From 6m to Surface after Deco

[Remy B.]

There are different criterias of the ascent rate after completing your Deco time at 6m.

But what could really go wrong after completing your mandatory time + that preventive little?

of course I'm not saying fly out of the water after Deco, but what will be the real side effects of faster ascents after the 6m stop ?

 

[scubadada]

I pad my shallow stop with a "safety stop" of 3-5 minutes and then ascend no faster than I was already ascending, 30 ft/min, often a bit slower. Never been bent, intend on keeping it that way

 

[Edward3c]

BSAC recommendation is one minute from 6 to surface.

 

[LiteHedded]

GUE teaches a six minute ascent for what that's worth.

I've done it all sorts of ways and never noticed much difference. I'm more careful on big exposures.

 

[DevonDiver]

But what could really go wrong after completing your mandatory time + that preventive little?.... what will be the real side effects of faster ascents after the 6m stop ?

Decompression Sickness.

I think you'd be shocked at how tissue gradients spike in those final few meters.

For what it's worth, I use the GF99 info on my Shearwater to dictate my final ascent. If I've set, say, GF85 as my surfacing tension, I'll limit my final ascent to a lower GF...let's say 75%. I'll ascend slowly from the final stop until I reach 75%, pause until it drops 2-3% and rise again. This creates a series of 'micro stops' towards the surface... a very fine curve...as the stops get longer as the surface nears. It's a slow crawl, where in the final couple of meters you're rising in 10cm increments.

Obviously, I've got the gas for it... mandatory deco is clear and I've got ample planned reserve gas... and here in the Philippines the water conditions are not prohibitive to fine depth control near the surface.

After surfacing, I'll stay on my deco gas as I exit the water, de-kit and, usually, for a few minutes longer. I make a point of keeping my exertion to the absolute bare minimum during the whole process and for an hour or so post-dive.

I've seen enough people get bent... and I don't want it to happen to me. Technical diving is my day-to-day job... and I've got many thousands of bend-free deco dives under my belt.

One thing you learn to appreciate is that it's the small things.. the attention-to-details habits... that really make a difference in avoiding DCS.

 

[Remy B.]

I see already many differences in ascent rates in each intervention.

9m/min
6m/min
1m/min

On the few Deco dives that I have done as well as practice Deco dives, I follow the bottom all the way up to shore, where possible.

This normally takes around 5min a little more or less depending how the slope is.

When on a wall I'm normally the last out of the water as I slow down my ascent from 6m to surface and try to hang at arbitrary depth in between.

The last 1m is normally a matter of seconds, because it is more about standing up.

But how far had investigations been done in to this 6m to surface ? If any had been done.

A lot of divers basically say I clear my Deco mandatory time and now I start the ascent at whatever speed they like or were taught and from what I hear agencies have different criterias as well.

 

[DevonDiver]

A lot of divers basically say I clear my Deco mandatory time and now I start the ascent at whatever speed they like...

Do they? I hadn't heard that...

 

[Kevrumbo]

I see already many differences in ascent rates in each intervention.

9m/min
6m/min
1m/min

On the few Deco dives that I have done as well as practice Deco dives, I follow the bottom all the way up to shore, where possible.

This normally takes around 5min a little more or less depending how the slope is.

When on a wall I'm normally the last out of the water as I slow down my ascent from 6m to surface and try to hang at arbitrary depth in between.

The last 1m is normally a matter of seconds, because it is more about standing up.

But how far had investigations been done in to this 6m to surface ? If any had been done.

A lot of divers basically say I clear my Deco mandatory time and now I start the ascent at whatever speed they like or were taught and from what I hear agencies have different criterias as well.

We all have venous gas bubbles (VGE or Venous Gas Emboli) to some degree as we surface, and while the presence VGE indicates decompression stress, there is still no positive correlation between surfacing VGE Doppler scores and onset of DCS. (IMO, there is also some inflammatory/immune system complement involved but that's beside the point).

Nevertheless, give yourself every chance to keep those bubbles small and off-gassing efficiently, and with a slow gradual 1mpm/3fpm surfacing ascent to help keep those supersaturated slow tissues in check.

 

[kensuf]

Years ago I used to do all of my O2 time at 6m (20'). I don't do that anymore, and I don't go straight from 6m to the surface. I break my O2 time into 6m, 4.5m, 3m, and a slow ascent to the surface.

Let's say I have a deco obligation that calls for 15 minutes of oxygen time. Typically, a Buhlman schedule will break that into 5 minutes at 6m and 10 minutes at 3m. While some people may choose to do all of the 15 minutes at 6m, I will do 5 minutes at 6m, a 1 minute ascent to 4.5m (15') where I'll hold for 4 minutes, followed by a 1 minute ascent to 3m where I'll hold until clear, then a 1-2 minute ascent to the surface.

If it's a bigger exposure my final ascent from 3m to the surface will be slower.

 

[Remy B.]

Years ago I used to do all of my O2 time at 6m (20'). I don't do that anymore, and I don't go straight from 6m to the surface. I break my O2 time into 6m, 4.5m, 3m, and a slow ascent to the surface.

Let's say I have a deco obligation that calls for 15 minutes of oxygen time. Typically, a Buhlman schedule will break that into 5 minutes at 6m and 10 minutes at 3m. While some people may choose to do all of the 15 minutes at 6m, I will do 5 minutes at 6m, a 1 minute ascent to 4.5m (15') where I'll hold for 4 minutes, followed by a 1 minute ascent to 3m where I'll hold until clear, then a 1-2 minute ascent to the surface.

If it's a bigger exposure my final ascent from 3m to the surface will be slower.

What will this approach do to your theoretical slow tissue decompression and behavior of the bubbles