Equipment Use & Maintenance Flashcards

After a saltwater dive, what is the most important first step when rinsing your regulator?

Answer: Blow air through the second stage before submerging in fresh water

Purging air through the second stage before rinsing prevents water from entering the first stage through the low-pressure port.

Which BCD component is most likely to trap salt crystals and cause corrosion if not properly rinsed?

Answer: The inflator/deflator mechanism

The inflator/deflator mechanism has small internal valves and passageways where salt crystals accumulate and cause sticking or corrosion.

When storing a wetsuit long-term, which method best preserves the neoprene?

Answer: Hang it on a wide hanger in a cool, dark area

Hanging a wetsuit on a wide hanger in a cool, dark location prevents creasing, UV degradation, and compression of neoprene cells.

A diver notices their submersible pressure gauge (SPG) reads higher than expected at the surface before a dive. What is the most likely cause?

Answer: Ambient temperature increase has raised cylinder pressure

Gas pressure increases with temperature; a cylinder filled in a cool environment will read higher when warmed by sun or ambient heat.

What does a milky or cloudy appearance inside a diving mask lens typically indicate?

Answer: Salt residue from inadequate post-dive rinsing

A cloudy mask interior usually results from salt crystal buildup caused by insufficient fresh-water rinsing after dives.

Which tool is specifically recommended for inspecting the interior of a scuba cylinder?

Answer: A borescope or cylinder inspection light

A borescope or dedicated cylinder inspection light is designed to illuminate and magnify the interior walls for visual inspection.

A diver's fin strap breaks mid-dive trip. Which field repair is most practical and safe?

Answer: Use a zip tie as a temporary strap replacement

A zip tie can serve as a temporary fin strap long enough to complete planned dives safely until a proper replacement strap is obtained.

What is the primary purpose of a tank boot (cylinder boot)?

Answer: To provide a stable upright base and protect the cylinder bottom

A tank boot fits over the curved bottom of a cylinder to allow it to stand upright and to protect the metal from abrasion.

During a post-dive equipment check, a diver finds that the BCD over-pressure relief valve (OPV) opens spontaneously at low inflation. What should the diver do?

Answer: Remove the BCD from service until the OPV is serviced or replaced

An OPV that opens at low pressure indicates the valve spring has weakened or debris is preventing a proper seal, making the BCD unreliable and requiring service.

Why must the dust cap be secured on a first-stage regulator before rinsing?

Answer: To stop water from entering the first stage and contaminating the internals

The dust cap keeps water out of the inlet port so it cannot reach internal components, which would promote corrosion and contamination.

Which symptom most clearly indicates a regulator second stage needs professional servicing?

Answer: A faint hiss of continuous free-flow at the surface

Continuous free-flow indicates the demand valve is not seating properly, wasting air and potentially overwhelming a diver's ability to manage gas supply.

What is the recommended interval for professional regulator servicing according to most manufacturers and NAUI standards?

Answer: Annually or after every 100 dives, whichever comes first

Most manufacturers and NAUI recommend annual servicing or after 100 dives (whichever comes first) to replace wear parts and ensure reliable performance.

A diver's dive computer floods during a dive. What is the safest immediate course of action?

Answer: Buddy up closely and follow the computer-equipped buddy's profile

Staying close to a buddy with a functioning computer allows the affected diver to follow a safe ascent profile without abandoning the dive.

What material are most quality diving mask skirts made from, and why?

Answer: Silicone, for durability and low-allergen properties

Silicone is the preferred material for mask skirts because it is durable, UV-resistant, hypoallergenic, and maintains its seal over many years.

When attaching a first-stage regulator to a DIN valve cylinder, which step is critical to prevent cross-threading?

Answer: Hand-tighten the DIN fitting slowly while ensuring it threads straight

DIN fittings must be started by hand and threaded straight to avoid cross-threading, which can damage both the regulator inlet and the valve.

Why should scuba cylinders never be stored fully empty?

Answer: Moisture and contaminants can enter and cause internal corrosion

A small residual positive pressure (typically 200–500 psi) keeps moisture-laden outside air from entering and corroding the interior walls.

A diver discovers a small crack in the plastic housing of their dive light before a night dive. What should they do?

Answer: Remove the light from service until it is properly repaired or replaced

A cracked housing can flood or implode under pressure, causing total light failure or injury; the equipment should not be used until properly repaired.

Which type of valve is found on most modern recreational scuba cylinders in the US and allows easy tank-on/tank-off operation?

Answer: K-valve (on/off valve)

The K-valve is a simple on/off valve standard on most US recreational cylinders, replacing the older J-valve with its reserve mechanism.

What is the function of the intermediate pressure port on a first-stage regulator?

Answer: It supplies reduced pressure gas to the second stage and BCD inflator

The intermediate (low-pressure) port delivers gas reduced to intermediate pressure (typically 120–150 psi over ambient) to second stages and BCD inflators.

After rinsing a BCD, how should it be stored to maintain the bladder integrity?

Answer: With a small amount of air inside and hung upright

Storing a BCD with a small amount of air prevents the internal bladder walls from sticking together, which can compromise the bladder over time.