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

[Texasguy]

My buoyancy and trim are getting better. I want to try something (wanted to do it for a long time already):

I usually dive steel but I have one aluminum 80cu catalina tank. I was thinking of diving where it is shallow with just a tank in my hands, no BC. I bet it would be an ultimate test of buoyancy.

Many years ago before BCs came to be popular, people would strap a tank to their harness and jump in. Thus, I am asking those pioneers. What was a method of weighting yourself and a tank?

I was thinking, give a tank as much weight so it would be neutral when near empty. Give yourself enough weight where you sink without air but rise with a full breath.

Now to the part of actual diving. Without BC, I believe, it would be harder to maintain buoyancy. Are there any tips and tricks?

 

[The Chairman]

This is not really a test of buoyancy. i was sold my first pair of fins back in 1969. I was told that I would be able to kick the crap out of the reef without harming the fin. I dove a small steel tank and did exactly that. Most of the divers back then could care less about the reef. Yeah, there are a few revisionists who claim that neutral buoyancy was paramount back then but it really wasn't.

Trim and buoyancy are a balancing act. Your breathing pattern is a part of that act is your gear. Work on the gear the way you dive it now. If you can hold depth and trim for five minutes with your eyes closed, you have reached nirvana.

 

[tempoffroad]

I have tanken my stage al. 80 or even 40 and just grabbed it threw a reg set on it and jumped I'm and done shallow dives. I have not had a problem with trim but it feels awefull wierd to me. On my 80 I have not dove with it below half tank but woild imagine I would get a little lite if I did.

 

[sphyrnidus]

Really back then we either swam or sat down (waiting for prey to shoot). Bouyancy was not part of the package. And yes we went up and down due to breathing, but when not swimming we just sank

 

[Skittl1321]

I was told that I would be able to kick the crap out of the reef without harming the fin.

It's nice to know times have changed!

 

[AfterDark]

The 1st thing I always needed to know was how deep I'd be diving. I would usually start out w/positive buoyancy because I'd weighted myself for the target depth. Then either fight for depth by kicking hard, pulling myself down the anchor line, or using weights that I'd leave on the bottom, often letting it go before I got to the bottom. A large rock worked well. At depth I'd be close to neutral buoyancy but not always, sinking slowly when motionless was good enough.

The ascent was done without the rock SS were not SOP back then. So a slow controlled ascent...mostly, the last 10' or so there was no stopping me. Most of my diving in the early days were shore dives so holding on to the bottom and crawling into the shallows was another option.

I eventually got a small grey Navy UDT vest. It had an oral inflator like SMBs have. I was able to add air and vent it as needed. Venting was tricky but doable.

So that's how one old bold diver did it.

 

[Rich Keller]

You need to get your lead just right, the amount and position. You can start by wearing all the gear you will be using on the dive with a tank at 500psi and then find out how much weight you need to be neutral at the surface. You want to be in the vertical position with your head tilted back so only your face is out of the water. In this position you should float with a full breath and sink when you exhale. If you only take half breaths and your face never dips below the water you are where you want to be with the amount. Positioning is going to be up to you as to what works best but you should have all or a large part of that weight on a belt rather then integrated so you can dump weight quickly in an emergency. The next thing you need to know is the weight difference between your tank at 500psi and full, this site will give you that info for the most commonly used tanks. Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan From there it will be your preference as to how heavy you want to be at the bottom at the start of your dive. You could go with the original amount of weight you came up with at 500psi or split the difference by removing a little weight so you are not that heavy at the start and a little light at the end. Just swimming forward will counter act the effect of being + or - a couple of pounds. Suit compression will be harder to calculate but for a shallow water dive it will not be too great. I use this technic even when using a BCD so I will be less dependent on it if it fails and I can use a smaller more streamlined BCD.

 

[Texasguy]

So, I guess, in the beginning of the dive one would be more overweight because of the tank. Thus, more finning would be needed not to sink, deeper breaths would be taken to give yourself more buoyancy.

Catalina 80cu is evidently -1.8lb when full and +4lb when empty. I guess 2 or 3lb weight strapped to the tank would do it?

 

[doctormike]

 

[paulw]

It sounds like you are talking about something like monkey diving monkey-diving.com - Home