Help with a better algorithm.

[jchance]

Help! The sticky at the top really hasn't been updated in 4 years. Wifey has been diving with a Genesis React Pro (old style). I picked her up a Smart Com cheap as her React will die in a couple of years unless Sherwood or Pelagic announce a trade-up program. She got locked out on her first dive due to a deco ceiling. Her Genesis, which she had with her, never was anywhere near deco.

Needless to say, she now hates the Scubapro as it is TOO conservative. Has Scubapro done anything to improve on the conservativeness of their product. She got locked out due to a failed 2 min stop at 10' that never got close on the other!

What are good reasonable alternatives now for someone who computer dives and uses Macs. Needless to say, she is sticking to her older React Pro for the rest of the week.

 

[KeithG]

Was it a "deco ceiling violation" or just a blown safety stop issue?

Your issue may not be due to a "too conservative" algorithm, but more related to a "feature" that requires mandatory safety stops, regardless of your NDL. And I am happy to concede the feature is really part of the overall algorithm.

My point is that the lockout may not be due to NDL violation from an overly conservative algorithm, but instead maybe caused by a safety stop (not deco stop!) violation.

We have seen a similar non NDL lockout issue with Suunto based computers during our liveaboard trips related to ascent violations. I am not sure of the exact details or affected models as I got third hand info via the DMs. Multiple people that were well within the NDLs got locked out due to ascent violations in the last few feet as they raced up the boat ladder. This had happened so often that the DMs on the boat would check all of the Suunto divers as they came aboard and would instruct the "ascent violators" to jump back in the water, go back down to the bottom of the ladder and come back up slowly with their arm in a fixed position to satisfy the dive computer and prevent an "ascent violation" lock out. A common cause was a diver that reached out for the ladder with their non computer arm and dangled their computer arm downwards. Upon grabbing the ladder they then used their computer arm to reach up above their head for the next hand hold. This sudden rapid upwards movement of the hand with the computer triggered a rapid ascent violation.

My ancient Uwatecs will trigger an ascent alarm when I do the same thing, but do not lock out.

From your description I assume your new computer has a "safety stop" violation feature. It's algorithm may mandate a 2 minute 10 ft safety stop regardless of your NDL.

 

[Dr. Lecter]

Putting all the tech abilities aside, a Shearwater will be one of the most Mac friendly computers you can find, and will never lock you to boot. That said, you can either learn about gradient factors, pay $75 extra for VPM, or ideally do both. Shearwater's algos are flexible, but you have to learn what the various settings do...though not having to read the manual to figure out the computer's UI frees up plenty of time for that IMO.

I've never understood why people pay to have a computer designed to cease functioning when they need it.

Or you could just get another cheap http://www.leisurepro.com/p-gnsrapw/genesis-react-pro-dive-computer-module

 

[clownfishsydney]

Uwatec computers (the Smart Com) are not very conservative compared to most newer computers. However, you can set a more conservative setting. Was the computer accidentally set for this?

 

[scubadada]

Sounds like she was simply penalized for skipping a mandatory 2 minute stop at 10 feet. Shouldn't this have cleared with a safety stop or was it actually 5 min and had 2 min to go after the SS? If you dive 2 computers you must clear the more conservative or lose it for a day. I did this once while initially diving 2 well matched Oceanic computers diving the same algorithm when I surfaced based on the slightly more liberal following a deco. The violation kept my backup out of the water for 24 h, it then cleared. I now make sure I check the slightly more conservative.

The Uwatec algorithm is generally considered middle of the road but is more conservative than the DSAT algorithm on the Genesis

 

[redacted]

If she is happy with her React Pro, why not go on ebay and buy a couple more for backup.

Scubapro computers are recognized as being conservative and they seem to be very proud of additional features they add to make them more so.

I dive old Oceanic Data Pluses, which I believe are the same algorithms as your React Pro and see nothing in more modern computers that would make me want to "upgrade".

 

[jchance]

Yeah, I know the Pelagic algorithm is more liberal. Her lock-out was due to a 6 min ceiling at 10 feet that was non-existent on the React. Yes, she had hit the NDL. If she had paid attention and remained 2 more minutes it would be a non-issue. I had her micro-bubble level set at L0 but had her work sensitivity set a little toward sensitive. I didn't think that this would affect the computation. A repeat dive the next day resulted in nearly the same thing with her hitting the NDL limit and getting a little deco time. What is strange is that her time at 10 feet was considerably more than any of the other 6 in the group.

i am looking for something that provides a little more downloadable info than the React, but is toward the liberal side. Tomorrow she will be going again with both, but with the work sensitivity set at minimum. I am curious to see if that will make any difference.

 

[scubadada]

Hi jchance,

What do you dive? Maybe you and your wife would like to dive the same algorithm. If she likes her old computer, she could stick with DSAT algorithm in a more modern computer by staying with Amercian Underwater Products (Oceanic, Aeris...). I really like my primary Oceanic VT3 and my backup Geo2. Prior to that I had a Pro Plus and a Pro Plus 2.

Good diving, Craig

 

[JulesSCUBAPRO]

It is difficult to say why the computer went into deco mode without knowing the the settings of the Smart Com. Please post the loogbook of the affected dive, if possible.

 

[jchance]

Settings were L0 for micro bubbles, air and work set in the middle. We were planning to try it again today with work set at minimum in tandem with her React and compare her download to my Smartcom afterwards but the weather in Cozumel was poor for diving this morning. My suspicions are that it will be better with microbubble at L0 and work sensitivity set at absolute minimum.

JulesSCUBAPRO, does the work setting factor into the algorithm for NDL and why doesn't it get explained anywhere in the manual like the microbubble settings? If it is true, then she is automatically dinged since she is a "heavy breather". Also, PM me and I can upload you the data for the dives she has made with it. I can even send you a dive I made using both simultaneously for comparison. Lastly, do the Sol and Luna share the same algorithm?