Matching Dive Computer Algorithms

[tursiops]

A man with three watches on the other hand...

I think if you're going to dive both, and you're diving anywhere near NDL's then you've got no choice but to follow the more conservative. Otherwise, your backup may very well be locked out due to an NDL violation when you need it most.

If you're nowhere near NDL then it doesn't matter.

Personally, I'd try and sell one of the two and pick up another identical to the one I kept.

And, if you're diving more than one computer/algorithm/setting, which of the computers is displaying the smallest NDL will possibly vary with dive and time during dive.

 

[scubadada]

Hi @divinh

I would not attempt to match decompression algorithms either. The Cressi will control your dives, if you're happy with the NDLs, go ahead. If you are curious, you could try DSAT + conservatism to see how close it runs to Cressi. DSAT + conservatism is quite conservative, more so than Pelagic PZ+, may be more conservative than Cressi RGBM, but will not be penalized on repetitive dives by quick ascent, short SI...

 

[Jay]

Maybe you should try asking people who actually dive them instead of reading posts from our resident Suuno-bashers.

Since @CandiveOz was tagging me I assume your snipe about Suunto bashing was aimed at me. If it was aimed at someone else then aim it to him/her so they can respond.

You seem to be a tad overly sensitive when it comes to Suunto / their NDLs. Those snipes are a bit boring and I would expect more from you than that; at least argue the point.

If you've read anything I've said recently re Suunto's Tec/Fused aglo w.r.t. SW's/16-C's for dive repetitive dives, particularly dives 3&4 of a day's diving, then following your logic you would need to call me a SW-basher, yet I see no one doing that.

 

[Centrals]

I have three computers with 3 different algorithms but only use two of them when I dive. The conservative one is the one that I follow and the "liberal" one is the back up. I have learnt the characters of each one over the years. It was interesting to compare the ndl during dive and I do understand why some divers prefer DSAT.

The limiting factor is the available of gas rather than ndl!!!

 

[tursiops]

The limiting factor is the available of gas rather than ndl!!!

Not for deeper and/or repetitive dives.

 

[Centrals]

Not for deeper and/or repetitive dives.

Gas is still the limiting factor unless you are talking square profile.

5 dives day and on the last dive I have to surface because my gas was low NOT the ndl.

 

[tursiops]

Gas is still the limiting factor unless you are talking square profile.

5 dives day and on the last dive I have to surface because my gas was low NOT the ndl.

Are you staying above 60 ft on all your dives? Sure, 5 shallow dives will work out fine. But not all diving is like that.

 

[Centrals]

All multi-level dives within recreational limit ie. 40m.
Submerged deep reef and deep wreck are the only exception on ndl over gas(square profile).
I only surface when my computer indicate 99 mins left on ndl.

 

[CandiveOz]

Maybe you should try asking people who actually dive them instead of reading posts from our resident Suuno-bashers.

@dmaziuk I did ask people who actually dive them. If you reread my post, I asked the OP himself.

Has this been your experience?

Sorry if you feel a bit neglected that I didn't specifically ask you regarding this issue. As for the quote from @Freewillow he stated that he dived with the Cressi Leonardo 100 times. Why would I question his experience or integrity? The entire post along with others is here for your reference. Cressi Leonardo- Too conservative?

But rather than have a baseless bashing argument, lets look at some facts. @divinh indicated that the Cressi Newton has the same algorithm as the Giotto. The table below is from the Scubalab 2016 report of the 4th dive. I highlighted the Vision, Cressi and Suunto Vyper since you mentioned Suunto. The dive goes to 60 feet and the Cressi NDL is 29 minutes which reduces to 20 by the time they leave. At 40 feet the Cressi credits 8 minutes but by the time they leave this depth its back to 20 minutes. By 30 feet, the Cressi credits 4 minutes for a total of 24 minutes NDL. But compare that to the Vision which is showing 111 minutes at 30 feet. Even the Suunto is double the Cressi at 48 minutes! So is my statement inaccurate compared to other computers?

regarding the Cressi computers, they don't seem to provide much, if any, NDL credit if you ascend to shallower depth's on a multilevel dive.

I am not suggesting that the Cressi is a bad computer. Many divers, like yourself, appreciate the computer and its conservatism. Fair enough. You won't get an argument from me since all deco algorithms are educated guestimates anyway. But going back to the original post, @divinh is in a dilemma since he owns two very different computers.

Now if you adjust the conservative setting on the Vision, you might get a closer approximation to the Giotto default setting. Why am I suggesting this? On the very first dive of the Scubalab report, the initial depth is 100 feet. The Vision reports an NDL of 17 minutes while the Cressi reports 14 minutes. Now look @scubadada table, the DSAT NDL for 100 feet is 19 minutes. Lets assume it takes 2 minutes to get to 100 feet - hence the 17 minutes remaining bottom time. Now DSAT +C is 13 minutes. Take off 2 minutes and you get 11 minutes. That's more conservative than the Cressi but as the dive progresses to shallower levels, they may come out even in the end. I don't know, but @divinh can verify this on his next dive. Its a suggestion that he may be happy with in bringing the two computers closer together with regards to NDLs.

@dmaziuk since you own a Cressi and you are a frequent participant on these forums, it would be great if you could post the NDL's of the Cressi default and Conservative settings like @scubadada so we can all gain a better understanding of these computers. I look forward to your table.

 

[vovanx]

Personally, I'd try and sell one of the two and pick up another identical to the one I kept.

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