PADI Wreck & Cave Diving Fundamentals 4 — Questions and Answers
Question 1: When selecting a penetration reel for wreck diving, what characteristic is most important?
- The reel must be brightly colored for visibility
- The line must be strong enough to pull against and be non-stretch (Correct answer)
- The reel must have an automatic locking spool
- The line must be rated for saltwater use only
Correct answer: The line must be strong enough to pull against and be non-stretch
A non-stretch, strong line (typically braided nylon or polyester) allows divers to confidently follow it under tension in zero visibility.
Question 2: Which fin technique is recommended inside a wreck or cave to minimize silt disturbance?
- Flutter kick
- Frog kick or modified frog kick (Correct answer)
- Dolphin kick
- Back kick only at all times
Correct answer: Frog kick or modified frog kick
The frog kick keeps fin tips angled upward and away from the bottom, minimizing silt disturbance in overhead environments.
Question 3: A diver notices a 'cookie' (small plastic marker) attached to the guideline during a cave dive. What does this indicate?
- The maximum safe depth at that point
- The starting point of that team's line laid that day (Correct answer)
- A hazard such as a restriction just ahead
- The location of an emergency gas supply
Correct answer: The starting point of that team's line laid that day
A personal marker (cookie) identifies a specific team's tie-in point on a shared guideline, preventing navigation confusion.
Question 4: What environmental hazard is especially common inside older steel shipwrecks and can injure divers who brush against interior surfaces?
- Electrical hazards from unshielded wiring
- Sharp corroded metal, broken glass, and deteriorating materials (Correct answer)
- Chemical burns from fuel residue
- Biological toxins from marine growth on metal
Correct answer: Sharp corroded metal, broken glass, and deteriorating materials
Corroded metal, collapsed materials, and broken glass inside aging wrecks create significant laceration and entanglement hazards.
Question 5: In the context of cave diving gas planning, what is the 'rule of halves' used for?
- Planning dives with only a single tank (Correct answer)
- Sharing gas equally between two divers at all times
- Planning gas for dives involving strong overhead currents
- Calculating decompression gas reserves
Correct answer: Planning dives with only a single tank
The rule of halves applies when diving solo or when conditions make the rule of thirds insufficient; turn back at half tank.
Question 6: Which type of wreck is generally considered safer for introductory penetration training and why?
- Deep wrecks, because poor visibility limits disorienting visual details
- Wrecks with large, open interior spaces and multiple natural light sources (Correct answer)
- Wrecks with heavy marine encrustation, which stabilizes the structure
- Wrecks in fresh water, which reduces corrosion hazards
Correct answer: Wrecks with large, open interior spaces and multiple natural light sources
Wrecks with large open spaces and natural light penetration allow students to see exits and feel less disoriented, reducing risk during initial training.
Question 7: What should a cave or wreck diver do if their primary light fails during penetration?
- Signal the buddy and both immediately exit using buddy's light (Correct answer)
- Switch to a backup light and continue the planned dive
- Inflate the BCD and ascend to the wreck ceiling to navigate by feel
- Stay in place and wait for the buddy to return with a surface team
Correct answer: Signal the buddy and both immediately exit using buddy's light
A primary light failure is a dive-ending event; both divers should immediately exit the overhead environment using the remaining light.
PADI Wreck & Cave Diving Fundamentals 4
When selecting a penetration reel for wreck diving, what characteristic is most important?