Examination Practice Questions And

Coast Guard QMED Fireman/Watertender Examination Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• Which type of boiler uses water tubes instead of a large steam drum?

a) Fire-tube boiler

b) Water-tube boiler

c) Scotch boiler

d) Electric boiler

Rationale: Water-tube boilers circulate water through tubes heated

externally, allowing higher pressure and faster steam production.

• What is the primary purpose of a feedwater economizer?

a) Increase boiler pressure

b) Recover heat from flue gases to preheat feedwater

c) Reduce steam temperature 1 / 4

d) Purify boiler water

Rationale: Feedwater economizers improve efficiency by transferring

heat from exhaust gases to incoming feedwater.

• Which safety device prevents overpressure in a boiler?

a) Water gauge

b) Blowdown valve

c) Safety valve

d) Steam trap

Rationale: Safety valves automatically release steam if the boiler

pressure exceeds safe limits.

• What is the function of a superheater?

a) Remove impurities from water

b) Increase feedwater temperature

c) Increase the temperature of steam above saturation

d) Lower boiler pressure

Rationale: Superheaters raise the temperature of saturated steam to

improve efficiency and prevent condensation in turbines.

• In a marine steam system, what is the main purpose of the condenser?

a) Increase boiler pressure

b) Convert exhaust steam back to water

c) Heat feedwater

d) Remove impurities from fuel 2 / 4

Rationale: Condensers turn exhaust steam into water for reuse,

maintaining efficiency and reducing water consumption.

• Which component controls the water level in a boiler?

a) Safety valve

b) Feedwater regulator

c) Steam trap

d) Superheater

Rationale: Feedwater regulators maintain proper water level

automatically, preventing low-water or high-water conditions.

• What is the typical cause of boiler priming?

a) Low water level

b) Excessive steam pressure

c) High water level and impurities

d) Dirty fuel

Rationale: Priming occurs when water is carried over with steam due

to high water level or dissolved solids.

• How often should a boiler blowdown be performed to control

sediment?

a) Monthly

b) Daily or as required

c) Yearly

d) Only during inspection 3 / 4

Rationale: Regular blowdown removes sediment and dissolved

solids, preventing scale and corrosion.

• Which type of fuel is most commonly used in marine boilers today?

a) Coal

b) Diesel oil

c) Residual fuel oil

d) Natural gas

Rationale: Residual fuel oil (heavy fuel oil) is widely used due to

availability and cost-effectiveness in large marine boilers.

• What is the normal operating pressure of a typical marine steam

boiler?

• 50 psi
• 100 psi
• 150–300 psi
• 500 psi

Rationale: Most marine boilers operate within this range for efficient

steam production without over-stressing the equipment.

• What is the purpose of a steam trap?

a) Increase steam pressure

b) Reduce water level

c) Remove condensate from steam lines without losing steam

d) Heat feedwater

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