Backup Computer with different algorithm?

[happy-diver]

So why is everyone looking at their backup are you bored why aren't you diving instead of computing

and what's this

‘foo foo’ diving

 

[Pangeababy]

I sold it years ago. Just buy a Shearwater. The screen started to degrade when I sold it. The buyer was okay with it but I doubt it didn't continue to degrade.

If you are in the US, the Deep 6 Excursion is a good non AI choice.

Thanks for getting back to me. Unfortunately Shearwater uses a different algorithm to both my current PDC’s. I was hoping to get a reliable back up that uses the DSAT algorithm. Had heard about the fading OLED screen issue with the A300 CS; was hoping it was rare and not the norm.

 

[Pangeababy]

So why is everyone looking at their backup are you bored why aren't you diving instead of computing

and what's this

Lol, my friend calls recreational diving ’foo foo’ diving. He prefers his wreck, tech and spear fishing at heart but he will buddy up with me to just dive and look and enjoy if I don’t have a buddy.

 

[broncobowsher]

Thanks for getting back to me. Unfortunately Shearwater uses a different algorithm to both my current PDC’s. I was hoping to get a reliable back up that uses the DSAT algorithm. Had heard about the fading OLED screen issue with the A300 CS; was hoping it was rare and not the norm.

I think you are looking too hard for a perfect match. The whole goal of a computer is to keep you safe. There are multiple ways of doing it. In the end if you get bent, those bubbles don't care what calculation was used. All the calculations are there to keep you safe. If one calculation is wildly different than another, there is a flawed calculation somewhere. If one computer says you are good for 36 minutes and the other says 38 minutes, is that really a problem?

 

[Pangeababy]

I think you are looking too hard for a perfect match. The whole goal of a computer is to keep you safe. There are multiple ways of doing it. In the end if you get bent, those bubbles don't care what calculation was used. All the calculations are there to keep you safe. If one calculation is wildly different than another, there is a flawed calculation somewhere. If one computer says you are good for 36 minutes and the other says 38 minutes, is that really a problem?

You are likely correct, and certainly it’s not really a problem when they’re close. I was thinking I wouldn’t want alarms going off on one when I’m following the other but I also realize I need to follow the more conservative. I’m just used to and like my Sherwood Amphos Air and, as it’s the more liberal of most PDC’s, that means it will have to be relegated to my ‘2nd’ not primary when I need to double up on PDC’s.

 

[Pangeababy]

Thank you everyone for all the comments and suggestions. I now know my Amphos is liberal, my Aladin is middle of the road and I can use a Shearwater (in the future). For now I will use my ScubaPro Aladin Square and Sherwood Amphos Air until one or the other dies Or I come into some ‘extra’ money.

 

[StfniFllr]

As one of my two identical computers died recently, I find myself in the same position. I'm using my wife's computer as a backup when she isn't diving with me. It's a pain in the arse and as tursiops says, you are obliged to dive the most conservative algorithm. An alternative might be to have one computer in gauge mode if that's an option. Either way, not ideal.

Guage mode? That will lock out the first time you use it. I had a Suunto computer that started 'accidentally???' going into gauge mode and it nearly ruined a trip.

 

[StfniFllr]

Lol, ok, that’s a valid point!

I'm curious, if you are diving with two computers, and you should follow the most conservative of the two, why even have less conservative computers on the market at all?? Some people dive all the time with less conservative computers, and they are fine. My thoughts are that I have a robust primary computer and an inexpensive backup, they are different algorithms just because that is what I ended up with, but the backup is only if there is a problem with the primary, so I have an alternative that knows my repetitive dive history. Actually, I prefer having different algorithms just for comparisons.

 

[Belzelbub]

I'm curious, if you are diving with two computers, and you should follow the most conservative of the two, why even have less conservative computers on the market at all??

That advise is not about the market at all. It's about what the diver is currently using. If the diver were to use two computers with different algorithms, they should be aware of what the more conservative one is telling them. Mainly for that next dive. For example, if the diver's primary was an Oceanic running DSAT, and they only looked at that during the dive, they might find that their more conservative computer (perhaps running an RGBM variant) has decided a violation occurred. If this wasn't identified, that computer will probably go into a 24 or 48 hour lockout. Meaning that the backup is no longer a backup, and should there be a problem with the primary there is no computer available with tissue history.

As far as why more conservative ones are on the market, I can't answer that. Apart from saying that there have been updates in decompression knowledge which led to some models being in favor at certain times, and they may have now fallen out of favor. There have also been many companies that add their own tweak to an algorithm, usually in the more conservative direction. I would guess that the aim there is to try to limit perceived liability by adding a bit of buffer.

It does seem, though, that more and more computer models are starting to offer at least some models using the same algorithm. That's at least a step in the right direction. However, one should not assume that just because the computers both run Buhlmann that they will behave the same. Some manufacturers offer different default presets, some offer custom presets, and some even indicate that they run fairly standard presets, but there is a safety padding on top of that.

I have a primary and a backup made by two different companies. Both run the same algorithm, both run that algorithm without additional padding, and both offer custom presets, so I can effectively set them as conservative or liberal as I want within the bounds of the algorithm. I have both set on the same custom preset, and they've always been within a minute of each other for NDL time, and I've never seen more than a 1% difference in SurfGF.

 

[MB NZ]

Guage mode? That will lock out the first time you use it. I had a Suunto computer that started 'accidentally???' going into gauge mode and it nearly ruined a trip.

The idea is that you put it in gauge mode and leave it in gauge mode.