How to dive without a BC, what is a technique for good buoyancy during the dive?

[Frosty]

Ok guys someone has to say it--Figger best be me before those that really believe it pipe up.
NO NO NO--you can't dive without a BC or you WILL die


---------- Post added August 14th, 2013 at 03:04 PM ----------

Thinking about it --other than floating around waiting for boat pickup OR when I gear up in the water I don't put air in my BC diving tropical.
Ive wondered how you would sling a tank on your back sanz BC. For that matter Ive wondered about the advantage of having the tank underslung for a bit of fun

 

[tracydr]

I do this all the time in our swimming pool with a small pony. I think it holds about 30cu ft and its aluminum. I get my weighting just right and use old Jet type fins. It's not that hard, although I wouldn't care to do it on the reef all the time.

 

[beanojones]

Ive wondered how you would sling a tank on your back sanz BC. For that matter Ive wondered about the advantage of having the tank underslung for a bit of fun

Almost all old hardpacks had no BCD, they were all retrofittable with horse collars.

That plastic plate still inside many jacket style BCDs is the plastic hardplate.

The way to dive without a BCD is to dive an 80 stage rigged, with the neck clipped off the the weight belt. It sort of drifts behind you while you dive. There is a weight belt, and a behind the neck looped reg in your mouth, and that's it.

It makes one understand the appeal of SNUBA, (which is diving without a BCD, and without a tank.)

 

[LeadTurn_SD]

... Back in the days of no BCD, one weighted oneself appropriately for the depth one intended to dive at. Diving on the West Coast (SoCal), wetsuits were usually a must so weighting was important. In terms of adjusting buoyancy as one moved vertically, that was done with our natural BCDs... our lungs. I still use my lungs while diving to make small adjustments in buoyancy.

Bingo!

Dr. Bill, Herman, Eric and Pete have (as always) done a great job summing-up the how-to.

Even with "thickish" wetsuits, you can dive sans-BC. Here in Hawaii in the 1970's we were using 2-piece Beaver Tail suits that were approximately the buoyancy of a contemporary 5mm full suit. No BC's.

We did not crash into any reef.... it really is not terribly hard to maintain decent buoyancy control using lungs alone if you get your weighting "right".

In 2007 I went to the "dark side" and got a BC.... funny, I rarely put any air in it. And the reef is still safe...

Best wishes.

 

[jezellw]

I've made quite a few dives with a back plate and a horse collar and no wetsuit. I don't know how it is today but at least 5 years ago most of the dive operators around Key Largo that I dove with would allow you to do this. I never needed any lead weights and I never put air in the horse collar. Didn't need it. But it was there to appease the dive shop. I'd pick up a couple rocks on the bottom to help control my ascent though.

 

[Texasguy]

Well, I have achieved this little dream of mine today. I dove 80cu in 3mm shorty in a fresh water lake. After a weight check, I put 3lb on my belt and 3lb on a tank (the weight for a tank was held by a single tank strap). Took the tank in my hands and dove in 30 feet max for a little over an hour.

Tank had only one 2nd stage and a pony gauge on the 1st stage. Therefore, one hose.

I was surprised how easy it was to dive. For trim I pushed the tank little forward or backwards, for buoyancy it was just a lung volume. One has to do pretty much the same thing when diving a BC, inhale/exhale to change depth. As tank got lighter, it was easier to push it around, near the end probably it looked like I was ridding a scooter as I pushed the tank ahead of me.

In the middle of the dive I went to the surface, wanted to see how easy it would be to stay afloat. Well, after 2-3 mins I started to get a bit tired as I was constantly finning, so I wouldn't sink with the tank. But, I would have made it to shore without a problem. When I was at the surface, I did stay in one spot, if I was to move, a momentum probably would have helped to stay afloat.

When I dove down again, I have relaxed as at depth it was very simple to be neutral. When the tank became around 500psi, I had no trouble controlling buoyancy.

Overall, I was ecstatic, I felt so free, much more hydrodynamic, in sync with the lake. And I dove solo.

 

[dumpsterDiver]

Well, I have achieved this little dream of mine today. I dove 80cu in 3mm shorty in a fresh water lake. After a weight check, I put 3lb on my belt and 3lb on a tank (the weight for a tank was held by a single tank strap). Took the tank in my hands and dove in 30 feet max for a little over an hour.

Tank had only one 2nd stage and a pony gauge on the 1st stage. Therefore, one hose.

I was surprised how easy it was to dive. For trim I pushed the tank little forward or backwards, for buoyancy it was just a lung volume. One has to do pretty much the same thing when diving a BC, inhale/exhale to change depth. As tank got lighter, it was easier to push it around, near the end probably it looked like I was ridding a scooter as I pushed the tank ahead of me.

In the middle of the dive I went to the surface, wanted to see how easy it would be to stay afloat. Well, after 2-3 mins I started to get a bit tired as I was constantly finning, so I wouldn't sink with the tank. But, I would have made it to shore without a problem. When I was at the surface, I did stay in one spot, if I was to move, a momentum probably would have helped to stay afloat.

When I dove down again, I have relaxed as at depth it was very simple to be neutral. When the tank became around 500psi, I had no trouble controlling buoyancy.

Overall, I was ecstatic, I felt so free, much more hydrodynamic, in sync with the lake. And I dove solo.

Was it sort like this?

Ascending with 13 cu-ft Pony Bottle - YouTube

[video=youtube;r-L9extLDZQ]http://www.youtube.com/watch?v=r-L9extLDZQ&feature=share&list=UUCqEgLaeW7E51-PfqVSG9Sg[/video]

 

[herman]

Based on what you wrote I would stay you were about 2 lbs overweighted. Ideally, you want your complete overall bouyancy to be dead on neutral at half tank which will have you about 2 lbs overweighted at the start of the dive and about 2 under at the end. With a wet suit you can shift the weight a little so you are neutral at 1/2 tank at depth. That may require you to swim down the first 15 feet or so but it will also give you a little extra bouyancy at the surface, esp tward the end of the dive. +/- 2 lbs is easy to deal with with just lung volume and breathing cadence alone. Drop another 2 lbs and I will bet you will have no problems at the surface and remember, the weight is ditchable if you really need the bouyancy.

 

[dumpsterDiver]

That kind of diving might be fun and all, but for me, I don't really feel comfortable doing dives without a BC, particularly with another diver. if an emergency develops and you need to assist another diver, having no BC to assist might compromise your ability to help. But hey, solo, shallow and in a lake, why not?

 

[Texasguy]

Based on what you wrote I would stay you were about 2 lbs overweighted. Ideally, you want your complete overall bouyancy to be dead on neutral at half tank which will have you about 2 lbs overweighted at the start of the dive and about 2 under at the end. With a wet suit you can shift the weight a little so you are neutral at 1/2 tank at depth. That may require you to swim down the first 15 feet or so but it will also give you a little extra bouyancy at the surface, esp tward the end of the dive. +/- 2 lbs is easy to deal with with just lung volume and breathing cadence alone. Drop another 2 lbs and I will bet you will have no problems at the surface and remember, the weight is ditchable if you really need the bouyancy.

At the end of the dive, on a beach, I took off 3lb to see if it is manageable and it was not, I had no way to leave the surface, I was too buoyant. Maybe, just maybe, I was 1lb overweight but not 2.