The goal for scuba divers is to maintain neutral buoyancy so they are not constantly bobbing up and down in the water. Devices that are used to achieve neutral buoyancy are called buoyancy compensators.
Divers will rise if they have positive buoyancy, sink if they have neutral buoyancy, and stay stationary if they have neutral buoyancy.
Buoyancy compensators have made great advances thanks to modern materials, science, and product design. Today you can find buoyancy compensators in a variety of styles, sizes and different materials. They also come in many different price ranges.
They are basically three styles of buoyancy compensators. The three styles are wings, jackets, and vests.
The wing buoyancy compensator is slimmer, lighter-weight wrap-ons uses bladders to trap air filled from the main tank. The main benefits of the wing style buoyancy compensator are they are easy to travel with and do provide good lift.
Full jacket buoyancy compensators allow for larger air pockets. This provide a lot more lift to larger divers or ones that happen to carrying more weight with such as an extra tank or maybe rocks from the bottom.
The vest style buoyancy compensator is more of a traditional design. The vest style looks more like what you would consider a life vest. Other names for the vest buoyancy compensator are horse collar and adjustable buoyancy life jacket.
There are a few disadvantages to the vest style compensator.
The life vest style compensator, with most of the jacket upfront, can be very bulky and uncomfortable. Also, there are less freedom of head and arm movement when the vest is inflated. One advantage to the vest buoyancy compensator is when the diver floats to the surface he or she will be force onto their back.
One problem with most contemporary designs is the buoyancy compensator tends to move the diver onto his or her face. During a normal surfacing that is not a problem, the diver can use their scuba diving fins to turn upright.
But if an unconscious diver surfaces and he or she is facing down instill of floating on their back, they are less likely to survive. If there is not a scuba buddy or topside observer to immediately lift the diver out of the water, the diver could drown within a few minutes.
In choosing a buoyancy compensator you should be tested for fit. Some buoyancy compensators are longer, riding closer to the thighs, other are shorter and even above the hip.
Most women prefer the shorter styles because they tend to have shorter backs than men. Another advantage of the shorter vest is they help avoid being bruised in the hips by any weight near the base of the buoyancy compensator.
As for the material, denier count is important. Denier is a measure of the thickness of the thread used in the weave of the jacket. A buoyancy compensator with a higher denier count, such as 1,200, would help to resist scrapes and tears. A buoyancy compensator with a lower denier count, such as 400, would be more puncture-proof.