Continuous Decompression AND Staged Decompression

[boulderjohn]

Not referring to the formal continuous decompression methods as employed in some sat or chamber operations here.. my bad referring to it as continuous deco, my query is more about.. micro-stops. Did some editing to clear it up

I don't see much difference. Perhaps I still don't understand.

 

[dberry]

I think the answer given by several people already is that your "micro stops" require too much fiddling with buoyancy to be worth it. Not to mention the accuracy for the micro changes in depths is beyond what most divers can achieve. Sure, hang the diver on a line and sloooowly bring him up - that's essentially the same as a chamber ride.

 

[Foothills]

I think I may have done "continuous deco" of the sort the OP is talking about. I call it "rolling deco" (don't know why, or where I picked up the term). After a deep dive (170' for ex.) it is a very, very, very slow ascent starting 10 or 20 feet shallower than your first stop - and by the time you get to that stop your computer has cleared that stop, so you slowly, slowly ascend to the next stop. I have also done the same coming up an anchor line, one hand span at a time.

It is sloppy deco, not planned deco, as you are letting your computer do all the thinking, and it works when you have a lot of gas and moderate deco (deepest stop 30' max, better if the deepest stop is 20'). It also helps if you have an interesting bottom with a fairly shallow slope.

 

[Kevin A.]

I think I may have done "continuous deco" of the sort the OP is talking about. I call it "rolling deco" (don't know why, or where I picked up the term). After a deep dive (170' for ex.) it is a very, very, very slow ascent starting 10 or 20 feet shallower than your first stop - and by the time you get to that stop your computer has cleared that stop, so you slowly, slowly ascend to the next stop. I have also done the same coming up an anchor line, one hand span at a time.

It is sloppy deco, not planned deco, as you are letting your computer do all the thinking, and it works when you have a lot of gas and moderate deco (deepest stop 30' max, better if the deepest stop is 20'). It also helps if you have an interesting bottom with a fairly shallow slope.

No, it's not that kind of deco. That's just taking it easy to reach your stops and by the time you get there it's cleared. It's not what I'm referring to.

I'm assuming nobody is familiar with the old VR3 here or perhaps they forgot about that feature.. I still have a manual of that thing, let me (try to) post a capture perhaps I refresh some memories

 

[Kevin A.]

VR3

• Kevin A.
• Jan 31, 2019

 

[Foothills]

I think I understand now. Is this feature the VR3 calculating a GF line or graph in the background and letting you deco on the "slope" rather than a "staircase" (thinking of 30', 20', 10' as steps on the staircase)?

I have not done that (never had a VR3, or regularly dove with anyone who owned one). It seems like a neat feature, and has me wondering if the ceiling function on the Perdix mimics this (although it might be aggressive for my tastes - I need to think about it). Off to the owners manual to check.

 

[Dan_P]

I don't anything to say "whether/or" regarding "stop-and-go" versus continuous ascend, other than two personal thoughts on the matter:

1) If the stops are long, it would maybe be more impractical to ascend continuously, compared to slower stops.
Also, one might have jobs to do that it would be nice to stop, get done, and then move on (consider bag shoots, gas-switches, unconscious diver, etc.)

2) If your stops are short, e.g. first deep stops on a tech dive or one-minute stops on an NDL-dive, the importance of whether you opt for one "method" or another, is less, relatively speaking, than if you're looking at more lengthy deco stops.

My personal conclusion is that the most practical approach is to STOP for long stops and stops where I have a lot of stuff on my plate, and just roll with a slowed ascend for e.g. 1-minute stops.

 

[rjack321]

No, it's not that kind of deco. That's just taking it easy to reach your stops and by the time you get there it's cleared. It's not what I'm referring to.

I'm assuming nobody is familiar with the old VR3 here or perhaps they forgot about that feature.. I still have a manual of that thing, let me (try to) post a capture perhaps I refresh some memories

Think about it this way....

You just arrived at 30ft. Minute 45 in your runtime. You have a 10min 30ft stop before you can move all the way to 20ft.
After 1min your actual ceiling has gone up to 29ft, so you move up.
Lather rinse repeat
You are still going to arrive at 20ft at minute 55 runtime after 10 minutes of deco (plus or minus maybe 15seconds)

The GFs you select have way more influence here (and those are a bit of a WAG) than riding the ceiling like this - which is a major pain in the butt to actually do.

 

[dmaziuk]

Deco stops are conventionally rounded to 3 msw so nobody would normally compute you an ascent like that. What you are talking about is the user interface feature where it shows you its calculated gas loading in some sort of real time.

Exactly how fast that changes depends on the half-time of the leading compartment. If it's the 5-minute compartment, then 1 minute (or just under) may be long enough, for slower ones it's probably not going to be (despite what computer may compute: it's "measuring with the micrometer").

You just arrived at 30ft. Minute 45 in your runtime. You have a 10min 30ft stop before you can move all the way to 20ft.
After 1min your actual ceiling has gone up to 29ft, so you move up.
Lather rinse repeat
You are still going to arrive at 20ft at minute 55 runtime after 10 minutes of deco (plus or minus maybe 15seconds)

But by riding the line you've off-gassed more by the time you reached 20ft and now your 20ft stop should be shorter. (Don't ask me how much.)

 

[rjack321]

Deco stops are conventionally rounded to 3 msw so nobody would normally compute you an ascent like that. What you are talking about is the user interface feature where it shows you its calculated gas loading in some sort of real time.

Exactly how fast that changes depends on the half-time of the leading compartment. If it's the 5-minute compartment, then 1 minute (or just under) may be long enough, for slower ones it's probably not going to be (despite what computer may compute: it's "measuring with the micrometer").



But by riding the line you've off-gassed more by the time you reached 20ft and now your 20ft stop should be shorter. (Don't ask me how much.)

If you play around in multideco or decoplanner and force them to do 1ft stops the "much shorter" isn't even a minute.