Does this BC product exist?

[jheil82]

Different types of bodies float differently, so different people will float differently in different types of a BC. Sure you can weight yourself so you are upright on top of the water, but if the goal is to use it underwater who really cares. Wear whatever gives you the best trim underwater. I have a jacket style that works good for me, but ill probally get a more compact travel back inflate for my next vacation.

 

[GreenDiverDown]

We have a lot of noise and claims, but no data. About fifteen years ago a chap named Steve Paulett did a bunch of tow tank studies on BCs. His finding was that the jacket style BC had the least drag. Now, "modern wings" were not available for testing then, so the closest things to wings were AT-Pacs and similar back-mounted wing BCs. You can download Dave's History of BCs which addresses Steve's work a little. But the fact remains that empirical testing showed that the claim of wings having less drag are simply not true. If there are more recent studies, I'm open to to them.

That does it... I'm going back to my Chute.

 

[dherbman]

We have a lot of noise and claims, but no data. About fifteen years ago a chap named Steve Paulett did a bunch of tow tank studies on BCs. His finding was that the jacket style BC had the least drag. Now, "modern wings" were not available for testing then, so the closest things to wings were AT-Pacs and similar back-mounted wing BCs. You can download Dave's History of BCs which addresses Steve's work a little. But the fact remains that empirical testing showed that the claim of wings having less drag are simply not true. If there are more recent studies, I'm open to to them.

Which version of the at-pac was tested? There was a large bladder cover, which presented substantial drag, but there was also a later version that had an elastic cover which kept it very compact when deflated. Watergill also made a fairing (SP?) that would accomdate doubles. I've still got three of the wings with the elastic cover and it's hard to imagine them being less streamline than a jacket. It's also worth noting that the at-pac had 60lbs of buoyancy.

 

[wreckchick]

Just courious........ if you dropped 4 lbs off your belt how much did the plate weight? Could it be you just moved that weight from the belt to plate?

In total I dropped 10# from the weight pockets. 6 to the plate and 4 just went away because I lost all the fluff on my old BCD.

R

 

[wreckchick]

My personal opinion... good trim is easier to get in a bp/w because of the distributed weight along the body's center of gravity.

Streamlining in the sense of being squared away has everything to do with proper length hoses and attachment points. One of the reasons that bp/w users look so darn good in the water is because of the hog system eliminating anything hanging below the body when it's horizontal.

R

P.S. Halcyon.

 

[Thalassamania]

I don't know, wasn't my work. I do remember he had about a falf dozen different types of back inflation wings plus one of those fairings. What folks need to rember is that there is not only cross sectionaly dependent drag but also surface area dependent drag. It appears that a basically smooth jacket BC has less drag than a deflated and wrinkeled wing flapping in the breeze, so to speak.

Anyone with more recent data?

 

[Thalassamania]

To deal with the OP: Yes it does exist, its the Oceanic Outrigger BC.

 

[ClevelandDiver]

I own both a BP/W and a jacket BC.

I primarily dive the BP/W as I find it more suited to the environment and gear configuration I typically dive: Cold water, bulky drysuit, BIG steel tank. No matter what BC you use, that's a bulky set up.

When vacationing in a warm water destination, I pack up the jacket BC as it easier to travel with.

I can honestly say I am not aware of any difference in drag underwater from one to the other. I am not saying there isn't a difference, it just is not something I notice.

Obiviously, the warm water configuration in total is more streamlined, but when I have used the Jacket with my cold water gear it didn't feel any more streamlined than the wing. My air consumption is the same in either cold water configuration, so the drag can't be that different. I have never used the BP/W in warm water, but I doubt it would make much difference either way.

The only time I have ever felt a HUGE difference in streamlining is when I dive my vintage gear. No BC, no dangling hoses, no gadgets on retractors, LP 72 instead of HP 130, just the bare minimum gear. I weight myself for the depth and glide through water effortlessly.

That said, I am not sure why people are making such a big deal over the minor differences in streamlining. I am not in a race to get anywhere. The fit, trim and versatility of the BC is far more important to me than the slight difference in drag from one type to another.

My advice, try them both for at least 20 dives each and decide which you like better. Or do what I did and buy both.

It's a big ocean out there, can't we all just get along?

 

[Thalassamania]

I just mention it in passing. The interesting thing to me that Steve Paulett's Honors Thesis at the University of Rhode Island set the stage for all of the "modern" BCs that you see on the market today and no one knows who he is.

Your right, in terms of being able to feel the difference: I sure can in my skin-two-side wet suit and Fenzy vs. "modern" gear. Or my Viking or Avon drysuits as contrasted with any other material. But "jacket" vs. wings? Steve measured the difference in a ship tow tank, but I don't know if I could feel it.

 

[StevenPaulet]

I know, I'm late to the party. A friend forwarded this to me today. It warmed my heart to see some of my previous work referenced. I haven't talked hydrodynamic drag in a few years, but I still have all my work, results, charts, even old u/w slides in a storage box here. I'll have to read this thread and see what's being tossed about. But from what little I read, I can answer many of the questions, if there is still interest. But I'm not here to bore anyone to death on it.

Steve