A300CS OLED Dive Computer

[jd950]

Doug Krause

What is the benefit of having the "DUAL ALGORITHM® / CHOICE BETWEEN PELAGIC DSAT* (SPENCER/POWELL DATA BASIS) OR PELAGIC Z+ (BUHLMAN ZHL-16C DATA BASIS)" feature for the user? Where would on algorithm be appropriate over the other and vice versa? Why should I pay more for this feature in your computer?

I am not Doug Krause and cannot speak for Aeris, but my belief is that you don't pay more for it; it is simply a feature that allows the owner to choose between two algorithms. Coupled with the ability to adjust the "conservative" factor this allows one to have meaningful input into how the computer tracks NDL and deco obligations. One potential benefit is that the computer can more closely match other computer algorithms if one is so inclined, or you can adjust the computer to be more or less conservative depending on dive profiles, dive conditions, age of diver, etc.

 

[BoltSnap]

I didn't mean to imply that one would have to pay extra for the option of having a choice of two algorithms. I know that they are included as part of the whole computer package. One is paying a lot more money for this computer for all of the features it has and this feature is one of them and thus one is paying more money for this computer to have this "unique" feature.

I am talking from a marketing point of view and pretending to be a customer on the other side of the sales counter asking these questions. Perhaps the better questions is, why is it important/nice/good/advantageous to have this capability in the computer? When would one use one algorithm over the other? I am looking for more "precise" answer than just saying: "you have the option to choose between two algorithms" The client wants to know the exact realizable benefit and utilization of this "choice" from his point of view

 

[Father]

Can you give a little more details about Dual Algorithm®?

 

[jd950]

I don't work for Oceanic/Aeris and am not trying to sell anything so I have nothing much to say about the marketing question. When using an Oceanic/Aeris computer I tend to use their pelagic Z algorithm. There are long articles and books written on the subject of decompression theory and how the various algorithms are developed and what they hope to accomplish.

Hopefully these can answer your questions:

Simply Scuba Blog » Oceanic Dual Algorithm

http://www.scubaboard.com/forums/oceanic/308215-oceanic-dual-algorithm.html#post4780306

I guess I could add this overly brief summary: The traditional Oceanic/Aeris algorithm has always been very liberal and also not well suited to deco diving. It is liberal enough that some people were uncomfortable using it. That is not to say that people are getting bent using that algorithm. For some people on some dives, this liberal algorithm is fine and gives longer NDL times. In other situations it was happy with you diving long after other computers would have put you in deco or made you get out of the water. On the other hand, the Pelagic Z algorithm is more conservative and much more in line with what you would find with computers by Suunto, Scubapro, etc. It is better suited to repetitive diving and better suited to decompression diving. Maybe Aeris offers the dual algorithm simply to have a broader base of customers, I don't know.

Which should YOU choose? That depends on a lot of factors and a better understanding of this subject than you are going to find on this thread. The benefit to the dual algorithm is that you can select the algorithm suited to the situation. I would probably not buy an Aeris computer just because of this dual algorithm, but assuming you like an Aeris computer, it removes the choice of algorithm as a complicating factor in making your choice.

 

[Hatul]

jd950 gave a pretty good answer. Another use for a dual algorithm is if you need to use the computer as a backup. In this case it's better that the backup be more liberal or the same as the one you're following, so you don't end up violating the backup computer.

 

[Agility]

The DSAT algorithm is good as long as you stick to recreational limits as NDL and max depth of 40m.
As soon a s you go into deco it racks up masses of deco-obligation. The model is not meant to be used for this sort of diving, so if you decide you want to exceed these limits you are better off with the Z+ algorithm see A sense of algorithm - Divernet for a comparison of algorithms outside the recreational limits.

 

[FyshEye]

UpDate:

I showed up at the diver shop on Friday. They had been receiving shipments from vendors and manufactures all day. Come to find out after waiting for more then an hour, they had received an email explaining that the A300 CS shipment had been delayed until May 6th. Bummer!

 

[hazmat]

They owe you a snorkel.

But seriously, thanks for all the algorithm info, guys. Very interesting reading.

 

[guyharrisonphoto]

When I went to Bali four years ago, the shop I dove with rented Oceanic computers with the DSAT algorithm. I found it substantially more liberal that the PADI tables (and even the slightly more aggressive Navy tables I trained on) especially for repetitive dives. I was not comfortable with the long dive times it was giving me but, being new to computer diving then, was told and believed it was just the computer giving me credit for multi-level diving. I never had a warning or violation from the computer.

I had been out of the water (and from shallow dives as my last dives) a full 24 hours before I caught the flight to Singapore, and when I landed I developed a skin rash on my thigh that had the earmarks of skin bends, but I had no other ill effects. The rash faded out in a day or two.

I think the DSAT algorithm can put some divers at the edge of risk on high-intensity dive trips with multiple days of multiple dives (even without deco). I would never use it again for my personal diving.

When I researched to buy my own computer, it was pretty easy after the research to decide on running the Buhlman Z8 (very similar to the Z16) for repetitive dives and especially deep repetitive dives. If you got the Aeris that is the algorithm I would set it to.

Looking forward to a report and some photos of it in action underwater (we don't demand much, here!).

 

[Doug Krause]

The sometimes dramatic differences between dive computer algorithms available understandably leads to the assumption that one must be right and the other wrong. It's not a question of right or wrong, or even "liberal vs. conservative". If any were "wrong", they wouldn't be around very long. It's more a question of which is more appropriate for the application.

The Pelagic DSAT Algorithm was validated using the same test data used to develop the PADI RDP. The data consisted primarily of no-decompression, repetitive, multi-level diving. The data best supports this kind of diving. Taking the computer outside the limits of the data (repetitive deep deco dives for instance) results in a more conservative profile.

Conversely, the Buhlmann database studies were predominately deep, deco, cold, and at altitude. Apply that to like profiles and the data supports it very well. If you take it outside the data set (multi-level repet dives), as with DSAT, you'll find that you'll generally get a more conservative profile.

The value of Dual Algorithm is that you don't need to make a specific brand or model dive computer choice to take advantage of either. You may be a JEEP fan, but it's not be the best choice for the Autobahn... as a Lamborghini may not be the best choice for off road.

Posts above have listed all of the benefits very well...

Choose Pelagic DSAT for:
1. Liberal Recreational Diving
The Pelagic DSAT Algorithm safely maximizes dive time for repetitive, multi-level recreational diving.
This algorithm relies on the human Doppler studies used to develop PADI’s Recreational Dive Planner (RDP),
and has been the basis of Oceanic's and other manufacturer's computer algorithms for many years.

To add additional conservatism, you can also adjust the:

• Tissue-Loading Bar Graph Alarm
• Conservative Factor Setting

Choose Pelagic Z+ for:
1. Conservative Recreational Diving
When applied to standard recreational diving, the Pelagic Z+ Algorithm basis increases the conservative
factor of the OC1 by 15-20%.

2. Liberal Repetitive Deep and Decompression Diving
The Pelagic Z+ uses the Buhlmann ZHL-16C data base, which was conducted to meet the more rigorous
demands of repetitive, cold-water decompression diving at altitude. The Pelagic Z+ mode maximizes dive
times at depth without penalties.

Dive in sync with any buddy, anywhere
Because Dual Algorithm allows you to adjust the algorithm basis and its conservatism, you can adjust to closely
match just about any other dive computer on the market, allowing you and any buddy to always dive in sync.
Diving the same profile increases safety for both divers, and eliminates the need for one person to conduct
a much longer or deeper stop when buddying with someone wearing a more liberal dive computer. On
repetitive dives, there is no more waiting for the more conservative dive computer to clear. Both buddies
will be ready to enter the water at the same time and can continue to dive the same profiles.
You can’t control which dive computer your buddy wears, but you can control your ability to dive the same profile.