Question buoyancy issues during 'open water' training

[rx7diver]

A full cylinder with cylinder valve and two first stages are negatively buoyant, and will want to sink below your (wetsuited) body usually. Your weights on your weight belt are in front of your hips, which is the "correct" way, I think. (At least, this is how I wear mine.)

I think that if you spend a bit more time, you will get used to keeping your cylinder above your body, and you will wonder why it ever seemed difficult.

One other thing: using a cylinder that has a big diameter, and/or using a single tank adapter (STA) on a doubles back plate will exacerbate that tendency for you to turn turtle.

Good luck.

ETA: Make sure you are NOT over-weighted. If you're diving with a lot of air in your BC, then the shifting bubble can exacerbate the problem, too.

rx7diver

 

[RobPNW]

As others have said, check your BCD sizing. If you're at the surface and it tends to ride up on you, it's too loose or it's too big. That will cause the tank to shift too much.

 

[J. Shaun]

From fellow new diver.

I left the pool cessions thinking I was terrible- Crashing into the bottom, shooting up for no reason…. Then I did my cert dives and still thought I was better but still terrible. It was pretty rough and I didn’t realize my lack of experience was the issue. The next two days were calm, clear and miraculously I was neutral, traveling nervously through beginner level swim-throughs!

You’ll be fine!!! The time between training cessions is definitely making it more difficult. When you get a few days in a row, with hours in the water, you’ll have the aha moment.

You got this!!!

 

[Aloha Joe]

Kidding aside, it's great you want to learn but you'll work stuff like this out with experience. It's also good experience having things go 'not quite right' especially when there's an instructor around. Have fun and enjoy the process!

 

[Nemrod]

Hello,

I am currently undertaking Ocean Diver training with BSAC and have had 2 pool sessions so far. After achieving neutral buoyancy, I immediately begin sinking on my right hand side, and have flipped over onto my back underwater twice. I'm quite frustrated with this and am looking for a way to fix it.

Some possible causes (could be completely wrong):

- Renting a reg set and my primary 2nd stage has one vent blocked (on the left side) by something that looks like a rock?
- Being completely relaxed underwater and not consciously engaging back+core muscles

My next pool session is tomorrow, looking for any tips I could try to fix this issue!

The rest of it, too many variable to entertain and sounds like typical newbie problems that a little water time will quickly cure and maybe some equipment changes. But, there probably should not be a rock or something that looks like a rock inside your regulator second stage or the exhaust tee.

You are rolling upside down because you likely have a heavy and very negative, especially when full, steel tank on your back and your body is buoyant as is your wetsuit or exposure garment so naturally they want to swap positions and roll you over. Neutral buoyancy/buoyancy control is a skill, neutral trim is a skill, they are related but are separate skills to be learned.

 

[Kendall Raine]

A full cylinder with cylinder valve and two first stages are negatively buoyant, and will want to sink below your (wetsuited) body usually. Your weights on your weight belt are in front of your hips, which is the "correct" way, I think. (At least, this is how I wear mine.)

I think that if you spend a bit more time, you will get used to keeping your cylinder above your body, and you will wonder why it ever seemed difficult.

One other thing: using a cylinder that has a big diameter, and/or using a single tank adapter (STA) on a doubles back plate will exacerbate that tendency for you to turn turtle.

Good luck.

ETA: Make sure you are NOT over-weighted. If you're diving with a lot of air in your BC, then the shifting bubble can exacerbate the problem, too.

rx7diver

The OP is doing pool sessions in a basic (Ocean Diver) course using rented gear. What made you think the instructor had the OP in a BP/W with a dual value outlet (two first stages) on a "big diameter" cylinder? What is a doubles back plate v any other kind of back plate?

 

[rx7diver]

The OP is doing pool sessions in a basic (Ocean Diver) course using rented gear. What made you think the instructor had the OP in a BP/W with a dual value outlet (two first stages) on a "big diameter" cylinder? What is a doubles back plate v any other kind of back plate?

@Kendall Raine,

No one here is thinking that "the instructor had the OP in a BP/W." At least, I am not thinking this, and did not mean to imply this in my post. I was simply attempting to use a couple of examples to illustrate this turtle-ing issue--you know: If you're using a heavy, 8" cylinder, you're likely to have more challenges (with turtle-ing) than if you're using a 6.8" old-school steel 72, for example. If you're using a single cylinder mounted on a doubles back plate with a single-tank adapter, you're likely to have more challenges than if you're using a singles plate like a Freedom Plate or a VDH Classic DH Plate or an old-school plastic backpack, for example. If you're using a single cylinder configuration that puts a lot of brass up top (like when using a Y-valve or H-valve with two first stages), you're likely to have more challenges. Etc.

Make sense?

rx7diver

 

[Kendall Raine]

doubles back plate

What's that?

 

[Kendall Raine]

What's that?

@Kendall Raine,

No one here is thinking that "the instructor had the OP in a BP/W." At least, I am not thinking this, and did not mean to imply this in my post. I was simply attempting to use a couple of examples to illustrate this turtle-ing issue--you know: If you're using a heavy, 8" cylinder, you're likely to have more challenges (with turtle-ing) than if you're using a 6.8" old-school steel 72, for example. If you're using a single cylinder mounted on a doubles back plate with a single-tank adapter, you're likely to have more challenges than if you're using a singles plate like a Freedom Plate or a VDH Classic DH Plate or an old-school plastic backpack, for example. If you're using a single cylinder configuration that puts a lot of brass up top (like when using a Y-valve or H-valve with two first stages), you're likely to have more challenges. Etc.

Make sense?

rx7diver

I must have been living under a rock for the last twenty years because, before thinking about (and looking into) what you were saying, I had not focused on the fact people had modernized/metalized the original plastic back pack and always thought a plate was a plate having used a standard (or, in your words, a "doubles") plate (ABS, stainless and aluminum) for both singles and doubles without ever feeling like I needed to do more than change wings. Since it has no channel, I can see where the tank rides closer to the back (lowers center of gravity) with a back pack (e.g. Freedom) design v a traditional plate. Perhaps this does perceptibly reduce roll. Dunno. I'll need to try it sometime.