Feedback on Mares Puck "Deco" Dive - Did It Malfunction or Did I

[Dave Pozzy]

On Feb 17th in San Pedro, Belize I had a “deco” warning as I was climbing up the boat ladder. Dive history below and profile attached:

1st dive Feb 17th @ 9:38am to 30.7m/100’, bottom time 52 minutes, safety stop for 3 minutes. Spent approx. 2 minutes max at 100' and started slow assent up. No issues with dive.

Surface interval for 1 hour and 12 minutes.

2nd dive Feb 17th @ 11:42am to 24.3m/79’, bottom time 56 minutes and a slow and gradual assent. Spent approx. 2 minutes max at 80' and started slow assent up. Mares puck computer did not signal a safety stop and did not signal (beep) "Deco". I stayed at approx. 12 - 10 meters for at least 15 - 17 minutes at end of dive. Even with a slow assent to 4 - 3 meters my puck did not signal a safety stop. But while climbing the boat ladder the “deco” alarm went off. It then went into “desat” mode for the next 24 hours.

Surface interval for 25 hours and 21 minutes. During this time I did not feel discomfort or show signs of decompression sickness. I made a total of 3 more dives over 2 days. But on the last dive I had stomach pains and still do. I quit diving for the rest of my trip.

The main question is, did I over step my boundaries on the first two dives on Feb 17th for Mares puck to go into "deco" mode?

NOTE: I spoke with Dan on my condition and "deco" warning and they recommended seeing someone in urgent care, to which I did. They deemed me to have a stomach bug and not DCS. I returned home and a week after the urgent care visit I still had stomach pain. Went to local Dr and they couldn't find anything. My stomach problem is still present. Going back to Dr tomorrow to get referral to stomach specialist.

 

[scubadada]

I'm not familiar with Mares. It looks to me that you went into deco on the 2nd dive (the red profile line) and failed to clear it, thus the lockout. Mares is conservative, more so on repetitive dives. I don't know how much deco time you might have had.

How did you do more dives without your computer? Your symptoms would seem unusual for DCS, see what your follow up appointment reveals.

 

[sharknutz]

Based on the red section of your second graph, I would hazard a guess that you ended up beyond your NDL around 34 minutes into the second dive.

Unfortunately, since the profiles are not very square and I believe mares uses RGBM it would be hard to identify what kind of deco obligation you may have had leftover at the end of the second dive.

Did your stomach pain start during the dive or after the dive?

 

[Dave Pozzy]

Based on the red section of your second graph, I would hazard a guess that you ended up beyond your NDL around 34 minutes into the second dive.

Unfortunately, since the profiles are not very square and I believe mares uses RGBM it would be hard to identify what kind of deco obligation you may have had leftover at the end of the second dive.

Did your stomach pain start during the dive or after the dive?

My stomach pain happened a couple days later during a night dive. This was after my "Deco" incident, where upon I did not dive for 25 hours. Had a single tank dive that went well. Next day had a morning single tank dive that went well. Than I had a shallow (max 25') night dive where the stomach paid kicked in.

 

[Dave Pozzy]

I'm not familiar with Mares. It looks to me that you went into deco on the 2nd dive (the red profile line) and failed to clear it, thus the lockout. Mares is conservative, more so on repetitive dives. I don't know how much deco time you might have had.

How did you do more dives without your computer? Your symptoms would seem unusual for DCS, see what your follow up appointment reveals.

I elected not to dive until "Desat" was gone from computer, this was 25 hours later. I dove with my computer without incident after that except for stomach pain. Will see Dr tomorrow for referral to specialist.

 

[sharknutz]

My stomach pain happened a couple days later during a night dive. This was after my "Deco" incident, where upon I did not dive for 25 hours. Had a single tank dive that went well. Next day had a morning single tank dive that went well. Than I had a shallow (max 25') night dive where the stomach paid kicked in.

Someone may need to correct me here, but it seems unlikely that if the stomach pain was a dcs hit for it to occur while you are mid dive.

 

[Bazzathemammoth]

Have you got deep stops turned on in your computer settings? I think you may have had a deco obligation that you didn’t clear on your second dive, and that you went into deco on your first dive but cleared it properly.

If you look on the log on your computer it will say deco on the dive if you went into deco. (That’s what it does on my mares smart)

 

[Rob9876]

I'm not familiar with Mares. It looks to me that you went into deco on the 2nd dive (the red profile line) and failed to clear it, thus the lockout. Mares is conservative, more so on repetitive dives. I don't know how much deco time you might have had.

My son and I both have Mares Puck Pro+ computers, and we dive them in the P0 (least conservative) setting that the OP's log entry attachments show. On this setting, the computer has not seemed to be too conservative -- we're often still some of the last divers to come up. And we have done a number of deep dives on air in Cozumel.

To the OP: Just from glancing, I'd guess that your Surface Interval (SI) after that first deep dive was probably not long enough to totally clear your nitrogen loading from that dive. Do you recall what the bar graph at the bottom of the Puck said about that before dive 2?

Then your description of dive 2 doesn't mention whether you noticed your NDL minutes reading going low -- were you watching that on dive 2? Again, just from glancing, it does seem reasonable that you exceeded your NDL about 34 minutes into dive 2 given your first dive, the SI length, and the somewhat deep nature of your 2nd dive.

One more question for the OP: you said on dive 2 the Puck did not signal a safety stop -- do you mean it did not start the 3 minute countdown that is normally automatic once above ~20 feet? I don't do deco dives, but I'm guessing the Omitted Deco Stop on the dive 2 log may be the cause of that. I don't always hear the alarms on my Puck, so I'm guessing that may be the case here for you -- that you didn't hear the Deco alarm, and perhaps weren't watching your computer very closely, so missed the Deco stop.

 

[stiebs]

What is the conservatism setting on your computer? If you download your dives into Subsurface, you can play with the algorithm settings to see what it reckons your deco profile should look like. I entered your two dives with an approximation of your profiles, and depending on the chosen algorithm, those profiles were kicked into deco. Note that subsurface only has VPM-B with conservation settings, and Buhlmann with GF hi/lo adjustment.

Using VPM-B with conservatism of +3, this is what I got. The green section is your deco ceiling. So in this case, Subsurface has you going into deco for most of the dive, but through your ascent as "safety stop" it is cleared.

On dive #2, you're in deco for most of the dive. At the 45 minute mark, you had a 4 minute deco obligation, which would have been washed off if you did a five minute "safety stop" (in quotes, because with this deco algorithm, it's a mandatory deco stop). Without doing a stop, the deco ceiling was breached. This would almost certainly kick your computer into lockout.

Dive #1:

Dive 2:

Changing to a less conservative model (eg, VPM-B with +0 conservatism, or GF 80/80) that profile went into a little deco, but all washed off very quickly.

Of course, just because your computer kicked off a deco warning doesn't mean you're going to get a DCS hit, much in the same way as just because you follow your computer doesn't guarantee you'll be safe from a hit.

 

[stiebs]

Continuing on from @Rob9876's post, what I suspect happened is that your dive computer kicked into deco mode, so it would have been telling you to do a deco stop, rather than a safety stop. Read the manual, and see how that looks different. It is quite likely that you were expecting to see a SS countdown, but instead it showed you a deco obligation, which you didn't recognise and didn't know how to interpret?

Looking at your profile, I had assumed that you skipped your safety stop for some other reason (couldn't hold it, low on air, etc etc), but upon re-reading your post, it seems that you skipped it because your computer didn't tell you you needed to do one. For future reference, *always* do a safety stop.