Looking for a more aggressive computer algorithm.

[hdugan]

Not really, true dual phase algorithms use a lot of prossesing power. They are rather hard to fit to real time use. Yes, it's been done, but it's not mainstream.

 

[gcbryan]

Not really, true dual phase algorithms use a lot of prossesing power. They are rather hard to fit to real time use. Yes, it's been done, but it's not mainstream.

Well, it's not the dissolved phase that takes the processing power as they both use the same models for the dissolved phase. For the free phase rather than doing true iterations they could use approximations just like Suunto.

 

[Offgassing]

We'd like to squeak out a little more time, so we were both wondering if there was a newer algorithm available in a new model of computer that could provide longer bottom times.

We always use safety stops and occasionally deep stops if the dive profile suggests a use for them. Our diving is entirely recreational, usually in the 70-110 fsw range.

This is the model we are using.
ALADIN PRIME - SCUBAPRO-UWATEC

I think this article will be somewhat helpful. I'll also attach links to real data that they gathered from chamber diving some of the newer units; it may help you make a decision.

14 New Computers | Scuba Diving Magazine (article)
http://www.scubadiving.com/files/old/images/pdf/200806_scubalab.pdf (feature comparison)
http://www.scubadiving.com/files/old/images/pdf/200806_chambertest.pdf (algorithm comparison)

I'm assuming you two aren't nitrox certified? I think bang for buck-wise you should look into a nitrox course if you haven't already. Your Aladin Prime is set up for recreational nitrox and your 70-110' normal diving levels are perfect for it. I think you will be surprised at how much it will extend your bottom times.

I don't think buying a new computer because you don't like the answer to be good. These are just models and its ok to be more conservative. I use oceanic computers but put my own conservative factor on the information it gives me based on the dive.

I think this is exactly what the poster wants to do. He wants to extend his bottom time while still remaining in the relative safety of a tested algorithm. He is doing deep stops and safety stops, and his depth ranges are relatively conservative. He sounds like a reasonable adult to me who wants to build in his own safety factors; just like you.

I absolutely agree with fppf, changing the computer just because you don't like the answer doesn't make any sense.

Sure it does. Would you dive with a mask you didn't like? With dive tables you didn't believe in? With a regulator that wasn't comfortable for you? Why dive with a computer that you feel is too conservative for you when you know there are other relatively safe models that allow you to extend your time a little further?

Seeking a more liberal/aggressive algorithm may IMHO be asking for a deco hit.

Ahh yes, the standard "You're gonna die!" post. I think if you re-read the OP; that is NOT what he is asking for.

You might want to set your expectations appropriately here.

It's not likely that you'll find a "more aggressive" computer will increase your bottom time in any meaninful fashion.

Even going from "the most conservative" to "the most liberal" computer, you're probably only looking at gaining a handful of extra minutes on a recreational profile.

There is a tremendous difference between the most liberal and the most conservative computers. For a real world example, my Galileo (which is moderately conservative and uses almost the same algorithm as the OP's) vs. my buddy's Vyper 2 on two consecutive dives. We stayed together during both dives and used identical EAN mixes.

Dive one: N34. Max depth 81 ft, average depth 62 ft, median depth 75 ft.
26 min into the dive, he gives me the the thumb; his Vyper displays 2 min no stop time remaining. My Galileo shows 26 min of no-stop time remaining. We make a slow ascent, do a 3 min safety stop at 15 ft. Total in water time 35 min.

Dive two: N37 max depth 64 ft, mean depth 61 ft.
35 minutes into the dive he thumbs it, 2 min no-stop time left on the Vyper 2; 68 minutes left on the Galileo. Slow ascent, 3 minutes at 15' to increase our safety margin. Total in water time 46'

I dive a Vytec DS, my buddy dives an Oceanic Datamask. We both have decent SAC rates. We've done literally hundreds of dives together all over the world; everything from 90min shore dives in Bonaire to ~160' wall dives in Caymans to 100' deep wreck penetrations in the Red Sea. In all that time we've never had a single dive where my Suunto wanted to send me up significantly earlier than his Oceanic.

I find that statement incredible.

Most people who get bent are within the NDL limits of their computer.

Yes, but most divers dive within the NDL, so this isn't particularly helpful.

There is no one magic point where on one side you are 'bent', and on the other you are 'not bent': it is a grey zone, which changes on every dive due to your profile, the conditions and the state you are in.

How far into this grey zone do you want to go?

I personally want to know where the thin black line is. I'll decide for myself how far into the grey I'm comfortable with.

 

[fppf]

The new oceanic computers don't and can't run both models at the same time. They run one OR the other, once you pick one you need to wait 24 hrs after the last dive to switch it again.

The processing power needed for these models is really not that much if you take into account the sample period. The model is only run once a second, that is thousands of operations for even the slowest energy conserving micro.

 

[D_B]

If I remember correctly, I've heard that one of the reasons that Oceanic computers are more liberal is that the sampling rate at which they update is more often then compaired to some others (not talking about the downloadable rate) they more closly monitor your profile

 

[Atom]

There is a tremendous difference between the most liberal and the most conservative computers. For a real world example, my Galileo (which is moderately conservative and uses almost the same algorithm as the OP's) vs. my buddy's Vyper 2 on two consecutive dives. We stayed together during both dives and used identical EAN mixes.

Dive one: N34. Max depth 81 ft, average depth 62 ft, median depth 75 ft.
26 min into the dive, he gives me the the thumb; his Vyper displays 2 min no stop time remaining. My Galileo shows 26 min of no-stop time remaining. We make a slow ascent, do a 3 min safety stop at 15 ft. Total in water time 35 min.

Dive two: N37 max depth 64 ft, mean depth 61 ft.
35 minutes into the dive he thumbs it, 2 min no-stop time left on the Vyper 2; 68 minutes left on the Galileo. Slow ascent, 3 minutes at 15' to increase our safety margin. Total in water time 46'

Hummm.... interesting... are you sure your buddy had it's computer setup properly for nitrox?

I've ran these profiles in the Suunto dive planner...

1st dive - 81' for 26min on EAN34 it shows 22 minutes of nodec time.
2nd dive - 64' for 35min on EAN37 it shows 30 minutes of nodec time. (Well this is a bit more sketchy since I don't know much about your SI, I assumed 1 hour)


Just for fun, I've redone the planning with air, and it gives me 2 min of nodec time after 26 min for dive 1, and I had to extend the SI to 1:14 to get 2 min of nodec time after 35 min on dive 2.

So maybe the problem is with a an incorrectly configured computer.

 

[StreetDoctor]

It depends on the dive of course.

But even on a recreational dive to those depths I follow thirds. Most times at those depths I will be diving off a boat, many times there will be surface currents. Returning to the line and making controlled accents with safety stops is high on my list. Direct accents can put you a long way from the boat after a controlled accent and safety stops.

But in a real case of gas planing even thirds is not enough, this has been beaten other places. On a recreational profile I find it much better practice then rock bottom 500 PSI.

rock bottom is NOT 500psi. Where did they ever say what kind of diving they're doing? As far as 3rds not being enough, I think I can say without any uncertainty they're not cave diving.

 

[hydropunk]

one word: oceanic

 

[DiveNav]

..... I've started diving 100's to keep up with her, and now we are both coming up due to NDL. We'd like to squeak out a little more time, so we were both wondering if there was a newer algorithm available in a new model of computer that could provide longer bottom times.

...... Our diving is entirely recreational, usually in the 70-110 fsw range......]

As someone else said already, changing dive computer will not change your body NDL loading.

Instead of changing dive computer you should change your set-up.
Get a rebreather and put some trimix in the diluent tank?

Alberto (aka eDiver)

 

[Offgassing]

Hummm.... interesting... are you sure your buddy had it's computer setup properly for nitrox?

I've ran these profiles in the Suunto dive planner...

1st dive - 81' for 26min on EAN34 it shows 22 minutes of nodec time.
2nd dive - 64' for 35min on EAN37 it shows 30 minutes of nodec time. (Well this is a bit more sketchy since I don't know much about your SI, I assumed 1 hour)


Just for fun, I've redone the planning with air, and it gives me 2 min of nodec time after 26 min for dive 1, and I had to extend the SI to 1:14 to get 2 min of nodec time after 35 min on dive 2.

So maybe the problem is with a an incorrectly configured computer.

After the first dive I thought the same thing; but I checked his unit and he had his %02 entered correctly. I checked again before dive 2. It is possible some user adjustable settings made his unit even more conservative. I admit I'm not a suunto user so I don't know the ins and outs of this unit as well as I do my own. But I have other buddies that dive suuntos and they are always the limiting factor on our dives. Just for the record I don't think there is anything wrong with more conservative; I'm just saying that there IS such a thing and it DOES make a difference. See http://www.scubadiving.com/files/old/images/pdf/200806_chambertest.pdf