Ascent / Descent - Safety Stop YoYo practice??????

[TSandM]

You really don't have to make the depth changes that great. The key is control; if you have some kind of visual reference, just move up 5' or so and hold; go back down 5' or so.

If you have any control issues, limit the attempts to two or three at most.

One of the most unpleasant evenings I've spent was a night where a friend and I were practicing ascents. Our max depth was about 25 feet, but we did six or seven ascents, of which we lost control of a couple. Driving home, I felt like I had been run over by a bus -- I hadn't been so tired since going days on end without sleep during residency. I learned a powerful lesson that night, and I truly believe that subclinical DCS manifests as profound fatigue. And I don't do multiple ascents during a dive any more.

 

[bracko]

another question... why don't you just pop an SMB up for every dive? visual reference, something to hold onto, practice makes perfect

 

[Divedoggie]

Maybe practice in a pool? If your trim and buoyancy are solid in swimming pool depths, then just apply those skills to your open water dives. Be disciplined on each and every one of your dives and during the safety stops. If you do not yet have great control then it is perhaps best to avoid any yoyo-ing at any depth on your open water dives?

 

[gcbryan]

I would just go diving. Hold your depth for a minute or so for "practice" if you like where ever you are and then continue on with the dive. When it's time to ascend just do it under control a few meters at a time.

I don't see any value in practicing something like this. Just do the dive and practice things as they naturally occur during the dive.

 

[LIVES4SHARKS]

I agree with working in a pool. Once you can control yourself from 10 ft, you will have no problem in deeper water. Plus it runs you at a lower risk for any injury. Just get your buoyancy/trim under control on the bottom and practice breathing your way up a little at a time. That is how I learned it, and for best results, work with an experienced diver as a mentor.

C:shark2:

 

[vladimir]

another question... why don't you just pop an SMB up for every dive? visual reference, something to hold onto, practice makes perfect

I think shooting an SMB might be a little challenging for somebody who can't hold a safety stop.

 

[bracko]

really? i actually find it worth the bother... I consider myself average at best for holding a safety stop with no visual reference in any direction.

I have watched a few demo videos on it though. *shrug*

 

[Saudi-Diver]

Why not at the end of your dive with about 60 bar remaining ascend to 5m and hold your safety stop for 5 mins and then ascend to 3m hold the stop till your down to 50 bar then surface. I did this while mastering my Dry suit, the 5m safety stop was usually easy the 3m stop could get a little exciting till I discovered all the contortions necessary to vent a dry suit. I had my buoyancy nailed in a pool in a shortie, but my dry suit in shallow water took a wee bit of getting used to. Plus you get to look at all the wee critters in the seaweed.

 

[Phishboy]

Thanks everyone for their input and advice. Every comment has taught me something.
All seems so logical when you put the science together with a little knowledge and experience.
As a result, I will continue to just practice diving normally and focus my attentions when I actually need to practice the various skills (safety stops etc.) I had a feeling the 'YoYo' method was not a moment of genius.
I will try the idea of coming up a couple of metres and holding then coming up a few more and controlling my trim and buoyancy as I slowly ascend. And I also like the idea of using a buoy with a line for visual reference - as I can also do with practicing some nav skills.

I am a little nervous of my/our skills because we got our C-cards in the Caribbean (28C water temp and perfect visability in 3mm shortie wet suit) and have done all but 2 of our (10) dives around the Caribbean in similar conditions. Our other one was 2 years ago in Italy (Mediterranean Sea with excellent conditions) and the last one was 2 days ago in a quarry in Poland (where I'm currently working and living). The dive in Poland was a disaster. There had been serious flooding in the region in the previous month and the visibility was 1m or less, water temp was around 7C and we were in 5mm farmer john wetsuits... so that was a real experience shocker compared with our previous dives.
We got down to 12m (bottom was 16m) and my girlfriend got claustrophobia as she momentarily lost visual contact with me, had a panic attack, hyperventilated and basically $hit a brick... that was around 5mins into the dive. I decided to end the dive and made a CESA as she did not know how to tell me she was having a serious panic attack (she made the shaky hand = I have a problem signal, but could not tell me what the problem was: ie. out of air or equalisation problem etc.). ps... is there a signal for 'I'm having a panic attack'? So I did not know what was happening with her... and went for the exit strategy.
I made a second dive with another (more experienced) buddy but also aborted after 13mins as the visibility was less than 1m and made the dive unworthy (for my enjoyment and my lack of experience in such conditions). However, next week we will go to another quarry where the vis is around 5/6 metres... and practice our skills with the advice gleaned from above comments.

I am new to this website, but having read many comments it has astounded me just how nice, humane, helpful and mentally well balanced divers [you guys] are. A credit to humanity!
Thanks for the advice

 

[DA Aquamaster]

There are a couple of possible approaches. One is to stay very slightly negative and swim your way up very slowly. You should be close to neutral when you start the ascent and the goal is to stay close to neutral. So initate the ascent by finning very genetly upward, then dump a small amount of gas.

If you stop kicking and are still rising, you need to dump a bit more gas from the BC.

If you are kicking and not rising in the water column you have dumped too much. However as long as you are only finning very gently, you will have some reserve power to kick upward a few feet to where you are now closer to neutral.

It is a little crude but effective until you get your buoyancy control down. The good news is that this naturally lends itself to the second method. As your skills improve, your target becomes to fin your way upward less and less until you only fin when needed to re-initate the ascent. Eventually, as your buoyancy control is perfected, you will be able to initate your ascent with a deeper/longer than normal inhalation and maintain a slow and steady ascent with no finning at all, stopping it at will in the water column with a small dump on the inflator or a greater than/longer than normal exhalation.

Doing it along a wall for visual reference is a good idea, especially if you need to stabilize your self, but even in mid water, you can gauge your ascent by focusing on particles in the water column, or even in crsytal clear water, you can gauge your ascent rate by focusing on an staying even with the tiniest exhaust bubbles you can see. Just remember that bubbles expand as they rise and as they expand they rise faster, so you have to keep switching to smaller bubbles to keep your ascent in the 10m/30 fpm range.

Finally, I prefer a 3m/10ft per minute range from the safety stop to the surface. That is most easily done by practicing an ascent about 1/3rd of a meter or 1 ft at a time. Rising then holding, then rising again.

Somewhere along the way you will have figured out the lag and inertia effects caused by the shift in buoyancy as you breathe and you will have figured out the need to dump more gas per foot/meter as you approach the surface and you will gain a solid understanding of how your wetsuit also becomes much more buoyant in the last 10 m of the ascent.

Once you get there, you'll be able to make a steady controlled horizontal ascent at less than 3 m per miunte with no foot or hand movement at all from 30 ft all the way to the surface.