Computer vs Algorithm

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Oldbear

Teaching Neutral Diving
Scuba Instructor
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Location
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# of dives
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I think we all have seen posts where someone asks for opinions on computer X or to compare computer Y to computer Z and the discussion always evolves into algorithm A is better than algorithm B, but algorithm B is much better than algorithm C because it comes in computer X.

So which is it...do you choose your computer based on the algorithm or select a computer based on the algorithm it has available? Or did you select a computer based on another parameter and just use the algorithm that comes with the computer?
 
I often get involved with those arguments so I might as well here too :)

For me it is a bit of both. I have a hardwired Shearwater on a JJ CCR. That choice was about the screen mostly. The competition at the time was a monochrome LCD and I was not about to spend £7k on something with a UI from 1983.

So I need a backup for that, at first I used the Helo2 which I had been using for OC diving. But to half properly track the deco I need to set a couple of extra gases and change gas as I ascend. That is a bit of a hassle. So I decide do to blow some money on a CCR capable backup. The choices were another Shearwater, a Suunto Eon Steel, or an OSTC. They all have advantages and disadvantages. The Shearwater is exactly the same UI as the CCR controller, less thinking is good, but the screen isn’t not so good as the others. The Suunto has a very nice screen but can’t be set to extreme kamikaze mode for use in the case of a CO2 hit. The OSTC can do that, has a nice screen but the UI is different. Also I read their code once.

In the end it came down to the UI being the same. If I have to bail out due to a CO2 hit I would still have the primary electronics to do a GF100 based ascent. The Suunto might bend but so what. If the primary electronics fail I could ascend on any of them, even a Helo2, as there is no rush.

Also, since Shearwater have the best marketing I know I can always sell it for good money. Like Apeks regs, Halcyon wings and a number of ther bits of kit there is a set of people who have read they are the dogs b******ks and will want to buy them.

Open circuit I am mostly diving with divers who have a Suunto. I usually dive the Perdix on one arm and the Helo2 on the other. I use the excellent ‘Dive Log’ app on my iPad so the Perdix is now my main logging computer because the Bluetooth works very well. The Suunto will left me know how much NDL/deco my buddy has (I set it to their mix) it is most unlikely I’d put them into deco but if I am on Nitrox and they are not it could happen.

Since MultiDeco runs on my iPad it is easy to plan GF dives on the boat. For the Suunto I need a laptop too.

Price. I deal with a lot of new divers. The thing I want is to have them continue to dive once they qualify. That lets us fill boats and provides buddies. The chances of that are not improved by a computer costing £812.60 ($1144 USD).

Gases. Having a computer, of more or less any algorithm, which allows more than one gas on a dive is an advantage. This allows an intermediate diver to take an accelerated deco course without entirely relying on tables. This doesn’t need to be the £812.60 computer above, most makes have that available one bump up from entry level.

So all in all, the algorithm matters to me for matching, but usability and features like the screen or Bluetooth are more important.
 
So which is it...do you choose your computer based on the algorithm or select a computer based on the algorithm it has available?
Both.
 
I think we all have seen posts where someone asks for opinions on computer X or to compare computer Y to computer Z and the discussion always evolves into algorithm A is better than algorithm B, but algorithm B is much better than algorithm C because it comes in computer X.

So which is it...do you choose your computer based on the algorithm or select a computer based on the algorithm it has available? Or did you select a computer based on another parameter and just use the algorithm that comes with the computer?

That has changed over the years. The first computer I bought that was worth the money I spent on it was a Suunto. At that point I was only no-stop diving and I didn't really have a sense of the algorithm being that important.

When I started diving technically it started changing. I bought my first computer capable of multiple gases in 2004. It was a Suunto because my previous experiences were positive. Starting in ... 2008-2010? ... or so it started becoming increasingly clear that deep stops weren't all they were cracked up to be and the focus started being put more on using Bulhmann for decompression diving. This was also supported in practice by what the extreme deep crowd were doing at the time.

Between 2004 and 2008, however, the technical computers that were common were generally unreliable. At that point in time I put off replacing my Suunto computer because investing in a new technical computer looked like a money sink. Everyone I was diving with were having trouble with their computers and with my old Suunto I was the only one among my friends that wasn't frustrated with unreliable crap.

Shearwater had hit the scene in.... I want to say 2005 or so.... but in that period of time I viewed it as one of the crowd. Since 2008 it's become quite clear that Shearwater's reputation for quality is well deserved so it puts their computer on the top of my list of options even though there is new competition on the horizon. Simply put, if you're going to spend quite a bit of money on a computer then you don't want it to frustrate you with all kinds of problems. For quite a while it appeared to me as though Shearwater was virtually unique in this respect.

The fact that Shearwater also uses Buhlmann with GF is a prerequisite for me for technical diving. The fact that Suunto does not use Buhlmann excludes it as an option for me. The same applies to Mares and some others.

So at this point there are really three things I look at, in this order:
1) how reliable is the product?
2) does it use Buhlmann and GF?
3) how good is the user interface?

This may change again in the future but it's how I look at it right now.

For strictly recreational diving I still have another opinion. With respect to recreational diving the algorithm discussion isn't as relevant as it is for technical diving. For a purely recreational computer I would also consider reliability but would put the ease of use and maybe even the price higher on the list than the algorithm. For purely recreational diving simplicity and a good user interface counts for a lot.

R..
 
Cochran EMC-20H or EMC-16
Yes I do work for Cochran Consulting, Inc.
Richardson, Texas
Sales Manager Worldwide for Cochran Military & Cochran Undersea Technology

Have a wonderful weekend
Safe Diving
John Corso
:unitedstates:
 
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For me it's kinda of looking at it in reverse.

I know which computers and which algo's I DON'T WANT TO DIVE.
 
Cochran EMC-20H or EMC-16
Yes I do work for Cochran Consulting, Inc.
Richardson, Texas
Sales Manager Worldwide for Cochran Military & Cochran Undersea Technology

Have a wonderful weekend
Safe Diving
John Corso
:unitedstates:
John,

I went to your site as I had never heard of your computer before. Very interesting.

My question is what makes your algorithms better?

Also I am curious about your sample population for the research behind your algorithms. Was it predominantly Navy SEALS, extremely physically fit divers performing strenuous activities? How does this relate to your typical non-commercial civilian diver?

Not bashing just curious... :)
 
The "computer" is really the interface to the algorithm. The algorithm is the engine behind the computer.

A slight over simplification as there are other features utilized before and after the dive. However the vast majority of people buy based on the interface not the engine. This applies not just to dive computers, but most everything.
 
https://www.shearwater.com/products/perdix-ai/

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