Purchasing your first dive computer. A non-technical approach.

[dmaziuk]

I disagree - one of my dive buddies has a Zoop and it is way too conservative in my opinion. Especially on multi day, multo dives per day trips, it's sending him up and even indicating deco at times way before my Shearwater ever would . I stay down longer and have had no issues (and no deco obligations) so I, personally, would not want a computer with the Suunto algorithm limiting my dives needlessly.

To me, audible alarms are a little annoying, especially since no one ever seems to know whose computer is pinging - many times, I've seen multiple folks looking around bewildered when alarms start sounding. However, to my point, if you want that function then it will drive the computer you choose (excludes Shearwaters, for example). The vibration alarms on the Ratio computers seems a better idea as the user will know when it is their computer alarming.

With respect to lockout, I also would not want an overly conservative computer locking me out if I did not follow it exactly - I don't plan on not following it, but I want to decide my risk tolerance myself.

I have a computer where you -- very annoyingly -- can't turn off the ascent rate alarm. So I have to flail around less to keep it quiet. I consider that a good thing.

The computer's job is to get you up not bent. It locks you out when, by its own calculations, you're bent into a hundred nazi crosses -- obviously, at this point it can't do its job anymore and it's game over, better luck next time. What this means to you as a diver is

• either the computer is right, you are bent into a pretzel, and you shouldn't be diving,
• or you "bent the computer" by grossly misusing it. Stuff happens, but if this is a recurring problem, you're not capable of operating your life support equipment properly. Should you be diving?

 

[Joneill]

On the other hand, thousands of people all over the world, including many divemasters who lead hordes of vacationers on dives every day, are happily using Suuntos.

I didn't say it was a bad computer - it's not, just just overly conservative (and can't be changed to be less). I prefer to not needlessly cut my dives shorter than they really need to be.

 

[stuartv]

The computer's job is to get you up not bent. It locks you out when, by its own calculations, you're bent into a hundred nazi crosses -- obviously, at this point it can't do its job anymore

There is no point where any computer CAN'T do its job anymore. There is only a point where the manufacturer has decided to not LET it do its job anymore.

 

[Joneill]

I have a computer where you -- very annoyingly -- can't turn off the ascent rate alarm. So I have to flail around less to keep it quiet. I consider that a good thing.

Why are you flailing around in the first place? I only look at my ascent rate indicator when I am actually ascending so I don't see the need for an audible alarm as I'm already checking my depth as I ascendl - but that just proves the point I was making: pick a computer with the features YOU need - not all computers have audible alarms so it will affects your choice.

The computer's job is to get you up not bent. It locks you out when, by its own calculations, you're bent into a hundred nazi crosses -- obviously, at this point it can't do its job anymore and it's game over, better luck next time. What this means to you as a diver is

• either the computer is right, you are bent into a pretzel, and you shouldn't be diving,
• or you "bent the computer" by grossly misusing it. Stuff happens, but if this is a recurring problem, you're not capable of operating your life support equipment properly. Should you be diving?

According to the manual, the Zoop will add a mandatory stop if your ascent rate even momentarily exceeds 12 meters/min and, if you violate that stop, it will penalize your NDL on the next dive. So you're flailing that is not really an actual ascending could cost you NDL - No thanks.

 

[dmaziuk]

There is no point where any computer CAN'T do its job anymore. There is only a point where the manufacturer has decided to not LET it do its job anymore.

Nope. Division by zero is an obvious example where it's not the manufacturer, it's those pesky numbers and stuff, that won't let it do its division thing.

 

[stuartv]

Nope. Division by zero is an obvious example where it's not the manufacturer, it's those pesky numbers and stuff, that won't let it do its division thing.

If your ambient pressure is ever 0, you probably don't need to worry about whether your dive computer is going to lock you out.

 

[stuartv]

Ditto for if your FO2 is 0.

 

[stuartv]

FO2, ambient pressure, and time are the only inputs that your dive computer needs in order to do its job (barring ScubaPro and any others that also use biometric data). I'm pretty sure all the dive computers have code to accommodate dive time of 0. So....

 

[scubadada]

On the other hand, thousands of people all over the world, including many divemasters who lead hordes of vacationers on dives every day, are obliviously using Suuntos.

Many, many divers never get past their gas consumption being the main limiting factor in their run times. NDLs never play a roll in their diving. Others of us are concerned about reasonable, predicable NDLs for our dive planning.

As I know you are using a Shearwater computer, I would be interested in hearing what GF settings you are using for recreational dives.

 

[stuartv]

Many, many divers never get past their gas consumption being the main limiting factor in their run times.

Which is probably in part because many of them never dive anything but an AL80 and also generally do mostly relatively shallow dives, where NDLs are quite long.

My anecdotal experience is that people who steadfastly claim that the algorithm really doesn't matter are either saying that it doesn't matter for "other" people, or they are saying that it hasn't been an issue for them, but it turns out they fall into the category of mostly diving an AL80 in relatively shallow water. As opposed to multi-day, multi-dive days using a 100 or larger and diving often past 100'.