NAUI Equipment Use & Maintenance 5 — Questions and Answers
Question 1: When should a diver perform a bubble check on their buddy's scuba unit?
- Only at the end of the dive as a quality-control exercise
- After descending a few feet below the surface at the start of the dive (Correct answer)
- At 30 feet depth once all equipment is equalizing to pressure
- Before entry into the water while still on the boat or shore
Correct answer: After descending a few feet below the surface at the start of the dive
A bubble check performed just below the surface allows both divers to confirm all connections are leak-free before committing to depth.
Question 2: What does the term 'annual visual inspection' (AVI) of a scuba cylinder refer to?
- An inspection performed by the diver before each dive season
- A professional inspection of the interior and exterior with updated sticker (Correct answer)
- A manufacturer-required inspection at the dive shop every January
- An inspection triggered only when a cylinder has been dropped or damaged
Correct answer: A professional inspection of the interior and exterior with updated sticker
An AVI involves a trained technician visually inspecting the cylinder interior and exterior and applying a sticker with the inspection date and results.
Question 3: Which type of regulator configuration is most appropriate for technical and cave diving where gear entanglement risk is higher?
- Yoke (A-clamp) regulators with hose protectors
- DIN regulators with a streamlined hose routing (Correct answer)
- Pony bottle regulators clipped to the primary BCD
- Balanced-piston regulators with extended hoses
Correct answer: DIN regulators with a streamlined hose routing
DIN regulators are recessed into the valve and have a lower profile, reducing snag risk, and they are preferred for technical diving environments.
Question 4: What is hydrostatic testing of a scuba cylinder designed to verify?
- The cylinder's internal cleanliness and freedom from corrosion
- The structural integrity by pressurizing the cylinder beyond its rated pressure (Correct answer)
- The cylinder's buoyancy characteristics at depth
- The valve o-ring seal under working pressure conditions
Correct answer: The structural integrity by pressurizing the cylinder beyond its rated pressure
Hydrostatic testing pressurizes the cylinder to 5/3 its rated pressure to detect expansion or weakness in the cylinder walls indicating structural failure risk.
Question 5: A diver finds their wetsuit zipper is difficult to close before a dive. What is the best field remedy?
- Force the zipper closed with a pull cord for additional leverage
- Apply beeswax or a zipper lubricant specifically designed for dive zippers (Correct answer)
- Rinse the zipper with warm fresh water and allow it to dry before closing
- Replace the zipper immediately, as forcing it will cause irreversible damage
Correct answer: Apply beeswax or a zipper lubricant specifically designed for dive zippers
Beeswax or a dedicated zipper lubricant reduces friction and allows the zipper to glide smoothly without damaging the teeth or tape.
Question 6: What is the primary reason a dive computer should not be shared between two divers on the same dive?
- Dive computers are calibrated to individual body weight and cannot adapt mid-dive
- The computer tracks only one diver's depth and time profile, making it inaccurate for the second diver (Correct answer)
- Sharing violates NAUI's equipment ownership policy
- Dive computers reset automatically when handed off between divers
Correct answer: The computer tracks only one diver's depth and time profile, making it inaccurate for the second diver
A dive computer records one continuous dive profile; the second diver's nitrogen loading differs and the computer cannot account for the profile it did not track.
Question 7: Which maintenance task should NEVER be performed by a diver without formal technician training?
- Rinsing the regulator with fresh water after a saltwater dive
- Replacing the mouthpiece on a second stage
- Disassembling and cleaning the first stage internals (Correct answer)
- Lubricating the BCD inflator with silicone spray
Correct answer: Disassembling and cleaning the first stage internals
First-stage internals contain precisely calibrated components; improper disassembly can alter intermediate pressure settings, creating dangerous breathing or free-flow conditions.
NAUI Equipment Use & Maintenance 5
When should a diver perform a bubble check on their buddy's scuba unit?