Third Assistant Engineer Practice Test (3AE01)

The first engineer-officer license on unlimited ships, motor and gas turbine side: diesels, gas turbines, safety. The NMC splits it into 3AE01 and 3AE02; your approval letter says which you sit. Coast Guard exam code 3AE01.

272 real questions from the Coast Guard National Maritime Center's public sample exams, free. Each module needs 70% to pass.

Passing score: Coast Guard pass marks module by module, and the retest rules

What's free: daily rounds, the Brig, the drills and the Pass Meter, for every license. Your first module test is free too. After that, the full Exam Room is $19, once. No subscription.

What's on the test

Picture questions link to the drawing in the Coast Guard's free sample PDF. A few that need reference tables are left out.

10 sample questions

1. Fuel injection systems are designed to primarily meter fuel, atomize fuel, and __________.

   • A.create turbulence in the combustion chamber
   • B.aid in completing cylinder scavenging
   • C.inject fuel at the proper time
   • D.minimize fuel penetration into the cylinder
   Show answer

   C. inject fuel at the proper time

   Q800, Junior Engineer, Part I

2. The process of scavenging a two-stroke cycle diesel engine serves to __________.

   • A.improve fuel flow volume
   • B.sweep the exhaust gases out of the cylinder
   • C.reduce the intake air charge density
   • D.increase the temperature of exhaust gases
   Show answer

   B. sweep the exhaust gases out of the cylinder

   Q800, Junior Engineer, Part I

3. The purpose of the main reduction gear in a marine gas turbine propulsion installation is which of the following?

   • A.To transfer high-speed gas turbine rotation to low-speed propeller rotation.
   • B.To increase gas turbine speed to engage the clutch.
   • C.To reduce gas turbine speed to engage the clutch.
   • D.To transfer low-speed gas turbine rotation to high-speed propeller rotation.
   Show answer

   A. To transfer high-speed gas turbine rotation to low-speed propeller rotation.

   Q606, Chief Engineer Limited: Gas Turbine Plants

4. Which extinguishing agent is the best for use on electrical fires?

   • A.Water fog
   • B.CO2
   • C.Dry chemical
   • D.Foam
   Show answer

   B. CO2

   Q451, Deck General / Safety

5. Which of the following problems could develop due to the accumulation of oil vapors in the crankcase of a diesel engine?

   • A.Reduced lubrication
   • B.Combustion knock
   • C.Crankcase explosion
   • D.Poor fuel economy
   Show answer

   C. Crankcase explosion

   Q808, Pump Technician

6. Compared to a naturally aspirated diesel engine, a supercharged diesel engine has __________.

   • A.a cylinder air charge of higher pressure
   • B.reduced cylinder mean effective pressure
   • C.less valve overlap
   • D.reduced blow-by
   Show answer

   A. a cylinder air charge of higher pressure

   Q800, Junior Engineer, Part I

7. On a GE LM2500 gas turbine powered vessel you are conducting a borescope inspection of the compressor. What is used on each compressor stage as a reference for indexing the blades?

   • A.Witness marks center punched on the #1 nozzle and blade
   • B.Scribe marks located on the stator and rotor diaphragm
   • C.The locking lug blades
   • D.The IGV actuator
   Show answer

   C. The locking lug blades

   Q606, Chief Engineer Limited: Gas Turbine Plants

8. The advantage of using a dry chemical fire extinguishing agent is __________.

   • A.its excellent cooling ability
   • B.permanent extinguishment regardless of the reignition sources
   • C.its good stability and non-toxicity
   • D.all of the above
   Show answer

   C. its good stability and non-toxicity

   Q801, Junior Engineer, Part II

9. Because of the close tolerances used in diesel engine fuel oil pumps, a worn plunger requires __________.

   • A.highly polishing both the plunger and barrel
   • B.grinding the spare plunger to the barrel
   • C.replacing the plunger and the barrel
   • D.replacing plunger only
   Show answer

   C. replacing the plunger and the barrel

   Q602, Chief Engineer Limited: Motor Plants

10. Which of the types of reduction gearing listed is best suited for medium-speed main propulsion units?

    • A.Hypoid
    • B.Helical
    • C.Cyclical
    • D.Spur
    Show answer

    B. Helical

    Q602, Chief Engineer Limited: Motor Plants

What the study guide does

• Short daily rounds of 10 questions, with a streak.
• Practice tests built like the real one, scored with the real pass marks (first one free, then $19 once for the full Exam Room).
• The Brig: questions you miss come back until you get them right twice.
• Pass Meter: your chance of passing every module if you sat it today, worked out from your own answers.