Buoyancy/balance issue

[mr.shark]

Newly certified and just took our first (lake) dive. When floating on top of the water, BC inflated, I can't stay vertical -- keep going face-down (not a position I'm comfortable with as it's difficult to communicate, etc.). When I try to stay vertical by kicking, it causes me to drift. I honestly don't remember what happens to me underwater as I'm still focusing on the basics of comfort & control (just staying in one place kind of thing).

Is there something I could be doing different with the position of my tank or my weights? I'm using rental equipment with a wt. belt -- I've had the wts. positioned slightly forward, just over the front of my hip bones.

Have my own fins which seem to be slightly negative. Boots are 5mm, med. sole.

Any suggestions appreciated!




mcdermott cues poison cues predator cues

 

[Agility]

You might try putting some of the weight farther back (some BCs have so called trim pockets for some of the lead). If you use an aluminium tank you might consider putting 2lbs on the strap that fastens the tank to your BC.
Less air in the BC (or one a size larger) might help, too.

But IMHO best would be to find an experienced diver (maybe your instructor?) to help you with the issue on site.

 

[g1138]

Try asking your instructor for help next time. It never hurts to ask them to correct or advise you on something, no matter how small the problem may seem. It's hard for us to diagnose the problem without seeing you in your equipment first hand.

You should also ask the instructor or shop if the BC you're using is a back-inflate.
If it is then you're probably inflating it more than you need to, which is causing a larger amount of +buoyancy to be located behind you. The simple solution would be to inflate only enough to get your mouth out of the water. If there's some surface splash, use your snorkel.

Another solution would be to tighten your cumber-bum or waist buckles/straps. If those straps don't snug you into your BC, you'll just get the back of the BC tipping over you and pushing you face down.

Even if the BC is not a back-inflate you should always keep with this habit. There's no need to ever overinflate at the surface. Most BC's will just ride up on you until they press under your armpits. Unless you have a crotch strap I find it hard for any BC to lift you high up out of the water. So really you just need to inflate enough to keep your mouth above the water.

 

[g1138]

Another thing to note. You don't need to kick to orientate yourself (in a vertical matter) when you're at the surface. Usually keeping your legs bent at the knees (to minimize torque and resistance) and just leaning one way or the other is enough.

If you need to kick to orientate yourself then there's something seriously uneven with your gear. Either too much buoyancy from your BC on one side or too much weighting on one side.

 

[tstormdiver]

I agree. More weight probably needs to be moved further back (trim pockets, if available). If the BC doesn't have trim pockets (non ditchable) they can be bought to go on the cam straps on either side of the cylinder. If the BC is a back inflate, only inflate it enough to float at chin level. I also will lean back against the cylinder, legs bent, as if I were sitting in an easy chair. I am quite relaxed that way, especially when teaching on the surface.

 

[ajduplessis]

It sounds like you over inflate your BC. You should only be floating with your top shoulder line level with the water line, anything more is a waste.

 

[Insta-Gator]

It sounds like you over inflate your BC. You should only be floating with your top shoulder line level with the water line, anything more is a waste.

+1 Agree with ajduplessis. You only need to be high enough in the water to allow you to breath. If you get too high, your center of gravity changes (head + Reg + Valve + part of tank) and the weight will shift. Keep the center of gravity below the water line.

 

[Lee Taylor]

As time passes you will find that 99% of the time a diver is NOT on the surface. I am speaking from a boat divers perspective. The only time it is really necessary to be vertical on the surface is to give the A-Okay signal upon entering the water, after that you can stay under the surface until climbing the ladder.

The reason I personally like the back inflation BC's is that they hold one in the face down position. I like that because I spend most of my time on the bottom, on shipwrecks, and on reefs.

 

[DivemasterDennis]

I think g1138 is spot on. You describe a situation I had with a weight integrated back inflating bcd when I was a new diver. The primary reason for your problem is that you are using a back inflate bcd. If their are weight pockets in the back, put 4 lbs back there. ( Don't put any more, as you cannot quickly "ditch" the weights in those pockets). If the bcd is not weight integrated, put the weight on your belt so that some is in the middle of your back, and some on each side behind your hip bone. That will help some, but not totally. If you still have an issue, I found I could lay back on the surface to avoid the forward tipping. With time I got used to that equipment.
( though I have been through several sets since then) I will say that beneath the surface I really like the back inflate bcd, but I have bought all jacket style bcd's after that first back inflate one.
DivemasterDennis

 

[TSandM]

If you truly cannot stay upright, then something is wrong with your weighting, the weight distribution, or the fit of your BC.

To begin with, if the BC is not snug around your middle, it will ride up over your shoulders, putting your body lower in the water, and a big air-filled balloon behind you. Not a recipe for floating comfortably! (This is the reason why I love crotch straps on BCs -- they prevent this.)

If you are overweighted, you will be very negative at the surface, which means you have to have a LOT of air in the BC to float at all. That shouldn't be necessary. You should be, at the beginning of the dive, at most about five pounds negative, and you add the five or so pounds of your head (which has to be lifted out of the water) and that's still well below the lift capacity of most BC bladders. If you're having to fill the thing to float, look at your weighting.

And finally, a lot of folks put their weights as far forward as they can, to try to create a "keel" to help counterbalance the tank. This will, of course, result in a tendency for you to pitch forward on the surface. Putting some weight behind you (like camband pocket weights, or using back trim pockets if your BC has them) will help defeat this.