Controlling Ascent Rate

[Air Boy]

I'm a fairly new diver, and have also become an avid one!  But the problem I keep encountering is controlling my ascent rate.  My instructor taught me that my inflator is not an elevator, nor should it be used as one.  When I don't have much air in my BC, I have trouble maintaing a steady and slow ascent rate.  On the the other hand, I have read articles that say to add air to your BC.  I think the problem here is that the air will expand as you get shallower and it will be impossible to control.  I just want some opinions/tips.  Thanks!

[scubafreek864]

I have never had to add air to my BC to ascend.  I do a little fin kick every so often to ascend, while having to dump air out while on the way up.  Now add diving a dry suit, and you have to dump air from both on the way up.

Just my 2 cents.

[Hydro]

You might not be weighted enough... you are prolly diving aluminum 80 tanks... so they become positively bouyant when near empty... id suggest check your weight at the end of your dive, you may need more?

[Air Boy]

I dive steel 80s, and I still have trouble

[scubafreek864]

Are you constantly feeling like you are going down?  You might be over weighted, if you have to add air just to ascend.

[Air Boy]

No, it feels like I'm fine when I'm at depth, it just feels like I rocket to the surface when I ascend.  Also, I don't add air when I begin my ascent.

[DetectorGuy]

Here is an idea... Burn up a tank down to 500 PSI on a shallow dive. Surface and dump ALL the air from your BC. Then adjust the amount of weight you have so that when you breathe out you sink and when you breath in you ascend. Then add a couple pounds and remember how much weight you have for that exact wetsuit, hood, gloves, tank, and anything else that may affect buoyancy. That will make you weighted about right for any dive with that configuration.

Then when you are at depth on your next dive, all you need to do to have a controlled ascent is get neutrally buoyant prior to the ascent, keep your thumb on the dump air button on your inflator, check your depth on your computer, fin a couple kicks to start the ascent. Keep an eye on your depth, and when you have risen about 10' in the water column, then stop finning. You should be on a somewhat steady automatic ascent. Keep an eye on the rate of ascent on your computer and just bump the air dump button as your ascent rate speeds up. You will be dumping air all the way to the top (just a little bit at a time). You may need to fin once in a while at for the first few times until you get used to it but after a while you won't have to fin much at all on the way up. I still fin most of the way up on 100'+ deep dives to ensure a slow controlled ascent but it is a big energy and air waster to do that. Another trick is to "flare out" or go horizontal on your ascent so the hydro dynamics work to your advantage. The resistance of water hitting the horizontal diver on ascent is more than on the vertical diver. This is what dry suit divers call riding the bubble.

My opinion is to be 2 to 5 pounds heavier than neutral when at the surface with an empty tank. The dry suit in winter conditions changes that a bit as I like to be a bit heavier so I can leave more air in the dry suit and therefore stay warmer. Hope that helps...

[Air Boy]

I'll give it a try next weekend.  Thanks for all the help!

[Hydro]

Also, if you have an inflatable dive flag or SMB, you can cheat and stay a little negatively bouyant as you ascend and just steal some of its positive bouyancy (I can never shake the feeling I'm holding onto a fancy balloon with a 70 ft string), it will prevent any uncrolled ascents until you get the feel for it.

[Shooter]

My Instructor taught me the same thing. I think it is something that needs to be taught to new divers to prevent uncontrolled ascents. With more experience and buoyancy control, I gradually moved over to riding the elevator to the second from the top floor  ;D. it will come with experience. With a dry suit it gets more complicated. A lot of my dives in the ocean regularly exceed 100 feet. If I am doing a planned decompression dive below 130', I will deploy my lift bag at my deep stop for additional control on my ascent. It's also nice to clip off and relax on those 15 minute deco stops. I will remain somewhat negative and hang on the line. Very relaxing, and if I have a string of bloody fish with me, I can keep a lookout for the taxman.  ;D