Question How to practice deco ascents?

[steinbil]

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.

This is pure gold. On ascent speed, do you mean 30sec ascent + 30sec hover for each step? Follow-up question: can 2 divers do a valve drill in 30secs?

 

[Imla]

This is pure gold. On ascent speed, do you mean 30sec ascent + 30sec hover for each step? Follow-up question: can 2 divers do a valve drill in 30secs?

30 sec ascent from leaving stop to arriving at stop. Then do task. Then new ascent.
Normally, a min deco ascent will either be done with a very slow 1 minute slide from stop to stop, or 30 sec slide, 30 sec full stop. This is usually a team preference what you do. Personally I like the stop and go method. It gives me some time to balance and sort out kinks.

The point of this exercise is to provide task-loading while remaining stationary in the water column. In the start, maybe just doing the stops will be enough. Then add the tasks. When doing the ascent while doing these tasks and still keeping chill and stationary...
the point about 30sec travel time is to challenge you to slow down and stay in control. Think like a dancer. Look smooth and elegant.

 

[ChuckP]

Thanks for the suggestions, but what about repeated ascents? If I can only dive once every two weeks or so, it doesn't feel like there's a lot of progress...

I myself would not practice repeated ascents - I hate it for my ears and only do that kind of thing when teaching OW or Rescue class.

The initial ascent and hitting your stop is the hardest to perfect but you really need to be moving some distance and have a good change in bouyancy to make the practice real - that is why I would not do it repeatadly.

The 3m ascents are really simple and you can practice those the whole dive while at depth - same thing with holding depth, you can do that the whole dive.

Your ascent method, what they teach you, I think it defines how you will practice. I practiced a lot of open water free ascents before class but that is not what we did in class - in class was up an anchor line, riding a SMB up to initial stop and hanging from a SMB - all this was open ocean diving. You quickly learn how many hand over hand and how far apart the hands are on an anchor line - even using the John line it becomes something you invision. The SMB is similar, how many wraps roughly and how fast.......

Then when you get that close in practice, add in the complications of a fake gas change, the steps you do etc...... We were taught efficiency - bang the stops, bang the gas changes - if at the beginning of ascent your run time was to be 102 minutes, why did it really end up 106 minutes kind of thing.......

The initial ascent is the hardest part by far......

 

[Lorenzoid]

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.

I'm not sure if you're being facetious or serious. The difficult part is arresting your ascent so that you decelerate and stop precisely at some planned depth. The deceleration part is especially difficult with a drysuit (bag-o-expanding-gas) and heavy steel doubles (inertia). You need to coordinate how you dump from the wing AND the drysuit. And you need to do this so as to maintain a certain rate of ascent between stops--not too slow and not too fast. Dump too much too soon and you slow down too much or even come to a stop. Dump too little or too late and you accelerate and perhaps miss your stop. It's a difficult skill to master for many of us. Practicing this skill, many times I was unable to stop myself at 3m/10ft and popped to the surface. Now, throw in some task loading at each stop like @Imla described and, wow--it is difficult to master.

 

[Dann-Oh]

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.

Can you expand on what you mean by "Flow Check" and Basic 1-5, please. I'm guessing I've heard these but explained in slightly different terminology.

 

[BlueTrin]

When I am practicing deco ascents I create a deco schedule based on a dive I want to do and follow it with focus on holding the shallow stops without variation in my depth. I do not go into deco if I am practicing deco ascents, just in case something were to go pear shaped you are not actually bound by a deco obligation.

Pretty much the same thing for me.

You don’t have to be in real deco, you can work out the deco you would do and just add the ascent bit to any dive you do … make sure to inform your buddy …

 

[BlueTrin]

Can you expand on what you mean by "Flow Check" and Basic 1-5, please. I'm guessing I've heard these but explained in slightly different terminology.

Flow check, you make sure all the valves are opened.

Basic 5 is a term used by GUE for 5 basic skills:

1. Take reg out of mouth and replace
2. Switch to backup reg
3. Simplified S Drill: you just give the reg and deploy the long hose
4. Mask clear
5. Mask removal and put back

 

[Wibble]

The difficult part is arresting your ascent so that you decelerate and stop precisely at some planned depth. The deceleration part is especially difficult with a drysuit (bag-o-expanding-gas) and heavy steel doubles (inertia). You need to coordinate how you dump from the wing AND the drysuit. And you need to do this so as to maintain a certain rate of ascent between stops--not too slow and not too fast. Dump too much too soon and you slow down too much or even come to a stop. Dump too little or too late and you accelerate and perhaps miss your stop. It's a difficult skill to master for many of us. Practicing this skill, many times I was unable to stop myself at 3m/10ft and popped to the surface. Now, throw in some task loading at each stop like @Imla described and, wow--it is difficult to master.

Even more fun on a rebreather with a third bag of wind to vent.

And winding up the SMB line!

 

[BlueTrin]

Even more fun on a rebreather with a third bag of wind to vent.

Maybe it’s fun for you, it’s probably still mildly annoying for me

 

[Wibble]

Maybe it’s fun for you, it’s probably still mildly annoying for me

The one I hate is pre-emptively dumping from the loop, whilst manually adding some oxygen to increase the PPO2, then stopping because you've over-dumped. Embarrassing at the least, dangerous if you've overdone the oxygen.

Practice is so important.