Brand new diver...buoyancy control issue or weight?

[Mrs. H.]

I just received my open water certification this past weekend, and I have a quick question.

During the first day, I had no trouble getting to the platform (20', freshwater lake). I would just let air out of my BC and sink. I finished the first day with about 1700psi left in my tank.

Day #2: I go down no problem the first two dives, then on my last dive (which was for fun and to celebrate our passing the open water skills), I just could not seem to get down to the depth I wanted to be at, which was about 25'. I would completely deflate my BC, only to end up with the very top of my head at the water's surface, and the rest of me underwater. When I forced it, I could dive down to my depth, and hold my buddy's hand (my husband), but when I let go, I would float away towards the surface. I started the dive with about 1500psi in my tank.

I have no idea how much weight was in my BC. I put one weight on each side, but I'm not sure how much they weighed...I think 4lbs. each. I know that's lame not to know, and I know our instructors should have taught us to do a weight check, but they didn't, and that's neither here nor there at this point.

Does this sound like a weight issue, or just something I need to practice to be able to control my buoyancy? Can a half empty tank really make you that much more buoyant at the end of the day, and should I be carrying more weight early on to compensate for later dives? I am 5'3", 130 lbs., and I was diving in fresh water in a 3mm shorty, with an 80cu ft. aluminum tank, if any of that matters.

Dh and I will be taking a quick dive trip to a scuba park in a few weeks, and I want to make sure I'm weighted properly so I can dive alongside of him and not holding on to keep from floating away. Thanks in advance for all advice.

 

[Jimmer]

If your instructor had taught you to properly perform a weight check, he would have explained that you should set your weights with an empty tank, because yes, you will get significantly lighter as the tank empties. Chances are you had weighting very close to ideal with a full tank, and that few pounds lighter at a half tank was just too much.

 

[PCBCaptChris]

As I am sure you are aware as you use the contents of your aluminum 80 cylinder, assuming that is what it is, it begins to become positively buoyant. However, a half full tank should be somewhere similar to neutral.

I have seen many a divers that are not truly draining the air out of their BC. Remember air floats to the highest point. If you try to dump somewhere other than the highest point it may not all drain out. Practice getting the air out of you BC from different angles in the water; maybe in shallow water first.

Other than that, not knowing your body type, and what type of buoyant gear you were wearing, I would say a guess of 12 pounds sounds a little more reasonable to wear than 8 pounds...

 

[Mrs. H.]

So what's the solution? Add a few pounds in the beginning and see if it's better at the end of the day, or wait and do a proper weight check when I start to have buoyancy trouble?

We are going to a small scuba park for one thing only: to practice our skills and gain more confidence in a smaller area that is fairly shallow (35' max). We are diving in the Carribean in a few months, and we want to be skilled and competent, so we're heading someplace for a few "practice" runs first. I would much rather learn to weight properly and control my buoyancy in a small lake, than find out that I always crash into the coral or can't stay underwater in the current in Cozumel or Roatan.

 

[Mrs. H.]

I am certain all the air was out of my BC, because I started dumping air out on the surface, and tried several times just to make sure once I finally got underwater. Thanks for the weight recommendation. I will try more next time.

 

[SparticleBrane]

You should be able to hover at ~15ft with no gas (or very little) in your wing at the end of your dive.

 

[PCBCaptChris]

Ultimatly the best thing to do is to do both add more weight AND check at the beginning to make sure it is not over kill. The common saying is be about "three pounds negative" at the begining of the dive. Essentially, you are trying to not float up at 15' on your saftey stop with your less than full tank. It will take a little trial and error to get this just right. On the flip side, you do not want to add to much weight because of the drag thing you mentioned...

 

[Teamcasa]

Overweighting is more common among new divers, but based on your description you are a touch light. Simply add maybe 4lbs and give it another go. Then test this weight at the end of your dive with 500-800 psi in the tank. If it is this right amount of weight you should be able to stay neutral at 15’ with no air in your BC.

If you sink, hand a pound or two off to your buddy and try again. If you float up, have your buddy clip on a pound or two. It helps to have some clip on weights for this exercise.
Make sure you don’t hold your breath, flail your arms or kick to hold the stop, breathe normally in a horizontal position. This will soon become second nature, don’t rush it or get discouraged, diving is supposed to be fun!

 

[Far_X]

Mrs. H., don't forget, in the Caribbean, you will need to add more weight as we are more bouyant in sea water than fresh. And we can't drink the water either.

Eight pounds, 3mm shorty, fresh water - I would say you hadn't completely drained your BC. I can get away with six pounds in the Caribbean and I am a "bit" more than 130lbs.

 

[CaseyJr]

Wow, your post almost describes my scenerio exactly - even down to the going to a scuba park to practice!

We did our OW cert. about 3 wks. ago. I was so frustrated because I couldn't even begin to maintain neutral buoyancy! On the bottom, I floated up. On the top, I sank! There was no in-between unless I was holding on to something. However, my instructors were happy with my weight (10#) and encouraged me to get as much practice time in as I could. [they were unbelievably patient with me]

Since then I've been spending some pool time in scuba gear (minus wetsuit, though I do understand the differences that exposure suit, etc. make) mainly practicing finning (I suck), buoyancy, and just getting comfortable breathing through a regulator. Yesterday I made a breakthrough and not only had more control over my buoyancy, but was able to use my breathing (somewhat) to correct myself!!! I know that doesn't sound like much, but I was so excited! It's a start!

Here are two things I noticed that probably made a difference - duh! I use a rental BC and was sized as "M." That's what I've used since day 1. It seemed like my BC was holding air (shoulders) and not releasing it when I dumped -- so I started going vertical to dump the remaining air. And the 2nd thing is that I tried on a size smaller BC and it fit sooooo much better. Well, that and practice.

Best of luck! I know what you're going through.