First Dive Computer

[Centrals]

The important thing to consider with Oceanics is if you're uncomfortable with DSAT (and I can understand that) you have three other options to dial the conservative factor to your taste, outside of how close you want to get to the indicated NDL.

No safety factor to change on Veo 180.
I trust my Aladin Pro Nitrox more than DSAT.

 

[scubadada]

I have been using Uwatec Aladin Air and Pro Nitrox well over 20yrs without any issue. Unfortunately one of them, Air, died few yrs ago so I bought a Oceanic Veo 180 as a "back up". Both the Aladin Pro Nitrox and Veo 180 have very similar ndl at max depth but the Veo 180 will "generate" a lot more on ascend. And the difference can be as much as 2 -3 times!!!
I can easily bend my Uwatec if I follow DSAT all the way to the surface.

And...

 

[Centrals]

I am looking for something slightly less liberal when My Aladin eventually dies and it won't be another Oceanic with DSAT alone.
Pelagic Z+ on i300 fits the bill and the cost(under $200.00) is also within my upper limit on dive computer.

 

[runsongas]

There is virtually NO difference between the Oceanic Geo 2 and the Aqua Lung i200. If you look at their Modes, software updates, functionality, etc. They are virtually the same. From a customer service perspective I have had excellent service from both now that Huish owns Oceanic. I am not sure but they might even be made at the same factory. Or Oceanic was made at the factory that now makes Aqua Lung...again not sure.

Michael

Both are made by Pelagic Pressure Systems, which used to be part of American Underwater Products (and which used to be the parent company for hollis, aeris, oceanic, and some other brands). Pelagic got sold to Aqualung, Oceanic and Hollis to Huish.

 

[KenGordon]

Both the Aladin Pro Nitrox and Veo 180 have very similar ndl at max depth but the Veo 180 will "generate" a lot more on ascend. And the difference can be as much as 2 -3 times!!!
I can easily bend my Uwatec if I follow DSAT all the way to the surface.

Sorry, I am not sure what you mean by generate. Is the ascent made to be slow such that the Uwatec increases stop time as you ascend? Otherwise the two sentences seem to be contradictory.

 

[Centrals]

Sorry, I am not sure what you mean by generate. Is the ascent made to be slow such that the Uwatec increases stop time as you ascend? Otherwise the two sentences seem to be contradictory.

NO.
Oceanic(DSAT)l always give longer ndl than Uwatec as I ascend from depth. And the difference is huge as the depth gets shallower.

 

[scrane]

No safety factor to change on Veo 180.
I trust my Aladin Pro Nitrox more than DSAT.

Yes, sorry. But the 180 has been out of production for quite a few years. I was thinking the OP would be buying a more modern DC.

 

[KenGordon]

NO.
Oceanic(DSAT)l always give longer ndl than Uwatec as I ascend from depth. And the difference is huge as the depth gets shallower.

Oh, sorry I was being thick.

 

[Jay]

Could you let me know why you are dismissive of ScubaLabs study?

All the computers could do all the dives. So it doesn’t matter which computer a diver used in that test.

They used a metric ‘NDL’ which is mathematically very sensitive. Very small changes in input result in large changes in the metric. So the EXACT dive profile is greatly magnified. Likely as not going a couple of m shallower a little earlier on a ‘conservative’ computer would increase the NDL by a large percentage.

If you want to know how conservative or aggressive a computer is really then do a deco dive and see how long the stops are. Long stops mean a lower surfacing oversaturation and less risk, so more conservative.

Thanks for that interesting point. I wonder, would running a series (and a variety of dive profiles) of Scubalab style tests (and not taking the computers into deco) be a valid method to compare conservatism for a Rec (only) diver (who typically wouldn't got into deco (as defined by a deco stop, exc a SS))?

Yes, but you’d need to dive the computers to the actual limits. That is practically quite awkward and these sorts of magazines turn out to have very limited staff resources

At the end you might be able to say brand X gave Y minutes more bottom time than brand Z though the day when diving such and such cylinders. Knowing what happens if you dive brand X to brand Z’s limits would be interesting though. If the answer is that the mandatory brand X stops are shorter than the brand Z safety stop then the dive profile could be identical.

Ken, if I could follow up on this again as I'm not sure I see why a Rec diver would need to take the computers to the (NDL) limits (or into deco) in order to assess their relative conservatism.

E.g. for a Rec diver, who happens to have two computers (A & B) on his/her wrist which run two different algos (let's call them algo A, and algo B). Let's say both those computers are programmed for a 3min SS and use usual ascent rates which the diver follows. That Rec diver dives to 25m, stays there for a while, and computer/algo A says 5min NDL, and computer B says 8min NDL. The diver then heads up, does a SS and surfaces. Therefore, for this particular dive, I could then state A is safer & more conservative than B. Correct?

Given that the rate of change of both of the NDL times should/must be the same in the above i.e. when A's NDL is saying zero, B's must say 3min when staying at 25m.

[edit start] And I assume that if the diver then went to 20m then the NDL differentials would also be approx the same [edit end]

And if the Rec diver did a whole variety of Rec dives over months with those two computers on his/her wrist and for each Rec dive A's NDL was less than B's, couldn't we then state A is generally safer & more conservative than B.

 

[Centrals]

And if the Rec diver did a whole variety of Rec dives over months with those two computers on his/her wrist and for each Rec dive A's NDL was less than B's, couldn't we then state A is generally safer & more conservative than B.

If you asked me the same question, my reply will be:
Since nothing happened to the diver then both computers are safe and A is conservative than B under the GIVEN conditions.