Purchasing your first dive computer. A non-technical approach.

[KenGordon]

Right - but if your flailing caused a mandatory stop that, for some reason, you did not complete - you end up getting penalized on NDL on the next dives for a false alarm.

After 3 days of diving on Air recently, I had to watch NDL on deeper dives the 4th day. For example, on this one, I got distracted and down to 1 min before I ascended (and it hit 0 as I ascended, but quickly went positive). Lesson learned for me.

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Same on this dive 4 days into our GC trip last year - was down to 5 minutes and ended up surfacing with lots of air as I could not stay on the reef as it was too deep for my NDL (and not much fun hanging way above the bottom).
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Computers do not limit these dives, your ability (skills and equipment) limit them. It looks like you might have had to do some stops had you got some reasonable time on the bottom. Learn (train?) to do those, make sure you mitigate potential failures appropriately.

The other thing would be to PLAN the dives. Then you'd know that you had little NDL available and chose a different site, or perhaps shorten the previous dives/have a longer SI to give enough NDL for your purposes.

 

[KenGordon]

There is no point where any computer CAN'T do its job anymore. There is only a point where the manufacturer has decided to not LET it do its job anymore.

Being bent is part of doing it's job. It is a disincentive to pushing. All those stories of people puzzled by bent computers having got into deco and surfaced without understanding - would their situation be getting better or worse if the computer carried on regardless?

 

[ronscuba]

The last few pages have several posts debating about Suunto computers. Have those discussing used a Suunto regularly ?

I dove with a Suunto cobra and gekko for hundreds of dives. It IS very conservative and you do not have to violate deco, violate safety stops or ascend fast to notice it. Do a liveaboard or do 2 long dives a day for a few days and you'll experience the conservatism too. This is old news. Conservative is not bad. The issue is Suunto computers at their most liberal setting are conservative to begin with. If you like liveaboards or long bottom times you will probably find them restrictive.

 

[george_austin]

The Zoop is not a piece of gear I would use on multi day / multi dive trips. You'll probably get locked out every day. I threw mine overboard on Day 3.

 

[KenGordon]

I have done multiple day warm water livaboards with a rebreather and a buddy on a twinset using a Vyper without finding the computer limiting the dives. Eventually you can run out of reef.

 

[Diving Dubai]

My anecdotal experience is that people who steadfastly claim that the algorithm really doesn't matter are either saying that it doesn't matter for "other" people, or they are saying that it hasn't been an issue for them, but it turns out they fall into the category of mostly diving an AL80 in relatively shallow water. As opposed to multi-day, multi-dive days using a 100 or larger and diving often past 100'.

Being one to buck the trend... I'm one of those who fall into the later category, and still I don't find that NDL is an issue (I do dive reefs so not so much a square profile of course, but even then...

The last few pages have several posts debating about Suunto computers. Have those discussing used a Suunto regularly ?

If you like liveaboards or long bottom times you will probably find them restrictive.

Nope. I've diver a Suuntofor 3 years and 400+ dives. Never found it to be restrictive. Actually I can match an OSTC for times.

Not that deco bothers me as I've had the required training, and not that I ride my NDL nor my gas to the minimums because I like extra head room for contingencies.

That said:

I limit my dives to 1hr

I don't do long deco hangs, as I find them tedious and boring

The 4th dive of the day needs to be extra special to persuade me away from a long hot shower and a Gin and Tonic

 

[Joneill]

Computers do not limit these dives, your ability (skills and equipment) limit them. It looks like you might have had to do some stops had you got some reasonable time on the bottom. Learn (train?) to do those, make sure you mitigate potential failures appropriately.

The other thing would be to PLAN the dives. Then you'd know that you had little NDL available and chose a different site, or perhaps shorten the previous dives/have a longer SI to give enough NDL for your purposes.

You miss my point. I was on a recreational dive boat - it's NDL diving, so deco stops are not really "allowed" if you want to keep diving with them (whether trained or not). Max dive time is set at 1 hour and you don't get to pick the sites or how long your SI is. I was not complaining about these things and still enjoyed these dives.

I know that NDL is affected by multiple days of repetitive "deeper" diving so I fully expected my NDL would be lower and made sure to monitor it to avoid a deco situation. I use the planner function on my Perdix to get a sense of NDL at expected max depth for the dive.

However, the actual dive usually unfolds a little differently - I may go a little deeper than predicted or stay at the deeper depths a little longer. Therefore, i would not want to be further NDL limited by a more conservative computer or one that might trigger the false ascent rate alarms due to flailing arms as was being discussed. That's all.

 

[scubadada]

...I've diver a Suuntofor 3 years and 400+ dives. Never found it to be restrictive. Actually I can match an OSTC for times...

Hi @Diving Dubai

I don't know about the other current Suunto computers, but the Eon Steel you dive nearly matches DSAT when dived on personal level setting -2, "more aggressive"

 

[dmaziuk]

I understand that. I have exceeded ascent rate for a short time and had a 1 minute Mandatory Stop, but that was not what he said .. It is still BS..

Well since I don't have a second me and we own suunto computers, the two of us can't go on a diving trip where one of us skips safety stops and the other one doesn't, so yeah... let's call it BS and leave it at that.

 

[dmaziuk]

"...If you continue to violate the Mandatory Safety Stop, the tissue calculation model is affected and the dive computer shortens the available no-decompression time for your next dive."

I have a pet theory that tissue calculation model should be affected by non-mandatory safety stop as well, and that repeatedly skipping the optional but highly recommended safety stop should eventually result in higher calculated residual loading and shorter ndls. And that 'there is no penalty' does not mean you'll get the exact same ndls whether you skip the safety stops or not, it merely means you won't get locked out. ICBW and there's no feasible way to test it, so... whatever.

I've seen about 10 people complaining how suuntos cramp their style on scubaboard, and at least 5 times as many divers wearing zoops and vypers on actual dives.