buoyancy & BC

[fncrow]

Quick question about buoyancy and inflating your BC while diving....

First, im OW certified and only have 6 dives (including the 4 course dives). On all 6 dives i wore a 0.5mm skin, was in salt water, used an 8 litre aluminium tank and had 3kg on my weight belt and I weight 170lbs.

In class, and in every post i've read on the subject and in youtube videos about becoming naturally buoyant they teach that when you reach the bottom and or planned depth to add air to your BC until you reach natural buoyancy right? At least thats what i took out of my OW course and stuff ive read.

So my question is, i noticed when i was diving on my 6 dives that i never needed to add air to my BC. i was able to maintain my depth and ascend/descend all with my breathing. Is this good or bad? If im able to do it should i do it or should i use my BC? By being able to do this am i not weighted right? By doing this am i using more air than i would if i relied on my BC?

Like i said every article i read on achieving natural buoyancy and every video i watch talks about putting air into your BC thats why im wondering if im doing something wrong.


Anyways, awesome site! I literally spend most of my work hours reading every thread lol.

- Joe

 

[fisheater]

Your buoyancy compensator is used to compensate for the loss of buoyancy at depth from the compression of your exposure suit.

If you only have a dive skin, there's almost nothing to compensate for.


Sent from my iPhone using Tapatalk

 

[gcbryan]

You're diving in warm waters with no exposure suit (to speak of) no problem as long as you are able to stay in one place without kicking.

If you dive in colder waters with an exposure suit that will compress with depth then you may need air in your BC.

(fisheater beat me to the keyboard)

 

[remmy137]

Question: Are you having to add ANY air to or releasing ANY air from your BC???

Normally you have to let air out of your BC in order decend. Once you get to your desired depth you normally have to add a little bit of air to gain your "neutral buoyancy". At this point is when you use your breathing to control your buoyancy. When you take a breath in you should rise and when you exhale you should decend. This is what you are looking for because it will allow you to glide over most objects without waisting your air via BC adjustments.

 

[fncrow]

Question: Are you having to add ANY air to or releasing ANY air from your BC???

Normally you have to let air out of your BC in order decend. Once you get to your desired depth you normally have to add a little bit of air to gain your "neutral buoyancy". At this point is when you use your breathing to control your buoyancy. When you take a breath in you should rise and when you exhale you should decend. This is what you are looking for because it will allow you to glide over most objects without waisting your air via BC adjustments.

The only time air in in my BC was on the surface. I let it all out to descend and never put any back in till im back at the surface.

I had no buoyancy issues doing this, if i wanted to go down i went down if i wanted to go up i went up if i wanted to stay level i stayed level. Im just wondering though if maybe i was using more air or something doing it this way than if i would use my BC to achieve natural buoyancy. Because everything i watch and read says use your BC which makes me think im doing something wrong by not using it.

 

[knowone]

Best you ask your boss to find threads on volume in bcds, he
may be smart enough but in your case probably not so much

 

[Spork]

The weights also compensates for the gas you use on the dive. An empty tank is lighter than a full tank and in order to make a safety-stop at 10ft (3 meters) you should need some weights that will make you negative at the beginning of the dive without gas in your BC.

Not using the BC (or using it less frequently) will lower gas consumption during dive. A more experienced diver will use less gas, not only for being more relaxed during dives, but also because of better handling of buoyancy.

 

[Kilili]

You're doing fine. I normally add air only on surface, dump it all when I go down.

Most new divers tend to overweighted, and this accounts for much of the need to add air.

The 80 cu ft of air in tank weighs about 6.4 lbs, and you need to be able to cope with that as you use it. If you can manage with minimal BC adjustment, that's good. Things are different with 5-7 mm suits, and suit compression is a big factor.

 

[gcbryan]

The only time air in in my BC was on the surface. I let it all out to descend and never put any back in till im back at the surface.

I had no buoyancy issues doing this, if i wanted to go down i went down if i wanted to go up i went up if i wanted to stay level i stayed level. Im just wondering though if maybe i was using more air or something doing it this way than if i would use my BC to achieve natural buoyancy. Because everything i watch and read says use your BC which makes me think im doing something wrong by not using it.

If you can hover just above the bottom without kicking and if you can do the same at your safety stop at the end of the dive you are correctly weighted (with 500 psi in your tank).

If you are correctly weighted and don't need any air in your BC you are fine. You are diving in warm waters where you don't have an exposure suit that is compressing. If you are using an aluminum 80 (rather than a larger tank) your lungs can probably handle that 6 lb swing.

 

[fncrow]

awesome, thanks guys