Questions concerning Backplates.

[rhwestfall]

well, sort of proves he just isn't "winging it"......

 

[stuartv]

The reality remains that for gas to transfer across the lower arc of a donut wing one needs to be almost completely heads downs.

So, the answer is, yes, the donut has an advantage over a horseshoe, but only in a head down situation.

We won't be adding a 2nd dump. All BC's need at least one OPV, to prevent rupture. Adding another OPV to solve a skills deficit is not a path DSS will be choosing anytime soon.
...
There will never be a substitute for planning ahead WRT to buoyancy.

And, no, there will be modifications to make the horseshoe equal to the donut, because if you end up in trouble because of this issue with a horseshoe, it's because you don't have good enough skills and should have planned ahead better.

This reminds of a article I read earlier this week regarding a shooting. Someone actually commented that the guy that got shot should have seen the other guy coming.

Fortunately, in scuba diving, nobody ever makes mistakes (in their actions or their planning) and nothing (that was legitimately) unforeseen ever happens that could cause someone to need to dump all or most of the air from their BC while being in and maintaining a head down position.

I'm writing that down in my notebook right below "you will never NEED to fix a pinch flat on a wing bladder while in the field."

I'm so glad to be learning about new (to me) things that will never happen. I am a worrier and I like being able to cross things off my List of Things to Worry About.

 

[rhwestfall]

 

[cool_hardware52]

So, the answer is, yes, the donut has an advantage over a horseshoe, but only in a head down situation.

All those who routinely end up making inverted runaway ascents should no doubt buy only donut wings and of course avoid drysuits unless they add butt and ankle dumps to those too......

Tobin

 

[Dhboner]

The correct answer is to take appropriate training to use the equipment you own and not rely on the internet to teach you how to dive.

 

[TSandM]

When I was a novice diver, I had a lot of buoyancy problems. I soaked my dry suit dump valves, because I was sure they weren't dumping. I'm sure I would have wanted a torus wing, too. I was convinced my undergarment was jamming my dump valve.

Interestingly, for the last 8 years or so, none of my dump valves have gotten sticky. None of my undergarments have jammed them, and I've survived with horseshoe wings on both my single and double setups.

I am not trying to be nasty. I'm just saying that, when a lot of experienced people are trying to tell you that a problem you had was of your own making, perhaps it was.

 

[ams511]

I am not trying to be nasty. I'm just saying that, when a lot of experienced people are trying to tell you that a problem you had was of your own making, perhaps it was.

What I see is a pattern. When anyone criticizes Tobin or his products then it is the user's problem. The user is inexperienced, careless, whatever.

Looking at the market for single's wings I know of only two that use the horseshoe design. 1) The DSS LCD series and the Zeagle Express Tech with the 24 lb lift wing. The Zeagle wing includes two dumps at the bottom outside of each pontoon. Why? Did Scott Zeagle (Zeagle was independent when the Express Tech was designed) not know what he was doing? Did he knowing and purposefully put forth an inferior design? Well according to Net Doc, the owner of SB, and the huge thread he started, it is the last BC you ever need to own.

Every other singles wing on the market I am aware of uses a doughnut shaped bladder. Why? Are people such as Jarrod Jablonski, Lamar Hires, Bob and Mike Hollis, inexperienced and don't know what they are doing? I don't think so. I have never once read a post where Tobin explains why a horseshoe shape is better than a doughnut. All that is said is that he offers both. If a horseshoe shape offers no advantages over a doughnut shape then why design it that way?

The DSS Torus line are the only wings I know that use an inner bladder but don't allow access to it. The supposed advantage is the wing is thinner when deflated and you really shouldn't patch a bladder. So if it gets a hole in it then send it back to DSS. What if I am in the Philippines with you and Peter and the wing gets a pinch flat because of rough handling by the DM. How do I send it back to DSS from there? My only option would be to borrow, rent or buy a BC to do the dives and wait until returning to the US to get the wing repaired. If a wing with no access is better then why doesn't every manufacturer do this?

Tobin does have some innovative designs on the backplate and accessory items but the wing designs are atypical of what is offered in the market place with no communicated advantage. Why design it that way if it gives inexperienced divers problems?

 

[danvolker]

What I see is a pattern. When anyone criticizes Tobin or his products then it is the user's problem. The user is inexperienced, careless, whatever.

Looking at the market for single's wings I know of only two that use the horseshoe design. 1) The DSS LCD series and the Zeagle Express Tech with the 24 lb lift wing. The Zeagle wing includes two dumps at the bottom outside of each pontoon. Why? Did Scott Zeagle (Zeagle was independent when the Express Tech was designed) not know what he was doing? Did he knowing and purposefully put forth an inferior design? Well according to Net Doc, the owner of SB, and the huge thread he started, it is the last BC you ever need to own.

Every other singles wing on the market I am aware of uses a doughnut shaped bladder. Why? Are people such as Jarrod Jablonski, Lamar Hires, Bob and Mike Hollis, inexperienced and don't know what they are doing? I don't think so. I have never once read a post where Tobin explains why a horseshoe shape is better than a doughnut. All that is said is that he offers both. If a horseshoe shape offers no advantages over a doughnut shape then why design it that way?

The DSS Torus line are the only wings I know that use an inner bladder but don't allow access to it. The supposed advantage is the wing is thinner when deflated and you really shouldn't patch a bladder. So if it gets a hole in it then send it back to DSS. What if I am in the Philippines with you and Peter and the wing gets a pinch flat because of rough handling by the DM. How do I send it back to DSS from there? My only option would be to borrow, rent or buy a BC to do the dives and wait until returning to the US to get the wing repaired. If a wing with no access is better then why doesn't every manufacturer do this?

Tobin does have some innovative designs on the backplate and accessory items but the wing designs are atypical of what is offered in the market place with no communicated advantage. Why design it that way if it gives inexperienced divers problems?

Of course this is conjecture, though I do know the people that created Halcyon wings ......I think the 18 lb horseshoe wing is/was slicker than the 30 lb wing, and this may partially be the hydrodynamics of the two shapes--how they differ. The horseshoe is more like a catamaran for the water flow--with two slick hulls.....The donut shape is NOT as good at being pushed or dragged through the water efficiently.... And then we go on to what the "market" cares about, and I am in the 1% that cares about the extreme low drag for a BC system....So what I am saying, is that I think that Halcyon and others decided that the market wanted what they wanted.....and the slickness of the horseshoe was not significant to them....and that the familiarity with the donut caused the "market" to have a more warm and fuzzy reaction to it, regardless of actual functional differences.

 

[cool_hardware52]

Why design it that way if it gives inexperienced divers problems?

If donuts provided real advantages over horseshoe designs I'd offer only donuts.

Donuts offer perceived advantages, not real advantages. One need only review the 1000's of threads where divers claim donut wings have all sorts of magically properties that require suspending the laws of physics to achieve.

My personal favorite is the myth that donut wings "allow" the gas in them to "circulate"

Or the contention that you can't preferentially maintain more gas in one side of a doubles donut to offset the weight of stages. Apparently these folks think the gas in a donut wing is going to move *down* under the lower end of the cylinders all by it's self.

Any one who has actually used a doubles donut knows it's no special trick to have more gas on one side vs the other.

One need only look at er ah well "general fluffiness" that has crept into several corners the BP&W world, adjustable harnesses, multiple drings, waist belt mounted weight pockets, plate pads, shoulder pads, multiple gas dumps etc. etc. etc. to realize that prepurchase perception vs actual performance in the water is now driving design far too often. It's all an effort to attract divers trained on jacket BC's that look at BP&W as uncomfortable and hard to use.

That most wings marketed today are donuts isn't proof that horseshoe style wings are inferior, any more than the predominance of jacket BC's is proof that BP&W's are inferior.

Tobin

---------- Post added March 28th, 2015 at 08:05 AM ----------

What is the genesis of the "Only donuts wings work" myth?

The first BP&W's were all an effort to provide a better means to mount and provide buoyancy for doubles, at the time there were other solutions for single tank diving.

That meant all of the wings available in the early days were high capacity, wide center panel, horseshoe style wings. 60-90 lbs with 10-12 inch wide center panels (the center panel of a wing does not inflate)

Eventually somebody rigged up a single tank adapter and fitted to a plate with the only wings available, i.e. a huge, wide , floppy doubles horseshoe.

If you have ever had the experience of diving such a set up you know it it near impossible to vent these monsters without going vertical in the water column. Same for some of the back inflate "Tech" BC's that claim to be fit for use with doubles. These invariably feature hugh capacity horseshoe bladders with 10-12 inch center panels.

At some point some body built the first dedicated singles wing, and it happened to be a donut, I suspect in part because of the construction method used, single layer. Very simple welding dies can be used to make smaller donuts.

If you compare the experience of diving a ~70 lbs doubles horseshoe with a Single tank to diving the same tank with a ~30 lbs dedicated singles wing it's quite obvious the smaller, narrower wing is *FAR* easier to vent, but not because gas is magically "circulating" across the lower arc of the donut. It's easier to dive because of the greatly reduced tank wrap allows gas to pass across the top arc of the wing without requiring the diver to be vertical. Slight heads up is all that is needed.

It was exactly these observations that lead me to weld shut the lower arc of donut wings and have divers test them, they could not tell the difference.

Donut wings are in "fashion" and if you sell only donut wings it serves you to promote the myth.

Tobin

 

[danvolker]

From the early 90's to around 1997, the average dive consumer was so "stupid", that they based their purchase decisions on new BC's, on the sudden availability of new colors, bigger or more pockets, and a host of features totally antagonistic to better performance of a BC....Halcyon was able to knock many "conscious" for a while, and DSS and others have continued this trend to attempt to push "Function" over DEMA hype.
Bottom line, the mass market is a place where what is selling well, often has no relationship to what is good...Remember "Pet Rocks", "Slinky's", and "Hula Hoops" ? The Dive industry has been selling "Hula Hoop BC's" with great success, for decades now