How often do you actually need a computer?

I find this interesting to think about sometimes...for how many dives that you typically go on do you actually need your computer?

I'm not talking about the school of thought that says you never need one...use the one between your ears...

I'm talking about how often it turns out that it's just not needed period. I have one on all the time but many times after the dive it's obvious that it just wasn't needed. It's interesting that we all spend so much money and effort picking out just the perfect computer but really for much of the time it's just a fun gadget to play with.

(I wanted a Nikonos underwater camera before I learned to dive and it was one of the first things I bought. It's flooded now and sits on my mantle as I still like to look at it...I didn't need it however...I just wanted it! Computers are like that sometimes I think.)

In many cases depending on location (and gas) it's hard to ever reach the NDL's.

With a smaller tank you are gas limited in many cases, with a little larger tank but using nitrox you may still be gas limited, in a location that's not especially deep you can stay there until you are bored. There are many locations that if you think about it you don't really need your computer because you are going to get bored, tired, cold, run out of air or you just can't get deep enough to run into the NDL.

There are many dives where you do run into the NDL's of course and multiple dives per day over several days on vacation is probably a very good use for tracking nitrogen loading!

There's also the situation of being able to get deep but not having enough to look at to stay long enough to hit the NDL..go deep look at something and work your way up slope.

Areas where the predominate diving is deeper with square profiles of course are the easiest places to run into the NDL's.

In my own area I could name many dive sites where you would never get deep enough or stay long enough unless you really tried to get into trouble. There are other places that get deep quickly but where there isn't enough to look at when you get to depth for you to stay long enough to have problems.

It's easier to know ahead of time that a computer isn't needed at local dive sites (I still carry one however) but even on vacation with ever changing sites this is still common. Some places are known for their shallow depths and some for their deeper depths naturally.

I'm talking about recreational dives here of course. Looking at your own dives how much of the time was your computer actually not needed?

I never use a computer, having done dives >2.5hrs in near 100ft range, down to the reef dives I did with my girlfriend over spring break, I just didn't see a need for a computer.

I wouldn't dive without a depth gauge, even on well known sites - it helps for orientation, and doing ascent in low visibility is easier with it. So to some extent, since my computer is my depth gauge, I always need it.

Now, if we're talking about the actual computing functions:

1. A couple time a year for 'simple' deco dive.
2. What used to be 20-25 "dive vacation" dives on the good years - independently, they would be NDL, but enter deco by the end of the week.
3. Maybe half a dozen dives a year which would be deco if planned using a square profile - but aren't with the computer.
4. Most of my 'early' training and diving was with deco considered standard (nothing much to see above 60ft, deep air considered normal). I'm not sure if that count as 'recreational' - and for sure doesn't fit in PADI criterias, but was not considered technical diving at the time.

Admittedly, 90% of my local diving (SoCal shores) would work without a computer.

Looking back, it was a good investment - and would have been even I already had a bottom timer. Actually, it's the only piece of my original gear I still use.

gcbryan:

I find this interesting to think about sometimes...for how many dives that you typically go on do you actually need your computer? .....I'm talking about recreational dives here of course. Looking at your own dives how much of the time was your computer actually not needed?

Click to expand...

I have not yet "needed" my computer in the 2 years I've owned it (And I also didn't need one during the years I didn't own one ).

So, I guess in my case the answer would be it is never needed....

The reason: My dives are typically < 50 feet, and often I just do a single shore dive. If I do a 2nd dive, it is after a long surface interval, and again < 50 feet.

So, at the shallow depths I typically dive gas consumption is the limiting factor for me, not NDL limits.

Despite that, I do find my computer quite useful and enjoy using it: It is nice to have depth and time displayed in one place, and I like that it activates automatically.

I if I ever do find the time to do more than 2 dives a day, or do an occasional deeper dive, it will be very useful.

Best wishes.

Same case. I really don't need a computer, reasons are simple:

1 - If I am doing recreational, in other words, not going on deco, I plan the dive this way, I know the NDL, so all I need is a botton timer and depth gauge, that is what I use.

2 - If I am doing tech, the dive is carefully planned ahead and the average (and most above average) computers cannot handle deco with multiple gases, and some do not work with bubble models, not asking for deep stops, which is the way I calculate my deco. Again I only need a botton timer and depth gauge.

Also was mentioned that "there are many dives where you do run into NDLs". I am afraid I disagree on that one, I only go into deco if I planned that way, if I planned recreational, probably I won't be equiped to a deco dive, so I simply do not run into NDLs, I calculate to end my dive before that, if I want to extend my botton time I use nitrox, but if that is not the purpose, I do not go into NDLs. This is a safety rule IMHO.

I need my computer about every dive. I often do multiple dives per day 3-6 with most of them up to, or over the no deco limit and I rely heavily on the computer for ascent rate information as well as nitrogen absorption and I dont ususally have to worrry about the oxygen levels with the mixes I use.


I've not looked at a dive table to plan a dive in years.

It seems to me that you can either dive the table (manually), or your can dive the computer, which will yield longer no-decompression dive times.

To the point of the thread, after I was certified years ago I dived many dives at resort areas when I did not yet own a computer and I simply relied on the dive guide. In hindsight, this was not a great idea. The problem remains that you are in effect using the dive guide's computer to calculate dive data. I would come back from diving and compare the depth and times of dives to the table and I would be way off the chart, because I was "borrowing" the dive guide's computer to get the benefit of multi-level diving.

Shallow, single dives might be OK, but it would depend on a rough guess that you are within the parameters of the dive table. What is the point?

I USE my computer on every dive...

I dive in a lot of VERY low visibility water, and am doing ascents from depth without lines... I use the super-accurate depth functions of the computers to watch my ascent rate (people say watch the small bubbles... but what if you can't SEE the small bubbles because the vis is too bad?) and to nail my safety stops which I have to do out in open water with nothing for reference at all.

I also use it on every dive to download it to my computer and study my dive profile.

Additionally, when I am shooting pictures, I use it for analyzing my photography. I fire off a shot just as the computer starts to mark the dive, and I am able to use that as a way to "time stamp" my shots... for example, I can look at the time the shot was stamped in the camera and compare that to exactly where I was depth-wise along the profile to determine any future adjustments I might need to make in similar water at similar depths.

I did a 20 ft beach dive last weekend with my cobra suunto. My computer told me tank pressure, how much time I had left, when I was layiing on the bottom, how much time I had left when I was swimming, how long I had been under water, what my depth was, what my max depth was. Combined with the compass it gave me constant useful information during the dive.

All I needed was a compass and air pressure but the other stuff was nice to have in the palm of my hand. I like having all my info in one spot.

So I guess we don't need tables either.