n00b question..

[scubatoys]

I have seen way more people miss a dive table question on a test than I have ever seen computers die... so in my unscientific approach... computers are more accurate.

Now back to the original question. If you really want to put a letter group in there, so you can compare... there is a way to do it... sorta'.

What you do is as soon as you come out, have it scroll the dive planning mode. Lets suppose it says you can do a 70 for 25... a 60 for 33 and a 50 for 45. You can take those numbers over to table 3 on your tables and then figure "what letter group would I have to be in to do those dives?" Since that is what your computer says you can now do - that should be equivalent to that pressure group on the tables.

Now I'll tell you if you are diving the computer - dive the computer - and you can't flip flop from tables to computer - but if you do want to put in some letter groups for any reason - that would be a logical way to do it.

 

[nereas]

I have seen way more people miss a dive table question on a test than I have ever seen computers die... so in my unscientific approach... computers are more accurate.

Now back to the original question. If you really want to put a letter group in there, so you can compare... there is a way to do it... sorta'.

What you do is as soon as you come out, have it scroll the dive planning mode. Lets suppose it says you can do a 70 for 25... a 60 for 33 and a 50 for 45. You can take those numbers over to table 3 on your tables and then figure "what letter group would I have to be in to do those dives?" Since that is what your computer says you can now do - that should be equivalent to that pressure group on the tables.

Now I'll tell you if you are diving the computer - dive the computer - and you can't flip flop from tables to computer - but if you do want to put in some letter groups for any reason - that would be a logical way to do it.

That is way too analytical, ScubaT, but clever! Very clever!

 

[The Anchor]

If you are worried about filling in all of the boxes in your dive planer, dive with your computer and use your max depth from that to determine your ending pressure group and required surfave interval.

I dive with my computer, an old timex watch and my table attached to my dive slate. I rely on my computer for depths and asscents, but if it goes down, I have my watch and a depth gauge with a max depth marker that I can work my dive out from. When I get to the surface, I change out my tank and then review my dive on my computer and use the wheel to work out my ending pressure group. From there I work the wheel to get my required SI and plan my next dive.

I have yet to do a dive that exceeded the NDL on my tabel, but I am strictly a rec diver.

 

[TheMotrCty]

I have seen way more people miss a dive table question on a test than I have ever seen computers die... so in my unscientific approach... computers are more accurate.

Now back to the original question. If you really want to put a letter group in there, so you can compare... there is a way to do it... sorta'.

What you do is as soon as you come out, have it scroll the dive planning mode. Lets suppose it says you can do a 70 for 25... a 60 for 33 and a 50 for 45. You can take those numbers over to table 3 on your tables and then figure "what letter group would I have to be in to do those dives?" Since that is what your computer says you can now do - that should be equivalent to that pressure group on the tables.

Now I'll tell you if you are diving the computer - dive the computer - and you can't flip flop from tables to computer - but if you do want to put in some letter groups for any reason - that would be a logical way to do it.

Perfect. That's exactly what I needed to know. I know this sounds silly, but I'm trying to get my progression stickers and I know my instructor will ask for the Pressure Groups for repetitive dives. The only thing that makes this a challenge is as follows:

I dive, go to 110ft for 30 seconds, spend the rest of the dive at 55' for a total dive time of 37 minutes. Go to Table 1 and there IS no 110 ft for 37 (round up to 40) minutes and you can't just go out columns, one at a time, adding five minutes per column.

Thank you.

Ron

 

[Steve_Dives]

I dive, go to 110ft for 30 seconds, spend the rest of the dive at 55' for a total dive time of 37 minutes. Go to Table 1 and there IS no 110 ft for 37 (round up to 40) minutes and you can't just go out columns, one at a time, adding five minutes per column.

You'd have break that 37 minute dive into several dives that you treat as repetitive dives without a surface interval. So you'd read for 110 feet and 5 minutes, get your pressure group, followed immediately by a 60 foot (rounding up from 55) dive for 40 minutes (rounding up from 36.5 minutes). That bounce to 110 feet probably gave you something around 10-20 minutes of residual time to add to the 40 minutes at 60 feet. That still might put you off the table.

 

[seiff]

I dive, go to 110ft for 30 seconds, spend the rest of the dive at 55' for a total dive time of 37 minutes. Go to Table 1 and there IS no 110 ft for 37 (round up to 40) minutes and you can't just go out columns, one at a time, adding five minutes per column.
Ron

Dude, how are you gonna end up at 110'? Let's have a realistic approach to all this. You just got certified, right? 60ft is your limit. If you are looking at your depth and saying "oops, 110 feet?" then you're in trouble. A 30 seconds jaunt to 110' is neither constructive, fun, or responsible so don't worry about things like this.

I wish people would actually read what others put on here, and for the record I never said that computers are dangerous or that tables are any safer. In fact, I DID mention that the computers are based on tables.

My point of view is this: I want to have complete control over my dive and complete understanding of the physiological effects I am experiencing.

Use both, for cryin' out loud, but computers CAN malfuntion, however rare that is. and IMHO if that happens I would rather have a grip on what's going on. And it's true, doing a rec dive with a computer will increase your bottom time. Also, if you think you are getting close to the end of your dive and you look at your computer and it says you have another 20 minutes left, then cool, you can take your time and enjoy a longer dive, that's why computers are nice. But the point is, you should know that you are in the ballpark of the NDL, and if you have no clue and you are just waiting for your computer to tell you when to turn around, that is an unsafe practice. -tadd

 

[Garrobo]

Being as I am a recreational Dork Diver, two dives a day in the morning with an SI between dives, I use my computer, totally. Most of my dives are 30-80 feet and an occassional 100+ if I'm diving a wreck, deepest dive first and less than an hour for any of them. Can't see how I would need any more than a three minute deco for any of them. Probably don't even need the computer to figure this out but it's nice to have along just to keep track of things.

 

[SNorman]

A question for you, why do you think your computer is safer?

I have been writing computer code for well over a decade now. If it's crunching numbers and monitoring sensors, I'm infinitely more confident in the computer doing the calculations correct as opposed to my brain.

I'd rather enjoy my dive then keep track of depth and time constantly at the level required to keep me safe and benefit from increased NDL time from multilevel diving. It doesn't take too much brain power to just make sure everything is working OK and the numbers the computer is giving you aren't inconceivable.

What if it was incorrectly programmed? What if you were diving nitrox and the the computer was programmed to calculate that you were breathing nitrox -- and not air -- on your surface interval? You don't have to imagine it, since it actually happened about a dozen years ago.

Just because you turn on your computer doesn't mean you have to turn off your brain. :no

John

What if you were diving on the moon?? What then??

 

[John_B]

I have been writing computer code for well over a decade now. If it's crunching numbers and monitoring sensors, I'm infinitely more confident in the computer doing the calculations correct as opposed to my brain.

Well its one thing to trust the computer to do the calculations its been programmed to do, its another to trust the programming is correct esp. when its all based on modeled data and theory.

I've been in IT going on 20 years, I don't trust any computer farther than I can monitor it.

John

 

[SNorman]

Well its one thing to trust the computer to do the calculations its been programmed to do, its another to trust the programming is correct esp. when its all based on modeled data and theory.

I've been in IT going on 20 years, I don't trust any computer farther than I can monitor it.

John

I've been using my brain for 30 years, unfortunately sometimes I don't trust it too much either