Why does an LDS push newbies away from BP/WINGS?

[grouchyturtle]

No.

I think your have horizontal and vertical backwards!

Horizontal Line ______
Vertical Line |

The more horizontal you are the better. Your legs cause less drag that way and your using less air and energy to move yourself throught the water.

The tank weight pockets are to help you get horizontal (aka: better trim). You may not need them. Depends on the rig, your body, how much weight you need, etc. I usually have about 2 lbs. in them in fresh water, 4 in salt.

 

[ABQdiver]

Aquanaught once bubbled...
Guys I got a question. I'm recently doing my OW and yes it's in a jacket style BC. Anyway I'm most likely to choose for a BP/W after I did my OW and when it's the right time to buy my equipment.

But now here is my question...
Now I had lessons in a Jacket style BC, is it a big difference when switching to a BP/W setup? If so how long will it take to get used to it? 1, 2 or 3 times diving in a swimming pool to practise?

From my experience, the BP&W is VERY easy to adjust to. I had struggled with my Ranger back inflate for a few months. After taking the plunge and buying the BP&W, I was loving it!! More stable, more horizontal and more streamline. It felt better the first dive, and only gets better after that.

Aquanaught once bubbled...

Another question is what do I need to buy...A backplate, a Wing and a harness or does it brings more to complete the setup?

You got it right. You might want to move on to a long primary hose and a bunged backup. Shorter SPG hose and be clipped off on the left hip d-ring. It all works very well making you very streamlined in the water.

Aquanaught once bubbled...

The last question is the weight system. I heard you can get easily in a face down position and that it's hard to stay in a vertical position. Is this true and if so how can you solve the problem?

Thanks in advance all...

I had the opposite problem with the "standard" BC. I was constantly fighting feet down position. With most of the weight in the integral weight pockets it pulled me down. With the BP&W the plate and the STA (single tank adapter) totals up to about 8# right at the center of my torso. This puts the center of gravity at a much better position.
Try one, you won't be disappointed!

 

[-hh]

Aquanaught once bubbled...
But now here is my question...
Now I had lessons in a Jacket style BC, is it a big difference when switching to a BP/W setup? If so how long will it take to get used to it? 1, 2 or 3 times diving in a swimming pool to practise?

If you're comfortable in the water, the transition to a BP won't be that big of a deal. You'll get the worst of it sorted out in a couple of dive-days, but how long it ultimately might take depends on how well sorted out your old BC was, and how sensitive you are to it overall - - it could easily take a dozen or more dives, many of which you're just noticing that you're still not as far up the power curve as you were in the old gear (FWIW, it doesn't matter which way you're travelling on this street).

The last question is the weight system. I heard you can get easily in a face down position and that it's hard to stay in a vertical position. Is this true and if so how can you solve the problem?

Yes, its true, although you should change to relative measures (easier; harder). And while some BP advocates will say that they can "easily" adjust their weighting trim to minimize its "face down" tendencies, they ignore that it is easier with a Jacket.

The real bottom line is that you can't argue with physics, and the only way to really solve the problem of tipping in various directions is by putting buoyancy on all sides of the diver's center of mass, which generally means that the BC bladder needs to surround the diver.

The trade-off is that a surrounding bladder's inflaction can cause chest squeeze, but this is also something that is argued to be an "easy adjustment" to "minimize". There is no such thing as a free lunch either way, so you have to choose your trade-offs objectively and carefully, in the appropriate priority (safety, convenence, comfort, performance, etc).


FWIW, the question and implications for what dive gear is appropriate for new students whose confidence in the water are unknown and untested are really quite obvious IMO. What it does appear to me that a lot of people assume that Diveshops are profoundly stupid as to why they make the choices that they do, and end up incorrectly second-guessing their priorities in an effort to "explain the vast conspiracy". It simply isn't so.


-hh

 

[MikeFerrara]

While some back inflation bc's do tend to push the diver foreward I don't find that with a bp/wing.

With my singles rig I can stay upright at the surface every bit as easy as in any jacket. With my doubles I am actually pulled slightly backwards when the tanks are full.

It's just a matter of balance. One of the forst things a cold water diver (heavy suit and lots of weight) should probab;y consider is a steel tank. That gets some of the weight off the hips. A bp also gets some of the weight off the hips. If the weight is on the hips (foreward of the wing) and there's significant air in a back inflate it certainly can push you foreward. It's also a situation that shouldn't exist in the first place.

A jacket masks the problem more because the bladder surrounds the diver and isn't behind. Things will seem all wonderful until they start to dive and then they'll be in a head up attitude (if the imbalance exists and it usually does) because the bladder is still above the weight.

 

[loosebits]

I asked my LDS this just the other day. The shop caters to a lot of technical divers so they have and sell bp/wings in addition to jacket style BC's. He told me the reason he teaches jacket is because they are easier to adjust to fit a particular diver. While there may be more sinister reasons, this is certainly true. While I haven't started diving with bp/wings (I plan on it soon), I know that webbing can become very stiff where it bends through slot if it stays there for any significant amount of time (I have my cam strap on my BC adjusted for an 8" tank and resizing it for a 7.25" tank is a pain). I can't imagine how difficult it would be to resize a bp harness for each student in a class.

While he rigs his students with jackets, he dives a bp/wing with twin steel 50's to encourage the students to be open to other configurations. I didn't take OW from him but I imagine it generates a lot of interest in bp/wings config.

 

[Gator Diver]

There are 4 LDS (used to be 5) within one
hour from me. This is what each place
told me after I found out about BP/wings
on this board.


LDS #1: "Get a BC. You dont need a jacket".

LDS #2: "Jackets are easier to use. You can consider
BP/wings once you get into technical diving"

LDS #3 (now out of business): BP/wings are good.
Was not reccommended for single tank diving
however and also not recommended for the ocean.


LDS#4: showed me both and recommended Halycon
if I was considering any advanced courses.

LDS#5 (EE): we all know what they think about bp/wings.
Just wish I knew there were so close to me earlier!!

 

[caveseeker7]

loosebits once bubbled...
I asked my LDS this just the other day ... He told me the reason he teaches jacket is because they are easier to adjust to fit a particular diver.

With the understandable exception of Halcyon, just about every manufacturer of backplates offers adjustable, QR-equiped easy to adjust harnesses. Some several, and usually in the addition to DIR-style. While many here don't like those adjustable ones, they're perfect for a student environment because of it.

 

[-hh]

MikeFerrara once bubbled...
While some back inflation bc's do tend to push the diver foreward I don't find that with a bp/wing...It's just a matter of balance.

Yes, it is just a matter of balance, and to stabilize a BP vertically at the surface requires sufficient mass "behind" it (the further, the better), to offset the mass of the diver & gear in front of it. A steel tank is one good candidate, but its not always an option. For example, when travelling, most dive resorts use AL80's.

It will depend on your dive environment as to which options are practical and which ones are not: for similar travel reasons, a 2lb AL backplate may be chosen over a 6lb - 12lb SS backplates, and guess how its going to act?

If the weight is on the hips (foreward of the wing) and there's significant air in a back inflate it certainly can push you foreward. It's also a situation that shouldn't exist in the first place.

Unfortunately, the situation must exist, because the air in our tanks has mass, and we will consume that mass during our dive.

What exasperates the condition is the situations under which the diver is most likely in greatest need: its not at the beginning of the dive, but rather, at the end, when the tank is empty and more buoyant (the diveboat is more likely to not be around at pickup, not dropoff). To rely on a full, negative tank to be present to trim out properly at the surface is a failure in planning.

A jacket masks the problem more because the bladder surrounds the diver and isn't behind. Things will seem all wonderful until they start to dive and then they'll be in a head up attitude (if the imbalance exists and it usually does) because the bladder is still above the weight.

First, it could still be acceptable and the choice that is made in the trade-off between UW trim performance and surface safety: we need to recognize that we're dealing with two, discrete requirements here, and that there is no guarentee that it is even possible to optimize the system for both requirements simultaneously (if we could, please give me a car with the most horsepower and best fuel economy...at the same time, please).

Second, I think you're overstating the significance of the Jacket's bladder's centroid above the weightbelt for two reasons: 1) contemporary designs have their main bladder well placed, at or below the diaphram, which results in a minimal separation distance, or moment arm for the torque "problem" you're alluding to. As such, its not a big problem to start with. 2) even though it is the more commonly used one, the weightbelt is not the only place that we can add mass to trim out the diver, so the center of mass can be raised or lowered to allign with the BC's center of buoyancy.

FWIW, its been my observation that most divers' trim problems can be generally resolved without the need to go buy new gear. But if a trim weight is going to be added, the most common one is in the form of an ankle weight, and interestingly enough, its purpose and design is to solve the exact opposite trim problem you describe as the "usual problem". What does it say that there's a commonly known solution to what is effectively being claimed almost as a "cannot happen"?



-hh

 

[MikeFerrara]

-hh once bubbled...


Yes, it is just a matter of balance, and to stabilize a BP vertically at the surface requires sufficient mass "behind" it (the further, the better), to offset the mass of the diver & gear in front of it. A steel tank is one good candidate, but its not always an option. For example, when travelling, most dive resorts use AL80's.

Not so much behind it but closer to it. hat's part of what a back plate does for a living. The diver especially wearing an exposure suit is buoyant.

It will depend on your dive environment as to which options are practical and which ones are not: for similar travel reasons, a 2lb AL backplate may be chosen over a 6lb - 12lb SS backplates, and guess how its going to act?

Phisics has it's limitations. You can't choose all the wrong stuff for the wrong reason and expect everything to turn out good.

If I need a significant amount of weight, I take care to get it as close as possible near my source of buoyancy which is not on my belt.

Unfortunately, the situation must exist, because the air in our tanks has mass, and we will consume that mass during our dive.

True to a point but like I said move things around so you get those centers close together. I have to do more moving with a jacket as the bp/wing does most of it for me. and the point is that mince, even with an AL tank has no foreward tendancy at all.

What exasperates the condition is the situations under which the diver is most likely in greatest need: its not at the beginning of the dive, but rather, at the end, when the tank is empty and more buoyant (the diveboat is more likely to not be around at pickup, not dropoff). To rely on a full, negative tank to be present to trim out properly at the surface is a failure in planning.

But this is when the diver should need the least air in the bc. Again no problem with my set up or those who set theirs up similarly.

First, it could still be acceptable and the choice that is made in the trade-off between UW trim performance and surface safety: we need to recognize that we're dealing with two, discrete requirements here, and that there is no guarentee that it is even possible to optimize the system for both requirements simultaneously (if we could, please give me a car with the most horsepower and best fuel economy...at the same time, please).

Second, I think you're overstating the significance of the Jacket's bladder's centroid above the weightbelt for two reasons: 1) contemporary designs have their main bladder well placed, at or below the diaphram, which results in a minimal separation distance, or moment arm for the torque "problem" you're alluding to. As such, its not a big problem to start with. 2) even though it is the more commonly used one, the weightbelt is not the only place that we can add mass to trim out the diver, so the center of mass can be raised or lowered to allign with the BC's center of buoyancy.

FWIW, its been my observation that most divers' trim problems can be generally resolved without the need to go buy new gear. But if a trim weight is going to be added, the most common one is in the form of an ankle weight, and interestingly enough, its purpose and design is to solve the exact opposite trim problem you describe as the "usual problem". What does it say that there's a commonly known solution to what is effectively being claimed almost as a "cannot happen"?



-hh

Diver trim problems can be fixed without buying gear. I can get trimmed with any bc. It just takes more imagination with some.

I also don't have a surface safety issue at all with the bp/wing. There's no comprimise at all.

I'll take your word that you solve trim problems with ankle weights but I've trimmed out hundreds of divers (students) and have never used a single ankle weight.

The reason that ist's not a big problem as you suggest is because most divers are used to the head up attitude. The whole situation is less pronounced in warm water where little exposure protection and little added balast is required.

Around here just about every one with a 1/4 inch suit and 20 pounds or more on the waste is severely head up in the water and they go totally vertical when they stop foreward motion.

We fix it by placing weight up on the tank and fixing body position.

the back plate does part of that for us.

 

[grouchyturtle]

-hh
just curious, have you ever even dove a back inflate or BP? I'm not trying to be a D**K, but it really just sounds like you have very little experience with them.

I'm still very much a rookie. My OW dives and the few right after my cert were with a jacket. Hated it! My buddy also a newbie, same thing. When we stopped, we were just like Mike described, VERTICAL BIG TIME.

Then the first BCs we got were back inflate. trim was 100 times better, even without moving any weight around. If I'm diving a 2 piece instead of just my full 7mm or diving salt, I move a few lbs to my top cam strap.

I recently just got a BP same thing, no problems, great trim. I usually dive cold water, 7mm full or 2 piece, and AL 80s, NOT steel. I've never had any problem, with face down at the surface. Just lean back and ride it like a little raft. And when I say lean, I mean with very little effort. It's so comfortable, I could almost take a nap while I'm floating there.

I don't know anyone else who's had a problem with that, and on this board every post I've ever seen with that concern was from someone who had only dove jacket BCs to that point.