Underwater Navigation and Buoyancy Control Flashcards

What is the primary function of a Buoyancy Control Device (BCD) during a dive?

Answer: To allow a diver to control buoyancy at any depth

A BCD allows a diver to add or release air to achieve neutral, positive, or negative buoyancy at any point during the dive.

A diver who consistently sinks feet-first in the water likely has too much weight placed where?

Answer: On the weight belt at the hips or ankles

Excess weight on the hips or ankle weights pulls the lower body down, creating a feet-first or head-up angle that increases drag.

What is the correct method to check if a diver is wearing the proper amount of weight before a dive?

Answer: Float at the surface with a full breath, eyes at water level, and a nearly empty tank

A diver is properly weighted when they float at eye level with a normal breath and a near-empty tank at the surface.

Which technique helps a diver maintain neutral buoyancy when breathing during a dive?

Answer: Use a steady, controlled breathing rhythm and avoid breath-holding

Maintaining a slow, controlled breathing rhythm allows small buoyancy adjustments through lung volume without excessive BCD inflation.

What should a diver do if they experience uncontrolled ascent due to over-inflation of the BCD?

Answer: Swim downward aggressively and dump air from the BCD immediately

The correct response to uncontrolled ascent is to immediately dump air from the BCD and use a flared body position while swimming downward to slow the ascent.

Why is it important to add air to the BCD in small bursts rather than large continuous inflations?

Answer: To prevent sudden, rapid buoyancy changes that are difficult to control

Adding air in small bursts allows the diver to make incremental buoyancy adjustments and avoid sudden positive buoyancy surges that are hard to control.