Buoyancy Question

[DivingPrincessE]

I’m sure this question has been asked here already, but I’m afraid that typing “buoyancy” into the search field may cause my computer to explode. I did my AOW course this past weekend to get some experience before a trip I’m taking in September. I couldn’t get under on the first dive at all. I tried deep exhales with only shallow inhales as well as the oh-so-newbie looking pushing water up with my arms. Nothing worked. Finally the DM had me just climb the rope down and once I got to about 20 ft I was ok. When we stopped for our safety stop at 15 feet I started to rise to the surface even though I had dumped all the air from my BCD and had to hold onto the rope yet again. The next dive we added only 4 pounds…and at that point I was a bit overweighed.

I know that when you are trying to perfect your buoyancy, being overweighed is one of the worst things you can do. However, I’m worried what would happen if I ever dive somewhere that doesn’t have a reference line to help me get under and stay under during the safety stop.

Any advice?

 

[STOGEY]

I’m sure this question has been asked here already, but I’m afraid that typing “buoyancy” into the search field may cause my computer to explode. I did my AOW course this past weekend to get some experience before a trip I’m taking in September. I couldn’t get under on the first dive at all. I tried deep exhales with only shallow inhales as well as the oh-so-newbie looking pushing water up with my arms. Nothing worked. Finally the DM had me just climb the rope down and once I got to about 20 ft I was ok. When we stopped for our safety stop at 15 feet I started to rise to the surface even though I had dumped all the air from my BCD and had to hold onto the rope yet again. The next dive we added only 4 pounds…and at that point I was a bit overweighed.

I know that when you are trying to perfect your buoyancy, being overweighed is one of the worst things you can do. However, I’m worried what would happen if I ever dive somewhere that doesn’t have a reference line to help me get under and stay under during the safety stop.

Any advice?

Is you AOW over with? If it is I'd get a weight that I can work with and critique my buoyancy as I get more experience with it. I'm not the type that does everything by the book, but instead I work with what works for me. Not as far as the basics are concerned but, because being safe is quite important.

If you are not quite finished with the aow class, I'd get it over with the class get,get the certification go by what they preach, and critique or customise yourself as you get more experience.

After all that's why they class it a classroom. You learn more techniques and go from there.

 

[scubapatton]

Try going only 2 pounds more than you started the Dive 1 with. Also, you can always flip over and go down head first. Then when you kick, you will be going in the down direction (vs doing the hand waving to get you down). Being heavily over-weighted is bad, but slightly over-weighted will not hurt you that much - you will just have to adjust your bcd more often.

If this happened on your first dive of the day, you may have had air pockets and such in your dry wetsuit. Did you try lightening the weight on dive 2? Once you get wet and compress the suit and get rid of the air pockets, you should be better weighted. I would try the extra 2pounds though on your next dive.

Have a great vacation in Sept.

 

[GA Under Water]

Take 2 pounds off from the last and take your time doing your Bouyancy check. Then if you are using an AL80 add 4 pounds, should keep you level at the end f your dive.

Or, if you have access to an AL80 with 500 psi, do your bouyancy check then replace with your full tank.

 

[Puffer Fish]

First off, discounting what some might say... you will be breathing around 5 lbs of air... so there is no "perfect" Bouyancy, unless you are 5 lbs heavy at 15 feet, at the start of the dive with an al80.

Being underweighted is far more dangerous. If you don't have a line, then an inverted swim during your safety stop is your only option... and that (I know for a fact) is not fun.

If you were diving with a new suit, then expect that it will loose some bouyancy as you dive, and the weight will come down some.

 

[STOGEY]

Also when and if I use aluminam tanks. I find myself a little underweight. If that is the case I just go down head first. Sometimes it takes a little work to get at that attitude. But it does work. Once you're near the bottom or at the bottom just use some rocks on the ground to help keep you down.

 

[jbd]

Finally the DM had me just climb the rope down and once I got to about 20 ft I was ok. When we stopped for our safety stop at 15 feet I started to rise to the surface even though I had dumped all the air from my BCD and had to hold onto the rope yet again.

This is a very poor solution to the problem and is an indication to me that the DM doesn't understand buoyancy control and its importance to diving safety.

You need to learn to do a proper buoyancy check or weighting determination. Properly weighted and with the BC completely empty you should be able to slip underwater easily but slowly by simply exhaling. You won't need an ascent or descent line for anything other than visual reference.

 

[alphonsis]

Also when and if I use aluminam tanks. I find myself a little underweight. If that is the case I just go down head first. Sometimes it takes a little work to get at that attitude. But it does work. Once you're near the bottom or at the bottom just use some rocks on the ground to help keep you down.

Do you mean to say you grab some rocks and stuff them in your pockets?

 

[SteveAD]

While being grossly overweighted is bad, being underweighted is worse. An ideal weight check should be done at the end of a dive with 200-500 psi in the tank and should allow you to sink on a full exhale and float on a full inhale. At the beginning of a dive the "extra" 5 or so pound from a full tank should alow you to sink quite readily.

 

[herman]

There are several things that come to mind, unfortunately I would have to be there to see if any of them are the problem. First off, is your BC really deflated? Just because no more air is coming out does not necessarily mean you have got it all. This is a very common problem. The vent you are using must be at the highest point on the BC. Assuming you are starting feet first and using your LP inflator hose, this means your left shoulder needs to be tilted slightly forward and up.
Are you fining? People tend to fin unconsciously when at the surface and in a vertical position, this is a very common cause of " can't get down". It takes a lot of weight to overcome this. It also makes you appear to be overweighed later (and you are).

So what to do. First make sure all the air is out of your BC, making sure what ever vent you choose is at the high point and if your using your LP hose, it also need to he above your head, chest high is not acceptable.
Make sure your not fining. I suggest new divers cross their legs at the ankles, it’s impossible to fin with your legs crossed.