Mares puck pro and deco question

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Scuba1821

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I was recently Lobster hunting and around 80 ft had some difficulty getting a lobster out of a hole and into my bag. I wasn't paying attention and went into deco. My mares Puck Pro wrist computer had me do a 5-minute Deco stop at 10ft. When that was done it automatically went into a 3 minute countdown for a safety stop at 15 feet. Clearly I was not thinking and just surfaced. My thought at the time was that did not make sense to go back down to 15 feet for safety stop after I had just done a deco stop at 10ft. The computer then put me into lockout and went into surface timer mode. So I guess I have two questions. One is it normal to do a deeper safety stop after a 10 ft deco? And second if a safety stop is optional then why did it go into surface timer mode?
 
Yes I guess I could have. I have never gone into deco before and had not planned on it this time so I really had him thought much about it ahead of time
 
Hi
Yes a safety stop, unlike a deco stop, is optional.
The safety stop taking place between 3 and 6M
When you arrive at surface, the Puck starts a 3min countdown before going into surface mode.
If you didn't "respect" it, the computer goes into lockout in the sense it won't compute your next dive in the following 24h but you still can use it in gauge mode.
Are you sure the comput "lockouted" :)
 
Well for future reference, if your computer gives you a deco stop at 3m then you can work it off at 5m, albeit more slowly, and your safety stop could probably have been done at 3m instead of 5m.

I have never had the puck in deco but normally the safety stop thing is just a count down timer that starts counting down when you are shallower than 6m.

The fact that it locked out probably just has to do with the manufacturer wanting to avoid any potential liability. Normally a safety stop is optional but I guess Mares decided that if you go in deco it's not.

R..
 
I have a Mares Smart which is basicaly a Puck in a watch
I do a lot of deco dives and for "fun" i take along the Smart and set it on 2 gas. On the first dive, it normaly gives me something close to my dive plan and i let it clear itself
The following dives are problematics as the Smart gives more deco than the plan and according to the situation, I wait to clear it or I just forget it and it becomes a gauge for the following dives (its intended usage). Sometime, I even let it attached at 3M down the SMB and let it clear itself while I got a suntan on the boat :)
 
The deco stop depth it showed is the "ceiling" or the shallowest depth you can go up to for the deco. stop. It also means that you have a "Deco Stop RANGE" where you have a couple of meters below the ceiling to do your deco stop. Had you stayed a little deeper for deco, you could have done both, required deco and safety stop at the same depth.

It must be noted that the Mares, Cressi and Suunto computers that are based on the RGBM deco algorithm get real uptight when the diver doesn't stop for the required deco stop or the "required" safety stop. These computers have two types of "safety" stops, "optional" and "required" safety stops in addition to the required "deco" stop. If you violate either of the "required" safety stop or the required "deco" stop, you get locked out for the next 24 hours (I think 24 hours or perhaps more). If you don't stop for the "optional" (but recommended) safety stop, it won't lock you out in the following dives but will curtail your NDL's in these repetitive dives. Curtailing/shortening the NDL for the subsequent dives also happens when you come up to the surface with your ascent alarm on and also in other scenarios I don't remember right now.
 
Checkout your Manual Section 2.2.1.6 Fast Ascent, Pg 7.
The only possible cause of your lockout would be a fast ascent, not the preceeding deco obligation. If you missed a deco obligation you would not be locked out, but would put the computer into gauge mode.

A Fast Ascent with the Mares Puck Pro is defined as higher than 40ft/min maintained for at least 2/3's the way up from your current depth. At 10ft you'd only need to speed 6ft at greater than 40ft/min. Pretty easy and quick to do especially if you raise your arm while doing it.

It becomes a possibility whenever you go to 40ft or deeper on a dive.
And the result is a lockout due to it perceiving a higher potential hazard for bubble formation in the diver. You do have a option to cancel out of this lockout.

So the question reflecting back should be did you speed the last 10ft ascent after having a bit of stress doing the deco stop?


Sidenote: Also the "15' | 3:00" display doesn't mean you have to do a safety stop at 15ft. It's just a stereotypical reminder display. You can do your safety stop anywhere between 10-20ft to satisfy to your computer as completing it. You can find this on Section 3.3 Pg 10 "Deep, Deco, and Safety stops".
 
Its interesting that the total is 8 minutes wonder if that is just a coincidence same total as padi RDP recommends. Ascent rate with padi is 60fpm vs the mares 40fpm


PadI RDP
If a no decompression limit is exceeded by no more than 5 minutes, an 8 minute decompression stop at 15ft is mandatory. Upon surfacing, the diver must remain out of the water for at least 6 hours prior to making another dive
 

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