Diving Without BCD

[Paladin]

As some of the other members here are aware, I began diving way back in 1965 at the age of eleven. We did not have BCs then and compensated by knowing exactly how much weight to use. First thing I would suggest is to get in a shallow pool with just fins, mask and snorkel. If you are a floater, determine how much weight you need by holding 2 pound weights until you no longer float and slowly sink with your lungs full. If you are a sinker by nature, then you obviously need no weight.

As for me, I need 4 pounds to overcome my natural buoyancy. Using a steel 72 (of which I still own several) and not wearing a wetsuit, I mostly dived without weights as the tank weighed five pounds in the water when full. At 500 psi, the tank weighed about a pound or less, so my natural buoyancy of 4 pounds, subtract 1 pound for the tank gave me 3 pounds of buoyancy and put me nearly neutral at the surface.

I didn't own a wetsuit or BC until 2009, when the rest of my family took up diving. They were trained using them, so I started using them. I still like to dive old school at times, even to using my old DA Aquamaster double hose.

Using a 3mm suit and an AL80 makes it a bit trickier. I first had to determine how much weight I needed to be slightly negatively buoyant (about 1 pound negative) on the surface wearing just the wetsuit, fins, mask and snorkel. This turns out to be about ten pounds for me. An AL80 is just a bit under 2 pounds negative when full and about 3 pounds positive at 500 psi. If I use 12 pounds of lead, I am slightly heavy at the beginning of the dive and around neutral on the surface at the end.

The point is, you have to know more about yourself and your gear if you want to dive without a BC.

 

[mcpowell]

This picture is of my buddy, Wayne, and me back in 1965 or so. You can see two different backpacks. The one I am wearing is almost identical to the one shown in post #7. My buddy's backpack is very similar to the Freedom Plate that @Eric Sedletzky makes today. (Here is where I will insert a shameless plug to be at the top of Eric's list when he makes another run of them) Frankly, if you could get one of Eric's plates, I think it would be perfect for what you want to do. The tanks that we are using are steel 72's. We usually weighted ourselves to be neutral at whatever depth we planned to be. That would mean using a little less weight when deeper in order to compensate for wetsuit compression, but we would have to swim down the first bit. When using the rig in this picture, I don't remember wearing any lead. I don't remember the straps being uncomfortable either; however, at that age we were also bulletproof.

Best of luck.


View attachment 457368

Awesome picture. That trunk is as large as the bed on my F150!

Also, is that frisbee sized disc the first stage? No need for extra weight if it is.

 

[pepperbelly]

As some of the other members here are aware, I began diving way back in 1965 at the age of eleven. We did not have BCs then and compensated by knowing exactly how much weight to use. First thing I would suggest is to get in a shallow pool with just fins, mask and snorkel. If you are a floater, determine how much weight you need by holding 2 pound weights until you no longer float and slowly sink with your lungs full. If you are a sinker by nature, then you obviously need no weight.

As for me, I need 4 pounds to overcome my natural buoyancy. Using a steel 72 (of which I still own several) and not wearing a wetsuit, I mostly dived without weights as the tank weighed five pounds in the water when full. At 500 psi, the tank weighed about a pound or less, so my natural buoyancy of 4 pounds, subtract 1 pound for the tank gave me 3 pounds of buoyancy and put me nearly neutral at the surface.

I didn't own a wetsuit or BC until 2009, when the rest of my family took up diving. They were trained using them, so I started using them. I still like to dive old school at times, even to using my old DA Aquamaster double hose.

Using a 3mm suit and an AL80 makes it a bit trickier. I first had to determine how much weight I needed to be slightly negatively buoyant (about 1 pound negative) on the surface wearing just the wetsuit, fins, mask and snorkel. This turns out to be about ten pounds for me. An AL80 is just a bit under 2 pounds negative when full and about 3 pounds positive at 500 psi. If I use 12 pounds of lead, I am slightly heavy at the beginning of the dive and around neutral on the surface at the end.

The point is, you have to know more about yourself and your gear if you want to dive without a BC.

The last paragraph says it all. There is no way to know what you will need until you test.

 

[TMHeimer]

Agree, but the knowledge on how to dive without a BC resides in the vintage section. Diving BC free discussions in basic typically lead to the "don't do it you are going to die" comments.

With the right setup it's not hard. I find diving with no BC rather enjoyable under the right conditions. Maybe the OP can find a like minded experienced individual in his area to mentor him.

I started no BC in a pool and then to shallow inland lake. I have also done ocean under the right conditions. As long as you have a balanced system without too much buoyancy swing it is pretty easy.

I tend to agree. I think my older brother dived without a BC (digging clams) in the early-mid 60s and I don't recall him having any problems. Though I doubt he even reached as deep as 30 feet from our boat in Long Island Sound. Kinda fuzzy, I was 5-10 years old at the time. There has been no reason for me to look into going BCless, but guess it makes sense if you have long walks to sites.

 

[BRT]

They have a buoyancy swing from use of air... but it just SEEMS like they don't because they remain negative empty, but they are MORE negative full. Also since they hold less gas to begin with using it up is using up less gas, hence less swing. The air weighs something, you breathe it, the weight changes, no matter what tank.
Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan

Yep

 

[Joseb111]

Seems to me the way to train for this would be to start out trying to deal with a completely empty BC. That way you can always abort but develop your sans bladder skills with a back-up.

I learned to dive without a bc this way. I adjusted my weighting over the course of a few dives trying not to inflate, and when I realized that I wasn't touching my inflator hose except to float on the surface, the transition to diving with just a harness was seamless.

Literally. My plastic harness had no seams.

 

[Charles2]

Awesome picture. That trunk is as large as the bed on my F150!

Also, is that frisbee sized disc the first stage? No need for extra weight if it is.

That trunk would get a pretty good sized group into the drive-in movie.

That Frisbee sized disc is the first as well as the second stage. I loved double-hosed regulators with all the bubbles on your back.

 

[boat sju]

sdavo,

I didn't read through all of this so sorry if I'm redundant. I like to dive the way you described in your OP in our local lakes here in Michigan. I'll use a 30 cft pony or a 63. I've learned I like having a snorkel along. Also, we have to tow floats here in the inland lakes so I use a small trailer tire. Nice to have if your weighting isn't quite dialed in.

boat

 

[kablooey]

First thing, I love backpack diving.

I got into backpack diving because of my interest in the early days of scuba from watching Seahunt and the Jacques Cousteau films. Once I started diving that way I quickly found that I liked the minimalism, streamlining, and simplicity of the gear.

Backpack diving is like a crash course in proper weighting. The things I learned about fine-tuning weighting have served me well in all my diving. I’ve never felt at risk using the backpack. I use a fully ditchable weight belt, without which it I would stay buoyant on the surface if need be.

One scenario where I have concern about a backpack is in my ability to control the ascent, and maintain surface buoyancy if I ever need to rescue another diver. For that reason I always inform my dive buddies of that limitation, and get their consent to make the dive with them.

My first dive with a backpack I remember very well. I already had several hundred dives using standard buoyancy systems. Weighting was my biggest concern. Would I sink uncontrollably to the bottom if I got it wrong?

So, the location I chose to make my first attempts was at the easiest shore dive site I knew, which happened to be the Avalon Dive Park on Catalina Island. I also chose as my diving companions two very experienced friends, who agreed to watch me closely. In the end, it all worked out very well. My original weighting calculations were close enough, and the dive went off without a hitch. The truth is, weighting would have to be way way off to result in an uncontrolled decent. From that point on I dived my backpack whenever it was appropriate for the location, conditions, and diving team.

Although most of my diving is with a standard BP/W, I’ve still managed to log about one hundred fifty backpack dives. Most of those dives have been from shore off Southern California, but I’ve also traveled overseas with that set up, including a week of liveaboard wreck diving at Truk.

So, a few of my tips to the OP:
• Make your first backpack dives with strong competent buddies. Also, let them know the limitations on you as a rescuer.
• You will find that on the surface you will sit lower in the water than you may be used to. So, a snorkel becomes a necessary piece of gear.
• You’re from San Diego, so I’m guessing you’ll be wearing a 7mm suit. So, suit compression is going to be a major factor. The deeper you go, the suit crushes and looses buoyancy. Keep that in mind when planning your dive. You may need to go down with slightly less weight if you’re going deep.
• Don't be surprised if you have to fight a little to get under at the start. If you're weighted properly you won't be completely negative until water presure puts a little crush on your suit. If you drop easily, you're overweighted.
• Keep a dive log with your weighting and gear data.
• Some of the So Cal charter boats will not allow backpack diving. So, check on policy before you board, or be prepared with a back-up BCD or BP/W.

Good luck. I hope you enjoy it as much as I do.

 

[Eric Sedletzky]

^^This^^
Couldn’t have described it better.

One thing I will add:
Always wear a weightbelt when back pack diving. Don’t have all your weight on your rig like some like to do with BP/W these days. Make sure you have enough of your overall weight on a separate, single release, ditchable weightbelt so that if you need to dump it to establish a lot of positive buoyancy at the surface (or wherever) you can quickly and easily. This is why lighter aluminum plates or plastic back packs work well. Stainless packs in the 4-5 lb range work too with aluminum tanks, or with thick wetsuits. Put your weightbelt over your crotch strap. Since dumping your weight belt is your number one safety device, make it easy to dump by putting it on last over all other straps.
I weight myself so that I start getting light at 20’ at the end of the dive. I just grab a rock if I feel like it, or if I’m nowhere near my NDL and never went that deep I just come up. No stop.
Back pack diving is really good for quick shallow beach or boat dives where you plan to cover a lot of ground and need a lot of athetisism and streamlining in your gear to minimize drag. Hunters like the configuration, but so do people who just like to experience the freedom of not having to constantly fiddle with an inflator and dump valves and like to glide around unencumbered. Not until you dive with just a tank do you realize just how much drag BC’s really create. Drysuits create a lot of drag too. A drysuit AND a big fluffy BC is like trying to drag a parachute through the water.