Deep Diving Techniques & Planning Flashcards

When planning a deep dive to 100 feet, which factor most critically determines your maximum bottom time?

Answer: No-decompression limit (NDL)

The no-decompression limit (NDL) defines the maximum time you can spend at depth without requiring mandatory decompression stops.

What is the recommended maximum ascent rate during a deep dive?

Answer: 30 feet per minute

PADI recommends an ascent rate of no faster than 30 feet (9 meters) per minute to allow dissolved gases to safely off-gas.

A diver at 100 feet suddenly feels task-loaded and anxious. What is the MOST likely contributing factor?

Answer: Nitrogen narcosis

Nitrogen narcosis commonly causes anxiety, impaired judgment, and task-loading difficulty at depths around 100 feet and beyond.

During pre-dive planning for a deep dive, what rule governs how you divide your air supply?

Answer: The rule of thirds

The rule of thirds allocates one-third of gas for the outward journey, one-third for return, and one-third as an emergency reserve.

Which condition is a contraindication for deep diving and requires medical evaluation before participation?

Answer: A history of spontaneous pneumothorax

A history of spontaneous pneumothorax indicates a risk of lung over-expansion injury under pressure changes, requiring physician clearance.

What is the PRIMARY reason deep divers should carry an audible and visual surface signaling device (DSMB)?

Answer: To signal their position to surface support when surfacing far from the boat

A DSMB allows divers who surface away from the entry point to be easily spotted by boat traffic and surface support personnel.

On a deep dive profile, what is the purpose of a safety stop at 15 feet for 3 minutes?

Answer: To allow additional nitrogen off-gassing and reduce DCS risk

A safety stop at 15 feet provides extra time for dissolved nitrogen to off-gas, significantly reducing the risk of decompression sickness.