Underwater Skills & Safety Procedures Flashcards

What is the primary reason for practicing controlled ascents during training?

Answer: To prevent decompression sickness and other injuries

Practicing controlled ascents during scuba diving training is crucial for safety, primarily to prevent decompression sickness (DCS) and lung over-expansion injuries. A slow, controlled ascent allows nitrogen absorbed by the body tissues to be safely released, preventing bubble formation that causes DCS. It also helps divers avoid rapid pressure changes that can damage lungs.

Why is the buddy system important in scuba diving?

Answer: To provide immediate assistance during emergencies

The buddy system is fundamental in scuba diving because it ensures divers always have a partner to provide immediate assistance in case of an emergency. This includes sharing air, helping with equipment malfunctions, or assisting a diver who becomes disoriented or distressed. It significantly enhances safety by providing mutual support and accountability underwater.

What does a slow ascent rate help prevent?

Answer: Decompression sickness

A slow ascent rate is vital in scuba diving to prevent decompression sickness (DCS), also known as "the bends." As a diver ascends, the ambient pressure decreases, causing nitrogen dissolved in the body's tissues to come out of solution. A slow ascent allows this nitrogen to be exhaled safely through the lungs, preventing the formation of bubbles that can cause DCS.

What is the function of a safety stop during ascent?

Answer: To allow for nitrogen elimination

A safety stop is a crucial pause during ascent, typically at 15-20 feet for 3-5 minutes. Its primary function is to allow the body additional time to off-gas dissolved nitrogen from tissues. This controlled elimination of nitrogen significantly reduces the risk of decompression sickness (DCS) after a dive.

Why is it important to equalize pressure in the ears during descent?

Answer: To prevent barotrauma

As a diver descends, increasing water pressure compresses the air in the middle ear. Equalizing pressure, by methods like Valsalva, introduces air into the middle ear to match the external pressure. Failing to equalize creates a painful pressure imbalance, which can lead to barotrauma, or tissue damage, to the eardrum or inner ear.

Which of the following is a sign of nitrogen narcosis?

Answer: Euphoria and poor decision-making

Nitrogen narcosis, often called 'rapture of the deep,' occurs when nitrogen under high pressure affects the central nervous system. Symptoms include impaired judgment, disorientation, and a feeling of euphoria, which can lead to poor decision-making. These cognitive effects can be dangerous, as they reduce a diver's ability to react appropriately to underwater situations.

What is the first response to an out-of-air emergency underwater?

Answer: Signal the buddy and use alternate air source

In an out-of-air emergency, the safest and most immediate response is to signal your dive buddy. Your buddy is equipped with an alternate air source (octopus regulator) specifically for this situation. Sharing air allows both divers to ascend safely and in a controlled manner, preventing panic and ensuring a secure air supply.

Why should divers never hold their breath while ascending?

Answer: To avoid lung over-expansion injuries

As a diver ascends, the ambient pressure decreases, causing the air in the lungs to expand according to Boyle's Law. If a diver holds their breath, this expanding air has no escape, leading to potentially severe lung over-expansion injuries. Continuous breathing during ascent allows the expanding air to exit the lungs safely, preventing barotrauma.

What does the 'S.A.F.E. Diver' acronym emphasize?

Answer: Slowly Ascend From Every dive

The 'S.A.F.E. Diver' acronym serves as a vital safety reminder in scuba diving. It emphasizes the importance of a slow and controlled ascent rate during every dive. This practice allows the body sufficient time to off-gas dissolved nitrogen, significantly reducing the risk of decompression sickness.