The following was compiled by an instructor/lds manager and a dm who have extensive knowledge regarding bp/wings and traditional bcd's:
Backplate and Wing Pros
At the heart of the backplate/harness and wing system, the back plate is infinitely adjustable, by YOU, for YOU (rather than by the manufacturer, who decides how it will fit you) Basically, a backplate and wing system straps the cylinder to the diver. Standard jacket BC's strap the tank to the jacket. The result is the weight is borne by the shoulders, and the tank often rests on less than optimally placed lead weights on the waist belt at the lower back. The backplate/harness design allows the tank to be located closer to the diver thus increasing stability.
The backplate and wing setup is more streamlined than a standard jacket BC. This will result in better gas consumption by a diver. Jacket BCs tend to scoop water on the front of a diver. The result is the diver has to perform far more kicks to cover the same distance. With a backplate and wing you will be able to kick and then glide a greater distance. The result is less gas consumption and less buildup of potentially dangerous CO2.
Traditional BCs and some back inflation BCs trap air. A properly design wing will not make use of bungee or other restricting devices. A nice feature of certain wings is the donut shaped bladder. A donut shaped bladder will prevent trapping of air as the wing can dump from the inflator hose or the rear pull dump. Never use the pull dump on corrugated hose of a BC. Pulling too hard can result in tearing the connecting elbow from the air cell. They are not designed to take that stress. Use the deflator button or rear pull dump. Trapping of air usually results in divers thinking they need more weight to offset positive buoyancy. Over weighting leads to increased gas consumption, tougher control of ones buoyancy and potentially dangerous rapid ascents and descents. The additional work required to dive over weighted is compounded by the increasingly elevated CO2 levels. Over weighted divers kick furiously instead of gliding around effortlessly like a properly weighted and trimmed diver.
A properly rigged backplate/harness and wing setup results in no dangling equipment. Dangling equipment is neither good for streamlining, the environment and is a potential entanglement hazard for the diver.
Traditional jacket BCs tend to place all the divers equipment on the jacket and/or in pockets. Backplate/harness and wing users rely on pockets placed on the wetsuit or drysuit. Pockets on the side of the legs are in the slipstream created by the diver and can easily be reached. Pockets located on the BC can neither be easily reached nor seen. Backup lights are secured to the harness of a backplate within the slipstream. These lights are easy to reach and will not be lost due to the method of attachment. A traditional BC diver may fumble for the light in an emergency. This may result in loss of one of the most important pieces of the divers gear.
The backplate harness and wing result in no squeezing of the divers torso. The traditional BC can result in squeezing of the chest cavity and putting pressure on the diaphragm. These will increase a diver's gas consumption and can be potentially dangerous.
The backplate and wing uses no quick-connects (typically plastic in the traditional BC) hardware. The one-piece harness eliminates potential failure points.
It is easier to reach all necessary dive equipment in a backplate and wing than in the traditional BC. Try to image a traditional BC diver carrying several stage bottles and a light. You wont see it because its not possible to do it safely. Proper harness hardware location is necessary to reach, remove and replace many types of equipment underwater. The traditional BC does not permit the use of proper harness hardware or correct attachment locations.
A properly weighted backplate and wing diver will carry less weight on the weightbelt and/or in an integrated weight system than the traditional BC diver. A stainless steel backplate typically weights approximately 6 lbs. An aluminum backplate weight approximately 2 pounds. A properly weighted diver only needs to carry ditchable weight in the amount of the weight of the gas in a tank. This is approximately 6 lbs. Anything more is overkill and can result in rapid ascents should the weight not be able to be dropped in increments.
The backplate and wing provide better trim characteristics. It is far easier to balance a divers center of gravity to the center of lift in a backplate and wing. Weight is placed in the optimal position on the diver, directly over the lungs. This weight is directly in line with the center of lift provided by the divers lungs and wing. Horizontal trim will result in a less tiring dive, decreased gas consumption, less CO2 buildup. Horizontal trim reduces damage to the environment and potentially dangerous silt outs. Proper trim results in more control during ascents and descents. Proper trim permits divers to watch each other during the ascents and descents. Vertical ascents while turning 360 degrees are good ways to loose contact with your buddy. Safety increases with proper horizontal trim.
The backplate and wing is more versatile than a standard BC. A backplate and wing can go from a recreational setting to more advanced forms of diving including overhead environments. The same cant be said of the traditional BC.
The backplate and wing packs up smaller for traveling than the traditional BC. This is increasingly important today with more restrictive size and weight limitations on airlines.
The backplate/harness and wing is a better investment. Although the initial cost is more than a moderately priced jacket BC, over the life of the equipment, the BP and wing design is more cost effective. Many high-end jacket BCs are more expensive than a backplate and wing. The whole backplate/harness and wing system sells for about $500 to $550 depending on the size of the wing. Individually the wing costs approximately $280 to $320, the backplate approximately $140, the harness approximately $40 including hardware and the tanks cam straps approximately $100. Some systems come with a storage pouch in the harness at no additional costs. That is approximately a $60 value. The backplate is good forever and should not need to be replaced. All hardware should last the lifetime of the gear. All you have to replace is about 12 feet of nylon webbing and potentially a wing. The wing will last just as long as the BC. So that is a wash. Traditional BCs sell from $300 to over $600. Back Inflation BCs run approximately $450. When the wing on a BC reaches its lifespan, the consumer starts from scratch.
A backplate and wing is more durable and easier to service. A backplate and harness is nearly indestructible. Todays wings are just as durable if not more durable than any bladder on a BC. These wings were designed to function in extreme environments such as wrecks, caves and ice diving. The wing can easily be removed in the event of a failure. A traditional BC air cell cannot be removed quickly like a wing. This means one must send the whole BC in when repairs are needed. It is far quicker to swap out a wing on a backplate.
Backplate/Harness and Wing Perceived Cons
Back Inflation devices float diver face down on the surface. Not true of a true backplate and harness. Due to the location and weight of the plate and placement of trim weights behind the diver, the diver will float upright on the surface.
It is harder to remove a diver from a backplate and harness during an emergency. No true. Cut the harness. A prepared dive buddy always carries a cutting device (preferably a knife and shears). This only takes a few seconds. The cost to the diver is only the cost of about 12 ft of nylon webbing. A BC costs much more to replace.
The backplate/harness system is not comfortable when caring tanks on land. Some people prefer padding on the shoulder straps to make the BC more comfortable. Are you a diver or someone who just carries likes to carry tanks on land for the fun of it? Get in the water. You wont feel a properly sized harness. Padding has no use underwater and causes excess drag. A properly sized harness allows the tank to be carried very near the divers back, the strongest part of the human body, without undue strain. On traditional BCs the tank tends to pull away from the divers back causing excessive strain and fatigue.
I cant wear a backplate and wing without a wetsuit, drysuit or some other rash guard because the straps dig into my shoulders. Divers should not be diving without thermal protection or protection from aquatic life in any waters. Diving in a swimsuit alone is a good way to lower the bodys core temperature. Hypothermia is bad for off gassing during safety/deco stops. Circulation to the bodys extremities is slowed and can result in poor off gasing, which can lead to decompression illness. There are virtually no waters in the world that wont drop your core body temperature. A thin wetsuit will help prevent a loss in core body temp and is more than adequate to prevent chaffing from the shoulder straps.
A backplate/harness and wing system costs more than a traditional BC. Initial cost is not a whole lot more expensive than a traditional mid to high end BC. Over the life of the equipment, the BP and wing design is more cost effective. The backplate is good forever. All you have to replace is about 12 feet of nylon webbing. The wing will last just as long if not longer than a BC. A BC must carry the weight of the tank(s). The backplate/harness take all the weight. The only wear and tear on an independent wing is user induced. Wings generally sell for about $230. Traditional BCs like a Zeagle sell from $300 to $500. The whole backplate harness and wing sells for about $500. In the long run, the backplate/harness and wing system saves money.
There are no pockets on a backplate/harness. Pockets on a BC make it harder to get to things since you cant see them and they are poorly placed. Pockets should be placed on the wetsuit or drysuit on the outside of the thighs. This permits one to easily retrieve objects without hassle. This also keeps them in the slipstream. Why would one put pockets on the front of a BC and induce more drag.
The backplate/harness and wing are for technical diving and have no place in recreational diving. Absolutely not true. This is the typical answer of someone who is uninformed, uneducated or lacks any real diving experience. There are no differences in the basic fundamental skills needed to dive recreational and technical environments. This belief is a result of the dumbing down of the dive industry. When diving was first available to the public, the courses were far more intense than today and the diver had to earn the card. Today there are far too many individuals in the dive industry only after increased certifications and money.
For diving to be fun and safe, the diver must be confident, competent and comfortable. Although the backplate/harness and wing setup wont make you a great diver, they do improve the chance that the diver will be able to dive fundamentally sound much easier. Only with training and a lot of practice outside of the classes will a diver become fundamentally sound in their diving.
