Tank Twisting To The Left

[scott964]

My tank tends to move off-center toward my left side during the dive. I end up adjusting it several times to get the tank centered on my back. Looking for opinions of what could be the cause. I use an older Scuba Pro G250/Mk10 regulator system and a 1996 Zeagle Ranger BC. I'm trying to recall but I think the same thing happened with my previous BC's (not back inflated). I know this may be an obvious question but could my regulator hose be what's causing this to happen? Weight is equal both sides, BC is correct size. The 2nd stage does seem to want to pull out of my mouth a bit. I am not using back mounted weights. I'm thinking i need to upgrade the 1st stage to something with a better swivel but I thought I'd throw it out to everyone here. I've been diving a while but am a new member to this board. From what I've read so far, you guys really know your stuff. Thanks in advance.

 

[idocsteve]

Maybe you swim sideways.

You know, sort of like the side stroke except you're under the water rather than swimming along the surface.

Hey I know it's a long shot but it would explain it.

 

[Scott L]

Sounds like you are not tightening your straps enough...whatever configuration that exists. Could it simply be too big for you?

I hate to sound like a broken record but a move to a BP/wing system will cure all your issues...

 

[halocline]

The swivel won't do anything; you already have one. How do you know the tank is moving to the left on your back? There's only two possibilities, either the tank is moving horizontally in the BC or the BC itself is shifting. The latter is far more likely, in fact I can't imagine tanks straps ever being loose enough to allow the tank to move like that and not fall out.

If you 'think' the tank is moving because your 2nd stage is getting tugged, try a longer hose between the 1st and 2nd stage, and make sure your LP inflator hose is the right length so that it doesn't pull or push the swivel around. I suspect the tank position is fine, you just need to deal with the hose length.

Most divers think that the 1st stage swivel can freely move around when you turn your head, but it can't because the LP hose is also connected to it and that tends to restrict it's movement. If the mouthpiece feels like it's getting pulled out of your mouth when you turn your head left, get a longer hose.

 

[mksmith713]

Try wetting your straps before cinching them down.
Sounds like they're not tight enough.
Wetting them first will help.
Also check and see if there's any stress on your second stage in your mouth.
You could be pulling it with your mouth.
I know..sounds hard to believe but it can happen.
If that's the case, try a little longer hose between 1st and primary 2nd.

 

[flots am]

My tank tends to move off-center toward my left side during the dive. I end up adjusting it several times to get the tank centered on my back. Looking for opinions of what could be the cause. I use an older Scuba Pro G250/Mk10 regulator system and a 1996 Zeagle Ranger BC.

If the tank is moving on the BC, stop down to a SCUBAPRo shop and ask them for a "Super Cinch" strap (the one SP uses on their BCs). It's very popular and they sell it as a separate accessory just for this reason.

It's about $30 and the tank will never move again. It also doesn't require any of that pre-wetting nonsense.

The other possibility is that the tank is fine, and the BC is moving. In this case, it sounds like it's just too loose.

flots.

 

[Crush]

Swivels won't help and they are not the problem.

Your first stage isn't the problem.

You are likely kicking vigorously and your body is wobbling from side-to-side. Your wobbles might be lower on your left side. The tank simply slides off the side. This used to happen to me. There are two solutions to this:

1. You need to cinch down your shoulder straps and possibly the sternum strap. Try tightening them when you are underwater. This assumes that your BC is not too big. I do not believe that your tank is shifting by itself - your whole BC seems to be shifting;
2. Swim more slowly using slow, deliberate kicks, paying attention to your roll. A modified frog kick would be good, if you know how to do it.

If the second stage feels like it is pulling, your hose routing might be incorrect or the hose is too short for you. It could also be that the second stage is heavy but not really pulling.

 

[scott964]

Yes, it is the entire BC that moves, not the tank alone. Sorry I thought I explained it better. Anyway, the BC is a large, I (unfortunately) am a large as well. I do tend to roll a bit when I kick, maybe I simply need to tighten the BC more. As for the regulators, the hose is standard length. It almost seems as if it could be too long. Mattboy, you write "If the mouthpiece feels like it's getting pulled out of your mouth when you turn your head left, get a longer hose." actually it's exactly opposite. The reg feels as if it is being pulled out of my mouth from my right to the left when I turn my head right. Feels okay when turning left. The LP hose seems to be fine, it does not bind or feel as if it is too short.

I have a ScubaPro R190/G2 setup that I had planned to use for a pony bottle. Maybe I'll give it a try. Maybe this will eliminate a few things.


Thanks again.

 

[Jim Lapenta]

Stop using a flutter kick and go to a frog or modified frog.

 

[Crush]

Stop using a flutter kick and go to a frog or modified frog.

Jim, I agree with you 100%. The only problem is that in all likelihood scott964 was never taught the frog or modified frog. I watched the 5th D videos (? help me out here) and tried to emulate them, and failed. Later, taking a cavern course, I managed to somewhat "get it."

scott964 - if you can get someone to demo the modified frog kick for you and give you some pointers, you will find it an invaluable tool in diving, especially close to the bottom. The flutter kick is powerful and efficient at the surface and on descent, but the modified frog is great near the bottom.