Educate me, back inflating BC vs. Normal inflation

[Peter Guy]

One of the interesting things, to me, about this discussion (and the many others on the same topic) is that you will find many people who have switched from a Jacket BC to a Back Inflate. OTOH, you will find very few who have done the opposite.

In addition, there are a number of "professionals" who write that they use a Jacket BC while teaching (particularly in confined water) but use a Back Inflate in open water or for their personal use.

Regarding the BI will force you onto your face issue -- I've found some truth to that IF I am in a wetsuit with an AL 80 and in the tropics -- but in cold water, never.

 

[MauiScubaSteve]

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

You are right; I have PM'd Phil seeking more pertinent data.

 

[MauiScubaSteve]

One of the interesting things, to me, about this discussion (and the many others on the same topic) is that you will find many people who have switched from a Jacket BC to a Back Inflate. OTOH, you will find very few who have done the opposite.

In addition, there are a number of "professionals" who write that they use a Jacket BC while teaching (particularly in confined water) but use a Back Inflate in open water or for their personal use.

I think your anecdotal observations are regional; I see less than 1% changing to BP/W, because that's how many divers I see who go tech. There are instructors who dive two rigs here, but the majority are old vests in the pool and new vests in the ocean. Those that do CW in the ocean are mostly training in vest, and that is the vast majority (only resorts have pools). There are some instructors and guides in BI, and I know of 4 instructors who dive BP/W, but only one would teach any OW in BP/W (your friend Tim).

I have my slate attached to my BI. If I do not plan to use my slate I dive my vest, because it is easier to dive, for me. The difference is minor, but there is a difference. As usual, I am only comparing my two BC's, for the way I dive.

 

[H2O 70]

- a back inflate bc will typically toss you forward slightly and this takes a couple of dives to get used to.

To me, a BI is more 'streamlined' feeling UW---?has a slight forward push to it on the surface but nothing an average diver can't get used to.....

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...

I think the whole thing of a BP/W or BI putting your face in the water is overblown bunk.

On the surface, if it is pushing you forward, you have too much air in the cell or wing.

Most divers were likely taught in jacket style BCDs. You could inflate these things and you may get a bit squeezed and you'd bob high out of the water.

You can't do that with a back inflate anything.

If you have enough air in your back inflate to keep your chin and head out of the water you will not be pushed forward.

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.

and to this I would add don't over inflate the wing or cell.

 

[Guy Alcala]

I think your anecdotal observations are regional; I see less than 1% changing to BP/W, because that's how many divers I see who go tech. There are instructors who dive two rigs here, but the majority are old vests in the pool and new vests in the ocean. Those that do CW in the ocean are mostly training in vest, and that is the vast majority (only resorts have pools). There are some instructors and guides in BI, and I know of 4 instructors who dive BP/W, but only one would teach any OW in BP/W (your friend Tim).

I have my slate attached to my BI. If I do not plan to use my slate I dive my vest, because it is easier to dive, for me. The difference is minor, but there is a difference. As usual, I am only comparing my two BC's, for the way I dive.

I suspect one of the big regional differences that probably accounts for a greater % of BI or BP/W is cold water; those of us who routinely dive dry in Monterey/Carmel almost unanimously dive BI or BP/W. There's so much less clutter around your chest it makes it fairly easy to route and connect a drysuit hose, and we generally need a lot of weight, so anything we can do to reduce that is valuable. As others have mentioned, a good, minimalist back inflate like the Malibu or Balance will generally require less weight and have less drag than a jacket because there's less material, and a BP/Wing goes even further down that road. I own the latter both because of that, and because I'll be tech diving soon. If I weren't planning to get into tech diving I'd be perfectly happy to own a Balance, other than the slight extra weight I'd need.

The LDS I did my OW and AOW training used Seaquest Malibu BIs as their standard rental BC, so I was used to BI from the start. But I found it possible to get good trim from a jacket style BCD when I rented a Seaquest ProQD+ from another shop, as it has similar trim pockets to the Malibu and Balance. OTOH, I detested the Cressi jacket I rented from a third shop (the weight pockets tended to flop away from my body slightly every time I rolled on my side, and there were no trim pockets), so I think it's more a matter of specific design and personal preference than anything else.

Guy

 

[Web Monkey]

One of the interesting things, to me, about this discussion (and the many others on the same topic) is that you will find many people who have switched from a Jacket BC to a Back Inflate. OTOH, you will find very few who have done the opposite.

I switch quite often because my SCUBAPro Classic+ just isn't sturdy enough for my double 98's, while it's much easier for classes and on boats.

However 100Lb+ tanks aside, when properly weighted and trimmed there is zero difference between the two underwater.

The major difference between the two is that over-weighted divers tend to remain horizontal due to the "basket and balloon" effect with a back inflate, which makes the diver more or less horizontal and covers up the weighting and trim problems. (I beleive credit goes to Uncle Pug for that phrase).

Terry

 

[MauiScubaSteve]

As promised, further data from Phil; I think the US probably has more % cold water divers than the world as a whole.

Aloha Phil,

I was wondering about a post you made concerning % of BP/W sales last year. Does the data from the Leisure Trend Dynamic Report cube tell us what percentage Back Inflate BC's had?

Mahalo,
Steve

The data does not provide that directly, but I have taken model-specific data apart in the past to arrive at an approximation of that information. Please remember, this is a snap shot of various discrete time periods, so it could be possibly off quite a bit.

Several times last year, I looked at monthly data and determined that AMONG THE TOP TEN VEST MODELS IN SALES, back-inflation amounted to about 18%.

Leisure Trends is a sales-specific tracking services, meaning that look at actual sales invoices and skew numbers for each panel store. My "quick look" may be distorted.

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

Thanks for your prompt response.

Do you / can you get any "feel" for worldwide numbers?

Could I quote you from this PM, or would you join the thread in progress?

Honestly, I have no clue on the worldwide situation. Since Leisure Trends does not report this distinction directly, please feel free to quote me as long as you make it clear that my snapshots are based on only a single month last year and are based upon my PERSONAL knowledge to properly identify a particular model is "jacket" or "back-inflated".

I will also join the thread if there is anything I think I can offer.

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

 

[PhilEllis]

As promised, further data from Phil; I think the US probably has more % cold water divers than the world as a whole.

There is an awful lot of information available in the Leisure Trends data cube, but I confess to being limited in my skills and abilities in getting that information out.

When we have completed out relocation and I have more time on my hands, I will explore the data and attempt to get some more detailed information about BC types over a longer range of time. As I think about it now, it would be nice to also distinguish between the increasingly popular "travel" vests, which are mostly back-inflated, from the more serious/higher lift traditional back-inflated vests.

As I have also said previously, BP/W outfits don't contribute heavily to the sales of back-inflated system statistics, as they comprise such a very small and unnoticeable share of the entire market.

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

 

[jfcl01]

I am actually in the market for a new BC and have been wondering about a BI. I have never used one. If I get one, I won't have time to use it before my next dive trip, which will be to Cozumel. I'm betting that none of you would recommend I just jump in on a drift dive in Coz for my first time with a BI, right? Would it be enough to just take it out on a shore dive my first day to learn it?

 

[rivers]

I am actually in the market for a new BC and have been wondering about a BI. I have never used one. If I get one, I won't have time to use it before my next dive trip, which will be to Cozumel. I'm betting that none of you would recommend I just jump in on a drift dive in Coz for my first time with a BI, right? Would it be enough to just take it out on a shore dive my first day to learn it?

Would you have time to at least get into a pool with it? Or possibly demo one in a pool and then order it and have it for Coz?