Dive Equipment & Technology Flashcards

What is the primary purpose of the BCD (Buoyancy Control Device) in scuba diving?

Answer: To allow the diver to control buoyancy at depth and at the surface by adjusting the volume of air in the bladder

The BCD allows divers to achieve neutral buoyancy at depth and positive buoyancy at the surface by adding or releasing air from the bladder.

What is the function of the first stage of a scuba regulator?

Answer: To reduce tank pressure to an intermediate pressure for delivery to the second stage

The first stage reduces high-pressure air from the tank (typically 200-300 bar) to an intermediate pressure for delivery to the second stage.

What is the purpose of the alternate air source (octopus) in recreational scuba diving?

Answer: A secondary second stage for sharing air with an out-of-air buddy

The alternate air source (octopus) is a secondary second stage provided to allow an out-of-air buddy to breathe from the same tank while both divers ascend.

How does a wetsuit provide thermal protection for divers?

Answer: By trapping a thin layer of water next to the skin which is warmed by body heat

A wetsuit works by allowing a thin layer of water to enter and become trapped between the suit and the skin, where body heat warms this water layer and reduces heat loss.

What information does a Submersible Pressure Gauge (SPG) provide to a diver?

Answer: The remaining air pressure in the scuba cylinder

The SPG shows the remaining air pressure in the scuba tank in bar or PSI, allowing divers to monitor their air consumption and plan safe air turnaround points.

What is the difference between a cylinder's 'working pressure' and 'test pressure'?

Answer: Working pressure is the normal fill pressure; test pressure is the higher pressure used during hydrostatic testing

Working pressure is the maximum pressure for normal fills; test pressure (typically 5/3 of working pressure) is used during periodic hydrostatic testing to ensure cylinder integrity.