How does your computer handle deep dives?

[DanielRJones]

Hi @fisherdvm

Your initial post was confusing to me, the discussion, following it, has gone all over the place. Clearly, it would be in your best interest to have a good understanding of how your computer(s) work and you should pursue that goal. I believe the fact, that you are a DM and a Solo Diver, made it more difficult for people to understand how you could not be more familiar with your computer. If you can not read your computer, you should take action to remedy that or get a computer you can read.

Your questions made me curious, so I perused the Mares Puck Pro manual:

Safety Stop: I don't see that the safety stop can be turned off or changed. It is 3 minutes between 10-20 feet. It is not mandatory, and can be skipped. It is displayed with SAFE and a time countdown

Deep Stops: I don't see that deep stops can be turned off or altered. Deep stops are generated as "you approach the no deco limit" The deep stops will be one stop for 2 minutes or two stops for 1 minute. I could not determine why one of the two strategies would be chosen by the computer. I believe the answer to your initial post is that the first two stops were the recommended deep stops and the third stop was your safety stop. The deep stops are not mandatory and can be skipped. When in no deco, the deep stop is displayed as DEEP no deco. If you are in deco, the deep stop is displayed as DEEP DECO.

Deco: Deco stops are mandatory. When in deco, it will be displayed as DECO with a depth, stop time, and total ascent time. Whereas the uncontrolled ascent lock out can be disabled, the missed deco stop cannot. If you miss a deco stop and surface, you will be put into violation gauge mode and will be locked out for 24 hours. The computer does have an erase desaturation option in set up. I don't know whether that would work after a missed deco stop or not

Good diving, Craig

All are displayed on the middle line. Deep stops that are not deco will show as a small writing on the very left side. Deco stops will show as full writing on the left followed by stop duration and total time to surface. Total time to surface is a bit incorrect as this adds in the standard safety stop. I have locked one of these computers out a few times (doing accelerated deco)
The computer can handle gas switches but due to not knowing the algorithm i cannot olan to the computer. Deep stops are normally added at 16m

 

[fisherdvm]

All are displayed on the middle line. Deep stops that are not deco will show as a small writing on the very left side. Deco stops will show as full writing on the left followed by stop duration and total time to surface. Total time to surface is a bit incorrect as this adds in the standard safety stop. I have locked one of these computers out a few times (doing accelerated deco)
The computer can handle gas switches but due to not knowing the algorithm i cannot olan to the computer. Deep stops are normally added at 16m

Like you said .... it was pretty clear when you understand the deco takes place at 10 feet plus or minus 2. In the early mandatory deco mode, there is a half depth stop of 2 or 3 minutes, as best as I recall. Once that early mandatory deco limit is passed - the air supply factor kicks in. And you are obliged to do only one deco stop at 10 ft. The deco clock does not appear until you are between 12 and 8 feet. It went up to 38 minutes and the alarm beeps at the surface for about a minute. Good thing there is an air supply logic built into a recreational computer, likely for an 80 cf single tank and average or slightly below average sac.

 

[fisherdvm]

It took me 3 dives to figure out their logics and the screen. The guide could have been written much better.

 

[fisherdvm]

The short mandatory deco was forgiven, and I was allowed to do the second dive. I am not sure doing the 38 minutes second mandatory deco would have been forgiven. Never know, as no dive boats would wait for 1 hr 40 min.

 

[DanielRJones]

Like you said .... it was pretty clear when you understand the deco takes place at 10 feet plus or minus 2. In the early mandatory deco mode, there is a half depth stop of 2 or 3 minutes, as best as I recall. Once that early mandatory deco limit is passed - the air supply factor kicks in. And you are obliged to do only one deco stop at 10 ft. The deco clock does not appear until you are between 12 and 8 feet. It went up to 38 minutes and the alarm beeps at the surface for about a minute. Good thing there is an air supply logic built into a recreational computer, likely for an 80 cf single tank and average or slightly below average sac.

There is no air supply logic. A computer does not know what you have or care what you have

 

[tursiops]

Like you said .... it was pretty clear when you understand the deco takes place at 10 feet plus or minus 2. In the early mandatory deco mode, there is a half depth stop of 2 or 3 minutes, as best as I recall. Once that early mandatory deco limit is passed - the air supply factor kicks in. And you are obliged to do only one deco stop at 10 ft. The deco clock does not appear until you are between 12 and 8 feet. It went up to 38 minutes and the alarm beeps at the surface for about a minute. Good thing there is an air supply logic built into a recreational computer, likely for an 80 cf single tank and average or slightly below average sac.

This post is nonsense, full of misinderstood and made-up stuff.

 

[fisherdvm]

This post is nonsense, full of misinderstood and made-up stuff.

It is not nonsense:

Testing Dive Computers : Undercurrent 10/1999

 

[fisherdvm]

Each computer is very distinct... some will factor in the air supply. Deco stop can be either at 20 ft or at 10 ft:

The Conclusions

All of the computers compared (and their siblings) are equally useful for decompression-stop diving. One cannot make a decision about which is most conservative simply by comparing them during a dive at one way point alone.

Because a computer gives you a mathematician’s idea of what might be happening to your body using model tissues rather than your own blood, skin, and bones, using one is an act of faith. You have to believe what the computer tells you. And you have to realize there is no way of knowing how close you come, each time you dive, to a decompression illness.

When using a computer, it’s your choice whether you make additional shallow water stops or surface when your computer clears the last stop from its display and reverts to no-stop diving mode.

However, we suggest that if you have a Group F computer, add optional conservatism (up to 50 percent is available) before undertaking this sort of diving. Those using Group E computers might do well to use them in “condition hard” mode rather than lesscautious “condition normal.”

If you use a Group B computer and dive with a buddy who uses a Group C or D model, you might adapt the algorithm by selecting an “Altitude 1” setting rather than “Altitude 0.”

Group C computer-users should note that their devices are not as cautious as others when used for a single dive.

Group A computer users should take heed of the additional and optional 3 min. safety stop offered between 16 and 30 feet (ST3 to ST1) on no-stop dives and perhaps add a similar safety stop to deco-stop dives.

Group D computer users should be sure to reserve enough air for the lengthy stops at 10 feet that might be required and have the necessary buoyancy control at that depth to be able to do the stop comfortably.

 

[fisherdvm]

Apparently the mares puck is in the group D: ""Group D computer users should be sure to reserve enough air for the lengthy stops at 10 feet that might be required and have the necessary buoyancy control at that depth to be able to do the stop comfortably.""

 

[fisherdvm]

This post is nonsense, full of misinderstood and made-up stuff.

You are a master instructor, and you can not explain to a diver how his computer work?? And why it makes 10 ft safety stop instead of 20 or 15??
All have flamed me, and yet... the Master Instructor can not answer a simple question without putting others down??

What right do you have to do that??

Qualification because you are a scientist?