Third Assistant Engineer Practice Test

1. 1. Which of the terms listed below represents the speed at which the natural period of vibration of a shaft or other machine part is in synchronism with the power...
2. 2. If point #1 in the diagram shown is the beginning of gas compression, which of the cycles listed is being illustrated?
3. 3. The action of which of the below components causes the intake ports of a two-stroke diesel engine to open and close?
4. 4. Where in the four-stroke cycle is cylinder #3 in the illustration?
5. 5. If the piston stroke in a four-stroke cycle diesel engine is 10 1/2 inches and the speed of rotation of the crankshaft is 720 RPM, what is the average piston sp...

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1. 1. An increase in the air inlet manifold pressure of a diesel engine will result in a/an __________.
2. 2. In a naturally aspirated diesel engine, the volumetric efficiency of the intake-air charge is mainly influenced by the __________.
3. 3. Cooling the intake air supplied to a diesel engine will __________.
4. 4. Excessive wear at part No.11, shown in the illustration would result in __________. Illustration MO-0027
5. 5. Wet-type exhaust silencers, that are used with some lifeboat diesel engines, utilize which design feature?

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1. 1. Which of the following drawbacks of a gas turbine engine provides the greatest potential for injury to personnel?
2. 2. An open cycle gas turbine engine is best described by which of the following statements?
3. 3. Why is a gas turbine considered to operate on the Brayton cycle?
4. 4. A gas turbine engine in which exhaust gas heat energy is added to the air charge between the compressor and combustion chamber is classified as which of the fol...
5. 5. The acronym MFC represents which of the following?

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1. 1. The wooden plug fitted tightly in the vent of a damaged tank may prevent the tank from __________.
2. 2. An acceptable method of temporarily sealing a crack formed in the hull of a vessel is to __________.
3. 3. The wooden shoring shown in the illustration is bearing against the hatch coaming and is supporting a load in the direction indicated by the arrows. Which of th...
4. 4. Progressive flooding in the engine room may be minimized by securing watertight boundaries and __________.
5. 5. Which type of respiratory protection is preferable for the repair/investigation personnel in a hydrogen sulfide (H2S) environment?

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1. 1. In a refrigeration system, from what location would air and non-condensable gases be removed?
2. 2. The rudder torque capacity of the four-ram steering gear illustrated, is rated at 44,210,000 inch-pounds with one power unit in operation. If the four-ram syste...
3. 3. The illustration is drawn to a scale of 3/8 inch = 1 inch. What is the full-size dimension of "X", if the scale lengths for "E" = 5/8", "F" = 1 3/8", "G" = 2 1/...
4. 4. In a flash evaporator, scale as a result of higher-than-normal temperatures is most likely to occur in the __________.
5. 5. Standard filter/driers used in many commercial type refrigeration units may contain what type of substance?

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1. 1. In the diagram of figure "4", the three-phase step-down power transformer has a turns ratio of five to one. If a three-phase 4160-volt supply is connected to te...
2. 2. If a digital multimeter is set up as shown in figures "A" and "B" of the illustration, what is the status of the silicon diode if the display reads 4.7 ohms whe...
3. 3. An open primary coil in a voltage transformer (VT) will be indicated by which of the listed conditions?
4. 4. To keep emergency lead-acid batteries in a full state of charge for emergency use, what is normally done?
5. 5. Which of the illustrated motors has an open, drip-proof (ODP) motor enclosure? EL-0001

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1. 1. Overheating of the generating tubes will occur when a boiler reaches its end point of __________.
2. 2. How is boiler water forced to circulate faster in accelerated natural circulation boilers as compared to free natural circulation boilers?
3. 3. In a boiler water gauge glass, a ball check valve is installed on the __________.
4. 4. The primary operational difference between a huddling chamber type safety valve and a nozzle reaction type safety valve is the __________.
5. 5. Arrow "B" shown in the illustration indicates the __________.

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1. 1. 8 ounces of oxygen, dissolved in 500,000 pounds of water, is a concentration of __________.
2. 2. As the pH of the boiler water approaches zero, the water becomes increasingly __________.
3. 3. Chemicals are added to boiler water to __________.
4. 4. A sample of boiler water can be chemically tested for alkalinity by initially adding a few drops of phenolphthalein and then slowly titrating the water sample u...
5. 5. The major reason dissolved gases are removed from boiler feedwater is because they may cause __________.

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