Scuba Diving Safety Diving 4 — Questions and Answers
Question 1: What condition is caused by inhaling water, leading to impaired gas exchange in the lungs even after rescue from drowning?
- Secondary drowning (delayed drowning) (Correct answer)
- Pulmonary edema from overexertion
- Immersion pulmonary edema
- Nitrogen narcosis
Correct answer: Secondary drowning (delayed drowning)
Secondary drowning occurs hours after a near-drowning event when inhaled water causes inflammation and fluid buildup in the lungs.
Question 2: A diver at 60 feet runs low on air with a full ascent needed. They should breathe from their octopus regulator while their buddy:
- Donates their primary second stage to the out-of-air diver while they share ascent (Correct answer)
- Immediately surfaces alone to get the boat
- Signals the out-of-air diver to hold their breath and ascend
- Drops their own weight belt to speed the ascent
Correct answer: Donates their primary second stage to the out-of-air diver while they share ascent
In an out-of-air emergency, the donor gives the primary reg (most familiar) to the victim and uses their own octopus during a controlled shared ascent.
Question 3: Which sign indicates a diver may be suffering from nitrogen narcosis at depth?
- Irrational behavior, impaired judgment, and euphoria (Correct answer)
- Muscle cramps and shivering
- Bluish lips and rapid heart rate
- Ear pain and blood from the nose
Correct answer: Irrational behavior, impaired judgment, and euphoria
Nitrogen narcosis ('rapture of the deep') impairs judgment similarly to alcohol intoxication, causing euphoria and poor decisions.
Question 4: What is the recommended minimum safety stop depth and duration for recreational dives deeper than 60 feet (18 m)?
- 15 feet (5 m) for 3 minutes (Correct answer)
- 30 feet (9 m) for 5 minutes
- 20 feet (6 m) for 1 minute
- 10 feet (3 m) for 10 minutes
Correct answer: 15 feet (5 m) for 3 minutes
A safety stop at 15 feet for 3 minutes allows off-gassing of residual nitrogen and reduces DCS risk.
Question 5: A diver experiences tightness in the chest and difficulty breathing immediately after surfacing. This most likely indicates:
- Pulmonary barotrauma or arterial gas embolism (Correct answer)
- Seasickness from wave action
- Overexertion causing muscle fatigue
- Mild dehydration
Correct answer: Pulmonary barotrauma or arterial gas embolism
Chest tightness and breathing difficulty after surfacing are classic signs of pulmonary overinflation injury and possible gas embolism requiring immediate oxygen and EMS.
Question 6: What is the purpose of the rule of thirds for gas management in cave or overhead environment diving?
- Use one third entering, one third exiting, and reserve one third for emergencies (Correct answer)
- Use half the tank going in and half returning
- Always turn around when the pressure gauge hits 500 psi
- Divide gas equally between both divers' tanks
Correct answer: Use one third entering, one third exiting, and reserve one third for emergencies
The rule of thirds ensures gas reserve for both the penetration, the return, and an emergency, critical in overhead environments with no direct ascent.
Question 7: Hypothermia underwater is dangerous primarily because it:
- Impairs judgment and motor skills, increasing accident risk (Correct answer)
- Causes nitrogen to absorb faster into tissues
- Triggers involuntary hyperventilation at depth
- Raises the risk of oxygen toxicity
Correct answer: Impairs judgment and motor skills, increasing accident risk
As core temperature drops, cognitive function and physical coordination deteriorate, leading to poor decisions and loss of control.
Scuba Diving Safety Diving 4
What condition is caused by inhaling water, leading to impaired gas exchange in the lungs even after rescue from drowning?