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riddler
January 6th, 2010, 02:19 PM
SSI has moved dive tables to the Appendix of the Open Water Diving manual, and given Instructors the option to not train with dive tables. As far as I know, the use of computers has not been mandated, however.


"Just like technology has entered our daily lives with the many advancements at our disposal - i-phones, laptops, etc. - dive computers have also become mainstream in recreational diving. For this reason, SSI has chosen to focus on the use of dive computers in our Open Water Program," stated Doug McNeese, SSI President and CEO.

McNeese continued,"We are not eliminating dive tables from the manual. We are simply placing them in the Appendix. This will allow Dive Centers and Dive Professionals the option to use the tables if they choose."

For the past 2 years, SSI has given Dive Centers and Professionals the option to train with either dive tables or computers. We moved the tables to the index and left the information on the DVD so that divers will still have the information.

The dive tables can still be used as another way to help students understand how we absorb, eliminate and track nitrogen. Then students will have the knowledge they need to complete their recreational dives with a computer.

We hope you are excited about this change as we are! SSI will continue to bring you these types of innovations to help you stay on the cutting edge of training and education.

Brian Sharpe
January 6th, 2010, 02:35 PM
While this is probably just recognizing the reality that most divers use a computer and forget how to use tables 5 minutes after finishing their OW training does SSI advocate the use of a backup computer?

With my dive watch on and tables in my log book my diving isn't over for the day if my computer croaks.

BDSC
January 6th, 2010, 02:35 PM
Makes sense to me!

ScubaRich
January 6th, 2010, 02:43 PM
:popcorn::popcorn::popcorn:

StreetDoctor
January 6th, 2010, 03:05 PM
doesn't suprise me :rolleyes: I'm sure PADI will follow

sdiver68
January 6th, 2010, 10:32 PM
doesn't suprise me :rolleyes: I'm sure PADI will follow

According to 1 PADI instructor I spoke with, tables are already optional.

tomfcrist
January 7th, 2010, 12:21 PM
Tables may not be MANDATORY, but if it were me teaching they would be thouroghly covered. If nothing else i've never seen rental gear in the tropics come with a computer......Students need to know the theory behind the tables and have a basic understanding of how to use them.

I teach tables, and even when a student has his/her own gear with a computer they log their cert dives using a table.

riddler
January 7th, 2010, 12:51 PM
While this is probably just recognizing the reality that most divers use a computer and forget how to use tables 5 minutes after finishing their OW training does SSI advocate the use of a backup computer?

With my dive watch on and tables in my log book my diving isn't over for the day if my computer croaks.
I can't say I know for sure if the latest manuals recommend a backup computer. My manuals are pretty old. I checked the online training, and no mention. However, SSI does have a Computer Diving specialty, which we include as part of the Open Water Diver course at my shop. I'm sure most of the instructors now talk about the fact that they have a backup (I'm the only one that doesn't dive with two computers).

From my own experience in SSI, training there, and eventually becoming a dive leader, I did not hear about backup computers until an instructor meeting, after I became a dive leader. Then I went out and bought a backup computer. Then I lost it.

Is it necessary to advocate backup computers? I don't think so - unless you are doing some serious diving, my answer would be, after you lose your computer, stay out of the water for 24 hours, and return with a new (or rental) computer. The only place I've dived and not had the opportunity to rent a computer was Fiji and lakes in the U.S. - everyplace I've been in the Caribbean had computers for sale or rent.

StreetDoctor
January 7th, 2010, 01:16 PM
I can't say I know for sure if the latest manuals recommend a backup computer. My manuals are pretty old. I checked the online training, and no mention. However, SSI does have a Computer Diving specialty, which we include as part of the Open Water Diver course at my shop. I'm sure most of the instructors now talk about the fact that they have a backup (I'm the only one that doesn't dive with two computers).

From my own experience in SSI, training there, and eventually becoming a dive leader, I did not hear about backup computers until an instructor meeting, after I became a dive leader. Then I went out and bought a backup computer. Then I lost it.

Is it necessary to advocate backup computers? I don't think so - unless you are doing some serious diving, my answer would be, after you lose your computer, stay out of the water for 24 hours, and return with a new (or rental) computer. The only place I've dived and not had the opportunity to rent a computer was Fiji and lakes in the U.S. - everyplace I've been in the Caribbean had computers for sale or rent.

And if you're a vacation diver on a 5 day trip you just ruined 1 out of 4 dive days.

Brian Sharpe
January 7th, 2010, 01:46 PM
Then I went out and bought a backup computer. Then I lost it.


Sounds like something I'd do!:D

Lead_carrier
January 11th, 2010, 01:12 PM
The unfortunate reality of the whole mess is, I would dare to say that most recreational divers that do the once or twice a year vacation dives don't have computers or know the tables. They just follow the divemaster and come up when he says come up. then they log the dive for however long and whatever depth they are told.

tomfcrist
January 11th, 2010, 01:25 PM
sad but true......wheres the scuba police when you need em'?

jscott099
January 14th, 2010, 06:28 AM
The unfortunate reality of the whole mess is, I would dare to say that most recreational divers that do the once or twice a year vacation dives don't have computers or know the tables. They just follow the divemaster and come up when he says come up. then they log the dive for however long and whatever depth they are told.

I like to stay in touch with former students when I can and this is precisely what happens for some. Over time I have modified my teachings to let them know this happens. I ask them if they really want to place the lives of themselves and their loved ones in someone else's (understanding we do it all the time on planes, taxicabs, etc).

I teach SSI Computer Specialty and strongly encourage students who begin to by their own gear to go computer.

I never suggest back up computers for OW divers and students. I have not seen failure rate statistics that would mandate such a thing. Tech and cave is another matter of course.

tstormdiver
January 14th, 2010, 06:58 AM
Our shop is currently in the transition mode of changing from tables to computers, which makes things a bit confusing right now, but will soon smooth out, once the transition is complete. At this point I still plan to teach the tables from a historical point. to show the student where the computers are getting the the information they are displaying. That way the students get the best of both worlds, they get to learn to use computers & they also have at least a very basic introduction to using the tables.

Adi
January 14th, 2010, 07:51 AM
as a newcomer to the forum I know I might be blasted by all the "people that know" out there...

Personally I believe that "moving Divetables to the back" / "making it optional" / "placing it in the appendix" is the most ludicrious thing that I can imagine. The saying "Out of sight - out of mind" comes to mind.

Divetables form the very essence and foundation of dive planning. Irrespective if you have a dive computer (which also calculates your dive planning based on divetable algorythms), as a diver you NEED to understand the fundamentals of dive planning and the theory behind the calculations - period.

equipment fail - most possibly at the most unexpected times possible. Thats why we use analog SPGs in conjunction with our dive computers... right?

moving dive tables into the "optional" pot... does that mean that soon we are going to be doing away with the EANx Nitrox courses, and call it a "how to change the EANx value on your dive computer Course"??

In my opinion there should be no "option" about learning about dive tables - it should be mandatory.

Doppler
January 14th, 2010, 10:23 AM
as a newcomer to the forum I know I might be blasted by all the "people that know" out there...

Personally I believe that "moving Divetables to the back" / "making it optional" / "placing it in the appendix" is the most ludicrious thing that I can imagine. The saying "Out of sight - out of mind" comes to mind.

Divetables form the very essence and foundation of dive planning. Irrespective if you have a dive computer (which also calculates your dive planning based on divetable algorythms), as a diver you NEED to understand the fundamentals of dive planning and the theory behind the calculations - period.

equipment fail - most possibly at the most unexpected times possible. Thats why we use analog SPGs in conjunction with our dive computers... right?

moving dive tables into the "optional" pot... does that mean that soon we are going to be doing away with the EANx Nitrox courses, and call it a "how to change the EANx value on your dive computer Course"??

In my opinion there should be no "option" about learning about dive tables - it should be mandatory.

I think you are confusing dive tables with dive algorithms and decompression theory.

I teach for an agency that does not require its instructors to teach nitrogen tracking with dive tables, and never has, but that does not mean in any way shape or form that we can ignore teaching students about decompression theory...

A dive table (the flexible printed sheet that was the standard 15 years ago) is simply a method to track one's status and in itself contains ZERO information about the algorithm it serves. Teaching students to use tables does NOTHING to educate them on the finer points of decompression theory... and in survey after survey tables and their use are mentioned as a roadblock for a huge percentage of occasional sport divers; who after all, make up the meat of this pastime.

carrielsal
January 14th, 2010, 10:28 AM
I'm not sure yet how I feel about this. I think learning the tables gives students a better understanding where NDL dive times come from, but I do think that some form of computer training should be included with an OW class.

Skooter
January 14th, 2010, 11:56 AM
I am in the middle of ADI and Doppler. I agree with Doppler that tables are just another tool in teaching deco theory. And I agree with ADI that students need to understand at least the basic use of dive tables. I have been expecting this change for awhile now so I did a poll of my own. After teachig tables to students I asked THEM how they would feel about us not being required to teach tables, and eliminating that from the classroom. I have recieved a unanimous don't stop teaching tables. The students told me that they gain the best understanding of deco limits and the way a computer works by understanding the way dive tables and decompression theory work. Most of these students have already purchased computers and had no intention of using tables. So I will continue to teach the dreaded (by the sudents until they understand them) tables until I begin to get a different response. FWIW I have been teaching the computer specialty with my open water classes for the last two years, so students have a very good understanding of the choice they have.

Mike Boswell
January 16th, 2010, 09:09 PM
IMO the teaching of tables is not really needed anymore.

1. Dive computers do everything needed and they do it better.
2. Dive computers are reliable - DAN has statistics to prove it.
3. A few years after their cert. classes, most people can't remember how to use the dive tables.
4. Tables are not a good backup strategy because people don't have the needed information or knowledge to make the switch from a computer to tables.
5. Dive tables don't teach you any more about decompression theory than a computer does, they merely present the information in a different - and less flexible - format.

KWS
January 16th, 2010, 10:39 PM
with out some background in tables. how does one know when they are getting bum info from the computer. knowing the basics of time and depth as it affects the gasses is as important as basic math and use of a calculator. i know each time i reduce depth i expect to see remaining dive time to increase on my computer. and if it doesnt it must be driven by other factors like air time remaining. i dont think that doing the table problems are perhaps necessary however questions like what is the effect on time remaining as depth increases ect. ..... it would probably take me some time to be profiecent with a table again. and the nitrox issue with the equivilant air table is yuk .... but understanding it is something that is needed. the computer is somewhat a standard as it spits out data. a far cry from trying to figure out how all the agencies table format works. and in the event of an accident the puter it the dive record. no table can do that so i think ow's should be using computers. lastly do ow's/vacation divers have a higher or lower probability of a dsc problems. that stat i do not know.. i can only guess.
training on computers is an issue i dont now how to overcome. the only way i can see it working is to have all students use the same puter model while in the course. instructors mastering the use of models availiable is tougher than mastering the various tables.

Mike Boswell
January 16th, 2010, 11:57 PM
with out some background in tables. how does one know when they are getting bum info from the computer. knowing the basics of time and depth as it affects the gasses is as important as basic math and use of a calculator. i know each time i reduce depth i expect to see remaining dive time to increase on my computer. and if it doesnt it must be driven by other factors like air time remaining. i dont think that doing the table problems are perhaps necessary however questions like what is the effect on time remaining as depth increases ect. ..... it would probably take me some time to be profiecent with a table again. and the nitrox issue with the equivilant air table is yuk .... but understanding it is something that is needed. the computer is somewhat a standard as it spits out data. a far cry from trying to figure out how all the agencies table format works. and in the event of an accident the puter it the dive record. no table can do that so i think ow's should be using computers. lastly do ow's/vacation divers have a higher or lower probability of a dsc problems. that stat i do not know.. i can only guess.
training on computers is an issue i dont now how to overcome. the only way i can see it working is to have all students use the same puter model while in the course. instructors mastering the use of models availiable is tougher than mastering the various tables.


While much is made in the dive community of the dangers of DCI, DAN's latest 2008 report has a section which reviews DCI incidents. In one major study, they say recreational divers reported 3 incidents in about 15,000 dives. This seems fairly low to me, and indicates that the almost universal use of computers is not a problem.

The computer training issue is one that is already being handled, so I think that is not a big problem, and if the classroom time (very considerable in my experience) now spent on tables was instead spent on computer use (very brief in my experience), the diver would have a much better understanding of the computer.

For those who feel the tables give some insight into the mechanics of decompression, I would point out that the computer's ability to plan and simulate repetitive dives is much more accurate, flexible and intuitive than a dive table.

With my computer I can perform a simulated dive, over realistic terrain, initial or repetitive, on air or nitrox, watching what happens to tank pressure, NDL time, remaining dive time, ascent rate, ceilings, and other variables as I swim along. Try THAT on your tables.

Swampdonkey
January 18th, 2010, 01:38 AM
Well I guess the medical community should get all their tables out of the back of the books... this is a much about nothing. Tables are important in the learning process but get forgotten as time goes on. Do I agree with it, no but it is the reality. Move on already.

KWS
January 18th, 2010, 04:55 AM
While much is made in the dive community of the dangers of DCI, DAN's latest 2008 report has a section which reviews DCI incidents. In one major study, they say recreational divers reported 3 incidents in about 15,000 dives. This seems fairly low to me, and indicates that the almost universal use of computers is not a problem.

The computer training issue is one that is already being handled, so I think that is not a big problem, and if the classroom time (very considerable in my experience) now spent on tables was instead spent on computer use (very brief in my experience), the diver would have a much better understanding of the computer.

For those who feel the tables give some insight into the mechanics of decompression, I would point out that the computer's ability to plan and simulate repetitive dives is much more accurate, flexible and intuitive than a dive table.

With my computer I can perform a simulated dive, over realistic terrain, initial or repetitive, on air or nitrox, watching what happens to tank pressure, NDL time, remaining dive time, ascent rate, ceilings, and other variables as I swim along. Try THAT on your tables.

i think you missed my point. i agree that computers should be tought. that is what is going to be used in the real world. howevre using them has a couple of problems. the student learns a computer in the limited use as it relates to the level of training receeived. in the case of ow 40-50-60 ft or less emvirionment. how can that depth get anyone in trouble. and as such who pays attention to the computer for other than an electronig depth gage and a timer for safety stop? how does that student know if the computer they are using is not set up for nitrox or something else not standard to thier training. without the background of table knowledge they do not know when the computer is lying to them. perhaps if they started woth non nitrox cmputers??? i dont know. and then the primacy issue of first learned hardest remembered, hardest to forget hardest to change. the best example of this is ,,, i asked one of my students in an electronic course what was harger 2 pi or 6? the student had to use a calculator to figure it. from the students perspective why learn the basics i have a calculator to do the test.

the computer issue may have been handled as far as the agency goes but student application is something else. in the 60's when i took my basic, we just mentioned the tables existed and that was it. the course was taught for the area environments. as such 60 foot lake 72 cube tank no way in $%^& can you stay down long enough to have a problem. ow is basicly an intro to diving let them use tables, advanced is just that. advanced skills, depths, and technologies. a review of tables is all that is necessary and concentraton on computers is the responsible course to take. now take 12 students and 12 different computers,,, how does the instructor deal with that,,, to the level of liability he has ,,,, and not confuse some student unnless the same computer is going to be used by all students.

its not so much the issue its the application of teaching the computer/computers and achievving student profiency.

i wil agree that the accuracy of the computer far exceeds the tables. but if the puter gives you a 4 hour ndl and the tables give you a 2 hour ndl and the student has no basic understanding of routine times he will believe what the puter tells them. are the acgencies going to get into which puters are liberal or conservitive is respect to the tables. i know that tables from one agency to another vary. but the agency has all students using the same table for training, so all students get the same results. (reinforcement of leaining) how do you explain that aeris and uwatec have different data calculation's and which are (in the students eyes) better to use. it adds a whole new level of liability by itself let alone having a class of 12 all bringing in thier own puters. as far as the handling of the puter issue, is it not handled by giving the instructor the option to use or not to use.

the ability to so simulated dives is moot to the issue using it for training. it only reinforces my position that 12 different puters have 12 ways to operate the simulator. and the time needed to train all the ways takes away from the effectivness of the training. and that once again goes back to all use the same model of puter. the last issue is how do you test table usage oops computer usage with a gradable answer criteria that verifies learning. you cant so it is left out of testing. and becomes nice to know info.

i have not looked at the instructor material of any of the agencies so i am speeking somewhat off the cuff. i do have 7 yrs of teaching behind me from the military. i have discused this with the lds and thier current position is teach the tables and then add computers as a bonus until they can figure how to get all students using the same puter in the same modes to produce the same results. they cite thier authority to do this from "instructor discresion to use or not to use computers.

there is more than just doing problems in a class, the students have to believe and trust the computer outputs. how can that be done when you do not have basic unserstanding of tables to validate the computer outputs.

lastly how do you have a student plan repeditive dives on a shop puter knowing they will not have the same instrument when they buy thier own. the tables will at least tell them that only 3 dives can be made (square profile) before running out of time. as opposed to the puter saying 5-6 dives because you pushed a wrong button or it was calsulating a 36% mix. it just seams that puter use is better left to aow as opposed to ow because its advanced not basic.. one other thing 3 problems in every 1500 dives. is that reported or does it include known or unknown incidents that were unreported?

i am nnot trying to pick a fight here


from another post

Our shop is currently in the transition mode of changing from tables to computers, which makes things a bit confusing right now, but will soon smooth out, once the transition is complete. At this point I still plan to teach the tables from a historical point. to show the student where the computers are getting the the information they are displaying. That way the students get the best of both worlds, they get to learn to use computers & they also have at least a very basic introduction to using the tables.
__________________
Tammy Storm
SSI OWSI # 46723
www.evvscuba.com

i think this poster has it right.

Mike Boswell
January 18th, 2010, 09:48 PM
Hello KWS,

I'm an old-timer like you, so I understand the feeling that we shouldn't just throw out the tried-and-true stuff. I think you raise a lot of good points and I know these issues are being debated within the agencies. That is probably why they are taking so long to make these changes.

I learned on the Navy tables and used them for many years because that was all we had. When I first saw a dive computer I laughed! Now that I have used a dive computer I realize how much better they are than tables, and as a diver I would never go back to tables.

But, you make good points when you say that there are some drawbacks to teaching computers and relying on computers. These are areas that the agencies will have to address.

Papa_Bear
January 19th, 2010, 12:23 AM
The word Knot comes from throwing a measured line with knots in it overboard and counting the knots that slipped through your hand in a given time! Well I will take my GPS every time, but I enjoy the history of the term! Everyone should know the history and what the tables tell and why, but the computer will only get better and continue to make Diving even safer! My 2nd 2500 have been much safer, longer, and more comfortable thanks to the Computer!

KWS
January 19th, 2010, 02:52 AM
Hello KWS,

I'm an old-timer like you, so I understand the feeling that we shouldn't just throw out the tried-and-true stuff. I think you raise a lot of good points and I know these issues are being debated within the agencies. That is probably why they are taking so long to make these changes.

I learned on the Navy tables and used them for many years because that was all we had. When I first saw a dive computer I laughed! Now that I have used a dive computer I realize how much better they are than tables, and as a diver I would never go back to tables.

But, you make good points when you say that there are some drawbacks to teaching computers and relying on computers. These are areas that the agencies will have to address.

thanks for you understanding. i too would never go back to tables. with a device that works real time instead of in theory i would be a fool to. just like trading in my motorcycle for a bike. the bike had its place and now i have moved on with no plans to return. i learned a lot from riding a bike like vulnerability to cars on the road. i took all those lessons with me when i got my goldwing.

KWS
January 19th, 2010, 03:28 AM
The word Knot comes from throwing a measured line with knots in it overboard and counting the knots that slipped through your hand in a given time! Well I will take my GPS every time, but I enjoy the history of the term! Everyone should know the history and what the tables tell and why, but the computer will only get better and continue to make Diving even safer! My 2nd 2500 have been much safer, longer, and more comfortable thanks to the Computer!

the history is nice. as many dives as you have the diversion into history is fun. i bet you remember the electrolung???? i know it is for me and i dont have any where near your logged dives. also you would be foolish to use a basic table for the complex dive profiles you have come to do. one thing the tables give you is the data where you can make hand profiles of your planned dive. you just don have that using a computer with out the laptop connection . they will never know just how much of a tool the computer is unless they have to do the job them selves first. and with many, it is just a few dives(perhaps <10) before they do the aow. use of a dive computer should be a given for an aow grad. its a bit much for the task loading of an ow the first dozen dives. too many clocks too many depths to keep up with and still try to get/keep some form of horizontal neutral bouyancy. i would guess that an ow is mostly concerned with tank presure and depth than any thing else. for the ow the puter (unless integrated) is a mighty expensive depth gage and probably would not buy one. so perhaps my point is all moot, but maybe not.

clint@uniquescuba.com
January 23rd, 2010, 05:19 PM
I see this as another "Tip of the Hat" to SDI.

Their slogan "SDI leads, others follow" couldn't be any truer.

mitsuguy
January 23rd, 2010, 07:01 PM
I see this as another "Tip of the Hat" to SDI.

Their slogan "SDI leads, others follow" couldn't be any truer.

Except for the fact that PADI has been advocating this since mid 2009... They even changed some quizzes and knowledge reviews to reflect the change...

I think teaching with computers is completely rational. I do think though, that if someone just learns with a dive computer, they don't learn the reasoning why and how time interacts with nitrogen... I teach that the letter is some amount of nitrogen that needs to come out, and how the tables relate - more time down = more nitrogen in, more time up= more nitrogen out... With a dive computer, the difference is that all you get is a number that says how much longer you can stay at that depth... people translate this to "I'm running out of time, I need go up" which works, but, they don't understand that it is much more than a timer, that it is following a set of tables that determine, essentially, whether you live or die...

I teach computers to those that have them, go over the basics with those that don't, but everyone learns the tables...

boulderjohn
January 23rd, 2010, 07:25 PM
I do think though, that if someone just learns with a dive computer, they don't learn the reasoning why and how time interacts with nitrogen...

What is preventing you from teaching that? Why do you need tables to explain how nitrogen goes into and out of tissues as divers descend and ascend? Why can't you explain how a computer measures that?

mitsuguy
January 23rd, 2010, 07:41 PM
What is preventing you from teaching that? Why do you need tables to explain how nitrogen goes into and out of tissues as divers descend and ascend? Why can't you explain how a computer measures that?

because there is no easy visual...

without breaking out the tissue compartment charts, there is nothing that shows where a diver is on a chart of any sort...

you are essentially left with telling them that the deeper you go, the faster you absorb nitrogen, and the shallower you are, the slower you absorb nitrogen, which holds true, but is not the way many people think of it... no matter what it seems, without some sort of chart, people (even experienced divers even) don't see the correlation with why it takes so much more time for a diver with more time at less depth than it takes for a diver with less time at greater depth... a quick for instance, if you will... if you spend half of your maximum dive time (PADI table) at 100 feet (10 minutes), then it takes 1:28 minutes to become an A diver, and in 4:28 minutes, your body is completely washed of nitrogen, per the table, at least, and you start your next dive as if you hadn't been diving that day. However, if you use half of your maximum dive time at 40 feet (70 minutes), it takes 2:31 minutes to become an A diver, and 5:31 minutes to become washed completely, per table again. So, without getting into tissue compartments and charts, the tables are an easy way for someone to visually see the ins and outs.

Here's another great example... With my computer, I have dived to the no decompression limits, and beyond. Doing a single deep dive, I find that I am washed of nitrogen, according to the computer at least, usually later on in the day, sometimes late that evening. However, if I do multiple, easy, shallow dives, I sometimes find myself with nitrogen still in my system well into the next day, even though I never even got close to my ndl's... It's almost as though you have to tell a diver to "just trust the computer" without giving them any information as to how it works...

Now that I think about it, it is probably easier to teach the tables than it is to try and explain why a dive computer works the way it does without the tables.

Generally, I find that once a student learns the tables, showing them how a computer works (I usually let them dive one on dive 3 or 4 of check out dives) is relatively simple, and they then understand the "why."

One great argument given is that many students simply don't retain the tables. I have nothing to argue with against that, because I do see it all the time. Given current training standards and the way most people dive (just a few times a year), I don't see a way to remedy this.

mitsuguy
January 23rd, 2010, 07:50 PM
While much is made in the dive community of the dangers of DCI, DAN's latest 2008 report has a section which reviews DCI incidents. In one major study, they say recreational divers reported 3 incidents in about 15,000 dives. This seems fairly low to me, and indicates that the almost universal use of computers is not a problem.

There are a lot of people that get LUCKY!

A while back, we had a large group of divers. The two divemasters we had on the boat briefed the second dive of the day carefully, because the depths could put some people close to their limits on their computers... As they briefed the dive, they said for everyone to watch their computers, ascend to a shallower depth if they started getting low on no-deco time, and to make sure they followed their computers if any ndl's were surpassed.

As the divers came back to the boat, our DM's remained in the water, showing people little things around the mooring, waiting on others to do their safety stops and whatnot. Neither of our DM's went into deco (and one dives a Suunto even). Back on the boat, with all divers out of the water, it was found that some divers ignored 8 minute deco stop warnings from their computers. Ones comment was something along the lines of "it said something about an 8 minute ascent time, so I just did my 3 minute stop and came up" This guy had plenty of air. He was not the only one of the bunch to do this. The divers completely ignored the warnings and times given on their computers and dived deeper for longer than our divemasters (who are always first in the water, last out).

I truly believe luck plays a big part in keeping that number so low.

Bogie
January 23rd, 2010, 07:55 PM
Dive computers are the current standard for diving. If you use the dive chart you get short dives and unrealistic dive profile. I know my dive computer well now but it would have been nice to get some training. I like knowing dive tables and learning dive tables is easy so I would teach both. Probably the vacation diving crowd would never look a dive table and probably don't need to.
Technical diving is another world and those divers need to know their stuff.

boulderjohn
January 23rd, 2010, 08:38 PM
because there is no easy visual...

without breaking out the tissue compartment charts, there is nothing that shows where a diver is on a chart of any sort...



Why do you need a chart?

I teach decompression theory in the beginning with Boyle's Law. It makes sense there. I teach tables later on, but they have the theory down long before that.

My students have no trouble understanding it.

boulderjohn
January 23rd, 2010, 08:40 PM
There are a lot of people that get LUCKY!

A while back, we had a large group of divers. The two divemasters we had on the boat briefed the second dive of the day carefully, because the depths could put some people close to their limits on their computers... As they briefed the dive, they said for everyone to watch their computers, ascend to a shallower depth if they started getting low on no-deco time, and to make sure they followed their computers if any ndl's were surpassed.

As the divers came back to the boat, our DM's remained in the water, showing people little things around the mooring, waiting on others to do their safety stops and whatnot. Neither of our DM's went into deco (and one dives a Suunto even). Back on the boat, with all divers out of the water, it was found that some divers ignored 8 minute deco stop warnings from their computers. Ones comment was something along the lines of "it said something about an 8 minute ascent time, so I just did my 3 minute stop and came up" This guy had plenty of air. He was not the only one of the bunch to do this. The divers completely ignored the warnings and times given on their computers and dived deeper for longer than our divemasters (who are always first in the water, last out).

I truly believe luck plays a big part in keeping that number so low.

What this shows is that they were not properly instructed on how to use their computers. Perhaps that would have been a good thing to do in their instruction.

waterpirate
January 24th, 2010, 08:34 AM
Bingo!
Four pages later we get to the real issue. It is the quality of the instructor/instruction, not the method used. The concept of tables vs. computer is moot, if either method is taugt thourougly. It also has nothing to do with agency. Any quality instructor teeaches well beyond the standards, which could be compared to a ged vs. a diploma from a privat academy.
I recently went with a old friend, new diver for a drysuit course. Prior to entering the water I asked the instructor what the dive plan was and got deer in the headlights. I asked my friend what was the max depth available in the quaurry and if he attained it what was his max ndl time. I got a blank stare. I blame this on the instructor solely.
As a foot note when my freind returns from Afganistan I will mentor him and straighten him right out.
Eric

Sask Diver
January 24th, 2010, 10:06 AM
This just seems to confuse me even more, I am taking my ow in Feb and a freind of mine has tried explaining the dive tables to me before the course, now my instuctor says PADI does not instuct with the dive tables anymore but with eRDP. Is this a safe way to go, am I supossed to trust my life to a $10 peice of electronics and a 25 cent battery.
If there is one thing I want to get down pat, it would be the dive tables so I will be around to enjoy many years of diving in the future.

waterpirate
January 24th, 2010, 11:55 AM
This just seems to confuse me even more, I am taking my ow in Feb and a freind of mine has tried explaining the dive tables to me before the course, now my instuctor says PADI does not instuct with the dive tables anymore but with eRDP. Is this a safe way to go, am I supossed to trust my life to a $10 peice of electronics and a 25 cent battery.
If there is one thing I want to get down pat, it would be the dive tables so I will be around to enjoy many years of diving in the future.

Here is what I consider good advice about your dilema. "slow and easy with good technique". Consider your ow a learners permit. Learn what you can in ow and never stop learning. Find divers in your local area who dive alot, dive with them. Someone in the group will mentor you and fill in alot of questions with practical knowledge. Take more classes and dive,dive,dive.
Eric

clint@uniquescuba.com
January 24th, 2010, 03:46 PM
Except for the fact that PADI has been advocating this since mid 2009... They even changed some quizzes and knowledge reviews to reflect the change..


LOL...so!

This was also a huge "Tip of the Hat" to SDI as well

How many of you know how long SDI has been doing this??? 2 years? 5 years? 10 years?


I also think it was absolutely hilarious:rofl3: in SSI's press release they stated "We hope you are excited about this change as we are! SSI will continue to bring you these types of innovations to help you stay on the cutting edge of training and education."

cutting edge and innovative!.....lol.... I'm about to pee myself this is so funny, making a statement like that when your like 10 years behind SDI

boulderjohn
January 24th, 2010, 04:04 PM
This just seems to confuse me even more, I am taking my ow in Feb and a freind of mine has tried explaining the dive tables to me before the course, now my instuctor says PADI does not instuct with the dive tables anymore but with eRDP. Is this a safe way to go, am I supossed to trust my life to a $10 peice of electronics and a 25 cent battery.
If there is one thing I want to get down pat, it would be the dive tables so I will be around to enjoy many years of diving in the future.

Relax.

There are many ways to plan and track dives. Tables are one way. Computers are another way. The eRDPml is another way. Dive planning software is still another way.

I taught the tables for years. They work. The eRDPml has only come out recently, and I have only taught a few classes in which students learned that way. They learned the eRDPml much easier than past students learned tables. They made far fewer errors. We were able to practice planning far more complex dives in class without the computational errors so common in table practice. (With tables, it is really easy, for example, just to read the wrong number because they are so small and close together.)

Don't worry about it. The important thing--as mentioned above--is to understand how decompression works and why you have to do the things you have to do. Once you are more into diving, you will make a choice as to how you will plan your dives. In all my years of vacation diving, I have rarely seen anyone pull out tables of any kind for recreational diving, so the odds are you would have gone away from them to something else--like a computer--anyway.

If you get into more complex decompression diving, neither the normal tables nor the eRDPml work anyway, so you will have to change.

mitsuguy
January 24th, 2010, 08:39 PM
Why do you need a chart?

I teach decompression theory in the beginning with Boyle's Law. It makes sense there. I teach tables later on, but they have the theory down long before that.

My students have no trouble understanding it.

But Boyle's law doesn't have a lot to do with decompression theory...

in fact, Boyle's law only relates to pressure and volume... the only part related to decompression theory is pressure... Boyle's law would be great to explain to students about why their air doesn't last as long at depth...

Henry's law is the one you are looking for when you talk about decompression theory - it is the law that explains why nitrogen becomes dissolved into the blood due to partial pressures...

utbiomajor
January 25th, 2010, 01:17 PM
I am also a pilot, and I see a lot of similarities between dive tables and VOR/pilotage.

VOR is an older method of navigation that uses radio signals and vectors to/from the station to give your location. It is still taught to every single pilot, and I've never flown a plane (even military training jets) that didn't have them. They're the most reliable form of navigation that doesn't require calculation. You plot a line from the station in the direction you are, then plot one from a different station. The intersection is you.

Pilotage is simply using your charts, a compass, and a watch to fly. It's also still taught, usually in conjunction with VOR as your primary navigation for training cross-country flights. You pick checkpoints and calculate the time it should take between them, then look for them when you fly.

Now, almost every pilot I know uses GPS on cross-country flights. It's extremely reliable and accurate, and many pilots rely on them for flight. Some systems are approved for instrument flying, but many of the handhelds that pilots affix to their yokes are not.

Even though newer technology is here that makes flying easier and safer, every pilot must learn pilotage and VOR navigation. They're the basics and they're great backups. Diving should be no different.

mitsuguy
January 25th, 2010, 01:48 PM
I am also a pilot, and I see a lot of similarities between dive tables and VOR/pilotage.

VOR is an older method of navigation that uses radio signals and vectors to/from the station to give your location. It is still taught to every single pilot, and I've never flown a plane (even military training jets) that didn't have them. They're the most reliable form of navigation that doesn't require calculation. You plot a line from the station in the direction you are, then plot one from a different station. The intersection is you.

Pilotage is simply using your charts, a compass, and a watch to fly. It's also still taught, usually in conjunction with VOR as your primary navigation for training cross-country flights. You pick checkpoints and calculate the time it should take between them, then look for them when you fly.

Now, almost every pilot I know uses GPS on cross-country flights. It's extremely reliable and accurate, and many pilots rely on them for flight. Some systems are approved for instrument flying, but many of the handhelds that pilots affix to their yokes are not.

Even though newer technology is here that makes flying easier and safer, every pilot must learn pilotage and VOR navigation. They're the basics and they're great backups. Diving should be no different.

exactly... what happens if the tech fails...

I teach tables, because I fully believe students should have a visual of where they are at all times...

I use two computers (I might be required to do 5-6 dives in a day), so redundancy is a must, but, if it came down to it, I would know about where I was on a table - its just something I visualize, and know, from the dives I plan on a daily basis using the table, (used to be wheel), and now erdpml.... Once you have experience, it's great to visualize where you are... until then though, a computer is an amazing piece of equipment, so long as you utilize it correctly...

correct use is the key to ndl diving whether you are using a computer, tables or ML computer...

boulderjohn
January 25th, 2010, 08:18 PM
But Boyle's law doesn't have a lot to do with decompression theory...

.

Wow.

I would think that the fact that they are breathing 4 times as many molecules of nitrogen at 99 feet as on the surface thus creating a significant gradient would important. I would think that a rapid ascent creating a significant gradient between the tissues and the inhaled air would be a factor.

mitsuguy
January 25th, 2010, 09:30 PM
Wow.

I would think that the fact that they are breathing 4 times as many molecules of nitrogen at 99 feet as on the surface thus creating a significant gradient would important. I would think that a rapid ascent creating a significant gradient between the tissues and the inhaled air would be a factor.

it has nothing to do with breathing 4x more molecules... it has to do with the partial pressures of those molecules against the tissues in the lungs that causes the blood to absorb more nitrogen...

it is this very fact that is why breathing rate has no (published) effect on decompression sickness rates... according to your theory, if you breathed 4x as fast on the surface, it would be the same as breathing 1x at 99 feet - your words, not mine. But in reality, that has nothing to do with blood absorption of nitrogen... it ONLY deals with partial pressures...

Henry's law states that when a gas comes in contact with a liquid, that said gas will dissolve into said liquid until partial pressures become saturated... so, when you dive to any depth, the partial pressure of O2 and N2 rises. This increase in partial pressures is what causes the N2 to be absorbed into the bloodstream. N2 in the bloodstream is what can cause DCS... Excessive, that is. The problem, and what causes DCS is that when the partial pressure of N2 in the inhaled air is lower than that in the bloodstream, the N2 tries to escape. On a normal ascent, it escapes through the lungs in the air we exhale, however, on a rapid ascent, there is not enough time for blood to flow through, or surface area, in the lungs, for the N2 to escape, thus it expands in small bubbles, thought to start out as microbubbles, then gathering together in what we call the bends, or DCS...

You actually sound like you know the theory when you state the simple word "gradient" meaning change in pressure, I assume. However, that is still not Boyles law, it is Henrys law...

Boyles law might deal with those molecules in the blood that expand when pressure is reduced, but, unfortunately, it still falls under Henry's law due to on-gassing and off gassing of the blood...

perhaps you should re-read henry's law...

boulderjohn
January 25th, 2010, 09:41 PM
who said anything about breathing rate/

Well, I was gong to explain to you that at 99 feet there is a pressure gradient that will cause nitrogen to be absorbed faster by the tissues. This will result nitrogen loading in the tissues. As they ascend, the effect of Boyle's law will be that the air they are breathing will have less nitrogen than they have in their tissues, so...

but we are really getting nowhere in this. I'm signing off.




it has nothing to do with breathing 4x more molecules... it has to do with the partial pressures of those molecules against the tissues in the lungs that causes the blood to absorb more nitrogen...

it is this very fact that is why breathing rate has no (published) effect on decompression sickness rates... according to your theory, if you breathed 4x as fast on the surface, it would be the same as breathing 1x at 99 feet - your words, not mine. But in reality, that has nothing to do with blood absorption of nitrogen... it ONLY deals with partial pressures...

Henry's law states that when a gas comes in contact with a liquid, that said gas will dissolve into said liquid until partial pressures become saturated... so, when you dive to any depth, the partial pressure of O2 and N2 rises. This increase in partial pressures is what causes the N2 to be absorbed into the bloodstream. N2 in the bloodstream is what can cause DCS... Excessive, that is. The problem, and what causes DCS is that when the partial pressure of N2 in the inhaled air is lower than that in the bloodstream, the N2 tries to escape. On a normal ascent, it escapes through the lungs in the air we exhale, however, on a rapid ascent, there is not enough time for blood to flow through, or surface area, in the lungs, for the N2 to escape, thus it expands in small bubbles, thought to start out as microbubbles, then gathering together in what we call the bends, or DCS...

You actually sound like you know the theory when you state the simple word "gradient" meaning change in pressure, I assume. However, that is still not Boyles law, it is Henrys law...

Boyles law might deal with those molecules in the blood that expand when pressure is reduced, but, unfortunately, it still falls under Henry's law due to on-gassing and off gassing of the blood...

perhaps you should re-read henry's law...

mitsuguy
January 25th, 2010, 10:22 PM
who said anything about breathing rate/

Well, I was gong to explain to you that at 99 feet there is a pressure gradient that will cause nitrogen to be absorbed faster by the tissues. This will result nitrogen loading in the tissues. As they ascend, the effect of Boyle's law will be that the air they are breathing will have less nitrogen than they have in their tissues, so...

but we are really getting nowhere in this. I'm signing off.

but that still isn't boyles law...

how in the world do you get p1v1=p2v2 into pressure gradients...

that is all partial pressure stuff and has nothing to do with boyles law...

it isn't that the air will have less nitrogen than is in their tissues, it is the same percentage - it is the partial pressure

here is the one:
Henry's Law (http://www.doalasvegas.com/html/henry_s_law.html)

Henry's Law (http://www.thescubaguide.com/certification/henrys-law.aspx)

Henry's law and divers (http://www.divepilot.com/diving-physics/henrys-law-and-divers.php)

So, you can keep telling your students you are teaching them Boyles law, but if you are talking decompression theory, it is most definitely Henrys law that you are talking to them about...

Or is it that you still don't understand - you keep talking about volume, but as far as on-gassing concerns, volume has no published effects. Volume is directly related to lung displacement and pressure. This is Boyles law. However, the amount of nitrogen that we uptake has nothing to do with the volume of air we breathe. If the volume mattered, then it would mean we could get DCS if we sat around and breathed really really fast on the surface. But we don't. Again, it has nothing to do with breathing 4x the density, it has to do with breathing 4x the partial pressure...

its partial pressure, partial pressure, partial pressure that determines nitrogen on-gassing and off-gassing, NOT volume....

please please re-read your laws and re-learn why our bodies absorb nitrogen...

tomfcrist
January 26th, 2010, 07:27 AM
its partial pressure, partial pressure, partial pressure that determines nitrogen on-gassing and off-gassing, NOT volume....

please please re-read your laws and re-learn why our bodies absorb nitrogen...

Hate to be the bearer of bad news, but Boyles Law, Henrys Law and Daltons law are all directly related.

mitsuguy
January 26th, 2010, 08:54 AM
Hate to be the bearer of bad news, but Boyles Law, Henrys Law and Daltons law are all directly related.

noooo... volume has nothing to do with henry's law, ZERO!

here is yet another site explaining henry's law... note that volume is not talked about once, because volume is irrelevant... henry's law works because there is an increase in pressure, but has ZERO to do with volume...

Solubility of gases in liquids, Henry's law (http://www.800mainstreet.com/9/0009-006-henry.html)


Now, wanna talk about related laws, then we can talk about Boyles, Charles, Gay-Lussac's laws, which together make up the combined gas laws. Add Avogadros and we have the ideal gas law.

Charles Law = volume and temperature
Boyles law = volume and pressure
Gay-Lussac = pressure and temperature
Avogadros = deals with the above three and makes some statements about the ideal gas law

then we have henry's law... henry's law = the absorption of molecules from a gas into a liquid because of partial pressures

here's why it doesn't deal with the above three...

I'll use the picture from the link above...
http://www.800mainstreet.com/9/0009-006-lo-henry.gifhttp://www.800mainstreet.com/9/0009-006-hi-henry.gif

in this image, we have a fixed amount of liquid at the bottom. on the left, we'll assume that the gas and the liquid are in equilibrium. On the right, we could use Boyles law to increase the pressure by reducing the volume - this would then cause more molecules to start being absorbed into the liquid at the bottom, because the new pressure of the molecules in the gas is higher, the partial pressure is higher. To figure this out, we would use Henry's law to determine how much would be absorbed into the liquid. Funny thing about Henry's law though, is that it doesn't matter the volume - there is no place to input volume on the calculation... So, lets theorize one other option... lets add pressure, but not reduce the volume... This is simple to do, and in effect, every breath we take on scuba, we are doing this - the volume of our lungs does not change a whole lot as we dive - we increase the pressure to prevent this... so, lets add air to the container above with an air compressor... volume has not changed, but the pressure is higher, so, does Boyles law matter? Absolutely not... because we have increased the pressure without changing the volume by adding more molecules to the container, we have increased the pressure without worrying about the volume... this causes henry's law to take action, and again, because the partial pressure of the gas is higher than the partial pressure of the gas in the liquid, the liquid will start absorbing the gas...

forgot you mentioned daltons law... it is related to henry's law, and essentially just says that the sum of all partial pressures in a gas equal the total pressure of the gas... that is the basis for calculating the differences between standard air diving and mixed gas diving... boyles law still doesn't come in to play, because volume, again, is irrelevant...

tomfcrist
January 26th, 2010, 12:37 PM
Boyles law IS about volume......However because your body stays in tune with the environment(depth doesnt decrease your lung capacity) it also implies that the air within tyour lungs at depth is more dense.........that is where Boyle's and Henrys, and Daltons laws all come together.....If your lungs got smaller the deeper you dive (therefore holding the same volume and density of a given gas) partial pressures would be irrelivant. when you calculate your PPO2 etc. do you use ata as part of the formula? Of course you do because the more of any given gas you have in your lungs, the more you will absorb.......All the gas laws relate directly to each other in one way or another.....OBTW Physics is kinda a specialty of mine, and with physics if you dont understand why a law is what it is and all the laws relating to it you are only getting half the story.

A quote from your link"This means the concentration to pressure ratio is the same when pressures change.".......Very true unless you are talking about human anatomy while diving where the concentration does change.

Doppler
January 26th, 2010, 01:11 PM
This thread is totally derailed but since you guys are well off-topic, may I point out that if one mentions Avogadro and gas laws, it is more correct to say that if we consider the gas laws en mass and include Avogadro’s hypothesis, then we can derive the Universal Gas Constant: PV=nRT, where R is derived as a constant from: PV/T=Constant, n is the number of moles.

If we consider teaching decompression theory and we want to discuss the real physics of it, we have to consider Fick's and Graham's; floppy tables or not.

tomfcrist
January 26th, 2010, 01:21 PM
This thread is totally derailed but since you guys are well off-topic, may I point out that if one mentions Avogadro and gas laws, it is more correct to say that if we consider the gas laws en mass and include Avogadroís hypothesis, then we can derive the Universal Gas Constant: PV=nRT, where R is derived as a constant from: PV/T=Constant, n is the number of moles.

If we consider teaching decompression theory and we want to discuss the real physics of it, we have to consider Fick's and Graham's; floppy tables or not.

off topic indeed......

mitsuguy
January 26th, 2010, 01:42 PM
If your lungs got smaller the deeper you dive (therefore holding the same volume and density of a given gas) partial pressures would be irrelivant. when you calculate your PPO2 etc. do you use ata as part of the formula? Of course you do because the more of any given gas you have in your lungs, the more you will absorb.......

no, it has nothing to do with volume of gas in your lungs - our lung volume does not change when diving... the density increases, but the volume stays the same... again, its not about volume, it is about pressure... why is that so hard to comprehend???

when you calculate P02, you use ata - ata is pressure... still no reference to VOLUME!

tomfcrist
January 26th, 2010, 02:15 PM
no, it has nothing to do with volume of gas in your lungs - our lung volume does not change when diving... the density increases, but the volume stays the same... again, its not about volume, it is about pressure... why is that so hard to comprehend???

when you calculate P02, you use ata - ata is pressure... still no reference to VOLUME!

One last time, As you decend pressure increases which in a closed system decreases volume. In an open system(your lungs) volume does not decrease but density increases, you will have X amount more molecules of air in your lungs.

The fact that there are more molecules of air in your lungs means that more will transfer into solution from your lungs to your bloodstream:to tissues.

Henrys law would make no sense in diving if you dont go through Boyles law, and Daltons law first.

I am not trying to tell you that boyles law is all you need to know when it comes to diving or Partial Pressures. What I am saying is that if you really think that Boyles law has no bearing or effect on Daltons law or Henrys law then you are horribly mistaken.
The gurus who came up with decompression theory knew this and that is why they constructed the General Gas Law(or Principle) and it is included in every dive text that i can recall, no matter the agency.

Recap: Boyles Law implies that as we go deeper the density of gas in our lungs increases(due to compression), Daltons law says that as density increases, the partial pressure is higher, and Henrys law says that the higher the partial pressure, the more you will in-gas.

Understand yet?

mitsuguy
January 26th, 2010, 02:32 PM
Recap: Boyles Law implies that as we go deeper the density of gas in our lungs increases(due to compression), Daltons law says that as density increases, the partial pressure is higher, and Henrys law says that the higher the partial pressure, the more you will in-gas.

Understand yet?

yes I understand... in fact, you may have just solidified my argument... my argument was that the original text said that he taught his students boyles law, and I said that that was not an accurate way to describe to students, or anyone, for that fact, why we on gas nitrogen...

because it simply doesn't matter... all we need to know about on-gassing and off gassing is that the pressure changes - it doesn't matter why the pressure changes, and it doesn't matter what the volume of the gas is either, it just matters that there is a pressure change...

when we talk decompression theory, henrys law is still the only thing we need to worry about teaching, because all students need to know is that pressure increases which causes the liquid (blood and tissues) to absorb nitrogen and any other gasses we breathe... trying to teach boyles law to describe this is completely inaccurate, because it is not the volume of air we breathe, but the pressure of the air we breathe...

take your recap, and delete boyles law from it - instead, we know that as we dive deeper, there is increased pressure on our bodies... as you said, daltons law says that the sum of the partial pressures in a gas is equal to the total pressure of the gas... we don't need to know from boyles why volume is affected other than when we calculate sac rates... we just need to know the pressure... so, 99 feet is 4 ata... simple... po2 = .21 x 4 = .84 pn2 = .79 x 4 = 3.16 nowhere in there does volume or density that we might have tried to find from boyles law apply... then we'd use henry's law to see what that 3.16 ata of N2 does as far as absorption into the bloodstream...

so, if you can tell me what we gain by figuring out boyles law when we do these calculations, then please, show me...

tomfcrist
January 26th, 2010, 04:42 PM
Once mor because they are all related. The poster didn't say that he doesn't cover the other laws, he just said that he starts with Boyle. Also, boyles law has alot to do with nitrogen coming out of solution, therefore it has to do with decompression.

mitsuguy
January 26th, 2010, 04:46 PM
Once mor because they are all related. The poster didn't say that he doesn't cover the other laws, he just said that he starts with Boyle. Also, boyles law has alot to do with nitrogen coming out of solution, therefore it has to do with decompression.

thats still more henry's law than boyles... boyles law doesn't do anything with offgassing though like you say... it has to do with bubble growth while still absorbed in the tissue... offgassing is still directly henry's law...

lets just agree to disagree...

dashthrash
January 26th, 2010, 08:14 PM
I heard that about computer and the dive tables. Here is what it comes down to.... Instructors don't have to teach tables if all the equipment that is being taught on has a computer... if not then they have to still teach tables. Now the $25000 dollar question is what shop is going to invest all the money and time in computers so they don't have to teach tables.

tomfcrist
January 27th, 2010, 09:31 PM
thats still more henry's law than boyles... boyles law doesn't do anything with offgassing though like you say... it has to do with bubble growth while still absorbed in the tissue... offgassing is still directly henry's law...

lets just agree to disagree...

We disagree without an agreement to disagree

boulderjohn
January 27th, 2010, 09:46 PM
I heard that about computer and the dive tables. Here is what it comes down to.... Instructors don't have to teach tables if all the equipment that is being taught on has a computer... if not then they have to still teach tables. Now the $25000 dollar question is what shop is going to invest all the money and time in computers so they don't have to teach tables.

What you heard is not accurate. It will not cost a shop a dime more to teach one way or the other.

clint@uniquescuba.com
January 27th, 2010, 10:29 PM
Off topic:

I had to give you a "Thank You" boulderjon, cause your thanks count of 666 was freaking me out...lol

boulderjohn
January 27th, 2010, 10:48 PM
Off topic:

I had to give you a "Thank You" boulderjon, cause your thanks count of 666 was freaking me out...lol

Glad you got me off that one. I would not want people to get the wrong idea about my intentions.

sweatfrog
January 28th, 2010, 02:19 PM
What you heard is not accurate. It will not cost a shop a dime more to teach one way or the other.Are you saying that students don't need computers for their OW dives?

boulderjohn
January 28th, 2010, 05:55 PM
Are you saying that students don't need computers for their OW dives?

If our shop were to do that now and we decided to supply the equipment to the student without charging a rental fee, then it would be just a matter of reaching into the rental gear and handing it out.

As it is right now, still in the tables era, our students have computers on their consoles when they do the CW dives, and we show them how they work. When they get equipment from us for their OW dives, they have computers as well. When we log their dives, we do it using the tables right now, but I show them how to pull the information from their computers.

I suppose that if a shop does not currently own a set of computers, then there will be an added expense, but a shop that does not own a set of computers these days probably deserves a kick in their retail planning pants.

sweatfrog
January 29th, 2010, 01:05 PM
If our shop were to do that now and we decided to supply the equipment to the student without charging a rental fee, then it would be just a matter of reaching into the rental gear and handing it out.We don't charge a rental fee on equipment.


As it is right now, still in the tables era, our students have computers on their consoles when they do the CW dives, and we show them how they work. In the CW the most you can get a computer to do is to turn on.


When they get equipment from us for their OW dives, they have computers as well. When we log their dives, we do it using the tables right now, but I show them how to pull the information from their computers. That makes sense, as long as the students are shown how to fill out the log. Many of them don't understand it's importance and forget how to use the log in way too short a period of time.


I suppose that if a shop does not currently own a set of computers, then there will be an added expense, but a shop that does not own a set of computers these days probably deserves a kick in their retail planning pants.That depends on a number of factors. These "state of the art" training agencies who say they lead the way seem to fall 10 years behind SDI on the computer issue. I am not and never have been an SDI Instructor.

Not many of my customers have rented computers from me in the past, even though I have them available. I realize it depends how many students you train at once, but each student needs their own computer on the OW dives. It's unethical to pass one computer from student-to-student due to nitrogen uploading and since we don't go to the lake every weekend a backlog of students sometimes exists, especially in todays economic troubles. That adds up to a lot more computers than I have in stock, or have needed in the past. This is great for the manufacturer's and they have been touting it for years, duh.

When computers were first promoted over tables, I thought it had the potential of a liability issue. However, those statistics didn't change and neither did the amount of people getting bent. I understand and see students readily accept the computer and more computer sales will be the outcome. But when Instructors are being told that the students need a backup table/ERDPML in case their computer breaks down, it seems to send the message that computers aren't reliable.

Why would any agency promote diving safety in a beginning class, unless it's just a marketing ploy. It would be interesting to see the percentage of accidents versus divers trained in a year, broken down by agency. I would be willing to bet they are all at the same place.

Lindzi258
March 24th, 2010, 03:26 PM
I just finished with SSI and we wear taught the tables, we wear taught them again in deep diving. They maybe optional but I have not heard of anyone not being taught them through SSI, PADI yes we were at the Comal river and a group of PADI divers were doing their OW, and not of them knew how to use them. I guess it is becoming a lost art But I feel you need to know them to understand how your computer works.

explorer08
March 24th, 2010, 04:21 PM
I use two computers (I might be required to do 5-6 dives in a day), so redundancy is a must, but, if it came down to it, I would know about where I was on a table ...

To use two computers is a good idea. But I believe, that somebody who believes - while doing 5-6 dives in a day - if both his computers would fail after dive no.3 or 4, that he would be able to track his dives with a dive table, will also believe that Santa Claus is coming on 24th of December.

boulderjohn
March 24th, 2010, 06:19 PM
To use two computers is a good idea. But I believe, that somebody who believes - while doing 5-6 dives in a day - if both his computers would fail after dive no.3 or 4, that he would be able to track his dives with a dive table, will also believe that Santa Claus is coming on 24th of December.

All you have to do is complete one multi-level dive with a maximum depth that would be a table violation with a square profile (which is what happens with the vast majority of resort area dives) and you won't be able to use the tables accurately the rest of the day.

warmwaterturner
March 24th, 2010, 06:57 PM
SSI may have done that but NOT my SSI instructor. We practiced and practiced and practiced. He actually just touched on the computer primarily because there are so many models and functions from one computer to another. I really appreciated the old school approach.

explorer08
March 25th, 2010, 06:02 AM
All you have to do is complete one multi-level dive with a maximum depth that would be a table violation with a square profile (which is what happens with the vast majority of resort area dives) and you won't be able to use the tables accurately the rest of the day.

I absolutely agree with you!

sweatfrog
March 25th, 2010, 12:10 PM
All you have to do is complete one multi-level dive with a maximum depth that would be a table violation with a square profile (which is what happens with the vast majority of resort area dives) and you won't be able to use the tables accurately the rest of the day.You just donít know what you donít know. No matter which set of tables you use, you can do a multilevel dive with them.

Letís take a dive below 80 feet for 20 minutes. Depending on which table you use, you come out with a pressure group. That pressure group is applicable for all depths on that pressure group designation. So, use that pressure group to ascend to 40 feet.

Youíll notice that your time for that pressure group has increased accordingly. Now if you want to dive for an additional 10 minutes at 40 feet, you just add that to your time stated at the 40 foot depth under said pressure group and voila; you have done a multilevel dive with the tables.

explorer08
March 25th, 2010, 02:20 PM
All you have to do is complete one multi-level dive with a maximum depth that would be a table violation with a square profile (which is what happens with the vast majority of resort area dives) and you won't be able to use the tables accurately the rest of the day.


I didn't remark it before, but I became aware of it right now.
I think boulderjohn didn't mean "a maximum depth" but "a maximum time". Because the depth is usually not the problem. But what usually will happen while doing multilevel dives with computers is, that the maximum times of any table will be exceeded by far. And because of that no table can help you if your computer fails.

sweatfrog
March 26th, 2010, 11:48 AM
Because the depth is usually not the problem. But what usually will happen while doing multilevel dives with computers is, that the maximum times of any table will be exceeded by far. And because of that no table can help you if your computer fails.Well, the Navy Dive table (for one) has pressure groups for decompression diving and if you look at my last post, you'll see that will work even though the diver is in decompression. S/he is off-gassing as the ascent is made and the new depth is reached.

Decompression tables and computers both use geometric progression to find how much nitrogen has been absorbed in the body. As time passed, a lot of tables have been made more conservative with the advent of doppler systems, to measure those silent bubbles.

SailNaked
March 26th, 2010, 01:01 PM
I love it when someone says you can not use the tables or a computer accurately. the word does not apply, the tables and the computers are all based on an inaccurate system of approximations. there is nothing wrong with using computers all morning and then the tables in the afternoon.
all you need to go from a computer to a table is to look at the plan feature on the computer and write down a depth and a time at that time and then compute the pressure group using a table. You are as accurate as you would be at any other time using either a computer or table which is to say not. a good practice would be to do that before every dive and write it on your slate.

PLEASE READ AND UNDERSTAND any system you use to determine your dive time

read the disclaimers that come with your tables or computer you are not guaranteed not to DCS using them. you are guaranteed to DCS doing anything I say so I can not be responsible if you do.:D

Dive Hawk
March 29th, 2010, 12:19 AM
Never mind.

glbtrekker
May 28th, 2010, 09:11 AM
SSI's recent decision to stop teaching tables is one of the reasons that I just went with NAUI for OW instead. Sorry...I just believe that a person should understand some of the theory and math that determines how long he or she can stay underwater instead of just depending on a computer and having no idea what drives the figures it displays. It's kinda like, teach my kid to add and subtract before you give them a calculator.

Ch3stnut
June 6th, 2010, 07:34 AM
Hey,
I am an SSI instructor in Australia and haven't heard about not teaching tables. We still teach that unless you have a back-up comp that tables can be very important even though that still only really DC's and instructors know how to use them.

PvtStash
June 6th, 2010, 11:05 AM
or at least a convenient Fringe benefit?

I mean, if you teach the tables and your student has a solid, working understanding of same, it makes it more difficult to sell them the lastest Suunto.

D_B
June 6th, 2010, 11:52 AM
Nope, dont believe that's about selling computers

It's far more likely that a new diver will see that using a computer is .. easier, allows more NDL time because of the accurate "infinit" level depth/time tracking, and it a piece of "cool" scuba gear ... and it's about teaching what someone will be most likely be using the most

A cheap citizen duplex knockoff watch is what I got to back up my dive computer for trips that involve 5 dives a day, etc

KWS
June 6th, 2010, 01:39 PM
ITS A 2 EDGED SWORD. If folks use the puter as muych as they yak on the phone they would be as familiar of the putter as thier phone. when they call someone and get a wrong number they know. when they get bogus data fron the puter can you say the same??? if you dont know the tables or basic theory then there is nothing to compare the puter results to. I dont mean specific info but general stuff like. The deeper i go the less ndl time i should have. 30 min ndl at 60 feet does not mean that i will have 1/2 time at twice the depth.

The 2 go hand in hand. The tables are good for planning events like max botton time based on square profile ect. the puter will work in reality.

Tech diving should not be the first time the tables are seriously looked at in relation to deco.

scubawheels
June 7th, 2010, 04:50 PM
Tables may not be MANDATORY, but if it were me teaching they would be thouroghly covered. If nothing else i've never seen rental gear in the tropics come with a computer......Students need to know the theory behind the tables and have a basic understanding of how to use them.

I teach tables, and even when a student has his/her own gear with a computer they log their cert dives using a table.

I agree completely. I use a computer but I still use the tables to log and find my group designation at the end of the day. Maybe its just personal preference, but I like knowing that information at the end of the day.

Too much knowledge cannot be a bad thing when entering an environment that we are not meant to live in.


If you're frequently looking for scuba info, reviews, and adventure stories or just scuba crazy all the time like me, check out talking-scuba.com for a great NEW scuba podcast each week.

mitsuguy
June 7th, 2010, 05:00 PM
I use a computer but I still use the tables to log and find my group designation at the end of the day.

That is just not possible with 80% of the dives I do... The only reason it is possible with the other 20% is because they are training or Discover Scuba dives and less than 40 or 60 feet...

That first 80% is leading divers and fun diving on my own...

Here is a typical fun dive for me, let me know how well you could use the tables, the RDP, eRPD, wheel, etc...

scubawheels
June 7th, 2010, 05:50 PM
I agree it is not always possible. There are occasions that the computer has taken me off the tables but I was still safely in the no-deco limits.

My reality is, I mostly dive inland lakes in Michigan and rarely hit deep water (60 feet) there. It is on the Great Lakes where I go off the tables and have no group desiganation at the end of the day.

I dive by the computer and if it fails, I have my buddy to get me back safely. (I have the luxury of doing most of my dives with an AOW Instructor as my buddy. This makes the case for diving with a buddy that you know and trust to not put you in a dangerous situaton.) I basically use the tables as a check after the dive. The point is, knowing to use the tables gives a new diver an understanding of the concepts involving time, depth, and the no-deco limits. I feel like not knowing the tables and the concepts behind them would make me a more ignorant diver. The certifying organizations don't need to help create more ignorant divers, there are enough of them already.

drbill
June 8th, 2010, 11:16 AM
Although I haven't used tables while diving in years, I think it is a good thing to teach them as a form of redundancy... or an alternate... to using a single computer. I dive with redundant computers, but would resort to the tables in the unlikely event both of them failed on a day of diving. I've had way too many problems with my office computers (Dells) to have 100% faith in ANY computer, including dive computers.

Sharkbait2005
June 13th, 2010, 09:57 AM
This may have been mentioned earlier, but the dive tables offer a square profile whereas the computer is constantly adjusting for your depth. As long as you stick with your safe diving plan inside the no-deco limits, you should be fine, barring anything unusal.
If a dive computer fails, your dive is over, your going to the surface, if your guages fail same thing. That is why I've started going with redundancy including a duplicate computer set the same way as the primary.
I do teach the tables also, and I agree that knowledge is a good thing. It gives the students a basis of why the computer does what it does. They are based on the theory of the tables.

smellzlikefish
June 14th, 2010, 02:10 PM
The tables are often all a new diver has until they pony up to buy a dive computer of their own. Plus, as new divers, they are also a great way to learn the principles behind decompression theory which forms the very basis around much of what we do.

shake-and-bake
July 7th, 2010, 05:22 PM
I just completed SSI training. The "study at home" materials include a DVD which teaches the tables. The book does not teach the tables, but they are in the appendix. The instructor thoroughly covered the tables in the classroom, but there were no questions about them on the final exam. Bottom line: I understand them and could use them, although who knows whether I ever will (I purchased a good computer).

KWS
July 8th, 2010, 01:31 AM
I just completed SSI training. The "study at home" materials include a DVD which teaches the tables. The book does not teach the tables, but they are in the appendix. The instructor thoroughly covered the tables in the classroom, but there were no questions about them on the final exam. Bottom line: I understand them and could use them, although who knows whether I ever will (I purchased a good computer).

good to hear. now you should have an idea ho w to manage you depth and remainng time and verify it on the computer. oh yea also when and if your puter starts to lie to you.

a quick sea story. i had a computer with the wrong date on it it was a day ahead . in the middle of a flower gardens trip i corrented the day from that point it gave me all bad data. to fix i had to change the date back. my second day of diving was being stamped the same day as the day before. had the opposite happened i would have had no residual calculated and would have been by the computer making a dive after a 30 hour si.

ZenDiver.3D
July 8th, 2010, 01:52 AM
Except for the fact that PADI has been advocating this since mid 2009... They even changed some quizzes and knowledge reviews to reflect the change...


I teach computers to those that have them, go over the basics with those that don't, but everyone learns the tables...

Except for the fact that SDI was begun in 1999, and has been mandating the use of computers from the very beginning of it's birth out of TDI.

DiveNav
July 8th, 2010, 02:02 AM
I like this thread :D

BTW, so far we have coded 72 dive computers models in our Dive Computer Research Tool (http://www.divecomputertraining.com/diveComputers.php) ..... and I estimate there are another ~20 to go before we are done :depressed:

Alberto (aka eDiver)

ZenDiver.3D
July 8th, 2010, 02:08 AM
And I teach tables and computers. I have found that if I connect the two, and students work both together, they get a much better understanding and respect for both. I also very carefully teach tables as part of my nitrogen loading section so they understand just what those pressure groups really mean to them, as opposed to being just a letter.

Redundancy, understanding, and a firm base for further learning makes me teach both tables and computers. They enjoy and understand my notrox, adv nitrox, etc... classe better if they have gotten the base to begin with. I should not have to introduce tables in the nitrox class.

Funny, SDI, who has mandated the use of computers for OW on, from 1999 has in their manual, complete sections explaining dive tables with sample problems and a copy of the Navy DiveTable in it, while other agencies who are just now espousing the use of computers, are taking them out. Interesting.
IMO, we need to understand and be able to use both, though we always have a computer.

Wy145
July 15th, 2010, 08:26 PM
I'm certified naui/padi (79) USCG , I learned on the tables ,I've never used a dive comp. I stick to the tables .I just signed my son (11 years old) up for OW SSI. Its good that they learn on the comps. He will dive with me for a long while anyways, so he'll learn about the tables no matter what from me using them. I'm sure he'll bug the instructor "why not " what if "

drbill
July 16th, 2010, 12:33 PM
The only times I've used dive tables were in the 60s when I was certified and when I started (and eventually terminated) a DM course. Most of my early diving was single tank and I know my profiles. When I started doing a lot of repetitive diving, I got my second dive computer (had an Orca Skinny Dipper earlier).

Despite this, I still feel the dive tables are good to know as backup. I've had computer batteries die on me mid-dive (while in significant deco). For years now I've dived with two computers as backup (one has a low battery as of last night). I still keep the tables as backup.

KP3S
July 16th, 2010, 10:11 PM
Two months ago I finished my OW certification and my instructor taught us how to use the tables, and he was very hard on us about learning to use the tables 100%. He told us that a computer is a tool but the real diver do not forget how to use the tables because as everything that is electronics sometime they fail.

I have a computer and I use it but I also use the tables just in case, just to check the readings of the computer. As NASA astronauts do, the computers do all the calculations but they also use the old fashion method to make sure everything is OK. ;)

diversdream
July 18th, 2010, 08:01 PM
SSI still teaches the dive tables if the instructor so chooses. But they do make it availible if anyone wants to learn. In the AOW it becomes standard and is taught then!

diversdream
July 18th, 2010, 08:05 PM
Heres a question for you? If you teach the tables for SSI it will be a different table than the Navy and Padi has there own, So why don't they get togeather and just settle on one?

diversdream
July 18th, 2010, 08:09 PM
SSI still teaches the dive tables if the instructor so chooses. But they do make it availible if anyone wants to learn. In the AOW it becomes standard and is taught then! My manual chapter 4 has now changed completely from what it was

mainediver8169
July 28th, 2010, 08:06 PM
I think computers have their place but just like morse code is rarely used I bet those that have learned it and have used it in a time of trouble are glad they had that knowledge. I hope most instructors will take the time which is not much to teach the tables even if the diver gets a computer they will at least be familiar enough with them to save a dive vacation if their computer craps out....

KP3S
August 2nd, 2010, 10:35 AM
You have hit the nail on the head, you are absolutely right. Everybody should learn how to use the tables, no matter if you use a computer. Like all electronics they often fail when you need them the most.

TheDivingPreacher
August 2nd, 2010, 12:59 PM
My son just completed the JOWD course with SDI. The instructor gave a nod to the tables as he explained that the vast majority of divers never use them. Then he gave all the students the same model computer for the duration of the course.

Like it or not he is correct. The vast majority of divers that DO learn to use the tables go right out and buy a computer, or rent one when they go diving. I learned the tables in my OWD class, reviewed them in each following advanced class to this point, and choose to dive with the computer as my primary means of following my gas loading. I understand the tables, I plan deeper deco dives using the tables, however for me it isn't necessary to spend the time on it for each dive. Someone mentioned luck. 3 people bent out of 15,000 dives is not luck.
Some people have problems with new technology and insist the old ways are better. Isn't it great that each of us can dive as we see fit?

DiveNav
August 2nd, 2010, 01:13 PM
.....The instructor gave a nod to the tables as he explained that the vast majority of divers never use them. Then he gave all the students the same model computer for the duration of the course. .....

Do you know the dive computer brand/model?

Thanks

Alberto (aka eDiver)

TheDivingPreacher
August 5th, 2010, 05:48 AM
Do you know the dive computer brand/model?

Thanks

Alberto (aka eDiver)

Yes,
they used a Suunto vytec

jar546
August 9th, 2010, 12:54 PM
Tables were certainly part of the SSI class that I just took and are still in the test. I see no reason to use a computer until you understand the tables first. I would not want to have to sit out for the day because my computer malfunctioned and could not be used.

I am under the impression that the dive tables are part of the ABC's of diving so why make them optional?

KWS
August 9th, 2010, 01:25 PM
Tables were certainly part of the SSI class that I just took and are still in the test. I see no reason to use a computer until you understand the tables first. I would not want to have to sit out for the day because my computer malfunctioned and could not be used.

I am under the impression that the dive tables are part of the ABC's of diving so why make them optional?

well said

diversdream
August 16th, 2010, 08:48 AM
SSI still teaches the tables. What has happen in our age of technology the consentration is on the computer. Chapter 4 has been changed so the instructor has the option to teach the tables or not. I Would always teach the tables but some instructors may not feel the need. I think that learning the tables is smart! Here's the deal though and part of the confusion! PADI has their own tables they teach! Then there is the SSI tables then NAUI has there's and to top it off we have the navy tables as well. All of them different! Try working out a no decompression series of three dives on everyone and you will come out a different group on every one of them. PADI also has the EDRL hand held that replaced the wheel that makes even more confusion. If you use the hand held and then use the RDP you will come up with a different answer as well in most cases. So if someone is diving and happens to pick up the wrong tables to calculate they could be in trouble. At least if you are diving a computer you know for sure that that's where you are. Yes it's true that if your computer is fried or something happens to it your done till the next day. I think we all need to be aware of the challanges the the tables present as well.

rgb1150ms
September 23rd, 2010, 04:21 PM
As an SSI OWI I can assure you that You will be taught the DIVE TABLES if you want to complete the course as taught by "OUR SHOP"

I have seen computers fail and I stress that everyone should know their table so all the time ,money and effort they have spent on a dive trip is not wasted by a crashed dive computer.

:cool2:

jar546
September 23rd, 2010, 10:35 PM
There are still plenty of people who routinely rent gear and cannot afford a computer. No reason not to learn the tables.

BedoMedo
September 28th, 2010, 05:21 AM
IMO the teaching of tables is not really needed anymore.

1. Dive computers do everything needed and they do it better.
2. Dive computers are reliable - DAN has statistics to prove it.
3. A few years after their cert. classes, most people can't remember how to use the dive tables.
4. Tables are not a good backup strategy because people don't have the needed information or knowledge to make the switch from a computer to tables.
5. Dive tables don't teach you any more about decompression theory than a computer does, they merely present the information in a different - and less flexible - format.

As new OWD i can say that i did my own calculation for surface time based on tables and always done more coffee drinking and sea looking than diving. On my last dive i was given Aladin computer and done more bottom time than in last all dives in past together.
After that im putting money aside for next investment.... COMPUTER...

DeusVerto
September 28th, 2010, 12:10 PM
...is about teaching the theories behind getting bent and how to avoid it. The ones debating are mostly very senior divers who at most at risk of it due to depth and time.

The debate focuses on what to tell new divers, assuming that more accomplished divers WILL seek to learn themselves how to not die from enjoying this sport.

For the newbies, I'd say do what I did for the vast majority of my diving career - stay the hell above 40 feet and start your ascent when your PG reads 700 PSI. You wanna know why? Look at these tables here....:-P

KWS
September 28th, 2010, 12:13 PM
As new OWD i can say that i did my own calculation for surface time based on tables and always done more coffee drinking and sea looking than diving. On my last dive i was given Aladin computer and done more bottom time than in last all dives in past together.
After that im putting money aside for next investment.... COMPUTER...

I HAVE NEVER USED A PLANNIG MODE wooops, of any kind on a computer. try yours using the same parameters of the dive you used on the tables. (square dive) what differences are there? i ask this because the tble planned dives are not what is actually done. so the premis is that if you tried the planner and did a surf - 60' for 30 min on both the planner and the computer if you get the same group and data then the computer is as accurate as the table. the difference must be acredited to the actual dive not being what was planed for. in that case the computer is better because it is dymanic. if not then it may be safety factors built into the program. if that is the case you should know what those factors are.

BedoMedo
September 29th, 2010, 09:45 AM
I HAVE NEVER USED A PLANNIG MODE wooops, of any kind on a computer. try yours using the same parameters of the dive you used on the tables. (square dive) what differences are there? i ask this because the tble planned dives are not what is actually done. so the premis is that if you tried the planner and did a surf - 60' for 30 min on both the planner and the computer if you get the same group and data then the computer is as accurate as the table. the difference must be acredited to the actual dive not being what was planed for. in that case the computer is better because it is dymanic. if not then it may be safety factors built into the program. if that is the case you should know what those factors are.

thing is i do a lot of shore dives.. and in the middle of dive im at 40ft .. but mejority of time i was not.. but still i have to calculate 40ft as max deepth. Thats way computer is more of use to me. I dont say that boat dive.. directly down to 40ft in couple of minutes and up again in timely matter will be diferent comp from table calculation.

KWS
September 29th, 2010, 12:10 PM
thing is i do a lot of shore dives.. and in the middle of dive im at 40ft .. but mejority of time i was not.. but still i have to calculate 40ft as max deepth. Thats way computer is more of use to me. I dont say that boat dive.. directly down to 40ft in couple of minutes and up again in timely matter will be diferent comp from table calculation.

afer reading the last post i see i was not clear at all. i ment to say do your pre dive on a dive table ie 60' 30 min and compare the results to pre planning the dive on the computer planning mode.; use square profile on both the preplanning using the table and the planning mode of the computer.

again sorry for the confusion

KWS
September 29th, 2010, 12:11 PM
ignore this comment

BedoMedo
September 30th, 2010, 04:48 AM
:)
will do..

i believe we are on same page but language makes a difference.

Insta-Gator
December 3rd, 2010, 05:21 AM
The unfortunate reality of the whole mess is, I would dare to say that most recreational divers that do the once or twice a year vacation dives don't have computers or know the tables. They just follow the divemaster and come up when he says come up. then they log the dive for however long and whatever depth they are told.

Accurate observation and I was guilty of this too. It wasn't until we started going out on our own that we acquired computers and referred to the tables as a pre-dive planning tool. :dontknow: I guess we're all a little lazy in the beginning, and students a accustomed to being told what to do, when to do it, what it meant.

Scuba Stew
December 3rd, 2010, 02:45 PM
Have not read the entire thread, but was recently open water certified through SSI. We were taught to read/use the tables with hypothetical examples in the class room sessions. When it came time for our first open water dives, our instructor cracked out his log and assisted us all in filling it out (our own of course) and answering any questions we had. Never once were we told to rely on computers, in fact, my buddy had already bought his gear including a computer, and the teacher was adamant about still using the tables as a backup in the very least.

yankeenica
February 9th, 2011, 02:04 PM
With the economic situation the way it is today, I stress to the students during class that with a timing device, a pressure gauge and a depth guage they will be able to plan and execute their dives successfully (bc, reg, fins, etc are assumed). I see part of my job to get the students in the water, have them become successfully certified and promote the sport as often as possible with them after their certification. I stress buying all their own equipment but let them know that a dive computer is not - repeat not - a prerequisite to enjoy scuba. Look at the section in the SSI instructor's documentation about getting and keeping customers. My attitude is that if you get them enjoying the sport enough, the equipmnent purchase will follow, but more importantly will be their affinity to you and your shop. This in turn translates into positive word-of-mouth promotion.

Moriar
March 28th, 2011, 05:37 PM
I was OW certified through SSI in october 2010, My instructor only briefly mentioned computers and we went over the dive tables in atleast 3 different classes and on our cert dive he made us do our own tables and see what class we ended up as and then he would correct those of us that were either WAY off and even those of us that were just 2 minutes off on the surface interval and make us redo them completely.

I guess it really boils down to the instructor and how he views basic knowledge / workings of scuba diving...

yankeenica
April 4th, 2011, 08:24 AM
It is up to the instructor. At SSI we do address computer capabilities and how they compare to using dive tables (bottom time, planning, etc). We also stress that if the diver purchase a computer, we go over the operation as part of the sale.

DiveNav
April 4th, 2011, 09:52 AM
well ... since this thread has been resurrected, I would like to update it with a recent SSI initiative regarding the topic; SSI has now several Unique Specialty Courses for model-specific dive computers. See List of SSI Computer Diver Unique Specialties (http://www.ediving.us/forum/viewtopic.php?f=67&t=941)

Alberto (aka eDiver)

Scubapro Marcus
April 5th, 2011, 09:04 AM
I just recently got my C card and during the class we did the computer Traing which was great I just wish I could have a few hours on just how to use the Luna and all the features. Or a class on a Luna

devildoc5
June 13th, 2011, 09:13 PM
I just finished my SSI OW course on sunday (yesterday) I can confirm that (at least my particular instructors) explained how a computer can help extend bottom times and what the different modes were (planning mode, divelog mode, gauge mode, etc.) this was covered for EXACTLY 5 mins in class and never brought up again.

However they both insisted on "you need three things to dive: a timing device, a pressure gauge and a depth gauge"

Also we were required to be able to use tables efficiently both in class and on our "final academic test"

We also had to tell the instructor (during our OW dives SI) what group we were in, how long we needed to have for an SI to complete the next planned dive, our RT and what our final group would be IF the dive went according to plan. Then fill everything in post dive and adjust if contingency depth was reached instead of planned depth.

once we passed our final academic test (then headed to pool two and OW dives for the next 3 days) we were expected to be proficient using tables to the point of planning "mock dives."

Our instructor even tried to trick us one time by giving us a depth and time that while normally would be ok, due to our built up Residual time it would have put us past NDL. (during our second dives pre dive briefing that is) Everyone kinda went "umm! that doesn't work"

So at least with my instructors and my books and my final academic exam it appeared to me as though computers were mentioned in passing with a LOT of time devoted to comfortability and accuracy with using tables.

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