BCD - Weighting question

[nshon]

Okay after dive #10(I'm at #30 now) I've got my buoyancy sorted, I can maintain depth while breathing normally and inhale/exhale to control ascent/descent quite easily , hover at will and do my 5m/3mins stop without deviating more than 0.3m(according to Suunto dive manager anyway).

Question is, the only time I use my inflator/deflator hose on the BCD is

• Before I enter the water (boat or shore)
• When I descend

I ascend just by inhaling more. This means I don't inflate the BCD until I hit the surface, this can't be right? I keep reading about how you'll become more negatively buoyant as you go deeper but I don't seems to notice.

Last dive profile for reference (dive ended early cause buddy was a hoover).

P/S: How do you guys get the graph off Suunto Dive Manager? I had to use a screen capture software, that can't be right as well? :10:

 

[The Kraken]

Nshon,
Welcome, you have arrived at proper buoyancy control.
If properly weighted, all one should do to initiate an ascent is to take a deeper breath.

Feels great, doesn't it ?!?!?!?!?!?!?!?!??

 

[donacheson]

Okay after dive #10(I'm at #30 now) I've got my buoyancy sorted, I can maintain depth while breathing normally and inhale/exhale to control ascent/descent quite easily , hover at will and do my 5m/3mins stop without deviating more than 0.3m(according to Suunto dive manager anyway).

Question is, the only time I use my inflator/deflator hose on the BCD is

• Before I enter the water (boat or shore)
• When I descend

I ascend just by inhaling more. This means I don't inflate the BCD until I hit the surface, this can't be right? I keep reading about how you'll become more negatively buoyant as you go deeper but I don't seems to notice.

...

As long as you can remain neutral throughout the dive, you're fine.

For most of us, air is needed in the BC at the beginning of a dive because (1) the tank is full of air and weighs 5 or 6 pounds more when full than empty and (2) exposure suit compression accentuated by the normal profile of deep early, shallow late in the dive.

However, if you can compensate for these two factors with your lungs alone while breathing easily, great!

 

[jonnythan]

You become more negative as you descend, yes, and that's why you inflate when you descend. You're doing everything right.

That's a perfect profile, btw.

 

[Divemastr]

nshon, the graph looks good to me. What part are you having issues with? As the graph is somewhat small to my old eyes, the numbers are not visible, but it appears that you descended at an OK rate and slowly worked your way more shallow. A good profile. You stated: "This means I don't inflate the BCD until I hit the surface, this can't be right? " That would be the right way to do it. Inflation of the BCD during the ascent could lead to a runaway ascent. Becoming more negatively bouyant as you descend is much more noticable if you are wearing a wet suit. Since air in the wet suit becomes compressed and air between the wet suit and your skin is removed as you descend, this decreases your bouyancy. Hope this helps. Larry

 

[nshon]

Thanks all! I arrived without knowing the destination.
:dazzler1:

Hmm, maybe time to get that Nitrox training so I can enjoy liveaboards more.

 

[Charlie99]

You didn't mention how much wetsuit you are wearing, but since you are in Malaysia, it probably isn't much.

The loss of buouancy with depth is caused by wetsuit compression, so if you have a thin wetsuit (<3mm), and don't have excess lead, then you won't have to fiddle with bc inflation much.

 

[Jim Baldwin]

Nshon,

Congratulations not only do you have your buoyancy down you now also understand how to breathe.

I work with Advanced Open Water students and one of the biggest problems I have is getting them to realize that they don't need 8 to 15 pounds to sink in a swimsuit and to breathe deeply and slowly.

Once that hurdle is crossed you can see the amazement when they're diving horizitional simply moving up and down in the water column by breathing. It's like clicking on the light switch. And if you haven't found out yet some people will never get where you are right now.

Your air consumption will now drop if it hasnt' already and will get even better as you refine your diving skills.

When I dive with an 80 AL with a full 3 mil and my plastic bp and wing I don't use any weight and rarely need any air in my BCD at depth. When I use a 95 or 120 steel I will have to add some air to compensate for the added size and weight of the tanks as well as the compression of the wetsuit on deeper dives.

Congrats again and keep diving.

Jim
Louisiana

 

[Randy43068]

are you hinting that it's not good to use lotsa weight to sink, when down to a hundered PSI , press the "bast to the surface button?"

I shouldn't joke about it. Some people actually dive like that. Or at least they call it diving.

Back to the point. I think he needs a download kit for his computer.

Nshon,
Welcome, you have arrived at proper buoyancy control.
If properly weighted, all one should do to initiate an ascent is to take a deeper breath.

Feels great, doesn't it ?!?!?!?!?!?!?!?!??

 

[nshon]

You didn't mention how much wetsuit you are wearing, but since you are in Malaysia, it probably isn't much.

The loss of buouancy with depth is caused by wetsuit compression, so if you have a thin wetsuit (<3mm), and don't have excess lead, then you won't have to fiddle with bc inflation much.

I have a full wetsuit (3mm) but I seldom wear it except for night dives, it just keeps me too warm. Out here, .5mm rashguard is plenty of insulation. No kidding.