Question How to practice deco ascents?

[ScubaWithTurk]

In the RAID Deep 40 course, which is a great primer for the Deco 50 course, stops are mandatory on every dive. Ascend to 10m and hold for 3 minutes, ascend to 5m and hold for three and then make a 1 minute ascent from 5m to the surface.

You can adjust this and start your stops at 9m and do 3 minutes every 3m. As @rjack321 said, if you can do these stops, the deeper stops are not hard do not require additional practice until you start a tech course where you will be stops with gas switches.

 

[rjack321]

Amending a bit here:
If I were in @steinbil fins here and wanted to practice ascents at a shore diving site. I might do a short 15-20min dive to 20-25m swimming around, looking at fish, maybe back kick intermittently. Ascend up the bottom to ~12-14m. Leave the bottom and go up to 9m and hold for 3mins, go up to 6m and hold for 3mins, go up to 3m and hold for 3mins. Go back down to 9m and repeat 2x more. That's a 50-55min dive and a mix of reality and concentrated practice.

 

[Alaskan Scuba Dude]

There are many technical divers who can't hold correct trim and buoyancy. They get lazy and hold shot lines or deploy SMBs. With modern computers operating in real time, you don't have to hover precisely at your next decompression stop. As long as you don't go above your ceiling.

 

[clownfishsydney]

I am not sure why you would ever need to practice a deco ascent. Really it is no different to any other ascent, just that you stop at certain depths for certain times. In any case, you do this on every ascent, just stop at 6 metres and then 3 metres (20 and 10 feet) on a normal dive any you have done it.

I cannot say that I have ever practised such a thing nor seen anyone do it.

 

[crofrog]

Not sure if this belongs in the technical or advanced scuba forum, as it concerns practicing to prepare for technical dive training...

Any ideas for practicing deco ascents in an efficient manner? It is a little frustrating to only be able to do one ascent per dive, especially in periods where I can't dive regularily. How can I get some repetition in training for ascent speeds and hitting/holding stops on a single dive?

Would it be more beneficial/safer to simulate ascents at depth where pressure changes are smaller - let's say stopping every 3 meters from 21m to 12m and descending to repeat? Or is it better to just do repeated shallow ascents in the beginning of a dive (before significant nitrogen loading) from 12m to 3m?

I also need to practice the different ascent speeds, 9m/min (which I guess needs to happen at depth) as well as 3m/min (could technically happen at any depth, but closer to the surface is more realistic and more challenging...).

Or is it better to just do repeated single stop ascents, let's say 9m-6m-9m-6m-9m etc. ?

For context:
I'm a GUE recreational diver preparing for GUE tech classes, so I'm practicing min-deco ascents (9m/min to half depth, then 3m/min as 30 second stops at each 3m interval).

PS.
I understand the concerns about doing several full ascents from depth in one dive (as mentioned in this thread), which is why I'm trying to find other ways to simulate ascents to be able to get more repetitions while practicing ascents.

Edit to add:
I don't know if it's frowned upon to tag people for answers here, so please excuse me if it is, but I would love to hear what the GUE technical instructors would have to say about this, like @johnkendall, @mer, @kierentec, @AnnikaPersson (Hei Annika!). Feel free to tag others (as long as it's an accepted practice...). Of course I would also like to hear the advice of tech instructors from other agencies (@tbone1004, @boulderjohn are names I keep seeing on here), as well as other experienced divers.

We spent a lot of time just doing 60–50-40-30-20 and then back to 60. Over and over again to get good at nailing the stops and dealing with the drysuits. It’s fine don’t over think it. The last 20ft are hard on the ears

 

[crofrog]

I am not sure why you would ever need to practice a deco ascent. Really it is no different to any other ascent, just that you stop at certain depths for certain times. In any case, you do this on every ascent, just stop at 6 metres and then 3 metres (20 and 10 feet) on a normal dive any you have done it.

I cannot say that I have ever practised such a thing nor seen anyone do it.

Then you’re probably not very accuracte and hitting them

 

[steinbil]

We spent a lot of time just doing 60–50-40-30-20 and then back to 60. Over and over again to get good at nailing the stops and dealing with the drysuits. It’s fine don’t over think it. The last 20ft are hard on the ears

That would be around 21m-6m, which sounds great in terms of efficient practice, optimally I would even some times do 9m/min from 21m to 12m to practice both speeds. I would love to do this. Is it considered safe, though, to do multiple ascents from 21m to 6m? There seems to be some debate about that?

 

[Wibble]

Any ideas for practicing deco ascents in an efficient manner? It is a little frustrating to only be able to do one ascent per dive, especially in periods where I can't dive regularily. How can I get some repetition in training for ascent speeds and hitting/holding stops on a single dive?

It's not hard to do that kind of practice.

If you're in a shallow lake, spend 30 mins next to a 6m/20ft platform and hold your position. Ditto in a pool, staring at tiles on a wall. For some variety ascend 1m/3ft and hold for 2 mins, descend 1m/3ft and hold again. This kind of exercise will challenge your buoyancy skills and ability to stop wagging the fins around; also becoming more efficient at spotting any change and counteracting it before it's an issue. Backfinning is your friend!

Do shallow dives, even NDLs, but treat the ascent as if it's a deco ascent. E.g. a quick ascent from 30m/100ft to 15m/50ft and stop for 2 mins, then ascend to 12m/40ft for 2 mins, then to 9m/30ft for 2 mins, then to 6m/20ft for 15 mins.

• Do that with a SMB thrown up from the bottom to give you the pressure of sorting out the line, ascent, drysuit dumping, wing dumping (and if on a rebreather, CCR loop dumping with PPO2 monitoring).
• Do that with a deco stage -- could be air or 50% -- and switch to it at 12m/40ft (pretend it's the 21m/70ft stop). Do all NoTox drills properly, with or without someone around you.
• Do that with two deco stages (if you're practising for Normoxic)
• With the SMB spool/reel, let it hang in front of you at the stops, don't hold on to it. It'll move with the surface wind.

Gradually work down to deeper depths so you get to learn how the ascent from 40m/132ft goes (e.g. feeling how the drysuit dumps).

Could plan a dive on MultiDeco/whatever; write that on a slate/notes and follow the ascent portion without incurring the decompression obligation. E.g. what would the ascent look like from 45m/150ft for a 45min bottom time? Then run that dive's ascent from 30m/100ft.

All practice is good practice. Just do it

 

[Sebek]

That would be around 21m-6m, which sounds great in terms of efficient practice, optimally I would even some times do 9m/min from 21m to 12m to practice both speeds. I would love to do this. Is it considered safe, though, to do multiple ascents from 21m to 6m? There seems to be some debate about that?

For 9m/min ascents, practice 12-6 timed to 40s or 9-6 timed to 20s. Similarly to how you do 3m/min by ascending 3m in 30s, then holding for 30s, you can do 12-6 in 30s and stabilize/hold for 10s, or something like that.

I personally don't think there's a problem with repeated ascents/descents if your max depth for the dive ends up around 12m. I definitely had training dives like that. For added difficulty, ascend while sharing air with the buddy.

To help gauge the ascent, what I did in the past is I tied down a deployed SMB on the bottom at 12m, then put markers on the line (either a wrapped bolt snap, or a plastic colored washline clip) at 9, 6, 3m. This works for me better that just staring at my depth gauge all the time.

 

[Imla]

So... You could do Gunnars Intervals for Divers. Normally an exercise done with stage rotations in mind, but of course it is adaptable. This is a simulated ascent from 21m.
Standard setup for 3 stages first. Alternate exercise second.
Dive to 10m
Shoot an SMB, tie to a rock
10m - First "stop" - Shake lose. Prepare.
9m - Chill
8m - Clip Light
7m - Switch to Back-gas
6m - Switch to 50%
5m - Rotate gases (100% front, bottomgas back)
4m - Clip light Switch, to Back-gas
3m - Switch to 100%, hover 3 min, Switch to back- gas, clean up, rotate back.

Go down, lather, rinse, repeat.

Alternate: Ascent speed 30 sec per m
10m - Shoot Smb, tie it off to a rock
9m - Chill
8m - Flow Check
7m - Valve Drill
6m - Basic 4 and 5
5m - Basic 1, 2 and 3
4m - Modified S-drill
3m - S-Drill, Hover 3 min - Clean up.

Focus on clean, calm, relaxed movements in exercises, not speed. Try to keep precise time for ascent, and clean stops. This is a difficult exercise, but really hones buoyancy and preciseness for Tech 1.

(Jeg er snart ferdig med oppussingen og kaoskontrollen, så er snart klar for dykking igjen! /Ingrid