Is this a crazy idea or am I over reacting?

[drbill]

You want something that's attached to the bottom, not the surface, because the surface moves.

But you live in California... surely you are aware the "bottom" can move here!

 

[Rayallyn]

I do not trust computers on ascent, I never go faster then bubbles and often I am the last one to surface. Even with that said sometimes my computer flashes a warning that I notice after I am on the surface or back on board. I know my ascent was not too fast and disregard the warning. This always seems to happen on shallow dives of 20 to 35 ft. I always follow these rules: never ascend faster than the bubbles, do not inflate BC until on the surface, slowly kick your way up if you stop you should hover.

 

[RJP]

I know my ascent was not too fast and disregard the warning... I always follow these rules: never ascend faster than the bubbles...

At what rate do your bubbles ascend to the surface?

 

[freewillie]

Congratulations on your certification. Just a few things about computers. They are a tool to be used while diving but their proper use depends on the diver not the other way around. Before computers where available you had to use a timing device. Published rate can vary between faster ascent of 30 ft./minute to a more conservative PADI recommendation of 60 ft./min. If you are using the bubble trick you should be looking at the smallest bubble, not the largest bubble.

You should be using your computer to make sure you are diving correctly, not depending on the computer to tell you if you are diving correctly. That comes with experience. But making multiple ascents and descents in a single dive is not recommended either. You should get in as many dives safely but not to simply bob up and down like a cork during a single dive just to practice your ascents. Simply focus your attention on ascent rate on each dive.

 

[Skittl1321]

Published rate can vary between faster ascent of 30 ft./minute to a more conservative PADI recommendation of 60 ft./min. If you are using the bubble trick you should be looking at the smallest bubble, not the largest bubble.

I think you made a typo- but just in case it wasn't a typo, and rather a misunderstanding: 30 ft/minute is slower than 60 ft/min.

PADI teaches 60 ft/min as a max (at least, the paperwork I signed two weeks ago for a refresher said that), but I know my instructors recommended 30 ft/min.

 

[DukeAMO]

At what rate do your bubbles ascend to the surface?

I've heard from Scubaboard and some other places that bubbles ascend at about 60 ft/minute: Scuba Diving Bubble Mechanics

If you have a line to ascend on, it's easy to stay at 30 ft/min. Get neutral and hover. Take a deep breath in, let the air in your lungs move you up 1-2 feet. Breathe out, and you'll stay at the new depth. Repeat. If you feel your BCD pulling you up a bit, dump some air right away to get neutral again, and grab the line for a moment if you have to. It's also easy on a shore dive: stay close to the bottom and follow it up slowly, checking out the view as you go.

Ascents and safety stops without a reference line or sloping bottom are tricky, and definitely take practice, even in a lake with no waves. I think it's fun, though. Do it facing your buddy and you can help keep each other in the right position.

Your BCD should be empty after the safety stop with a mostly-empty tank. This makes that last 10-20 feet of the ascent a lot easier to manage, because you don't get pulled to the surface by the expanding air in the BCD. If you still have air in your BCD at 15 ft with about 500 PSI in the tank, you're overweighted, so get rid of a couple pounds of weight on the next dive. You'll still get to the surface easily if you're neutral at the safety stop.

If your BCD is empty at the end of the dive and you STILL get pulled to the surface ("corked"), you might be a bit underweighted, so you should add a pound or two of weight for the next dive to see if that helps.

The Peak Performance Buoyancy class is definitely a winner for this type of thing. That was one of my favorites, along with Night diving. Beyond taking that class, I agree with the posters who say to just practice it on every dive, not over and over again on one dive.

 

[trsills]

Thanks everyone for the feedback and encouragement. A couple items noted by the posters...in terms of the weighting, I added several more pounds for the last set of dives cause the 10% rule just wasn't working in that with an empty BC I couldn't get myself to easily descend and conversely those last 10 ft on ascent were a PIA cause I was fighting to keep from uncontrollably ascending (again with no air in the BC). So I fixed that part with a few extra pounds.

Regarding the bubble theory, I used to read dive mags years ago and knew about pacing off of the bubbles and had actually asked the instructor about that theory. The suggestion was to stick to the computer although that could be an option.

So it sounds like it wouldn't hurt to also use the small rising bubbles as a reference point as well, so I'll keep that in mind.

thx again.

 

[tursiops]

" I was watching the computer ".......So this how some 'new divers' do an ascent??..ie watching their computer???...........Practice staying below your smallest bubble---if you want/need a guide/gauge---& it's colorless.................

This is total nonsense, but I'm not surprised to see you write it. The smallest bubble don't even go up....they just fizz and dissolve. But, it is what was taught eons ago, and you've already proved you have a good memory. Now it is time to learn something new.

---------- Post added September 25th, 2014 at 03:20 PM ----------

I've heard from Scubaboard and some other places that bubbles ascend at about 60 ft/minute: Scuba Diving Bubble Mechanics

Read that link again! It does NOT say bubble ascend at 60 ft/min. They may go faster. [Also, the smallest one don't go up at all. So if you follow the bubble of a certain size, maybe you are OK. Which size? Depends...] So the linked article says don't follow your bubbles.

This bubble myth is a zombie...can't be killed...keeps coming back...

 

[Bob DBF]

I've heard from Scubaboard and some other places that bubbles ascend at about 60 ft/minute: Scuba Diving Bubble Mechanics

The smallest bubble ascent will work, but the trick is switching to the smallest bubble again and again as you ascend. Since the ascent is no longer taught, few remember the entire procedure. And as Akimbo says, "there is no 30'/min bubble", so you need to monitor your computer and don't move your arms quickly.

If you still have air in your BCD at 15 ft with about 500 PSI in the tank, you're overweighted, so get rid of a couple pounds of weight on the next dive.

I believe it is an excellent idea to know your Ideal weight at 15', 500#, and an empty BCD, however I believe in carrying a bit more weight in case I want to be less than 15' deep, have less than 500#, am in a boat traffic area and need to descend quickly, am shallow in the surge and don't want to be pulled to the surface, and so on. Your weight needs to based on the dive as well as the ideal.



Bob
------------------
I may be old, but I'm not dead yet.

 

[TSandM]

Nobody has really addressed your original question. Yes, practicing ascents is the only way to learn to control an ascent - but NO, don't go out and do a bunch of them, even in shallow water.

After I took my Fundamentals class, I was gung-ho about nailing buoyancy control. My buddy and I went out and did a night dive to practice ascents. We must have done 8 or 9 of them, from no deeper than 30 feet, but some were not well controlled at all (which is something you have to expect when you are practicing). Driving home that night, I felt like I did in my residency, when I'd been up for three days at a time. I couldn't keep my eyes open, and my foot slid off the clutch at stop signs. I am absolutely certain that it was decompression stress (because I was well rested and it wasn't late). I HIGHLY discourage more than two or three ascent practices in a given dive.

It takes time. It takes learning to anticipate buoyancy changes. It takes learning to divorce your breathing from your concentration or your stress level. It takes mastering a neutral hover. It just takes time . . . but the good news is, time means diving, and when you're in SoCal, you have so much beautiful diving at your disposal, it's nothing but fun!