BCD's Demystified

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Dive Right In Scuba 2

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You’ve been diving for a while and either own a buoyancy control device(BCD) or have exhausted all of your possible rental options and are ready for a new rig. Where do you start? Of course as you begin your search for the perfect BCD for you, confusion quickly mounts. With the many options of BCD’s on the market, they can be simplified into three main categories with each possessing their own attributes. So, with that in mind let’s talk about the three main categories and attributes of each.
First, let’s discuss the most widely seen BCD out there...the jacket style. There’s a reason you see these type of BCD’s in rental fleets at just about any dive operation out there, and that reason is simplicity. Simple in the sense that you can strap on a single tank, hook up the inflator, tug on a few adjustment straps and dive! Jacket BCDs can be inexpensive, although some models can be higher end. So with that in mind, they are often the logical choice for the new diver. However, the weaknesses of jacket style BCD’s lie in the fact that they cannot grow with your diving as they are only designed to accept a single tank and usually don’t possess any modular characteristics. If you’re looking for a solution that can be adjusted as your diving grows, read on.
The BCD that many divers see as a good “middle ground” is the back inflate BCD. While many are simple like a jacket style BCD with a bladder that inflates behind you, many are modular and can be adjusted and altered to grow with your diving. Some of these consist of units manufactured by Dive Rite and Hollis. These units feature the ability to change bladders to adjust lift for larger and multiple cylinder use, as well as bolt on accessories like butt plates to add the ability to carry accessories needed for technical and specialty diving. While back inflate BCD’s can be a great option, there are some who are looking for these features in a more streamlined package.
The final option we will discuss is the backplate and wing BCD, or BP/Wfor short. These units were once thought to be only for the hardcore diver but many are finding them to be excellent options for the novice diver as well, mainly for their simplicity and infinite adjustment and modular characteristics. Like many back inflate BCD’s tthe BP/W can be adjusted for type and complexity of diving but accomplishes it in a simpler and more minimalistic fashion. The BP/W begins with a hard backplate, simple 2” webbing harness and an air cell and can be altered in a number of ways to adjust to your diving style.
So there you have it, if you simply place BCD’s into these three main categories and determine your needs, your search will be a little less daunting, and remember that the team at DRIS is here to help!
 
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I'm still mystified by one thing.

I had two days of pool work recently as part of my OW certification. The first day in the pool, I had serious difficulty because I could not float vertically on the surface. Well, it was very difficult. My BCD was trying hard to flip me on my face. When I asked an instructor about it they said they needed to switch me to a back-inflate BCD. I guess my first one was a jacket style.

This seems counter-intuitive to me. It seems like a back-inflate would have MORE tendency to flip me on my face at the surface rather than less.

The back-inflate I had the next day was way better. But, I attribute that to the weight pockets on the tank band where I moved a good percentage of my weights. But, since those weight pockets were just ones that had belt loops and slipped on over the tank band, it seems like I could have done the same thing with a jacket style.

So, why did two or three different instructors that I asked about my problem on Day 1 all respond with "we need to switch you to a back-inflate BCD"? It seems like the more correct response would have been "we need to put some weight pockets on your back and move some weight around to there."
 
You comment on growing with you as a goal, and for some this is a significant thing (but many more will likely never push the envelope). However, better than that is "sized to fit you". If you are outside the design mannequin (things like: broader shoulders, pear shape, long-ish torso, chesty, or even the complete opposites of these), a proper fit just won't happen. This then adds to challenges.

Walk a mile in ill fitting shoes. Can it be done? Sure. Is it a really good idea? NO!

All things considered, make sure it fits!!!!!
 
Stabilizing Jacket!

I'm still mystified by one thing.

I had two days of pool work recently as part of my OW certification. The first day in the pool, I had serious difficulty because I could not float vertically on the surface. Well, it was very difficult. My BCD was trying hard to flip me on my face. When I asked an instructor about it they said they needed to switch me to a back-inflate BCD. I guess my first one was a jacket style.

This seems counter-intuitive to me. It seems like a back-inflate would have MORE tendency to flip me on my face at the surface rather than less.

The back-inflate I had the next day was way better. But, I attribute that to the weight pockets on the tank band where I moved a good percentage of my weights. But, since those weight pockets were just ones that had belt loops and slipped on over the tank band, it seems like I could have done the same thing with a jacket style.

So, why did two or three different instructors that I asked about my problem on Day 1 all respond with "we need to switch you to a back-inflate BCD"? It seems like the more correct response would have been "we need to put some weight pockets on your back and move some weight around to there."
Actually, the correct answer is to use a Stabilizing Jacket sp-classic-2013.jpg

It is the only B.C. that will keep you floating face-up on the surface when it is fully inflated, except for the old horse collar B.C.'s. The Stab. jacket acts as a life jacket on the surface and U/W allows the small air bubble to travel freely.
 
So, why did two or three different instructors that I asked about my problem on Day 1 all respond with "we need to switch you to a back-inflate BCD"?

Do they all work for the same shop? Maybe they're trying to sell back-inflate BCDs? I think your logic is sound--it seems counter-intuitive that a BCD that puts all of the buoyancy on a diver's back would exert LESS of a pitch-forward force than a BCD that puts all or most of the buoyancy on the diver's flanks. Isn't the tendency to pitch a diver forward an often-heard complaint about BP/Ws? In any event, as you've discovered, proper distribution of weights and inflating no more than necessary at the surface is the key to avoid pitching forward on the surface.
 
Yes, they all work for the same shop. But, the shop provided all the equipment for the class. And they sell everything from jacket style to back inflate to BP/W setups, so I don't think the response was sales-motivated.

Anyway, thanks for the confirmation on my line of thought.
 
Actually, the correct answer is to use a Stabilizing Jacket View attachment 198720

It is the only B.C. that will keep you floating face-up on the surface when it is fully inflated, except for the old horse collar B.C.'s. The Stab. jacket acts as a life jacket on the surface and U/W allows the small air bubble to travel freely.

Tried one of those two seasons ago. It was the most uncomfortable, confining, unsafe feeling BC I have ever had on. The pockets were useless. The chest too cluttered and would have been a pain to cut me out of if necessary. The weight pockets did not release smoothly in every direction. D rings were poorly positioned and it had one of those elephant trunk like AIR II's on it. Compared to my BPW and the Zeagle Express Tech I had it was a disconcerting feeling to even have it on in the water. Did three dives with it and that was enough. No crotch strap and that was a problem as well. On the surface it kept wanting to ride up.
 
And they sell everything from jacket style to back inflate to BP/W setups, so I don't think the response was sales-motivated.
Could depend on their profit margin with each mfr.

Most people start in jackets since they're one size fits all so optimal for your shops rental fleet. Some keep them since they're comfortable with better versions of what they learned with. Other divers switch to something back-inflate at some point. I actually know of one person in my circle of 50ish diving acquaintances who actually switched back. But she's kind of short so I think she liked being taller in the water - we dive in some dicey conditions occasionally. So maybe the instructors who suggested you switch the first day were just going on historical recommendations that they'd made 100's of times previously.

Fundamentally a jacket BCD will keep you higher in the water when fully inflated than a back inflate BCD with the same lift. This is because of the location of the air cell.

As you already figured out, you can trim so you float vertically in a back-inflate by correct weighting. I use 60/40 F/R typically although 70/30 is optimal when I can rent 1lb. weights.

A back inflate BCD or BP/W inherently make it easier to float horizontally while actually diving. For me that's the more important part...
 
Tried one of those two seasons ago. It was the most uncomfortable, confining, unsafe feeling BC I have ever had on. The pockets were useless. The chest too cluttered and would have been a pain to cut me out of if necessary. The weight pockets did not release smoothly in every direction. D rings were poorly positioned and it had one of those elephant trunk like AIR II's on it. Compared to my BPW and the Zeagle Express Tech I had it was a disconcerting feeling to even have it on in the water. Did three dives with it and that was enough. No crotch strap and that was a problem as well. On the surface it kept wanting to ride up.

Sure, that's all true. But he sells them, so they must be awesome! :D
 
Tried one of those two seasons ago. It was the most uncomfortable, confining, unsafe feeling BC I have ever had on. The pockets were useless. The chest too cluttered and would have been a pain to cut me out of if necessary. The weight pockets did not release smoothly in every direction. D rings were poorly positioned and it had one of those elephant trunk like AIR II's on it. Compared to my BPW and the Zeagle Express Tech I had it was a disconcerting feeling to even have it on in the water. Did three dives with it and that was enough. No crotch strap and that was a problem as well. On the surface it kept wanting to ride up.
Jim, We're talking the Beave here. He has a giant "S" branded on his forehead. What do you expect?
 

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