weight at depth

[Rhino1701]

Hi im just new to this game and i just started my advanced open water on the weekend and did the deep and wreck dives. when i did the deep dive i felt overweighted at depth, i really struggled with neutral bouyancy. i assume this is due to the pressure causing loss of bouyancy to my wet suit.
i have read all of bettyrubbles post on weighting/breath control and have been practising this, i check my bouyancy at the end of each dive and with 50 bar in the tank and a lung full of air i can sit at eye level in the water. also while under water i can use my breathing to raise or lower myself in the water without filling my bcd but i had to add air during this dive and at this earlier stage use of air is important to me i am only lasting about 35 mins underwater.
apart from pratice and more experience is there anything else i should be doing?

 

[Quero]

It's perfectly normal to have to add air to your BCD when you go deep--it doesn't mean you're "overweighted" when that happens. You can inflate your BCD orally with exhaled air rather than using the power inflator if you don't want to pump "virgin" air from your tank straight into your BCD.

 

[WB2GLP]

Try not to get caught up with reducing your air consumption. You will start trying to breath slower and shallower which end up in a headache from increased CO2 levels or worse. Enjoy your dive. If you're still sucking down tanks after 50 to 100 dives, just get a bigger tank.

 

[fnfalman]

It's perfectly normal to have to add air to your BCD when you go deep--it doesn't mean you're "overweighted" when that happens. You can inflate your BCD orally with exhaled air rather than using the power inflator if you don't want to pump "virgin" air from your tank straight into your BCD.

What he said.

 

[TSandM]

This is precisely why you have a BC! In shallow water, or in warm water with minimal exposure protection, you can do almost all of your buoyancy control with your breathing. But in heavy neoprene, and especially deeper, you HAVE to "compensate" for wetsuit compression by using the BC. It's what allows you stay neutral and use your breath for fine maneuvering.

As far as making your tank last longer, take a look at THIS post I wrote a while back. Hope some of these ideas help!

 

[herman]

Hi im just new to this game and i just started my advanced open water on the weekend and did the deep and wreck dives. when i did the deep dive i felt overweighted at depth, i really struggled with neutral bouyancy. i assume this is due to the pressure causing loss of bouyancy to my wet suit.
i have read all of bettyrubbles post on weighting/breath control and have been practising this, i check my bouyancy at the end of each dive and with 50 bar in the tank and a lung full of air i can sit at eye level in the water. also while under water i can use my breathing to raise or lower myself in the water without filling my bcd but i had to add air during this dive and at this earlier stage use of air is important to me i am only lasting about 35 mins underwater.
apart from pratice and more experience is there anything else i should be doing?

This caught my eye, that should be with mid full- half way between full and empty, not full lungs. The average adult male has around 10 to 12 total pounds (4.5-5.5 kilos) of total shift from empty to full lungs. If you do a weight check with full lungs you are starting out somewhere in the 5 to 6 lbs (2.25- 2.75 kilos) overweighted range. Now add that to the extra negative bouyancy of wetsuit compression and yea you will need to add quite a bit of air to your BC. Get your weight check correct and you will find you have an easier time.

 

[boulderjohn]

As people have said already, if you are wearing a lot of neoprene, you have no choice but to add more air than you would like to your BCD to compensate for its compression on a deeper dive. There is nothing you can do about that, unless you take along a "weighter" to whom you can hand your extra weights at depth and from whom you can get them back when you ascend. (I'm kidding, of course.)

On the other hand, there is something you can do to minimize the difficulty this creates.

The big problem most people find when they are in that situation is that the unneeded weight pulls them out of trim (the head to toe balance they need to dive properly). If you have more weight than you need on a weight belt or BCD pockets at the hip level being compensated for by more air in the BCD at chest level, your hips will be pulling you down and your chest will be pulling you up. As a result, you are constantly fighting to keep a good swimming position as you dive.

The solution is to distribute your weights so that not all of it is on the hips. Some divers use a steel back plate to distribute much of it. Some BCD's have additional pockets by the shoulders to move a portion of the weight higher on the body. It is possible to buy what are called trim pockets that can be added to your BCD so that you can add weight up high, usually on the cam band that holds the tank to the BCD.

When I am diving with a single tank now, I use a back plate system with some strategically placed weight pockets. I still own an old ScubaPro Nighthawk, a BCD with trim pockets near the shoulders. I found that with that BCD, I was perfectly balanced if I put the same amount of weight in the shoulder pockets as the waist pockets.

I think that you will be much happier if you experiment with weight distribution on your dives.

 

[eponym]

If you're concerned about the gas you use in your BC during a dive, please don't be.

The amount of gas used in your BC is really quite small in comparison to what you breathe.

Don't hesitate to inflate when necessary. Focusing on that "lost" gas is just one more thing you have to let go of in pursuit of relaxation. The relaxation is what will lower your consumption, and that comes with practice. Eventually you'll develop your own breathing rhythm. Eventually even that will be automatic, not something you focus on.

It's a lot like golf: the best shots are those where you manage to keep your expectations and concerns out of the swing.

Welcome to the sport!


PS. Good advice on trim from Boulderjohn, above!

 

[Rhino1701]

As far as making your tank last longer, take a look at THIS post I wrote a while back. Hope some of these ideas help![/QUOTE]

Thanks for the pointers, I am taking slow and deeper breaths and try to keep movements to a minium, i believe i am horizontal in the water as when i kick i dont move up or down, just straight ahead. I want to do the peak bouyancy to keep practising all of this and get better.
We did have some surge on the weekend, it was fun to float along with it but had to kick five or six times to maintain position when it switched. This wouldn't have helped my air usage I guess.
thanks for the help

---------- Post added April 2nd, 2013 at 11:32 PM ----------

Herman, sorry i thought they meant full lungs, gives me another excuse to get back in the water and check my bouyancy again. Thanks

Boulderjohn, I assume this would be better checked with a buddy to see exactly how out of trim I might be? Would this be worked on in the bouyancy class?

Eponym, isn't that the truth, the further I try to hit the ball the more my slice takes over, relax and let it fly

Thanks again guys and girls for the advice now time to get practicing.

 

[Quero]

We did have some surge on the weekend, it was fun to float along with it but had to kick five or six times to maintain position when it switched. This wouldn't have helped my air usage I guess.

Oh, yeah, you'll burn up air if you fight a surge. Soooo...... don't fight it! In a surge I don't try to maintain position when it's against me and float when it's with me--I let the surge flow over me and carry me a little ways back, and then when it switches I kick while it's carrying me forward. Essentially I go two or three steps forward, one back, two-three forward, one back.