[Andy C]

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Hi all,

This is a question that I was wondering about a while ago, but having just managed to break my computer on the first day of a weeks holiday, made it something other than academic.

How do people keep track of their nitrogen loadings ?
Do you rely on your computers all the time (how do you log it?) or do you calculate it from tables and note it in your log books?

 

[Mark Chase]

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Unless your doing big dives IE long, deep or deco and not having a decent surface intervall ie min 2 hours. I wouldent worry about it. If your doing a weeks liveaboard 3 dives a day in the red sea get a computer you will need it.

You can of course log it using a PADI rec planning table but thats a major pain in the bum

atb

Mark Chase

 

[And]

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<font color='#000080'>Hi

I'm a little puzzled. How did you break it in one day ?

Did you miss some stops or ascend too fast?

During my Red Sea trip in June I managed 41 dives over two weeks and just used a dive timer. Just be mindful of your profile. Another couple on the trip had computers and followed similar profiles, never getting near mandatory stops or extended surface intervals.

Hope that helps

Andy

 

[Andy C]

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Andy,

I actually broke it, rather than "bent" it. It locked up during the ascent from the first dive and flatly refused to do anything afterwards, couldn't turn it off or on - it's on it's way back to Suunto now.

Mark,

If your only doing one dive a day, I agree with you, but would be concerned to try and track residual N2 for the second dive, otherwise how do you plan it ?

Cheers

Andy C

 

[Dominic]

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Get yourself a PDA with some deco calculation software?

 

[Kate R]

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i don't really understand your question.....

do you mean so that you can work out no-deco limits for subsequent dives? if so, surely you know how to use the PADI wheel/BSAC tables to do that? (no matter how many dives you do)

if you're doing this, yes you would need to note down depths, dive times and surface intervals for every dive. isn't that the way that everyone dives who doesn't have a computer?

sorry if you meant something completely different, and i just didn't get it!

also, i don't understand the question 'how do you log nitrogen loading when you have a computer?'. you don't need to keep track of nitrogen loading as the computer keeps a record of it for you, that's what it's for.

again apologies if i've misunderstood.

 

[Andy C]

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Kate,

I think you've answered the question anyway  

I suppose I was really asking whether people used tables to backup their computers or not. It looks like I'm in the paranoid minority and still log using the RDP as well as using a computer (when it decides to work  

 )

Cheers

Andy C

 

[Kate R]

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Quote[/b] (Andy C @ Dec. 17 2003,16:33)]I suppose I was really asking whether people used tables to backup their computers or not. It looks like I'm in the paranoid minority and still log using the RDP as well as using a computer (when it decides to work  

 )

well, why do you do that?

do you mean so that if your computer breaks you can still work out your next dive using tables? that seems like a sensible thing to do - all you'd have to do is keep a note of depth, time and surface interval, which quite a lot of people do anyway. i carry a dive timer and a slate with tables on in the pocket of my bc in case my computer fails on the dive (or, as has happened, i've forgotten to change it from nitrox back to air - doh!). of course for that work properly i should really note my tissue code before every dive, and i don't (for most dives) - but it is good for first dives where i have no previous nitrogen loading.

on the other hand, if you actually dive using tables AND a computer, then what's the point of having a computer? tables are almost always going to be more conservative than a computer, so if you do that you'll be diving by tables and using your comuter as backup. and that's an expensive backup!

hope this makes sense

kate

 

[Mark Chase]

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Quote[/b] (wetlettuce @ Dec. 17 2003,15:53)]Hi

I'm a little puzzled. How did you break it in one day ?

Did you miss some stops or ascend too fast?

During my Red Sea trip in June I managed 41 dives over two weeks and just used a dive timer. Just be mindful of your profile. Another couple on the trip had computers and followed similar profiles, never getting near mandatory stops or extended surface intervals.

Hope that helps

Andy

3 dives a day for 13 days streight with no Nitrogen tracking is not something I would risk but it demonstrats that two no deco dives a day with at least a 2 hour surface intaval is unlikley to be a problem. I would just stick well within no deco times and do a 6min safety stop and 5 min ascent on the second dive to be sure. Mind you I think even two dives a day for two weeks is pushing it a bit but i am old and worry too much

The oficial line if you bend your computer is dont dive for 48 hours then start again from scratch.

ATB

Mark Chase

 

[Andy C]

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Quote[/b] (Kate R @ Dec. 17 2003,16:44)]do you mean so that if your computer breaks you can still work out your next dive using tables? that seems like a sensible thing to do - all you'd have to do is keep a note of depth, time and surface interval, which quite a lot of people do anyway. i carry a dive timer and a slate with tables on in the pocket of my bc in case my computer fails on the dive (or, as has happened, i've forgotten to change it from nitrox back to air - doh!). of course for that work properly i should really note my tissue code before every dive, and i don't (for most dives) - but it is good for first dives where i have no previous nitrogen loading.

Kate,

Yes, that's exactly what I mean, including the timer & slate, but I sit and work out my tissue code during the surface interval. So far, in my short diving career, I have only seen one other person doing this, so out of idle curiosity I was wondering what every-one else did.

Cheers

Andy

 

[Kate R]

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Quote[/b] (Andy C @ Dec. 17 2003,16:59)]Yes, that's exactly what I mean, including the timer & slate, but I sit and work out my tissue code during the surface interval. So far, in my short diving career, I have only seen one other person doing this, so out of idle curiosity I was wondering what every-one else did.

just don't think most people can be bothered!  

if you have tables, a timer and your tissue code written down on every dive, then you are absoloutely sorted if your computer breaks.

if you are going to bother to do that, though, perhaps it would be easier to just write your planned depth, time and stops on your slate (which you can get from your computer, assuming it has a dive plan function). that way you're sorted if your computer breaks without messing around with tables. obviously it means that you can't deviate from your plan, but if your computer fails you're on your way up anyway, right? and the advantage is that you're not trying to use tables at depth (perhaps not easy with nitrogen loading) - instead you're just looking at a number.

kate

 

[Dave Crampton]

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<font color='#000080'>I use both a computer and a set of tables. I make a note of the no stop times verses depths on my slate so that if my puter dies I have a backup. I also make paper logs of my dives in a log book.

I use the tables to tell me my tissue code post dive and to plan what options I have for my second dive. I use the computer for accurate depth, dive time and no-stop dive time, as at the moment I'm not diving into stop dive times. I back this up with a watch but have to admit to not always looking at the start and finish times on my watch. (Perhaps my computer looks after my time lazyness). I know for some this sounds excessive as people use either a set of tables or a computer. But as a senior diver in my club recently said "people seem to move from tables to computers and just trust them, without looking at the differences between what the Computer and Tables will allow them to do". Yes Tables are supposed to be safe because they assume a square profile (which is conservative) but Computers are also supposed to be safe as they allow for dynamic depths.

I don't know how many divers looking to buy a computer rate the different models available by conservatism? I know it was not something that was high on my list of priorities when I bought my computer.

I suppose looking at how I record my dives I will be able to look back in the future and cross check what the differences between tables and my computer are.

At the moment, as I'm quite new to diving and I find dive planning and recording the dive in a log all part of the dive experience.

I currently use a Suunto Vyper and BSAC tables.

Dave C

 

[parahandy]

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Suppose everyone has to ask themselves this question.

Do you do Computer Controlled Diving? or
Do you do Computer "Assisted" Diving?

Agree a dive timer and a slate showing RDP Tablesetc etc should be a back up.