Practicing deco stops w/o going into deco

[DiveLikeAMuppet]

All valid suggestions for practicing the mechanics of holding a deco stop, but the original poster also wanted to observe how his computer operates while in deco, which is not a bad thing to understand...

Just set it to somewhat conservative gradient factors - default 30/70 would work - and put it into few minutes of deco? There is no scuba police and few minutes of deco won't kill you even without a redundant gas source, which the original poster already has.

And then get some tech training ASAP to plan gas properly.

 

[happy-diver]

Nitrox

How about a big % of this stuff giving you a reasonable depth, heaps of time, also with your comp set correctly

If you lie to your computer, then your computer will lie back to you
The calculation will be forgotten when it is imperative to remember

 

[grantmac]

What's the difference between diving 30/50, doing a "deco" stop then exiting with a GF of 50 vs diving at 50/75, doing a "safety" stop and exiting with a GF of 50?

 

[rhwestfall]

If actually doing deco, it isn't practicing...

 

[inquis]

What's the difference between diving 30/50, doing a "deco" stop then exiting with a GF of 50 vs diving at 50/75, doing a "safety" stop and exiting with a GF of 50?

Physiologically nothing, which is basically the point. The difference is what is shown on the dive computer. They wanted to see those "mandatory deco" displays and/or warnings while still under the "no stop" conditions afforded by their choice of conservatism.

 

[SpeedyJ]

What's the difference between diving 30/50, doing a "deco" stop then exiting with a GF of 50 vs diving at 50/75, doing a "safety" stop and exiting with a GF of 50?

You're comparing only the controlling compartment tissue loading, and depending on the dive, the controlling compartment could even be different based on profile and the different ascent rates. The other compartments will have different tissue loading as well between the two ascents. This is getting at a core point of the Simon Mitchel "Decompression Controversies" talk.

 

[ScubaSquatch]

Just end your NDL dives with 1 min @ 30', 2 min @ 20', and 3 @ 10'. You don't have to have a computer telling you that you have a deco stop to practice making them. When I was doing my cave training we did the above on every dive that didn't rack up deco just for the practice. Use the timer on your perdix for the stops.

 

[grantmac]

You're comparing only the controlling compartment tissue loading, and depending on the dive, the controlling compartment could even be different based on profile and the different ascent rates. The other compartments will have different tissue loading as well between the two ascents. This is getting at a core point of the Simon Mitchel "Decompression Controversies" talk.

Yes but you've still exiting with the controlling compartment at the same GF. Not talking about pushing so deep into "deco" that you're adding a lot of additional dive time.

 

[L13]

What's the difference between diving 30/50, doing a "deco" stop then exiting with a GF of 50 vs diving at 50/75, doing a "safety" stop and exiting with a GF of 50?

The first one is safer! You surface with a GF of 50% rather than 75%. Actually if you exit with 50% on the second they would be the same. But, depending on the profile, you would likely surface somewhere between 50 and 75% after a standard stop.

 

[rx7diver]

I would like to practice deco stops without actually going into deco. I have thought of ways to do this, ...

Any considerations, inputs or better altenatives? ...

An alternate, simpler approach is to use a set of established tables for the gas you plan to dive (e.g., U.S. Navy Tables for air) and plan a deco dive (e.g., 100 fsw for 60 minutes) using your personal SAC rates. Write the important numbers on your slate. You will perform this dive using a bottom time of 10 minutes (say), instead of 60 minutes, so adjust the numbers on your slate to reflect this. Do the dive, being sure to hit the (adjusted) numbers you've written on your slate.

Your time required to ascend from 100 fsw to your first deco stop will be the same regardless of whether you run this planned 100 fsw / 60 min dive using, instead, a 10 min bottom time. And you should require the same amount of time, and use the same amount of gas, at each step during the ascent.

Simple.

rx7diver