Buoyancy compensator (diving)

Referred to the BCD, also known as BC or BC ( Buoyancy Compensator) or BCD ( Buoyancy Control Device), is part of the diving equipment. With their help, by blowing or exhausting air, the diver can regulate its buoyancy at any depth and weigh accurately. In addition, the buoyancy compensator serves as a support frame for the compressed air bottle. At the water surface, the inflated buoyancy compensator helps the diver to stay without great expense over water, but BCs are mostly no life jackets, which also injured or save an unconscious person from drowning.

• 3.1 ADV Jacket
• 3.2 Wing Jacket
• 3.3 Hybrid Jacket
• 3.4 Stabilizer Jacket
• 3.5 General

Construction of the BCD

A buoyancy compensator consists of several modules: the buoyancy takes over the main function, the buoyancy of the diver to hold it at the desired depth, or that he may fall and rise. The Harness is used to attach and adjust the Jackets the diver's body. Furthermore, the Jacket is the carrier unit: At the back carrying the jacket is the Atemystem attached consisting of regulators and scuba tank.

Buoyancy

The buoyancy buoyancy compensator is constructed in two sections: The exterior is usually made of sturdy nylon (Cordura ), inside there is a bubble. These can be filled and emptied, depending on the design of the BCD it has a volume of 15 to 45 liters. The term vest describes the design of this piece of equipment best: Dressed as a sleeveless vest it encloses the upper body of the diver and is closed at the front of the diver.

Certain designs, such as the jacket or the hybrid ADV jacket not only in the back area, a bladder, as is the case in the wing jacket, but have lateral parts which are loaded as part of the lifting body as well as with air. In this Jacket pockets are often integrated, which are closed with Velcro or zipper. In the shoulder region, on the side panels and at the bottom of the BCD are - depending on the equipment of the respective Jackets - mostly D- rings; these are larger and smaller loops in the form of the letter D made ​​of metal or plastic for mounting of equipment such as dive light, underwater camera, octopus and much more.

Harness

All Jackets are fixed in the abdominal area the diver's body, this hip and Bauchbegurtung is often done in two ways: Two wide, usually flexible textile tabs, called cummerbund, run close to the belly along and be connected by Velcro. In addition, an adjustable strap with quick release buckle secures the connection. Some models dispense Jacket, mostly for reasons of weight, to the fixation with ' cummerbund ', which, however, no safety, maximum comfort brings a disadvantage. In the chest area in addition adjustable chest straps on some models fitted to hold the BCD at the top. From the shoulder to the side parts carry adjustable shoulder straps with which the buoyancy compensator size of the diver is adjusted. On some models, but especially in designs such as the Wing- Tec jackets or jackets there is still a crotch strap, which is attached to the lower back area and leads to the front, where it is connected to the hip belt. This slippage of the equipment in head-first dive location is prevented.

Back shell, baby carrier

The back part of the BCD is the carrying tray. This is either rigid plastic or metal, made ​​relatively flexible padded fabric in very light jackets, mostly travel Jackets. With a Flaschentragegurt, a special type of belt tensioning the scuba tank is attached to the backpack and so on Jacket. Some models also have two of these bottles risers. Often the bearing surface of the bottle to the diver 's back padded to make carrying the heavy equipment a bit more comfortable.

Corrugated hose / inlet valve / inflator system

On the left shoulder of the inflator hose is connected to the air bladder in the conventional systems. It is a corrugated tube, at its outer end a connection for the coming of the first stage of the regulator low pressure hose is, furthermore, an intake valve, by which the air supply from the regulator is controlled in the BCD, a relief valve for venting the BCD and a mouthpiece for inflating said buoyancy compensator to the mouth. The corrugated hose allows the diver to keep the drain valve when bleeding the BCD about themselves, so that the rising always up air can escape freely.

Drain valves

As mentioned increases air always upward. Therefore, always allow the highest drain valve air release and the position of the diver under water must meet these physical laws. For this reason, are located at several Jackets drain valves: Some BCDs in the corrugated hose, a quick release is integrated. Pulling the Inflator the drain valve is actuated on the left shoulder with a pull rope, allowing the venting of the BCD. There is another drain valve that allows ventilation while diving locations with the head down to the lower back side of the BCD. A third drain valve is located on the right shoulder and is like the back valve usually operated directly. These valves also act as pressure relief valves, so that the air bladder can not be damaged, it should be taken in too much air. This can be done by human error, but also when the filling unit, the inflator, the air supply is defective and does not break.

Inlet valve / indeflator system

Some newly developed BCD eliminates the corrugated hose and is replaced by an integrated intake and exhaust valves. This system is also referred to as indeflator system, this designation is not yet standardized. Three forms of the integrated control of the valves can be found on the market today: Mechanical through linkages, hydraulic oil filled through hose connections and pneumatically by compressed air.

The main argument for inflatorlose valve control is that the disturbing, hanging corrugated hose is eliminated and the operating unit always at the same point is to find - in contrast to the dangling Inflator. The venting of the lifting body is possible in almost every submersible able to straighten up the diver is not required, as is necessary for example to the vent via the inflator.

Main argument against this integrated valve control is that the inflator unit can not be performed as the corrugated hose to the mouth in order to be filled manually with pressure drop of the scuba tank the jacket. For this emergency, Indeflatorsysteme have a small hose to the air filling with the mouth. The practicality is over the corrugated hose, however, significantly limited. On the other hand also is the fact that the operation of the corrugated hose is a standardized learning procedure in diver training and a helping buddy in an emergency with a high probability is common. The operation of the Indeflators, however, should be usefully explicitly agreed prior to the dive.

Corrugated hoses generally

Corrugated hoses are used as described in the diving area above to Tariereinheiten. But also on previously used two hose machine set to a corrugated hoses. When transporting a corrugated hose should be flexible though, not too heavily loaded or kinked.

Types

There are four types:

ADV Jacket

The most common form of the buoyancy jackets is the Adjustable Divers Vest ( ADV; , adjustable diving vest ' ). ADV jackets have at the back on a stable, usually made ​​of plastic backpack where the bottle with the help of one or more straps is attached. The majority of the buoyancy bladder is located under the arms in the hip area of the diver, a small portion around the backpack in the back of the jacket to high at the shoulders. There are of this type Jacket many models, which differ significantly in their equipment part. ADV Jackets are just individually adjustable; the lift is less than Stabilizing jackets.

Wing Jacket

Wings (English, wing ') have only a lifting body on the back, making the diving is facilitated in a horizontal attitude. Guide may have an adverse effect on the surface, because the diver's face is pressed into the water. Due to the usually large air bladder, so compared to other structures usually superior buoyancy, as well as the free on the front and the sides of the upper body Wings are often preferred by divers who perform much equipment with you, such as Tec - divers.

Hybrid Jacket

Combines the advantages of both previous types. It has a larger volume than the ADV Jacket, but can not reach the superior buoyancy of Bcd in the rule. The swimming position underwater is similarly stable and optimal as the Wing, but without giving up the comfort of a ADV Jackets ( especially at the surface ). Hybrid Jackets tend to be overall slightly larger and heavier and therefore not necessarily optimal for the small luggage - but the diving industry is trying to offer solutions here.

Stabilizer Jacket

Own at the shoulders through Tarierschläuche and behaves when diving similar to the ADV Jacket. Some models of this type are " safe against unconsciousness " be and accordingly meet certain security requirements. In the area of ​​sports and recreational diving Stabilizer BCs are, however, only rarely encountered, as their disadvantages (including voluminous, some more elaborate harness and restricted freedom of movement ) usually predominate. Another major disadvantage of this type of jacket is very cumbersome to put on and take off. You must be able to bend to rule, to get into the jacket, because you can not open straps completely. In addition, the available size range is very tight. It must fit when buying almost 100 percent; and at a greater weight gain, for example, after pregnancy, the jacket then must often be discarded.

General

The jackets can also already have integrated weight pockets, make a weight belt unnecessary and contrary to this, the spine significantly relieve that. Basically, lead bags are now designed so that they can be shed quickly in an emergency.

Another clue to the choice of the appropriate size:

A jacket should always have the right size, even if the lure of a cheap used lures. Is the jacket a size too big, so the seat is bad; this means that the bottle is not firmly attached to the body. This gives the diver skew and never optimal swimming position. Is the jacket too small, so sit the weight pockets not optimal. Another disadvantage of a too small Jackets: You lose usually about two liters of buoyancy volume of the smaller bubble. If you, however, of the body size was exactly between two sizes, so getting the smaller should be chosen because the disadvantages not as severe as that of the large ones.

For cave diving, there are special jackets with two independent air chambers.