Torn as to which computer to buy

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The Petrel comes "out of the box" running Buhlmann GF at 30/70, which is pretty conservative. There is also a new "recreational" mode available for download, and which I assume will be appearing on newer stock, which presents a more simplified interface, similar to a recreational computer. I run my Petrel as a decompression dive computer, I don't see any reason to put it into gauge mode. On a rebreather dive, which is mostly what I'm doing these days, it tracks the Predator controller on my Prism 2 pretty closely, although it isn't hard wired into the unit.

Here are the release notes concerning the recreational nitrox mode.
 
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i bought my Atom3.1 months after my recreational courses around 2 years back.
i use it as a watch on any holiday trips i make whether it's a dive trip or not.

just started my tech courses, so i now use it in gauge mode.
thinking of either a petrel or an x1 as a primary.

the Atom3 and the Geo are similar i think. main difference i think is that the Atom3 can support AI.
overall it is a nice computer and an ok watch.
 
John,

That was the first thing I noticed here in Kwaj; my Atomic Cobalt or Aeris Epic (rec dive computers) are not even remotely in sync with my Petrel. I was going to down load the Sherwater Nitrox Rec upgrade and see if they come closer.

My experience was that the Cobalt was significantly less conservative than the Petrel unless I really played with the GFs. Even VPM-0 wasn't much less conservative than the Cobalt on max conservatism.
 
For those of us who know a little of the Petrel (e.g.: tech. diving computer) but not much (e.g.: how conservative or liberal the algorithm is), I've got some questions.

1.) Does the Petrel run 'out of the box' like the recreational computers some of us are more familiar; with a default algorithm, or maybe a choice between a liberal & a conservative one, and you go dive?

2.) Is anything about the Petrel's handling typically customized by the diver? From what I've read a number of tech. divers use software (e.g.: VPlanner), and 'cut their own' tables for a given dive, then dive that plan closely. I understand tech. divers tend to run recreational computers in gauge mode when doing tech. dives; is that how they are running their Petrels?

3.) If the answer is 1.), not 2.), then does the Petrel tend to be particularly conservative or liberal compared to recreational computers? In other words, 3 divers, 1 Suunto (conservative), 1 Oceanic (set to liberal algorithm) and 1 Petrel, drop to 80 feet and sit till they need ascend to avoid violating NDL. Where's the Petrel expected to fall?
People who "cut tables" using a software program like V-Planner and follow it carefully using a computer in gauge mode would not do that with a Petrel. Total waste of money. If you are going to use a petrel, use it. If not, buy a bottom timer for a quarter the price.

Some people will cut tables and use a computer as back up in case enough caca hits the fan that they are too far off their precut program. In that case, you want to make sure you have a computer like the Petrel, which will keep adjusting and allow for the possibility that you are using it as a backup. In contrast, a computer like the Suunto HelO2 will get really mad if you ignore it too much and shut down on you in mid dive.

Some people will cut tables as a backup in case the computer fails and follow the Petrel. In doing so, some people will combine the two and use the Petrel for both. You can pre-program your dive plan, see what the Petrel says the ascent profile will be, and then write it down so that you can follow it in case of a failure, using a bottom timer as a backup.

Some people will use two Petrels, so if one craps out they have the other.
 
Some people will use two Petrels, so if one craps out they have the other.

And then there are those of us who believe the three is two, two is one, one is none thing, and dive with two Shearwaters in computer mode plus a timer, DG, & cut tables as an analog backup. Especially for long, deep solo dives with a big deco obligation, I hate relying on one system--even two separate iterations of it--completely.
 
The Suunto algorithm is practically useless for multi-day diving.
And yet, probably tens of thousands of people have taken week long trips, had plenty of no deco times on their dives, and enjoyed many dives per day, all on their practically useless Suunto's.
 
https://www.shearwater.com/products/swift/

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