Upside Down Turtle - Please don't Laugh!

[Ronniemu]

I am a new diver with a total of 27 dives. My body weight is 145 pounds and I am 5' 6" tall. A back inflated BCD with integrated weights and an 80 cu ft aluminum tank was used for all my dives. After completing my Nitrox course I purchased a HP steel 100 cu ft cylinder to be used for Nitrox. Trying this new tank in my pool I reduced my normal weights from 16 pounds to 10 pounds to allow for the extra weight of the steel tank. I sank and landed in the bottom of my pool on my back. I felt like an upside down turtle. After some difficulty I manage to turn myself in a more appropriate diving position and decided to reduce my lead. I removed two additional pounds and tried it again. Although the amount of weight I was using seemed about right, I had trouble keeping myself from rolling upside down. I have had no difficulty with my aluminum tank on all my previous dives with the exception of getting light when my aluminum tank became near empty. I am very frustrated, I am trying to become a more advanced diver and literally find myself going backwards. Any advice would be greatly appreciated!


Ronnie

 

[MeiLing]

I'm laughing with you not at you!

I just starting diving again after a long hiatus and am using a new BDC (ScubaPro SuperHawk NT) that I bought about the time I stopped diving. The inflation on it is entirely in the back and it feels like a liferaft underneath me. I pretty much feel like a turtle on my back on top of the water! I've only dove it twice so far so I haven't quite gotten used to it!

Good luck and I hope someone has some answers for you!

 

[DennisW]

You are probably still overweighted, but you will get that right after some experience. I think some diving with the AL80 first then some shallow dives with the steel 100 to get used to it. I am 5'9", 180lbs and use 12 lbs with a 5mm full wet suit and an AL80. However, everyone is different and the weight I use may not be the weight you use, but at 5'6" and 145, I will bet you are overweighted by quite a bit with 16 lbs.

 

[Ann Marie]

What exposure suit are you wearing in the pool? Do a buoyancy check, you may not need all the weight you have on.

Once you get the weight down, play with the placement of the weights. If you are falling backwards, put more weight in the front pockets and less in the rear pockets. When I work in the pool, I have no weight in my non-ditchable weight pockets, if I use weight I'll put it in the front (or ditchable) weight pockets.

If you put all of the gear on that you'll wear in the ocean and do a buoyancy check in the pool, you will probably need only 4 more pounds to make up the difference for the salt water.

 

[Ronniemu]

What exposure suit are you wearing in the pool? Do a buoyancy check, you may not need all the weight you have on.

Once you get the weight down, play with the placement of the weights. If you are falling backwards, put more weight in the front pockets and less in the rear pockets. When I work in the pool, I have no weight in my non-ditchable weight pockets, if I use weight I'll put it in the front (or ditchable) weight pockets.

If you put all of the gear on that you'll wear in the ocean and do a buoyancy check in the pool, you will probably need only 4 more pounds to make up the difference for the salt water.

When I dive in a quarry with my 80 Aluminum tank I normally use 14 pounds of weights using a 5 mil suit. I have very little or no air in my BCD. With this new steel tank I went down to 8 pounds and still am having trouble. My body starts rolling sideways and then I landed on my back. I will try again over the weekend.

Thanks for your ideas and assistance, Ronnie

 

[Ronniemu]

I'm laughing with you not at you!

I just starting diving again after a long hiatus and am using a new BDC (ScubaPro SuperHawk NT) that I bought about the time I stopped diving. The inflation on it is entirely in the back and it feels like a liferaft underneath me. I pretty much feel like a turtle on my back on top of the water! I've only dove it twice so far so I haven't quite gotten used to it!

Good luck and I hope someone has some answers for you!

Thanks, we will laugh together

 

[rockjock3]

Weight trimming and moving it around (yes, you might even have to add a little) towards your front can balance out the load a little. Fact is if you have a lot of negative weight on your back and none on your front it is going to be a constant fight to keep your proper orientation.

This is where a BP/w helps. The bladder actually comes up around (not all the way) the sides of tank and helps to lower the center of gravity of you and the tank, in relation to the buoyancy.. A back-inflate bc puts the buoyancy between your back and the tank, so if you weigh less negative in the water than your tank your bc will act as the pivot point for you and your tank to switch places.

 

[Teamcasa]

A dozen factors enter in but I’ll assume you have the basics down.
When switching to the HP100, a fine tank I might add, reducing your weight by 6-8lbs is a good place to start.
As for the turtle factor, you said your BC was a back inflate and you use the integrated weight pockets. Fine.
One contributing factor is BC fit. Supporting the weight of the new tank and lead, your BC needs to fit right and tight. A slight puff of air in the BC will also turn you over pretty quick!

My lovely bride had the same problem when she switched to a HP80. The solution for her was to stop using the integrated pockets and started using a weight belt. The lead is more secure and with a belt you can move the lead around to improve your trim.


Dave

 

[Ann Marie]

Good post Dave. I also see so many people wearing BCs that are too big for them. They fit it like a t-shirt, not that snug-it's-hugging-me fit.

 

[hudson]

I've lost count of the number of hours I spent moving my weight around.

If you are always getting rolled to the same side before you go belly up, then you have to shift some of your weight to the other side. Shift till you feel you are in an unstable equilibrium.

Also if you end up feet down when motionless, moving the tank or some weight up top will help a lot.