Suunto OK for liveaboards?

[Lorenzoid]

@Bubble: Having one's computer go into deco mode may be fine if one is prepared for it and understands what it means and what to do, but I had never seen it, and it caught me totally off guard. I don't think I had even read the section of the manual on deco because I never intended to do deco dives, which is why the first time it happened I ended up blowing it. By the second time, I had at least read the manual and understood what the display was instructing me to do and the 48-hour lockout that would occur if I ignored it. After the second time, I indeed informed my dive buddy that this might happen and the hand signal I'd make if it did. But I have been vigilant to avoid it since then. My only point in relating my story was that when one person in a group has a computer that's apparently more conservative than the computers used by the other five or six people, it can lead to a situation that it sounds like the original poster here would like to avoid. Just trying to add an anecdote that may be relevant to the OP's question, not suggest that my computer is "to blame" for the incident. If anything, a good lesson would be to read the manual in its entirety, including the parts that you think you won't need because you "don't do deco dives." Any dive can suddenly become a "deco dive" if your computer decides you need to make an unexpected stop. Please excuse me if I'm stating the obvious.

And not to hijack the thread, but as to my own question above, unless someone suggests that there is an advantage to two buddies having computers with different algorithms, then I think my logic of my wife and I using computers with the same algorithm is sound. I like the conservatism of the Suunto, and my wife would, too. My only complaint was getting caught with a deco obligation when I didn't expect it and barely understood it. If one is prepared do these these "extra stops" when called for, the Suunto can be a great choice.

 

[scubadada]

@scubadada: Thanks for the statistics from Bove and Davis. The numbers raise a bunch of questions, though...specifically regarding how the data were collected. Although one might be tempted to conclude that Suunto computer users have a lower relative risk of DCS than Pelagic users (due to differences in the algorithm used), a deeper look into the numbers might prove surprising. I think we can all acknowledge the importance of minimizing bias in the study population -- specifically with regard to age, gender, pre-existing medical conditions, aerobic shape, dive profile specifics, etc.
Along these lines, a skeptic might pose the following questions:

• Did the divers included in the study "ride the NDLs" or did they dive more conservatively?
• On a similar note, did they all dive a specified profile? If so, how closely did they adhere to the designated profile?
• Were dive computers randomly distributed to study participants? (If there's a perceived notion that Pelagic computers are more liberal, then is it possible that more "aggressive" divers gravitated to that brand?)
• Were all computers set to the most liberal setting?

One can easily see how any of these flaws in experimental design could affect the results. In fact, I really wouldn't be surprised if a properly controlled study demonstrated no significant difference at all between the groups.

[soapbox]
As a scientist, I know that it's easy to "fall in love" with the data when they appear to support our hypothesis (in this case, that a diver using a more conservative dive computer will have a lower incidence of DCS). I submit, however, that drawing any conclusions at all from a poorly constructed study is foolhardy.
[/soapbox]

Just my 2 cents...

P.S. I really do appreciate the fact that Craig went to the trouble of sharing the data with us. I realize that this post might be slightly off-topic, but hopefully some people out there will find it informative.

That's a great post, and I really appreciate the info-
I just want to point out to everyone who reads it that these are "mathematical estimates"- unless I'm mis-reading, they are not empirical data.

Craig's comment about "no zero risk" is on the money. Safe diving is all about managing risk, not eliminating it. How you prepare for diving and use your computer is likely more important than its algorithm, IMHO.

I use an Oceanic, my brother a Suunto. We have no problems diving safely together.

Bubbletrubble,

I'm quite sure you meant well in your comments on my post, however, you missed the mark by a mile. On the other hand, Aspendiver got it just right. As a scientist and clinician with more than 20 years experience on you, I try to get my facts straight. I rather carefully pointed out that the information I shared was mathematical estimates as no useful experiential data currently exists comparing different computer algorithms. That is all it is meant to illustrate, nothing more, nothing less. It would behoove you to check the source of information prior to launching into extensive comments that are entirely nonapplicable. Your soapbox comments are insulting, I would suggest stepping off. You come off as pompous, arrogant, and condescending and your comments are based on incomplete information and incorrect assumptions.

The intent in my post was not to suggest there are significant safety differences between the various computer algorithms but simply to share the kind of information that is available in the public domain with the interested diver. As does Aspendiver, I have used an Oceanic computer as my primary computer for the last 7 years. I take full personal responsibility for all of my dive profiles. I pride myself in making educated, rational decisions using all available information at my disposal.

Good diving, Craig

 

[Bubbletrubble]

I'm quite sure you meant well in your comments on my post, however, you missed the mark by a mile. On the other hand, Aspendiver got it just right.

@scubadada:Yep. You're correct. I totally mis-read your post. I didn't realize that the numbers you quoted were merely estimates. I saw the DCS rate of the Suunto and Pelagic algorithms and perceived an implicit comparison. What threw me off was when you wrote the following:

The NDL times at 60 fsw for these 2 algorithms was 50 and 56 minutes. This makes sense to me, the longer the exposure near the limit, the greater the risk.

I interpreted your comments as drawing a conclusion about risk based on the cited estimates. In my subsequent post, I was very clumsy in trying to express that no conclusions regarding relative risk should be made from the cited numbers. I see now that you provided the Suunto and Pelagic numbers to give us an impression of the range.

Your soapbox comments are insulting, I would suggest stepping off. You come off as pompous, arrogant, and condescending and your comments are based on incomplete information and incorrect assumptions.

Upon re-reading my post, I'd have to agree with you. I did not intend for the post to be insulting in any way. My words were rash and tangential to the discussion at hand. I surrounded those thoughts with the [soapbox] specifier so that others wouldn't take the words so seriously. Mistake on my part.
FWIW, I did locate the Google Book preview of the source in question. Unfortunately, the entire section (pages 154-156) containing the estimated numbers was omitted from the preview, so I was unable to learn the specifics of how those numbers were estimated.
Since you have access to the source, could you please elaborate on the specifics of how the authors arrived at those estimates? Feel free to respond by PM if you think it would be more appropriate.

The intent in my post was not to suggest there are significant safety differences between the various computer algorithms but simply to share the kind of information that is available in the public domain with the interested diver.

Once again, I apologize for mis-reading your post. I hope that my posts haven't stifled open discussion on this thread. Looking forward to your response...

 

[Bubbletrubble]

@Lorenzoid: One quick question: How aggressive were your dive profiles when you were diving during and after the 48-hr lockout period? The reason I ask is that, as you know, use of the computer after the lockout would not take into consideration any previous nitrogen loading. But I'm sure you already thought about that.
BTW, thanks for clarifying things. (Boy, I really feel like I have some reading comprehension issues today. ) I think your experience (being surprised by what deco mode looks like and the ramifications of not complying with a required deco stop) is a strong argument for manufacturers including software-based interactive training with the purchase of a dive computer. I bet a very small percentage of divers actually read the manual for a new computer. Perhaps that's a good reason to go with a computer with an intuitive interface.
FWIW, I really can't think of a strong argument for getting your wife a dive computer that uses a different algorithm.

Have fun and dive safe...

 

[Aspendiver]

Wow-gracious, humble, and intelligent divers on this thread...

 

[ptyx]

I have not experienced my Suunto computers going "berserk" with see-saw patterns or inverted profiles (whether it be intra- or inter-dive on a repetitive dive day). When I used to wear the Mosquito on my left wrist, I had one incident where I exceeded the ascent rate due to a quick hand movement above my head to dump air from my wing via the corrugated hose. Ever since I started wearing my computer on the right wrist, I've had no problems at all.

One particular case I remember was a dive practicing assisted ascent/rescue scenarios - happily largely exceeding ascent rate, ignoring recommended safety stops and doing way too many of those. Not the most intelligent thing I've done, although now I'm good at it . One diver had a Sherwood - and at the end of the dive had had no deco. My Vyper was at 11 minutes. Since we were bringing each other up, the profiles were really similar.

It might be an example of the Vyper being - if not a lot more conservative - more intolerant to dangerous profiles than some other computers.

All that said I never felt constrained by the Vyper for the type of diving I do - I do get in deco quite often on triangular profiles, but I usually clear the stop obligation before reaching the ceiling.

 

[tboxcar]

I have been diving with my Suunto Mosquito for over 5 years now, had a problem with the early one, between dives it was losing SI and would reset back to 00-00-0000, but LP kindly sent me a brand new one.
Since then no problems, was on a liveaboard in Tubbatahah, Philippines we were doing 5 dives a day for 4 days straight. Sure it's conservative and if I recall correctly some of the dives were close to deco and some went into deco. But never an issue as you were able to come back up and easily 'clear it' (assuming you are not an air hog). Changing the battery is a real pain, as the back door/seal gets really cemented 'in there'. I just take it to my LDS and they change the battery and pressure test it for $25, I feel safer then.
I'd buy a Suunto again!

 

[mason417]

How does everyone feels about the alarms? I just dove with it and I cant hear none of the alarms unless I knew it was coming and in my face/ next to ear. Anyone else have this problem of not hearing them?

 

[Bubbletrubble]

How does everyone feels about the alarms? I just dove with it and I cant hear none of the alarms unless I knew it was coming and in my face/
next to ear. Anyone else have this problem of not hearing them?

The only alarm I experimented setting on my Mosquito was the 30-min dive time alarm. I could hear it faintly through my thick 7mm hood while on a dive. When the computer trips into deco, I can also hear the beeping. The screen lights up, too.

For the most part, I find audible alarms to be annoying more than anything else. On local dives, we wear thick neoprene hoods that tend to mute the sound anyway.

The way I look at it, if I need an audible alert to remind me to look at my computer/watch, then I'm doing something wrong. YMMV.

 

[mason417]

The only alarm I experimented setting on my Mosquito was the 30-min dive time alarm. I could hear it faintly through my thick 7mm hood while on a dive. When the computer trips into deco, I can also hear the beeping. The screen lights up, too.

For the most part, I find audible alarms to be annoying more than anything else. On local dives, we wear thick neoprene hoods that tend to mute the sound anyway.

The way I look at it, if I need an audible alert to remind me to look at my computer/watch, then I'm doing something wrong. YMMV.

True, but I just thought it would be useful. I dive in the tropics, so no hood needed.