Underwater Navigation & Dive Planning Flashcards

What is the significance of 'current' in dive site selection and how should PADI instructors manage it during training?

Answer: Current affects diver safety, air consumption, and navigation — training should begin in current-free or minimal-current conditions before progressing to drift diving

Water current significantly affects diver safety and navigation; student training should start in calm conditions, with drift diving introduced only as a specialty skill for more experienced divers.

How does a thermocline affect a diver's experience and what should instructors explain about it?

Answer: A thermocline is a sharp boundary between water layers of different temperatures, which can affect visibility and significantly affect diver comfort

A thermocline is a distinct temperature change between water layers — crossing it can cause a noticeable temperature drop and reduced visibility, affecting diver comfort and planning.

Why does PADI recommend a controlled descent rather than a free fall during recreational diving?

Answer: A controlled descent allows equalization of ears and sinuses at the diver's own pace and prevents barotrauma

A controlled descent allows divers to equalize their ears and sinuses as pressure increases, preventing potentially serious barotrauma injuries.

What is the purpose of a 'debrief' after a training dive and what should PADI Instructors cover?

Answer: A debrief reviews dive objectives, skill performance, successes and areas for improvement, and previews upcoming training — it is a mandatory component of every training session

Post-dive debriefs are mandatory teaching moments covering performance review, skill feedback, environmental observations, safety reminders, and preparation for the next training session.

What is the PADI 'Plan-Brief-Execute-Debrief' (PBED) instructional process?

Answer: The four-step instructional cycle for every PADI training session: plan the session, brief students, execute the dives, debrief afterward

PBED is PADI's four-step instructional framework applied to every training session: planning content and objectives, briefing students, executing the session, then debriefing performance.

What is 'shallow water blackout' and how does it relate to freediving versus scuba diving?

Answer: Loss of consciousness during breath-hold ascent due to hypoxia — a risk in freediving, not scuba diving

Shallow water blackout is a risk in breath-hold (free) diving where a diver loses consciousness near the surface due to falling oxygen levels — scuba divers breathe continuously and do not face this risk.