Better off with bp/w???

[danaero]

Big advantage BP/W has over jacket is that it puts the weight nearer to your center of buoyancy (lungs) versus having the weight around your waist which can create a seahorse effect. I have found swimming horizontal is easier with a plate/wing.

 

[tbone1004]

I disagree, buoyancy control has little to do with the BC but rather it is a matter of understanding buoyancy control. A BP may help some with better trim and any back inflate will help keep it in place but it is not the panacea that so many think it is. A well trained diver who understands buoyancy control can dive and have spot on control with any BC...or no BC at all for that matter. Don't buy a BP thinking it will cure all your problems, it will not. Learning to properly control your buoyancy through proper weighting, proper trim and breath control from someone who actually understands them is the only way that you will improve your buoyancy control. Finding that person is the hard part, many instructors I see don't have a clue much less actually teach buoyancy control. I dive and prefer back inflates so I am not trashing the BP but thinking it will cure buoyancy problems is avoiding the real issue. Don't try to cover up poor technique with equipment, it does not work.

Herman, your solution is no BC at all which is an important skill to learn, but the crotch strap on any rig will really do the trick and the BP/W's are a lot more forgiving to being "apple shaped" than the jackets that if you aren't contoured they way they are, tend to bunch up and you have to tighten them down way too tight.

 

[george_austin]

Practice diving with no wing or BC vest, jacket etc., after you've been able to get yourself properly weighted for the equipment ( tank and wetsuit ) you're using. You'll then know that you are proficient in basic scuba buoyancy skill. You'll realize that your lungs are your BC device.

Here on the boats in southern California, I am seeing more and more people exiting the gate with a 7mm full suit, hood, gloves boots, steel tank, backplate and harness 8lbs of lead and no BC.

It's not a big deal. Just takes practice and a willingness to learn and being open minded. Remember when you got your C-card and everyone said to you: "This is your learners permit" ? - This is what they meant.
If you're light, pick up a rock, if you're a little heavy, deal with it and take off a pound or two before the next dive. That's "learning"

However, if you don't like diving without a BC, wear one! It's your choice.
For many years I dived with a BC and one day I'm swimming around underwater thinking to myself, " when was the last time you put air in this thing?" - couldn't remember so I put it in the dive locker and forgot about it.
Caveat: I am a sport diver, a recreational diver and I don't carry or do dives requiring me to bring a half dozen gas bottles or a ton of gadgets to do "technical" - it's just me and maybe a spear gun or a camera. Have fun! - and always use a crotch strap. You can use a BP without one put you might have to swim around with your thumbs hooked around the waist strap of your harness - especially with aluminum tanks at the end of a dive as they try to get to the surface

 

[boulderjohn]

I want to take a look at your problem from another angle--literally.

You have an apple shaped body, and you had trouble keeping the BCD in place without tightening the straps a whole lot. Of course, air wants to go up, and if you are wearing a weight belt while upright in the water, the BCD will want to go up while your body will want to go down.

Let's start with understanding why you are upright in the water. Many beginning divers will both descend at the very beginning of the dive and ascend at the very end of the dive in a vertical position. For the remaining 97% of the dive, you should be swimming in a horizontal position, meaning the BCD will not ride up on you at all. If you are properly weighted and properly trimmed, you should lie effortlessly in that horizontal position.

Now that I have brought up being properly weighted, my best guess is that if you are having a problem with your BCD going up and your body going down, then you probably were wearing too much weight. I don't know how much wet suit you were wearing, but if it was only a 3mm suit, you should have had very little air in the BCD, too little to have a major effect on pulling the BCD up. If you were significantly overweighted, then you needed a lot of air in the BCD to balance all that weight on the hips. That will make the problem much worse.

I also brought up trim. Your weights should be distributed in such a way that it helps you to swim horizontally. If you have a back plate and wing, the back plate usually helps with that. With a BP/W or a BCD, it is a good idea to have some of your weight in trim pockets either built into the BCD or placed on the tank cam bands. this will not only help you swim horizontally, it will help keep the BCD in place when you go vertical. I myself prefer to have only as much weight as the amount of air in my tank on a weight belt or weight pockets. With the rest on the BCD/tank combination, there is no problem with the BCD riding up.

Now that I mentioned weight pockets, if the ditchable weight near your hips is inside integrated weight pockets instead of a weight belt, your problem will also go away.

In summary, if you are properly weighted with your weights distributed properly while swimming horizontally, you should not be having the problem you describe no matter what kind of BCD you are wearing.

 

[scubadiver888]

Hi there! Had my first dive trip with a vest, and had trouble controlling buoyancy. I am "apple" shaped and needed to really tighten the vest to keep it down. Wondering if that made it hard to fully expand my lungs, which could have contributed to my problem. Does this make sense? Would a bp/w make it easier?

I think using a BP/W with a crotch strap will solve the symptom but not necessarily solve the problem.

I have watched new divers wearing jacket style BCDs. A common problem with new divers is wearing too much weight. So they have too much weight on their hips. This tends to pull THE DIVER down. To fix the imbalance they add air to the BCD. This causes THE BCD to float up. The end result is that the BCD rides up on the diver. If they stand on the training platform and dump all the air from their BCD, it drops down and stops running up on the diver. But now they are too heavy.

One solution is to wear a crotch strap. I have seen more and more divers doing this. However, this does not solve the problem of the diver being overweighed.

Now you could do this instead. Get all your gear on with no weight or maybe half of what you think you need. Put a couple of 2 pound weights at your entry point. If you are at a dock, leave them on the dock. If you are on a boat, leave them at the back of the boat. You need to be able to reach these from the water or have someone hand them to you. You then get in the water with the BCD inflated. If you are wearing a wetsuit you should be positively buoyancy. If you have less weight than needed to make you sink you will float UP into your BCD. With a full breathe let all the air out of your BCD. Before you got in the water you wanted to make sure you don't have any air pockets in the crotch, armpits, elbows, etc..

When you let the air out of the BCD you should NOT sink. Now with all the air out of the jacket you should be able to use your breath to start sinking. When you exhale (regulator in mouth, mask on) you should start to sink. If you do not start sinking, you need to add some weight. I usually add 2 pounds at a time then try this again.

Once you found that point where you can control going up and down with your lungs and a completely empty jacket then you are properly weighted WITH A FULL TANK OF AIR. The air will have weight. As you use the air the volume of the cylinder does not change. Changing weight (no air) without changing volume (cylinder is rigid) will increase buoyancy. The weight of the air will be 6 pounds for an AL80 tank. So you need to add 6 pounds. When you start the dive you will be a little heavy (to compensate for the air you will use) but it should only be by 6 pounds.

For example, I got new gear this week. I did this when I went diving today and found I could sink with 2 pounds. So I added 6 pounds for a total of 8 pounds. This was a new, very buoyant wetsuit. With my old wetsuit I could sink with no weight so I only used 6 pounds.

Now all this said, you might find that you still need a crotch strap because of your body shape but it is important to make sure you are properly weighted first. Getting properly weighted will definitely help you be a better diver and it won't cost you anything. If you still need the crotch strap then you can look into purchasing the strap.

 

[buddhasummer]

Herman's accurate comments aside, I find that using a rigid backplate with a webbing harness and minimal wing is FAR more comfortable and enjoyable to dive with than a jacket BC. This is one instance where choice of gear really does make a big difference. So try one.

Jeesh, I haven't been lurking on this forum for a couple of months, nice to see that the same old "BP/W vs jacket BC" horse is still not beaten to a bloody pulp.

Stay tuned I think HOGs up next.

 

[Nemrod]

The problem with most BCs is they are kinda like wearing a potato sack. There is no crotch strap, there is usually a lot of fluff and puff in them and unwanted doodads, multiple plastic D-rings and generally only one tank retention strap and worst of all, they have generally way more buoyancy than needed for buoyancy control because somewhere along the way people got the silly notion that a BC was a life jacket and therefore as long as you were safely ensconced in your poodle jacket you were as safe a bug in a rug.

These reasons alone are more than enough to make me a BP/wing diver since the mid 70s back when we called them back inflation BCs. Whatever you call them the modular concept is much better suited to enthusiast divers than a bag-O-air BC. But, that said, the compromises required to use a tech bent doubles plate for the more common singles tank diving is annoying. There need to be more choices for true single tank plates.

N

 

[Colliam7]

Hi there! Had my first dive trip with a vest, and had trouble controlling buoyancy. I am "apple" shaped and needed to really tighten the vest to keep it down. Wondering if that made it hard to fully expand my lungs, which could have contributed to my problem. Does this make sense? Would a bp/w make it easier?

My colleague Herman is right - don't expect a piece of equipment to solve technique problems. But, for many of the reasons given in multiple replies, a BP may have some advantage.

1. A crotch strap - a number of back inflation units have a crotch strap option, many / most jacket BCDs don't, although i have sewn a crotch strap into a jacket BCD just to prove (to myself) that it can be done. The crotch strap may help stabilize the unit on the diver's body, particularly at the surface. The surface issue often is, the diver is over-weighted, with a considerable amount of lead on a weight belt, and has the feeling that they are slipping down and out of the BCD. The real issue is over-weighting, and the crotch strap addresses a symptom, but not the real problem.

2. Weight distribution. Many / most jacket BCDs, and weight-integrated back-inflation units position the diver's added weight in the wrong place - 'lower' / 'beneath' the diver's inherent center of lift (the lungs, as pointed out by danaero), and the diver ends up in a foot low orientation, and finds that their buoyancy seems to change between finning and stationary positions (not surprising, since in a foot low position, part of the finning thrust vector is upward, not just forward). A metal backplate helps address that issue, by putting more weight adjacent to the lungs. But, the fundamental technique problem is weight distribution - a 'technique' issue.

3. Weight requirements. Many divers (new and old) go into the water over-weighted. That is a technique issue, and a BP will not solve the problem, but may offset some of the weight requirement - by removing the 'floaty' jacket / soft back-inflation BCD, which adds to the diver's weight obligation, and replacing it with a negatively buoyant (or, at the worst, neutrally buoyant) BP/W. Again, the technique issue is over-weighting, and the metal BP won't solve that, but does address one of the symptoms. Unfortunately, Herman is also right in his comment about some instructors - it is too easy to over-weight OW students for convenience, it takes time to properly adjust weighting requirement (and distribution) during class. Students come out of OW training believing that they need far more weight than they actually do. Of course, that is a topic for another thread, entirely.

Practice diving with no wing or BC vest, jacket etc., after you've been able to get yourself properly weighted for the equipment ( tank and wetsuit ) you're using. You'll then know that you are proficient in basic scuba buoyancy skill. You'll realize that your lungs are your BC device. . . . Here on the boats in southern California, I am seeing more and more people exiting the gate with a 7mm full suit, hood, gloves boots, steel tank, backplate and harness 8lbs of lead and no BC.

A great comment, and an idea well worth trying as a learning experience.

 

[Dorian]

I agree that with good buoyancy skills it shouldn't make a difference what kind of BC you are wearing, BUT..... With newer or less experienced divers, equipment that is comfortable and fits well makes a difference. After diving in a jacket style BC for more than 20 years, I switched to a BP a few years ago and I love. My body changed as I got older. I got bigger around the middle and now I find that the cummerbund around my waist restricts my breathing and makes it harder to keep my BC as stable as when I was in my 20's. I have also found that the crotch strap really helps. If I am shooting video or trying to look into small crevices keeping the BC from sliding up and down my body really helps. The BP fits my body better than the jacket styles today. It's more adjustable and it stays put. I am not focused on the fit of my BC and I do think that has allowed me to be more aware of how I adjust my weights and buoyancy.

 

[Rayallyn]

I wear an IST Proline JT-40 Tech BC without the crotch strap and love it. It has pockets for integrated weight system but I prefer a belt. It has a stainless stl. plate and I only need 6lb. of weight. If the current is strong I add a two pound donut to the top of the tank as swimming into current and tilting my head and shoulders up sends me upward. I can turn on my head exhale and drop down between coral for the photo. inhale and come up out between the coral. Have to be careful of the current though -don't want it sending you into the coral. But overall I love the tech BC over my Scuba Pro jacket style.