Warped Dive World Evolution - BP/W Subgroup Mindset

[Eric Sedletzky]

I'm going to develop a drag-o-meter.

I'm going to find a swimming pool machine, one of those swimming tubs that is like a treadmill for swimming. I'm going to rent a bunch of poodle jackets from my LDS and make sure they fit, and I'm going to put them up against several different BP/W rigs.
I am going to find a point on the grate of the water inlet on the front inside of the pool to attach a pulley. I am going to attach a line to me up front somewhere like maybe under my chin from a special harness. Then I am going to run the line through the pulley and attach the line to a digital fish weighing scale outside of the pool which will be attached to a fixed point.
I will have a technician watch how much load is put on the scale as the water begins. The test will include many water speeds with both the jackets and the plate/wings. All the data will be recorded by the technician, an there will be a videorgapher present recording the whole experiment as it happens for proof.
I will just be laying prone in the pool hooked up and staying in the water column completely submerged as the water flows by. I will keep my arms to my sides and hold the exact same position with both setups. I will not be kicking at all, my legs will be behind me and still. The tank and reg/routing used on all units will be the exact same.

The whole purpose of this is to see just exactly what the difference is with the slipstream efficiency of each unit tested and the resulting load on the scale.

This is about as scientific as it gets. I will post my findings once I find someone with one of these swimming treadmills that I can use to complete this experiment.

Which ever system wins, I want to end this once and for all with positive scientific proof.

 

[Sas]

Please Sas, go on!

Please show us more of your pictorial science of how any BP/W would be better for any and every diver.

Sure.

Here is me in a jacket BC, look I am walking around on my knees.

Here is another one of me asleep on the bottom in a jacket BC, exhausted from the excessive drag I have had to suffer.

But then I got a BP/W.

And my trim got great:

Also I was able to run line without huge bags of air hanging off my stomach as an entanglement risk:

And finally it makes me look cool, like a ninja

BP/W is better than vest BC.

Q.E.D

 

[Hepcat62]

Please quote me where I have ever "advocated Vest BC's for those intro tec classes I referenced."

Ah, good. So, we're on the same page with regards to the fact that, regardless of whether or not a BP/W is superior for "basic OW diving", a jacket/vest BC is insufficient or inappropriate for divers pursuing certain forms of advanced training. Right? I would say that we're also - at best - at a stalemate with respect to any discussions involving "streamlining".

Given all of that, let's talk about this equipment choice as diving instructional professionals. One of the accepted principles of learning is the Principle of Primacy. One way of interpreting this is that it is always easier to learn something the first time than it is to unlearn and relearn again later. I can speak to this from experience, with numerous examples.

As instructional professionals, our standard of excellence ultimately has to come down to how well we prepare our students to safely enjoy diving and pursue progressively more interesting adventures in the future (whatever that may end up meaning for them). Surely we are better instructors if we can teach things in such a way that they will carry through the new diver's entire diving career, without having to unlearn and relearn them.

If we can agree (which it sounds like we can) that a BP/W is not INappropriate for "basic OW diving", and is either necessary or highly advisable for certain types of advanced diving, then would we not be doing new divers a favor by teaching them in a configuration that will carry them wherever they may want to go in the future? I don't know anybody who planned to be a technical diver when they took their OW course. Despite that, I've somehow managed to meet a fair number of technical divers...

Obviously I'm not saying that I expect the entirety of the dive industry to suddenly switch gears and standardize on the BP/W. Nor am I saying that it is inappropriate to teach somebody basic OW in a jacket/vest BC. What I AM saying is that there are a number of axes of evaluation along which a BP/W could be considered superior, and this one seems very important and should be relatable.

 

[MauiScubaSteve]

I'm going to develop a drag-o-meter.

I'm going to find a swimming pool machine, one of those swimming tubs that is like a treadmill for swimming. I'm going to rent a bunch of poodle jackets from my LDS and make sure they fit, and I'm going to put them up against several different BP/W rigs.
I am going to find a point on the grate of the water inlet on the front inside of the pool to attach a pulley. I am going to attach a line to me up front somewhere like maybe under my chin from a special harness. Then I am going to run the line through the pulley and attach the line to a digital fish weighing scale outside of the pool which will be attached to a fixed point.
I will have a technician watch how much load is put on the scale as the water begins. The test will include many water speeds with both the jackets and the plate/wings. All the data will be recorded by the technician, an there will be a videorgapher present recording the whole experiment as it happens for proof.
I will just be laying prone in the pool hooked up and staying in the water column completely submerged as the water flows by. I will keep my arms to my sides and hold the exact same position with both setups. I will not be kicking at all, my legs will be behind me and still. The tank and reg/routing used on all units will be the exact same.

The whole purpose of this is to see just exactly what the difference is with the slipstream efficiency of each unit tested and the resulting load on the scale.

This is about as scientific as it gets. I will post my findings once I find someone with one of these swimming treadmills that I can use to complete this experiment.

Which ever system wins, I want to end this once and for all with positive scientific proof.

I have spent some time thinking about coefficient of drag testing.

At first I also was thinking an endless pool would answer the question, but the lack of depth is an issue.

Also, the drag meter test does not test how a diver actually propels themselves through the water. Different divers in different rigs have different angels of attack and use different leg motions with different fins. Even different divers in same rigs and same fins will angle and fin differently.

The same applies to dive scooters; some are experienced with riding the nose or saddle and others are experienced with being towed.

I would love to swim against current, at various depths, and over varying terrain, side by side against a svelte BP/W diver who also uses Cressi Gara2000's and is in the neighborhood of 6' tall, 175 lbs, trading BC's for equal testing in all those different depths and terrains in both rigs, and then have some sort of comparison data to make conclusions from.

Even that would have at least a couple hard to take into consideration variables; like perhaps one diver not having any experience in one style of rig and the other diver having experience in both styles and one diver perhaps having a better SAC during nominal current dives and the other perhaps having better conditioning, thereby closing the SAC gap as current increases.

My favorite test facility would be something like a 10 meter long, 3 meter in diameter aquarium tunnel section, with perhaps 4 scooters mounted to thrust "into" one end, suspended horizontally from a support boat with winch lines so it could be set at any depth down to 30 meters. There could be ink nozzles and many video cameras and divers could test different gear to find what they are best streamlined using. Even with all that, I would expect some divers to get better results in different gear than other divers.

 

[MauiScubaSteve]

Ah, good. So, we're on the same page with regards to the fact that, regardless of whether or not a BP/W is superior for "basic OW diving", a jacket/vest BC is insufficient or inappropriate for divers pursuing certain forms of advanced training. Right? I would say that we're also - at best - at a stalemate with respect to any discussions involving "streamlining".

Given all of that, let's talk about this equipment choice as diving instructional professionals. One of the accepted principles of learning is the Principle of Primacy. One way of interpreting this is that it is always easier to learn something the first time than it is to unlearn and relearn again later. I can speak to this from experience, with numerous examples.

As instructional professionals, our standard of excellence ultimately has to come down to how well we prepare our students to safely enjoy diving and pursue progressively more interesting adventures in the future (whatever that may end up meaning for them). Surely we are better instructors if we can teach things in such a way that they will carry through the new diver's entire diving career, without having to unlearn and relearn them.

If we can agree (which it sounds like we can) that a BP/W is not INappropriate for "basic OW diving", and is either necessary or highly advisable for certain types of advanced diving, then would we not be doing new divers a favor by teaching them in a configuration that will carry them wherever they may want to go in the future? I don't know anybody who planned to be a technical diver when they took their OW course. Despite that, I've somehow managed to meet a fair number of technical divers...

Obviously I'm not saying that I expect the entirety of the dive industry to suddenly switch gears and standardize on the BP/W. Nor am I saying that it is inappropriate to teach somebody basic OW in a jacket/vest BC. What I AM saying is that there are a number of axes of evaluation along which a BP/W could be considered superior, and this one seems very important and should be relatable.

I have never typed or said that divers should not consider BP/W. I have been very consistent in only typing or saying that if a goodly amount of divers (IE. Vast Majority) are evidently diving just fine in Vest BC's, in similar conditions to the person asking for advise and opinions, it seems they should consider Vest BC's. Especially if they were trained in Vest and might also end up renting instead of packing their own gear in the seemingly only rising in cost air travel future.

My beef is with typing anecdotal opinions as if they were facts when giving divers advise of what gear they should chose. Qualifying ones statements with simple words, like "I feel" "for me" "where I dive" "seems to me" and many others, allows for a more accurate and less angry discussion where learning and understanding are not drowned out by attempts to affirm, sell, convert, denigrate and assimilate.

 

[Sas]

My beef is with typing anecdotal opinions as if they were facts when giving divers advise of what gear they should chose. Qualifying ones statements with simple words, like "I feel" "for me" "where I dive" "seems to me" and many others, allows for a more accurate and less angry discussion where learning and understanding are not drowned out by attempts to affirm, sell, convert, denigrate and assimilate.

Do you give people so little credit that you think they can't work out when someone is posting about what type of gear to get, that it is their opinion and not scientific fact?

Perhaps you struggle with working this out, but most do not. And the ones that do probably clarifying it won't help either as they're just thick.

 

[Eric Sedletzky]

I have spent some time thinking about coefficient of drag testing.

At first I also was thinking an endless pool would answer the question, but the lack of depth is an issue.

Also, the drag meter test does not test how a diver actually propels themselves through the water. Different divers in different rigs have different angels of attack and use different leg motions with different fins. Even different divers in same rigs and same fins will angle and fin differently.

The same applies to dive scooters; some are experienced with riding the nose or saddle and others are experienced with being towed.

I would love to swim against current, at various depths, and over varying terrain, side by side against a svelte BP/W diver who also uses Cressi Gara2000's and is in the neighborhood of 6' tall, 175 lbs, trading BC's for equal testing in all those different depths and terrains in both rigs, and then have some sort of comparison data to make conclusions from.

Even that would have at least a couple hard to take into consideration variables; like perhaps one diver not having any experience in one style of rig and the other diver having experience in both styles and one diver perhaps having a better SAC during nominal current dives and the other perhaps having better conditioning, thereby closing the SAC gap as current increases.

My favorite test facility would be something like a 10 meter long, 3 meter in diameter aquarium tunnel section, with perhaps 4 scooters mounted to thrust "into" one end, suspended horizontally from a support boat with winch lines so it could be set at any depth down to 30 meters. There could be ink nozzles and many video cameras and divers could test different gear to find what they are best streamlined using. Even with all that, I would expect some divers to bet better results in different gear than other divers.

The whole point of the drag meter test is to eliminate any and all physiological human elements from the test so the test won't be skewed in any way. As soon as you put one diver against another or introduce different fins or finning techniques you will have a skewed test and it will be compromised due to too many variables. The dead drag test changes nothing except testing only drag with different BC systems.

 

[gypsyjim]

My first BCD tried to kill me. :shocked2:

Seriously, I first learned dive before the BCD things were heard of, and the first one I tried, I had no training in, AT ALL, so things got a bit out of hand. My own dam fault, of course!

Since then I dived in all kinds of rental gear, which means a variety of jacket BCD's for many many years. They all do basically the same job.

As I began to upgrade and repurchase gear I went from a Sherwood jacket BCD, to Riptide back inflate BCD, and eventually I tried a used H BP/W this last spring. Loved the thing so much I bought the borrowed wing on the spot.

Diving the back inflate for a number of years, I was already quite familiar with the butt dump, but the fit, control and maneuverability I discovered with the wing made an instant believer out of me.

I figure at this point I can dive in pretty much any old thing that fits and does the job, but there is an element of control that the wing brought to my diving that personal experience convinced me of, far more than anyone's words ever would have.

 

[Blackwood]

I have spent some time thinking about coefficient of drag testing.

At first I also was thinking an endless pool would answer the question, but the lack of depth is an issue.

Also, the drag meter test does not test how a diver actually propels themselves through the water. Different divers in different rigs have different angels of attack and use different leg motions with different fins. Even different divers in same rigs and same fins will angle and fin differently.

Why do you need depth to measure drag? Deep enough to completely submerge is deep enough for the test.

And if it's C_D you are concerned with, then kicking styles and scootering positions are irrelevant. An endless pool or a water tunnel would be fine. So would a low-speed wind tunnel or an illicit copy of Fluent.

Do you give people so little credit that you think they can't work out when someone is posting about what type of gear to get, that it is their opinion and not scientific fact?

Exactly. This is an opinion based board (except maybe within a few subforums). I often disclaim my own posts ("in my experience," "for my dollar," etc.), but not always, and I'm not intending to purport unequivocal fact when I don't.

It's not like "He begot She, She begot Them, and They begot Bill Main who bestowed the Hogarthian Gear Configuration, and it was good, and in the seventh cave he rested."

I imagine most users understand that and wouldn't take as gospel that a Jet Fin is better than a Twin Jet because I responded to a thread titled "what do you like better?".

 

[adurso]

No one has linked Jep's video yet?