Computer or watch and RDP ?

[DiveNav]

Unless people can do the math in their heads as accurately and quickly as a dive computer.......

that's easy ..... just repeat the computations below for each compartment (16 times) every second
Of course you also need to remember all the values for the set of variables associated to each compartment ... and ... if any one of the 16 ndt is zero then you need also to calculate the deco plan (ceilings, stops depths, stops times, total ascent time) :depressed:

pn2i = Pamb*N2mix;
N2cmpt.pn2i = pn2i;
ppci0 = N2cmpt.ppci;
ppci = N2cmpt.ppci + ((pn2i - N2cmpt.ppci)*(1-pow(2 (tconst/N2cmpt.ht))));
N2cmpt.ppci = ppci;
pcm0 = N2cmpt.pcm0;
if (ppci > pcm0) {
cld = 1+ ((ppci - pcm0) / ((Pamb * N2cmpt.dm + N2cmpt.a) - pcm0));
} else {
cld = (ppci - PPN2) / (pcm0 - PPN2);
}
N2cmpt[].cload = cld;
N2cmpt.ndt = -ndct/N2cmpt.k;

good luck

 

[Jaydubya]

Computers are not a fad (of course).

They are generally beneficial but it really all depends on the circumstances. For certain diving a computer provides little benefit but for other diving I can't imagine not having one.

I think understanding the tables is a good thing even if you use a computer.

 

[Tigerman]

I use a computer and I love it. However having tables and a dive watch youll have a certain idea if the computer makes sense or if it crash you can atleast continue diving even if you dont have a backup computer.. Alas, I have both..

 

[Jaydubya]

I use a computer and I love it. However having tables and a dive watch youll have a certain idea if the computer makes sense

Agree.

or if it crash you can atleast continue diving even if you dont have a backup computer.. Alas, I have both..

I think this reasoning is often mentioned but seldom practiced. It sounds great in theory, but to work in practice it requires logging dives right away so that you figure out your pressure group (residual nitrogen time). I'm sure there are those who do this but I don't personally know of any.

 

[cloudflint]

Unless people can do the math in their heads as accurately and quickly as a dive computer, methinks that the dive planner/bottom timer/watch dealie is pretty much relegated to very specialized applications such as knowing in advance that all you will do are square profile dives, or plan for some serious tech dives.

You find after a while of diving tables that you can remember the no stop times for the various depths. I had to be able to recite the no stop times from 30 meters to 20 meters and do repetitive dive calculations in my head without any references to get certified which was a pain at first but once i had the times memorised i found it great being able to just look at my depth gauge and watch and know how long i will have left, how deep i can go and how long i can stay and still get x amount of time on the next dive and stuff like that.

In the end ive found it makes very little difference in the actual profile, at least for the diving I do. Ive seen me and another group go in on the same dive, them using computers and me using tables and we enter at the same time, go round the same places and come up at the same time. The only thing though is if im on holiday doing lots of dives or something like that I will dive the computer since otherwise i max out my time quite quickly calculating everything on a square profile

The thing to remember is that regardless of whether you use tables or a computer, the actual amount of time you can stay at depth and not get bent will be exactly the same. So long as the time you get from your table or computer ends up less than that you could use a magic eight ball to plan your dive and it would make no difference.