COMPARISON: Backplate and Wing to Stab Jacket BC

[rcohn]

Comparison: Backplate and Wing to Stab Jacket BC -- PART 1



After reading glowing reports for over six years online about the wonders of backplate and wing (BP&W) buoyancy compensators, I decide to try one for some dives to find out for myself. I would have tried one earlier, but no friends had offered to lend me one and I don’t know of any local shops here in New England that rent them. So, on a Memorial Day weekend trip to Florida I decide to rent one and see what all the fuss is about. Please bear in mind that my opinions/conclusions are based on my personal prospective, which I will try to explain. I hope this report may be of some help to divers considering switching to a BP&W.



I have been using a ScubaPro Classic stab jacket BC for six years. I initially used a horse collar back in the late 70s. My only previous experience with a back inflate BC was a brief pool test of a Zeagle. I have had occasion to use other jackets for a few dives over the years, mostly when assisting in BOW pool training sessions





Fill Express and the gear we rented



After searching online and asking some Florida divers for recommendations, I decided to use Fill Express in Pompano Beach, FL http://www.fillexpress.com/, which proved to be a terrific choice. I can’t say enough good things about the time and effort Mark the owner put in helping us get set up and fitted and answering all our questions. The low cost of the rental was in no way commensurate with the time and help Mark gave us. Fill Express is an exclusive Dive Rite dealer (the shop only carries Dive Rite products) therefore all pieces rented were of course made by Dive Rite



I rented a Deluxe Harness aluminum backplate with a Venture Wing (donut type with 30 lb rated buoyancy) and a plastic or fiberglass dual-strap single-tank adaptor (STA). Mark initially suggested I try the Transpac for recreational use, but I requested the BP. With the adjustable straps, Mark was able to fit the plate rather quickly after changing the waist belt to one small enough for me. I requested a pocket and Mark added a small one saying that I’m too skinny to have space on my belt for a larger one. He also supplied a couple of clips to hold gear in place and an inflator hose. I tested the regulator and BP&W with a tank, listening for leaks and making sure the wing (brand new) held air. I wore the full system and was surprised to find my left shoulder hurt under the weight. “So much for the perfect harness” I initially thought. Later I realized it was the plastic quick release on the left side pressing directly on my collarbone. This formed the best argument I know against adding a quick release to the harness.



My wife has been complaining for some time that she finds her ScubaPro Classic to be a poor fit, too loose and riding up at the surface. The Dive Rite Rec Pac Jacket BC looked like a potential alternative providing a Transpac type harness on a non weight-integrated jacket. This option was quickly eliminated when the smallest size proved to be too large. Mark then offered to fit here with the “perfect BC”, the Transpac II with Travel Wing. We were hesitant, but decided to take the opportunity and she was easily fitted with the Transpac II. This harness fitted her very snugly.



My preference would have been to try an easy beach dive to test out the new gear, but under the travel circumstances with my wife, this was not possible. Donning the gear back in our room and drilling her on the location of the buttons and dump valves would have to suffice. I added a signal mirror, pair of shears and folding knife to the pocket, but my Carter safety sausage would have to stay behind, there was no room. It fits comfortably in a pocket on the SP Classic. We were off the next morning to dive at Boynton Beach with DCI.



Once on the boat, I set up the BP&W with a 4 lb tank weight at the top and 4 lb on my belt, assuming the Al BP gave me around 2 lb. I had last been using 5 lb weight at the tank top and 5 lb belt with the SP Classic and the 4/3 mm Bodyglove wetsuit (plus 7 mm hood and 5 mm booties) being worn today. Placing the tank weight at the top appeared to make the tank ride very high (but I can usually tolerate a rather high tank). For my wife we placed all the weight on her belt to keep the tank at a reasonable height.

 

[rcohn]

Part 2 -- The story of the dives



I’ll digress from the BC discussion for a bit to tell you about the dives, you can skip down if uninterested. My wife is recovering from a herniated disk in her neck therefore; we made the request that her tank be donned in the water. She requested that we dive the shallower inside reef ~60 ft rather than the deeper outside ~85 ft.



We were assigned to dive with another pair of divers (these are drift dives, each group gets a flag). One diver was a cave diver and an instructor; I don’t know the experience of the buddy. I’ll just refer to them as Cave Diver and Buddy,



Here is the gist of the conversation once they found out we were diving together. Cave Diver said, “Well how do you two do on air?” I replied we were ok but we were testing new BCs today, which might have an effect. A more direct question followed, “are you air hogs?” my wife assured them we weren’t, but they looked skeptical. Note that both C.D. and Buddy were rather heavy set, appeared out of shape, and our age or older. We told them that my wife takes a long time to descend and they should proceed with the dive and we would follow the flag line down at our own pace.



I jumped in first, had a quick chance to see how the wing felt on the surface and then took my wife’s tank and helped her get into the Transpac. When she was set, I looked around and saw Cave Diver at least half way to the bottom with Buddy still on the surface. I also noticed a blue fin slowly sinking into the depths. I found the inflator, dumped air, dropped down to catch the fin (my first descent with the wing) and brought it back to Buddy. I then told my wife to get started down, as the boat races up with the DM yelling, “Are you ok? Are you ok?” I signal I’m ok and check with Buddy getting an ok sign back. We then get a brief loud lecture from the DM that waving is a sign of distress. There were three divers on the surface and I can assure you neither my wife nor I were waving.



We begin our descent and as I looked up I see Buddy still on the surface, he then proceeds to return to the boat. After the dive, he told me he was under-weighted. Once we reached the bottom, after looking around Cave Diver holds up 3 then 4 fingers with a question. When I realized what he was asking, I replied only 3 divers left.



After awhile on the bottom Cave Diver signals his gas supply, 1500 psi, and asks for mine. I reply 1700 psi. He repeats this with my wife who has 2000 psi. Awhile later, the air checks are repeated and the gap has widened in our favor. At some point, he gave the flag to me, waved goodbye and began his ascent. We left that bottom after 43 minutes and surfaced at 54 minutes average depth 45 ft, max 60 ft. We did a very slow ascent with a deep stop at 30 ft, knowing we’d have the standard Floridian short surface interval (1 hr for air, 30 minutes for nitrox.) On the boat he again checked our gauges. I had a bit over 650 psi and my wife replied 1500 psi (I checked her gauge to see that one for myself).



My tank was very high during the first dive, but my trim worked out very well. For the second dive I placed the tank weight between the twin straps and placed the STA near the top of the tank, the tank was still too high, a different STA might be in order. The trim was slightly more foot heavy but still acceptable. I would probably mount the tank weight on the upper STA strap if I continued with that setup.



The second dive went more smoothly and my wife felt confident enough to take her camera. Cave Diver asked me to take the flag this time and I agreed. Normally carrying the flag is no problem, but with at least 70 ft of line out in a strong current I felt like I was being pulled along by a large kite. I could make no real progress against the current towing the flag, which prevented pausing to check out interesting critters. All four of us made it to the bottom. Air checks were repeated. At about 20 minute into the dive, Buddy signaled he had 1000 psi left, waved goodbye, and began his ascent. I looked up several times to check on him and it seemed like he reached the surface rather quickly, but I wasn’t watching closely enough to be sure. He told me after the dive he was over weighted this time, which caused the short bottom time. Several of minutes later Cave Diver came by and repeated the 3 or 4 diver question, I replied 3. I didn’t note the time he waved goodbye, but in the end only the “air hogs” were left on the bottom. We started our ascent after 44 minutes and surfaced at 54 minutes average depth 47 ft, max 61 ft.. I noted from the air in the wing when I reached the surface with about 650 psi that I could drop around one to two pounds.

 

[rcohn]

Part 3

Impressions of the BP&W performance



Now for my impression of the BP and Venture Wing, it was clearly an excellent BC. It held the tank very stably on my back with the belt possibly a bit looser than needed with the SP Classic. It was very comfortable, no pain in the left collarbone underwater and the belt fell below my ribcage where I like it. I could move to and easily maintain any position I wanted underwater, inverted, roll to the side, or vertical. My trim was reasonably horizontal but the tank was much too high (not a major problem my neck isn’t that flexible). I donned my weight belt over my crotch strap where it fit comfortably. My chest was now very uncluttered, BFD. It felt rather streamlined but I had no way of testing for comparison to a jacket BC, it may have merely been my imagination. I could feel the air traveling from side to side under the bottom of my tank when I rolled. It pulsed through the restriction caused by the tank, “blub, blub, blub” a minor annoyance, but it proved air does readily travel around the donut under the tank and this prevented air trapping and provided stable positioning.



On the surface, I found it extremely easy float on my back, trying this with both full relief-valve-popping inflation and partial inflation. Surface conditions were calm. Only very minimal effort was required to maintain this position. However, minimal effort was required, this means that as expected the Al BP with 4 lb tank weight is stable in the face-down position and unstable in the face-up position. When I went limp, I rolled onto my face after a few seconds regardless of whether the wing was fully or partially inflated. Significantly more ballast would be needed on the back to make the face-up position stable. For warm-water diving, this would typically overweight the diver.





My viewpoint on face-up floatation



Here is my decidedly minority viewpoint on heads-up floatation for recreational diving. I believe that the BC is one of the few pieces of safety gear we have available and ideally it should support our basic needs both below and on the surface. A significant fraction of the deaths reported each year occur on the surface not at depth, although DAN does not provide a statistic in the 2004 Report on Decompression Illness, Diving Fatalities and Project Dive Exploration. I try to keep in mind thats**t can happen in the ocean that will disable any diver, stings from jellies, bristle worms, scorpion fish, etc.; medical conditions such as heart attack or stroke; waves slamming a diver into the rocks or a hit from a jet ski; exhaustion from fighting strong currents or drifting for hours if lost; and of course AGE or other dive related injuries. Many divers assume that their buddies will save them (usually the same divers that argue for self sufficiency in all other areas). I know I do not always dive with a reliable buddy. Some days I dive solo, or with beginners, or photographers, or any highly qualified buddy who doesn’t keep his or her eyes glued to me every second. None of us can breathe water. In some circumstances, it may only take a few seconds with your face underwater to inhale water, which has very serious medical consequences even if you are promptly rescued and revived.



While configuring for heads-up floatation is certainly no guarantee of safety in all circumstance, I like to increase my chances of surviving a rare, but critical, accident. I also believe that the divers who obsess about any piece of plastic in their rig should spend more time thinking about issues that actually might kill them.

 

[rcohn]

BP&W vs. ScubaPro Classic



Ø Both BCs hold the tank stably, BP has slightly less tank motion with a possibly slightly looser waist belt which is a small advantage, but I find both BC’s more than adequate. [+ for the BP&W]

Ø Both BCs are very comfortable, easy to move in, and not noticed when swimming in the water.

Ø Both BCs can easily be trimmed for a comfortable horizontal position.

Ø Both BC’s support the weight of the tank comfortably (ignoring the quick release/collarbone issue) when walking out of the water.

Ø The BP leaves the chest area uncluttered, but I really don’t care.

Ø No crotch strap is needed with the SP Classic. To me this is an advantage, the crotch strap can be an issue when dealing with a weight belt. [+ for the SP Classic]

Ø My SP Classic has generous pockets (newer weight-integrated versions may not) Safety gear (strobe, sausage, mirror, and spool) always goes in the left and the right is free for gloves or items picked up during the dive. The right small zippered pocket carries a folding knife or line cutter. I have a good way of attaching a snorkel as well. [+ for the SP Classic]

Ø Face-up flotation an obvious advantage of the SP Classic which is rated as a Life Preserver by the US Navy when used with a properly weighted tank. [+ for the SP Classic]

Ø I believe that a shoulder dump is an important safety feature for recreational divers. The cable to the Venture Wing dump is in the hose and there has been extensive discussion about the safety issues with this design on Scubaboard and others. Shoulder dump on my SP Classic is on the right shoulder with a separate pull cord. Note newer SP Classics have two shoulder dumps, the second in the hose. [+ for the SP Classic]

Ø Many on the boards would suggest that the BP&W, the “ideal BC”, is really two ideal BCs, an aluminum BP with small wing for warm water and steel backplate with larger wing and heavy STA for cold water. Obviously, this would be a bit pricey. The SP Classic great in all conditions. I’ve worm mine comfortably from drysuit diving in 36 degree water with layered undergarments to 3 mm shorty in Bonaire. [+ for the SP Classic]

Ø The SP Classic has relatively high lift (I think rated at 44 lb for my medium) which is very stable because the air cell wraps around your body. Many users report larger wings have stability and air trapping issues if used with single tanks. I believe higher lift can be a safety factor in some circumstance (e.g. supporting or lifting an injured buddy) [+ for the SP Classic]

Ø BP&W is somewhat easier to get in and out of due to larger arm openings, but not nearly as easy as adjustable straps [+ for the BP&W]

Ø Neither BC compresses my chest when inflated. My SP Classic has never caused any body compression while diving. If fully inflated on the surface there is firm pressure on my sides but the chest remains unrestricted.

Ø Both BCs allow good freedom of movement.

Ø More streamlined??? This is the big question and I wish I had an answer. Many have claimed it, but no one to my knowledge has offered a shred of evidence. Lepomis on the D2D board is threatening to run a BC test similar to his fin testing (see: http://www.ndsu.edu/instruct/grier/fins.html) and I’ll be eager to see the results. If I get the chance, I may even help with the tests.





My wife’s impressions of the Transpac II with Travel Wing



She was very happy with the stable fit of the Transpac II, no more problems with the BC riding up. Because we were donning the BC in the water, the crotch strap was placed over her weight belt, I would rather see the weight belt on top. My wife felt that the SP Classic was easier to don in the water. The Transpac II needed to be completely buckled with the crotch strap in place or it floated up high above her back. She only needed her arms in SP Classic to get it to the proper orientation, making fastening the belt and chest strap much easier. Furthermore, she reported that is seemed that her head floated higher above the water with the SP Classic. She managed the surface conditions easily and had no trouble floating on her back. However, she strongly prefers the face-up position of the SP Classic. She knows if she feels uncomfortable, she only needs to lean back, hit the inflator button, and the BC will support her. This is something some of the local experts might want to consider when directing every newbie, whose level of skill and comfort you know nothing about, to a back inflate BC.



At the end of her dives, there was a large amount of water in the wing. This seemed surprising because she was slightly over weighted. She found the Transpac II to be comfortable and easy to control underwater, however she also felt there was little difference in this respect from her SP Classic.



Her complaint about the ScubaPro Classic has been that it rides up on her, particularly on the surface. She is still using the cummerbund that the BC came with. I hated mine because it covered my lower ribcage restricting breathing, so I replaced it with a simple webbing and buckle three or four years ago. She has never dived with less than 5 mm of neoprene on her torso; therefore, a cummerbund is not required for comfort. I suggested we replace the cummerbund and add a crotch strap, which is what we did for Sunday’s dive. Her new crotch strap now has a brass scooter ring, very teckie. She found this configuration to be much more comfortable (why does it take her so long to try my suggestions?). She noted the BC was now very stable, not quite as stable as the Transpac II, but certainly she would not spend $550 to change it. She will try diving without the crotch strap in the future to see if the webbing belt alone is sufficient.

.



Were Saturday’s BP&W dives better than Sunday’s Jacket dives?



I have to admit the answer is YES. On Saturday, the visibility was better, the water was warmer, and we saw a huge ancient-looking loggerhead turtle on the second dive. We’ve seen our share of hawksbill and green turtles but this was our first loggerhead sighting. The Cave Diver, who has much more Florida diving experienced, identified it as a Loggerhead and said it was the largest he has ever seen. We also saw two hawksbill turtles, as it was the time of year that turtles lay their eggs on the local beaches.



Were the different BCs a factor in my enjoyment of the dives? Absolutely not, both were comfortable, stable, and balanced during the dives effectively disappearing. If I hadn’t been concentrating on the BP&W during the first dives I hardly would have noticed I was wearing it, but the same statement applies to the SP Classic.

 

[rcohn]

Conclusion



The Dive Rite backplate and harness together with the Venture Wing was an excellent BC, stable, balanced, and controllable, and I’m sure any diver who wants a back-inflate style would be very happy with it. Of course I can’t say that it is the ideal back-inflate system having never tried any of the others such as a soft Transpac or Zeagle style.



However, the ScubaPro Classic is also an excellent BC and still my choice, as well as my wife’s. As you can see from the greater number of plusses it earned in my comparison, it remains my choice for warm and cold water diving. Each decision about gear selection is based on the assumptions about conditions and risks and the stab jacket better satisfies my personal set of assumptions and priorities than does the BP&W. I have no preexisting agenda, if I felt switching to a BP&W would significantly increase my enjoyment of diving without compromising my safety I would certainly make the change. I simply found that for me that both BCs were equally comfortable and effective underwater and I was equally happy diving with either of them.



There is one key remaining issue that might alter my decision in the future. If it can be quantitatively shown that the BP&W is significantly more streamlined than a jacket, I would reconsider. I’m not talking about 5% better, but something more like 50% better. The ability to swim against currents, downdrafts, and cover large distances if needed is also an important safety issue and a major factor in enjoying challenging dives. These conditions are more commonly encountered than face-up flotation when incapacitated, and would probably sway my choice to the BP&W



.I hope a few readers have made it through this long report and my comments are somewhat helpful. I’m sure I will receive many warm and appreciative comments from the BP&W fans on the board. The assertion has been made many times that once you try a backplate and wing you will never go back to a jacket. Well please give me a break with the over-hyping of this system. I’ve finally tried a BP&W and I’m heading straight back to a stab jacket BC.





Ralph Cohn

 

[SubMariner]

[I hope a few readers have made it through this long report and my comments are somewhat helpful. I’m sure I will receive many warm and appreciative comments from the BP&W fans on the board. The assertion has been made many times that once you try a backplate and wing you will never go back to a jacket. Well please give me a break with the over-hyping of this system. I’ve finally tried a BP&W and I’m heading straight back to a stab jacket BC.

Wow, Raph... what a great report!

Many thanks for sharing it with us. Maybe we need to make you the unofficial SB gear tester?

 

[DutchDown]

Thanks for taking the time and efort to write the report!

Phil

 

[japan-diver]

BP&W vs. ScubaPro Classic


Ø No crotch strap is needed with the SP Classic. To me this is an advantage, the crotch strap can be an issue when dealing with a weight belt. [+ for the SP Classic]

Ø My SP Classic has generous pockets (newer weight-integrated versions may not) Safety gear (strobe, sausage, mirror, and spool) always goes in the left and the right is free for gloves or items picked up during the dive. The right small zippered pocket carries a folding knife or line cutter. I have a good way of attaching a snorkel as well. [+ for the SP Classic]

Ø Face-up flotation an obvious advantage of the SP Classic which is rated as a Life Preserver by the US Navy when used with a properly weighted tank. [+ for the SP Classic]


Ø Many on the boards would suggest that the BP&W, the “ideal BC”, is really two ideal BCs, an aluminum BP with small wing for warm water and steel backplate with larger wing and heavy STA for cold water. Obviously, this would be a bit pricey. The SP Classic great in all conditions. I’ve worm mine comfortably from drysuit diving in 36 degree water with layered undergarments to 3 mm shorty in Bonaire. [+ for the SP Classic]

Ø The SP Classic has relatively high lift (I think rated at 44 lb for my medium) which is very stable because the air cell wraps around your body. Many users report larger wings have stability and air trapping issues if used with single tanks. I believe higher lift can be a safety factor in some circumstance (e.g. supporting or lifting an injured buddy) [+ for the SP Classic]

Ø BP&W is somewhat easier to get in and out of due to larger arm openings, but not nearly as easy as adjustable straps [+ for the BP&W]

[
Ø More streamlined??? This is the big question and I wish I had an answer. Many have claimed it, but no one to my knowledge has offered a shred of evidence. Lepomis on the D2D board is threatening to run a BC test similar to his fin testing (see: http://www.ndsu.edu/instruct/grier/fins.html) and I’ll be eager to see the results. If I get the chance, I may even help with the tests.





]

Overall a good comparison but just a few things to add:

A crotch strap is not needed on a BP and wing if single tanks are used. Although this is almost standard on most BP/W harnesses sold it can be removed for single tanks.

Pockets on a BP/W can be added/removed as needed. If the waist is to small a thigh pocket can be added to the harness. I like the DR thigh pocket when I need it I use it when I don't I leave it in the bag or use a smaller pocket on the waist band. This ability to easily customize the harness for dives I think is a big plus for the BP/W set-up.

I have a SS BP and wing and use it for warm and cold water with the only change being adding a heavy STA in cold, total set-up still cheaper than a SP classic. No need to change the wing a 30lb wing works in warm or cold water. If lots of lift is desired, don't agree its needed, but if desired a OxyCheq makes a very small 45lb single wing, Halycon a 36lb and I'm sure I'm missing some others.

Harnesses can be custom fit also for thick suits or thin and can provide a more perfect fit through the range of suits a diver may wear. Also if you like adjustable straps there are numerous harnesses available (Trans-Plate etc) that offer that option.

BC as life jacket, for proper trim while diving the BC won't work as a life preserver- not whats its there for and definately not to be counted on. Scuba Pro jackets are the most common BC we see over here in Japan and I don't think many would hold an unconcious diver in a face-up position on the surface as they are worn.

Bp/W or jacket for streamlining- again I haven't measured resistance but looking at numerous video clips of divers the BP offer much less surface area then most jackets by a huge margin. I have also noticed that divers changing to a BP/W are dropping more weight off their belts than just the weight of the plate would suggest. (Change from a Zeagle Ranger to a 5.5lb SS BP/W -9lbs from the belt) I have seen this in numerous instances- less weight = less drag. Although I agree this is not scientific.

Anyway just a few thoughts to round out the evaluation.

 

[rcohn]

Overall a good comparison but just a few things to add:

A crotch strap is not needed on a BP and wing if single tanks are used. Although this is almost standard on most BP/W harnesses sold it can be removed for single tanks.

Pockets on a BP/W can be added/removed as needed. If the waist is to small a thigh pocket can be added to the harness. I like the DR thigh pocket when I need it I use it when I don't I leave it in the bag or use a smaller pocket on the waist band. This ability to easily customize the harness for dives I think is a big plus for the BP/W set-up.

I have a SS BP and wing and use it for warm and cold water with the only change being adding a heavy STA in cold, total set-up still cheaper than a SP classic. No need to change the wing a 30lb wing works in warm or cold water. If lots of lift is desired, don't agree its needed, but if desired a OxyCheq makes a very small 45lb single wing, Halycon a 36lb and I'm sure I'm missing some others.

Harnesses can be custom fit also for thick suits or thin and can provide a more perfect fit through the range of suits a diver may wear. Also if you like adjustable straps there are numerous harnesses available (Trans-Plate etc) that offer that option.

BC as life jacket, for proper trim while diving the BC won't work as a life preserver- not whats its there for and definately not to be counted on. Scuba Pro jackets are the most common BC we see over here in Japan and I don't think many would hold an unconcious diver in a face-up position on the surface as they are worn.

Bp/W or jacket for streamlining- again I haven't measured resistance but looking at numerous video clips of divers the BP offer much less surface area then most jackets by a huge margin. I have also noticed that divers changing to a BP/W are dropping more weight off their belts than just the weight of the plate would suggest. (Change from a Zeagle Ranger to a 5.5lb SS BP/W -9lbs from the belt) I have seen this in numerous instances- less weight = less drag. Although I agree this is not scientific.

Anyway just a few thoughts to round out the evaluation.

Thank you for the thoughtful comments.



Most sources I've read recommend the crotch strap. I haven't tried it without one so I can't comment.

I know about the thigh pocket but it seems like one more complication and an issue when a weight belt is used.

An SS backplate is rather heavy for international travel, particularly to remote locations. Some small planes only allow around 50 lb per person. If a diver is using only say 8 lb it would leave only 2 lb of ditchable weight.

On cost, I see "used" SP Classics in mint condition of the same vintage as my BC selling on EBAY for $100-150, much cheaper than BP&W. New SP Classics are outrageously overpriced.

The United States Navy disagrees with you on the BC as a life jacket. They have rated the ScubaPro classic military version as a Life Preserver when used with a properly weighted tank. You either need a heavy tank or a weight added to a lighter tank about 6 lb with an Al80. I believe it is the only jacket approved for dives where a life preserver rating is required, all the other are horse-collar models. Of course the US Coast Guard PFD ratings are for a different purpose and no BC is approved as a USCG PFD.

On streamlining frontal surface area and total surface area are both important. I know I can’t eyeball the BCs and know what the difference will be. You need to measure it. It can be measured very easily, particularly if the difference is as great as most back-inflate proponents claim. I don’t understand why no one has made data public. Could it be that any tests performed failed to show the desired results?

Thank you again for the comments.

Ralph

 

[rcohn]

Thanks, every couple of years or so I feel I need to contribute something.

Ralph