Basic Parts of a Scuba BCD – BCD Components Explained in Detail


The piece of equipment which enables a diver to breathe from a scuba tank is a scuba diving regulator. The regulator is so called because the pressure of the oxygen a diver breathes is regulated. Inside a scuba tank, the compressed oxygen is at an incredibly high pressure that could kill a diver who is attempting to breathe directly from the tank, and it is important for the regulator to decrease the compressed oxygen pressure to the pressure that the diver can breathe.

The part of the regulator that achieves the first level of pressure reduction, reducing the oxygen from the high-pressure tank to an intermediate pressure, is a first stage scuba diving regulator. Usually, a first stage open-water regulator connects to four hoses, three holding the second stage intermediate-pressure oxygen and the buoyancy compensator’s oxygen pump, and one allowing high-pressure oxygen to pass directly from the tank to the submersible pressure gauge.

The buoyancy compensator is one of the diving equipment products that needs most skill and attention throughout service, as control is fully manual, and adjustment is essential during the dive as weight decreases due to gas consumption, and the buoyancy of the diving suit and buoyancy compensator system varies with depth.

Fine buoyancy adjustment may be achieved by open circuit breath control, minimizing the amount of real volume adjustment necessary for the buoyancy compensator unit, and a professional diver can develop the ability to change volume to maintain neutral buoyancy while remaining mindful of the environment and performing other tasks. When properly used, the buoyancy compensator is both an effective safety device and a major hazard when misused.

  1. Oxygen Vesicle

The oxygen vesicle is the most significant feature of a scuba buoyancy compensator system. The oxygen vesicle is like an oxygen carrying sack. How much oxygen is within the vesicle of oxygen determines how buoyant you are. In other words, how much oxygen is inside the vesicle depends on whether you float up or sink farther down. Here, learn how to master the buoyancy. A greater upward force is produced by growing the oxygen within the vesicle so that you rise up or float.

Reducing the oxygen inside your vesicle increases the downward force that causes you to sink down. The exact position of the oxygen vesicle depends on the system type. Typically, the oxygen vesicles are positioned around the diver’s waist or on his back.

  1. Oxygen pumps

Two kinds of oxygen pumps are available – a power oxygen pump and a manual oxygen pump. Both do the same thing – bringing oxygen into your buoyancy compensator for scuba diving. From the first stage of your scuba diving regulator, the power oxygen pump is attached to your tank via a low-pressure hose. All you have to do is press the oxygen pump button and bring oxygen into your scuba buoyancy compensator. With the manual oxygen pump you bring oxygen into the buoyancy compensator oxygen vesicle by blowing into a mouthpiece on the oxygen pump hose. To open the hose linked to your buoyancy compensator, all you have to do is press a button and then blast.

It is normally placed right next to the button for the power oxygen pump. The buoyancy compensator stands for the compensator of buoyancy. It fits like a backpack, and maintains your tank’s weight above water, but the most important feature of a buoyancy compensator is to help you control your place in the water column. You rise toward the top by adding oxygen to an internal vesicle; you sink toward the bottom by venting oxygen from it. The control buttons are part of the power oxygen pump found on the diver’s left side at the end of the corrugated hose. You should simply press a catch on the oxygen pump hose to allow some oxygen flow into your buoyancy compensator for the manual deflator.

The best way is to go upstanding, raise the hose over your head and push the deflator button to allow some circulation in. Normally, a scuba buoyancy compensator would have at least one dump pipe. These are processed by pulling on a string that enables the vesicle to be ventilated. One dump pipe is usually located near to where the hose is attached on the left shoulder. A standard location is on the lower base of the buoyancy compensator system for a second dump pipe.

  1. Deflators and Dump Pipes

These do the opposite of the power oxygen pump – namely, let oxygen out of your dive buoyancy compensator, as you probably guessed from the word. All you have to do is press a button on the oxygen pump hose for the manual deflator to let the oxygen out of your buoyancy compensator. Going upright, raising the hose over your head and pressing the deflator button is the best way to let oxygen out.

  1. Scuba Fins

Scuba fins transform the kicks through a medium that’s 800 times denser than oxygen into smooth, powerful movement. On your bare feet, full-foot fins go; open-heel or adjustable fins enable you to wear neoprene booties for a proper fit.

  1. Dust Cap

It is highly necessary that no water reaches the first-stage body of the regulator. When the body of the first stage is tightened into a tank, the tank pipe provides a water-tight seal. However, when the body of the first stage is removed from the tank, it is possible for water in the first stage to enter the opening through which oxygen moves from the tank to the regulator. The dust cap is a rubber cap that can be placed over the first stage opening of the regulator and tightened down using the yoke screw of the regulator. This seals closed the opening on the first stage.


They are the key to a safe dive, so familiarize yourself with each feature and where your system is mounted. Of course, they could have additional parts for more specialized dive buoyancy compensator systems. I hope that you have found this short guide better than any diagram of scuba gear and that it has clarified for you to understand all the parts and uses of Buoyancy Control System components.