DDE Unlimited Practice Test (Designated Duty Engineer, DDE01)

The one-engineer ticket with no horsepower cap: big tugs, ferries and supply boats. Coast Guard exam code DDE01.

413 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. What statement concerning fuel cetane rating and the ignition delay period is true as it applies to towboat main propulsion diesel engines?

   • A.The ignition delay period is the lag in time between when fuel injection actually begins and when combustion actually begins, and the higher the cetane rating of the fuel the longer the ignition delay period.
   • B.The ignition delay period is the lag in time between when fuel injection actually begins and when combustion actually begins, and the higher the cetane rating of the fuel, the shorter the ignition delay period.
   • C.The ignition delay period is the lag in time between when fuel injection is initiated and when fuel injection actually begins, and the higher the cetane rating of the fuel the shorter the ignition delay period.
   • D.The ignition delay period is the lag in time between when fuel injection is initiated and when fuel injection actually begins, and the higher the cetane rating of the fuel, the longer the ignition delay period.
   Show answer

   B. The ignition delay period is the lag in time between when fuel injection actually begins and when combustion actually begins, and the higher the cetane rating of the fuel, the shorter the ignition delay period.

   Q630, DDE: Motor Plants

2. Of the many impurities commonly found in marine lubricating oil, which of the following CANNOT be removed by a centrifugal purifier at normal operating speeds and temperatures?

   • A.Carbon particles
   • B.Water
   • C.Diesel fuel oil
   • D.Metal particles
   Show answer

   C. Diesel fuel oil

   Q808, Pump Technician

3. A gas turbine engine's main lube oil system pump check valve serves to maintain system prime and perform what other function?

   • A.To prevent reverse flow of oil through a secured pump
   • B.To return oil to the main reduction gear sump
   • C.To increase system pressure
   • D.None of the above
   Show answer

   A. To prevent reverse flow of oil through a secured pump

   Q606, Chief Engineer Limited: Gas Turbine Plants

4. 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

5. In general, the thermal bulb for a thermal expansion valve used in a reciprocating air conditioning system is usually charged with what substance?

   • A.mercuric sulfate
   • B.bees wax
   • C.the same refrigerant as the system
   • D.distilled water
   Show answer

   C. the same refrigerant as the system

   Q801, Junior Engineer, Part II

6. What is an ammeter used to measure?

   • A.circuit continuity
   • B.current flow in a circuit
   • C.the voltage between two points in a circuit
   • D.total or partial circuit resistance
   Show answer

   B. current flow in a circuit

   Q802, Electrician

7. Prior to starting a diesel generator set engine fitted on your salvage tug, it has been determined that the transfer of make-up oil is required. At what checked level should you stop adding make-up oil?

   • A.When the oil level rises to the ADD mark on the dipstick.
   • B.When the oil level rises to a level well above the FULL mark on the dipstick.
   • C.When the oil level rises to the FULL mark on the dipstick.
   • D.When the oil level rises to the between the ADD and FULL marks on the dipstick.
   Show answer

   C. When the oil level rises to the FULL mark on the dipstick.

   Q630, DDE: Motor Plants

8. In a four-stroke cycle diesel engine, badly worn intake valve guides can cause excessive _________.

   • A.exhaust temperatures
   • B.exhaust pressure
   • C.lube oil consumption
   • D.cooling water temperatures
   Show answer

   C. lube oil consumption

   Q602, Chief Engineer Limited: Motor Plants

9. 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

10. Which of the following statements is true concerning carbon dioxide when used as a fire extinguishing agent?

    • A.Its smothering effect is excellent for class B fires.
    • B.Carbon dioxide is corrosive when exposed to fire.
    • C.Its total cooling effect is far greater than water.
    • D.Carbon dioxide should be applied slowly to a large engine room fire.
    Show answer

    A. Its smothering effect is excellent for class B fires.

    Q802, Electrician

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.