dive in Bonaire. I had only been diving to 40 feet for about an hour that day. Rather than giving up the rest of the day, at 10:30 am, in Bonaire, I was able to fall back on the training I received 3 year before and successfully, and safely, complete the next three dives.

I think we need to face the fact that the generation of divers being taught now will by-and-large never need and never use a table. I'm not against learning about them but I think for most recreational divers it's quickly becoming an historical curiosity, like the double hose regulator or the J-valve. You could still use them, but most people will never do so.

Just because I will likely never have to remove my BCD underwater, unhook my inflator hose, or execute other actions, does not mean that I should not be taught them. When you do need these skills, be it removing your BCD or using a table to finish diving, you do need them. Tables are not a “historical oddity”.

Not learning manual backups is NOT like discarding double hose regs and J-valves. We UPGRADED, not downgraded the standard. Single hose regulators are safer and simpler, as are J valves. This is increasing the standard, because now divers are expected to know how to buddy breath/air share and monitor their air pressure, instead of simply waiting for the tank to feel empty and activating a reserve (which could have already been activated).

Not teaching them a tool like tables is lowering the standard.

---------- Post added March 15th, 2014 at 08:09 PM ----------

If you would like to discuss it, then please start another thread. I think we owe it to the OP to not make this thread into yet another flogging of a dead horse.

It's not "flogging a dead horse" to bring up relevant situations as to why the OP would want to learn to use tables.

 

[Diver0001]

Once again, if you would like to discuss this, please start another thread. We're way off topic as it is and I'm not comfortable polluting the OP's thread with this.

R..

 

[T.C.]

Once again, if you would like to discuss this, please start another thread. We're way off topic as it is and I'm not comfortable polluting the OP's thread with this.

I think we should let the OP decide that.

As I said, he wanted to know if it was "nuts" to want to learn tables, not just rely on a computer. Providing a relevant situation where it is beneficial to know tables is NOT "off topic".

 

[Eric Sedletzky]

I don't think it's nuts at all to want to learn tables. What if somebody doesn't have the money right away for a computer or only plans to do easy fairly shallow shore dives for the first few years?
You don't need a computer to do these dives, but it would be easy with tables to at least know in your head what kind of time you allowed at what depth.
Tables are crude but still the most reliable technology out there because they're a physical chart that you can hold and look at and memorize in your head. You don't have to make sure you changed the batteries in your table.
The only thing is tables are designed to use for square profiles, whereas computers will constantly adjust remaining bottom time according to the changing depth.
Some people don't think this is always a good thing since computers have the capability take you all the way to the edge. However, computers do have different settings to adjust away from agressive profiles.
Tables have a built in safety factor because of the square profile, but some people have even taken tables a notch up by learning to "depth average" instead of using the deepest depth for setting the time.

I still like the idea of an analog system to fall back on in case all else fails. Nobody can take the tables out of my head.

 

[hroark2112]

My issue is the statement "Trust your computer" here.

I'd much prefer the student actually understand what their computer is telling them and what the hell it means. That's the big problem with some of the teaching right now.

When I got my computer, I didn't know what it was telling me. I had to dive into it (pardon the pun) to figure out what everything meant, how to set it properly for my dives, and how to use it as a tool for planning my diving. That's what we need to learn as divers, not "just jump in and trust your computer!"

If I were on my "ultimate dive trip" I'd make sure I have a backup computer. If one poops the bed I have the other with me in the water to cover my ass. I usually have one with me even on quarry dives, just in case.

That being said, I understand the tables, how to use them to plan dives (and I'm an SDI AI) and would gladly help any student who wants to understand them how to use them for planning dives.