Educate me, back inflating BC vs. Normal inflation

[Scubagolf]

Like just about everybody, I dove a jacket getting certified and then used jacket rentals for about a year. When I got around to buying my own equipment the back-inflate was (for me) the obvious choice and six years later I am still very happy with my Zeagle Brigade.

 

[BadabingM3]

thanks for all your inputs folks,

Still unsure but I will keep all inputs in mind.

Cheers,

 

[MauiScubaSteve]

It's good that you are still unsure; divers with more dives than everyone who has responded are also still unsure.

Has anyone ever done tests to measure the amount of drag the various configurations produce? Without any data how can anybody say one is more streamlined than the other.

Everyone is different; proper trim for one is not the same as proper trim for another; plenty of divers with good trim dive in vest BC's.

"Quick Summary: try one out, it is a preference thing, it's just that most people prefer the back -inflation. And myself am an official convert as of 2 days ago."

This is only a quick summery of the very vocal back inflate fans on SB; industry sales numbers indicate less than 5% annual sales of back inflate vs vest; the vast majority of divers most evidently don't prefer back inflation, or there would be more back inflation BC's sold.

 

[Reggieb]

It's good that you are still unsure; divers with more dives than everyone who has responded are also still unsure.

Has anyone ever done tests to measure the a?mount of drag the various configurations produce? Without any data how can anybody say one is more streamlined than the other.

Everyone is different; proper trim for one is not the same as proper trim for another; plenty of divers with good trim dive in vest BC's.

"Quick Summary: try one out, it is a preference thing, it's just that most people prefer the back -inflation. And myself am an official convert as of 2 days ago."

This is only a quick summery of the very vocal back inflate fans on SB; industry sales numbers indicate less than 5% annual sales of back inflate vs vest; the vast majority of divers most evidently don't prefer back inflation, or there would be more back inflation BC's sold.

1) Many divers will never try back inflation BCs, I think that you will find that a freshly certified diver, who has been taught that back inflation BCs are going to push you on to your stomach on the surface, and you might drown, is probably going to buy a front-adjustable. This is an exaggeration of what is taught in open water classes, but is the ultimate extension of what the books say. As a result, these new divers don't even consider back-inflation.

2) Cheap, durable, front-adjustable BCs are, I would venture a guess, the most commonly sold BC for ONE reason, many are purchased as rental gear. I have yet to see any other style as rental gear.

3) As I said, I maintained good trim with my front-adjustable jacket for my last 12 years of diving. Never had a problem. Wouldn't even make the switch if my current BC still fit, but now that I am, and I have tried the back-inflation, I, like many others who have tried both find them easier and more comfortable.

Think about that statistic for a minute.

OP, again, TRY a couple of different styles. I will reiterate exactly what I said before. It comes down to preference. Buy what you are most comfortable in.

EDIT: straight from my Open-Water certification book (it is old, but I can check what my girlfriend's current PADI book says to see if it has changed). This is a NAUI book, fyi:
"The disadvantage to some back-mounted systems is that they tend to push you forward into a face-down position on the surface if you do not actively kick to maintain a face up position...Jacket-style BCs tend to be the most popular systems. These systems are comfortable to wear, provide good trim underwater, and most enable you to maintain a face-up position when you are resting on the surface" (emphasis added)

I KNOW when I was 13 and getting certified, my mother read that line and had the horror scenario come to mind that I would get knocked out and drown on the surface because I had a back-inflation style system. I am 25 now, and just tried a back-inflation system for the first time. I mainly do recreation dives on vacation. I am finally finishing grad school, and I will have more time to dive. I want to do some specialty classes, get some higher certifications, but I characterized what is a very common diver for a long time. I dove on vacation, and owned what seemed perfect for me when I knew very little about diving. All of it has worked beautifully for me in this very leisurely style of diving. I, like everyone else in my certification class, never even considered a back inflation style because of what our open water certification book said about them. I have now used one, and it simply isn't true. In fact, that book also says that it's just photographers that use the back-inflation style, because it lets them carry more gear with less clutter. Who is going to read that and think, "I am trying this out on vacation, so THAT is what I need!! The set-up that NAUI says is for pros!!!"

/rant

At the end of the day, the BC that gives you the best trim, and that you will be most safe, and feel the most secure in, is one that you feel comfortable in. You might be like the many who try the back-inflation and fall in love. You might not. But I would venture a guess that at least a plurality of individuals that own a front-adjustable jacket style BC never tried anything else.

 

[TSandM]

We need to talk apples and apples here . . . There are jacket BCs, and back-inflate BCs, and backplate systems, and they are all different.

If you are diving a single tank and are correctly weighted, you will have very little gas in your BC at any time. No gas will be in the front part of the jacket BC if you are horizontal, and there will be little discernible difference between it and a back-inflate BC. There will be differences on the surface, where the jacket inflates all the way around you and you can feel this; some people don't care for that feeling, and I am one of them.

A back-inflate BC doesn't wrap around in the same fashion. When fully inflated at the surface, without a crotch strap, it is possible for the BC to ride up behind you and push you forward. This will not occur if the BC fits properly, is correctly adjusted, and especially if it has a crotch strap.

I'm convinced that the reason a lot of people are immediately taken with a backplate system is mostly the movement of weight up onto their back, where it aids in correct trim. (There is also a matter of tank stability, and the virtues of the aforementioned crotch strap.) Jacket OR back-inflate BCs that offer well-placed trim pockets (as, for example, the SeaQuest Balance does) can provide the same effect.

To me, the big appeal of a back-inflate was that it was far less bulky, and didn't squeeze. The backplate rig took that another step, reduced total weight I had to carry by the amount of the inherent buoyancy of the other BC (2 to 3 lbs, often), and gave me modularity. Back-inflate BCs can have inherent buoyancy and are not modular. For some reason that I don't understand, they also seem to be much more expensive than the jackets, often more expensive than an equivalent backplate setup.

 

[Wayne at DiveSeekers]

This is only a quick summery of the very vocal back inflate fans on SB; industry sales numbers indicate less than 5% annual sales of back inflate vs vest; the vast majority of divers most evidently don't prefer back inflation, or there would be more back inflation BC's sold.

First off, can someone tell me where this 5% came from (it seams very low)?

I know that we can't be the only exception case but BI is all we basically sell at our shop.

If BI wasn't so popular then you wouldn't be seeing all these mainstream manufacturers (Oceanic, ScubaPro, etc..) not only having 1 option but now having multiple options for BI BC's.

 

[MauiScubaSteve]

In reviewing the source thread for my statements, I find I have been generous to the BI crowd

This thread is a very informative discussion on some aspects of the subject;

http://www.scubaboard.com/forums/bu...t-more-dive-shops-display-more-any-bp-ws.html

I think it can be explained purely in terms of market share.

I am right now on the Leisure Trend Dynamic Report cube, where I can search retail sales in categories and brands for this year and past years.

I can tell you that backplates and wings make up considerably LESS THAN 1% of the entire market of buoyancy vests sold so far this year in the United States. For an opportunity of part of that 1% of the market, they buyers are fairly brand and model specific in their wants. So, of an aggregate average dive shop that can sell 100 buoyancy devices in a year, they can expect (if sales are completely random) to sell about 1 plate, harness, and wing kit.

Given that dollars available to invest in inventory are small for most stores, and given that most of them have NEVER had a customer walk in and ask for a BP/W set-up, I think it can be expected that they will not invest their money in that inventory.

Now, for shops that have a specific customer base, the plan is completely different. But those types of shops are less likely to be seen.

Phil Ellis
Discount Scuba Gear at DiveSports.com - Buy Scuba Diving Equipment & Snorkeling Equipment

 

[SkimFisher]

My dive buddy and I often comment on the huge inventory of stab-jackets in the shops around us (granted, with the exception of a few shops, they all have a nice BI/BPW inventory as well). Typically the comment is something like, "Why the hell would ANYONE want to wear something like that?!?"

If it's not function, it's definitely form - they are hideous to look at for starters. That said, there is definitely an unencumbered feel to SOME BI's. I have seen poodle-jackets in the BI variety and to me that defeats the purpose. I don't dive a BI to achieve better trim, I dive it because I don't have a bunch of unnecessary pockets/material/etc wrapped around me.

A BI does not automatically equate to perfect trim and anyone that's trying to sell you one based on that is full of crap. I dive a Ranger LTD and it took some tweaking to trim out because I am naturally leg heavy and sink like a rock. I know PLENTY of guys who dive BI and STILL have horrible trim. Good trim doesn't come "out of the box" - it may for some, but not many.

For the type of diving I do, a BI or BP/W makes more sense and is more comfortable. That's basically what it comes down to.

 

[Reggieb]

In reviewing the source thread for my statements, I find I have been generous to the BI crowd

This thread is a very informative discussion on some aspects of the subject;

http://www.scubaboard.com/forums/bu...t-more-dive-shops-display-more-any-bp-ws.html

As has been pointed out several times in this thread, back inflation and BP/W are not the same thing.

 

[Reggieb]

My dive buddy and I often comment on the huge inventory of stab-jackets in the shops around us (granted, with the exception of a few shops, they all have a nice BI/BPW inventory as well). Typically the comment is something like, "Why the hell would ANYONE want to wear something like that?!?"

If it's not function, it's definitely form - they are hideous to look at for starters. That said, there is definitely an unencumbered feel to SOME BI's. I have seen poodle-jackets in the BI variety and to me that defeats the purpose. I don't dive a BI to achieve better trim, I dive it because I don't have a bunch of unnecessary pockets/material/etc wrapped around me.

A BI does not automatically equate to perfect trim and anyone that's trying to sell you one based on that is full of crap. I dive a Ranger LTD and it took some tweaking to trim out because I am naturally leg heavy and sink like a rock. I know PLENTY of guys who dive BI and STILL have horrible trim. Good trim doesn't come "out of the box" - it may for some, but not many.

For the type of diving I do, a BI or BP/W makes more sense and is more comfortable. That's basically what it comes down to.

I would say that you are dead on in your evaluation of BI (although I am not sure I agree in regards to BP/W) not necessarily providing better trim. I am a rowing coach, and I think that this is analogous to my equipment philosophy in rowing, the fastest boat is never the one that a robot would row fastest , but the one that a crew is the most comfortable in. And this is mainly because it is the horses, not the chariot, which make a boat move. You are going to have better trim, and be a better diver, in a setup that you are more comfortable in.

That is why I said that many (if not most) who try BI or a BP/W might make the switch, but the OP should try any BC before he buys it, and pick one he is comfortable in.