Third Assistant Engineer, Revision & Practice Exams

While air is being compressed in a centrifugal flow gas turbine, what happens to the direction of air flow?

1. Changes only at the compressor discharge.
2. Changes only at the compressor inlet.
3. Changes at each separate component. ✓
4. Changes only once from inlet to outlet.

Two functions of the compressor stator vanes include which of the following?

1. Direct air flow to each rotor stage at the correct angle and deliver air to the combustor at the correct velocity and pressure. ✓
2. Direct air flow to rotor blades at the correct angle and are shaped to cause a velocity increase and a pressure decrease.
3. Direct air flow to rotor blades at the correct angle and are shaped to produce a velocity increase and maintain a constant pressure.
4. Direct air flow to rotor blades at the correct angle and are shaped to maintain a constant velocity and produce a pressure increase.

In a compartment that has been completely flooded with water, the greatest pressure will be exerted __________.

1. along the top of the bulkhead
2. at a point that is one-third from the bottom of the bulkhead
3. along the bottom of any bulkhead ✓
4. at the vertical center of the bulkhead

The wooden plug fitted tightly in the vent of a damaged tank may prevent the tank from __________.

1. collapsing
2. developing free surface moments
3. developing free surfaces
4. filling completely ✓

Which of the listed characteristics applies to a semi-portable CO2 system?

1. Each cylinder must weigh less than 50 pounds.
2. It has distribution piping installed permanently.
3. The cylinders are mounted horizontally.
4. It has a portable hose and nozzle. ✓

Modern marine diesel engines equipped with mechanical fuel injection operate on a combustion cycle which is __________.

1. entirely constant pressure
2. entirely constant volume
3. a combination of constant volume and constant pressure ✓
4. a combination of constant temperature and constant pressure

Which of the following conditions would NOT be considered a valid reason for the diesel engine to operate in the area indicated by letter "B" shown in the illustration? Illustration MO-0126

1. Operating the vessel against high winds and current
2. Operating the vessel in shallow water
3. Operating with a fouled or damaged propeller
4. Operating with minimal hull drag and under light draft ✓

The piston pin shown in the illustration should be classified as __________. Illustration MO-0011

1. full floating
2. fixed
3. semi-floating ✓
4. anchored

What is the function of a diesel engine's stationary parts?

1. To add power to the engine.
2. To keep the engine firmly attached to its auxiliary pumps.
3. To maintain the engine's moving parts in their proper relative positions. ✓
4. To rotate the crankshaft.

Item labeled "R" as shown in Fig. 5 of the illustration is identified as the __________. Illustration MO-0025

1. exhaust manifold
2. air filter
3. non-return scavenge valve
4. aftercooler ✓

The thrust bearing shown in the illustration has over eight years of ahead running time. Measurements show "i1" is 4 mm and "i2" is 1 mm. Which of the following conditions is indicated and what steps should be taken, if any? Illustration MO-0121

1. No appreciable wear has occurred, and the proper maintenance procedures should continue to be followed. ✓
2. A wear rate of 1.6 mm per year occurred. Although not excessive, this condition may require more frequent monitoring.
3. The stops in which the thrust bearing block rides are worn, and it is necessary to return these to their original specifications.
4. A wear rate of 1.6 mm per year is excessive and requires immediate assistance from the manufacturer's field support.

The vessel to which you are assigned is fitted with generator drive engines of the type shown in the illustration. In terms of operating cycle and cylinder configuration, what statement is TRUE? Illustration MO- 0163

1. This is a two-stroke cycle, 60o V-type engine.
2. This is a two-stroke cycle, 90o V-type engine.
3. This is a four-stroke cycle, 90o V-type engine. ✓
4. This is a four-stroke cycle, 60o V-type engine.

Prior to starting an auxiliary diesel engine on your vessel, the crankcase oil level must be checked. At what checked level would you be required to add make-up oil?

1. When the oil level drops to where it is no longer visible on the dipstick.
2. When the oil level drops below the ADD mark on the dipstick. ✓
3. When the oil level drops to between the ADD and FULL marks on the dipstick.
4. When the oil level drops below the FULL mark on the dipstick.

The most crucial time for any bearing with regards to diesel engine lubrication is __________.

1. During periods of low load
2. During first warm up
3. During initial starting ✓
4. After load reversals

Which of the following statements is true concerning a main diesel engine oil cooler?

1. The oil temperature is less than the cooling water temperature.
2. The oil pressure is less than the cooling water pressure.
3. The oil pressure is greater than the cooling water pressure. ✓
4. The oil flow control valve is always installed in the oil input line.

In terms of the diesel fuels burned in auxiliary and main propulsion diesel engines onboard vessels, which of the listed fuel properties would be most critical to consider when transferring and forwarding fuel in extremely low ambient temperature conditions?

1. Pour point ✓
2. Heating value
3. Ash content
4. Flash point

Which of the following statements is true concerning the cetane number of diesel fuel?

1. The cetane number affects the amount of injection lag.
2. The cetane number is an indication of the fuel's viscosity.
3. Ignition lag is reduced with fuels having a high cetane number. ✓
4. The cetane number is of little significance in the combustion process.

From the graph shown in the illustration, determine the size of the regulating ring required for the proper operation of the fuel oil centrifuge if the fuel oil specific gravity is 0.9 kg/dm3 at 68°F, and the separating temperature is 158°F. Illustration MO-0113

1. 86 mm
2. 104 mm
3. 110 mm ✓
4. 117 mm

The vessel to which you are assigned has a main engine fuel system as shown in the illustration. Besides preventing the attached fuel oil pump and the hand priming fuel oil pump from discharging through the other, what other purpose do the anti-flood check valves serve? Illustration MO-0152

1. They prevent backflow of fuel from the engine to the day tank when the engine is running and when the day tank is located above the engine.
2. They prevent backflow of fuel from the engine to the day tank when the engine is shut down and when the day tank is located above the engine.
3. They prevent backflow of fuel from the engine to the day tank when the engine is running and when the day tank is located below the engine.
4. They prevent backflow of fuel from the engine to the day tank when the engine is shut down and when the day tank is located below the engine. ✓

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

1. create turbulence in the combustion chamber
2. aid in completing cylinder scavenging
3. inject fuel at the proper time ✓
4. minimize fuel penetration into the cylinder

When a nozzle tester is used to check the spray pattern of a diesel fuel injection nozzle, which of the following statements is true?

1. The valve should normally begin to open at 1/2 the popping pressure
2. The needle valve spring should always be removed first before testing
3. A serious hazard of blood poisoning exists if the fuel spray penetrates the skin of the operator ✓
4. The needle valve should remain open after the nozzle pops open

Under what condition would valves "4" and "5", as shown in the illustration, be closed? Illustration MO-0077

1. Operating the main engine on DO.
2. Loading the HFO bunkers.
3. Operating in normal mode. ✓
4. Operating DO purifier on HFO.

According to regulations, what is the minimum nominal pipe size for a fuel oil service tank vent line?

1. 1.5 inches
2. 2 inches
3. 2.5 inches ✓
4. 3 inches

Wet-type exhaust silencers, that are used with some lifeboat diesel engines, utilize which design feature?

1. The exhaust gases are preheated in the silencer to reduce noise.
2. A cooling water spray and internal baffles break up the exhaust gas flow. ✓
3. The silencer is equipped with a water seal.
4. The exhaust temperature always increases when passing through the silencer.

Antifreeze solutions containing ethylene glycol should not be mixed with corrosion protection oils, as the resultant mixture __________.

1. promotes scale buildup
2. is dangerously flammable
3. may cause frothing ✓
4. has a higher chloride content

What may cause a diesel engine cylinder head to crack?

1. Overheated intake valves
2. A leaking oil control ring
3. Heat transfer from exhaust valves
4. Scale on cooling passages ✓

The average exhaust temperature of a two-stroke cycle diesel engine with a turbine-driven supercharger is lower than a similar four-stroke cycle diesel engine at equal loads because __________.

1. Two-stroke cycle diesel engines have a higher M.E.P. than four-stroke cycle diesel engines
2. Four-stroke cycle diesel engine exhaust is cooled by scavenging air
3. Two-stroke cycle diesel engines have a lower M.E.P. than four-stroke cycle diesel engines ✓
4. The opening of the two-stroke cycle diesel exhaust ports or valves occurs much later than in four-stroke cycle diesel engines

Clutching takes place nearest the bearing shown in the illustration, located at number _____. Illustration MO- 0086

1. 1 ✓
2. 2
3. 3
4. 4

How is lubrication provided to the device shown in the illustration? Illustration MO-0120

1. The lube oil enters through the supply pipes shown as #11 and eventually drains to the main engine sump. ✓
2. Only silicate ester based synthetic oils have the capability and necessary characteristics to be used in this type of application.
3. A separate system containing oil under extremely high-pressure is used due to its ability to provide a high film strength.
4. The lubrication system closely resembles the system used with standard line shaft bearings.

The pneumatic propulsion control system used on your vessel uses a diaphragm-operated relay valve as shown in the illustration. Periodically, the valve is to be disassembled for cleaning and inspection. What statement best describes the proper technique? Illustration MO-0052

1. Rubber parts such as the diaphragm should be cleaned with non-flammable solvent, and metal parts such as the valve discs and seats should be washed with soap and water.
2. Rubber parts such as the diaphragm should be washed with soap and water, and metal parts such as the valve discs and seats should be cleaned with non-flammable solvent. ✓
3. Rubber parts such as the diaphragm and metal parts such as the valve discs and seats should all be cleaned with non-flammable solvent.
4. Rubber parts such as the diaphragm and metal parts such as the valve discs and seats should all be washed with soap and water.

The vessel to which you are assigned is fitted with a totally pneumatic propulsion control system as shown in the illustration. If propulsion control functions perfectly from the engine room control station, but will not function at all from any of the remote stations, which of the following system faults best accounts for these symptoms? Illustration MO-0168

1. The attendance valve at the pneumatic remote-control station has a blocked outlet port.
2. The local/remote transfer valve at the engine room control station has a blocked local port.
3. The pilot house/remote transfer valve at the pilot house has a blocked remote port.
4. The local/remote transfer valve at the engine room control station has a blocked remote port. ✓

Adjustments to the compensating needle valve in a hydraulic governor should be made with the engine at __________.

1. Maximum power at a normal load
2. Maximum power and load under normal conditions
3. Half-speed and normal temperature
4. Normal operating temperature without a load ✓

The hunting of a diesel engine may be caused by which of the following?

1. Excessive speed droop
2. Poor quality fuel
3. Fluctuations in load
4. Excessive governor control ✓

With reference to the chart, if a boiler generates saturated steam at 385.3 psig, how much heat per pound was required to change the water into steam if the feedwater temperature was initially 220°F? Illustration SG- 0004

1. 96.85 BTU
2. 97.15 BTU
3. 1016.40 BTU ✓
4. 1196.45 BTU

The auxiliary steam boiler on your vessel is equipped with a gauge glass for local level indication. On which of the following auxiliary boiler types would this gauge glass be attached to a flash chamber also known as a steam accumulator or steam separator?

1. Water-tube forced-circulation steam boiler ✓
2. Fire-tube steam boiler
3. Water-tube natural-circulation steam boiler
4. Electric steam boiler

On which of the following auxiliary boiler types would soot blowers be equipped for maintaining heat transfer efficiency?

1. Electric steam boiler
2. Fire-tube steam boiler
3. Water-tube natural-circulation steam boiler ✓
4. Water-tube forced-circulation steam boiler

The water-tube natural-circulation steam boiler on your vessel is equipped with soot blowers for maintaining heat transfer efficiency. Which of the following statements best describes the conditions that must be met before tubes can be safely blown using the soot blowers?

1. The boiler draft must be increased AND the boiler fires must be lit before tubes can be safely blown. ✓
2. The boiler draft must be decreased AND the boiler fires must be lit before tubes can be safely blown.
3. The boiler draft must be decreased AND the boiler fires must be secured before tubes can be safely blown.
4. The boiler draft must be increased AND the boiler fires must be secured before tubes can be safely blown.

On which of the following auxiliary boiler types would soot blowers most likely be fitted?

1. Water-tube natural-circulation steam boiler ✓
2. Water-tube forced-circulation steam boiler
3. Electric steam boiler
4. Fire-tube steam boiler

Which of the following conditions could cause the feed pump for an auxiliary boiler to lose suction?

1. Increased suction head pressure
2. Decreased feedwater temperature
3. Pump recirculating line being open too much
4. Excessive feedwater temperature ✓

The correct procedure for giving an auxiliary boiler a bottom blow, is to begin __________.

1. when the boiler has been cooled to ambient temperature
2. only after raising the water level to within 1/2 inch of the high-water cutout
3. when the boiler has been secured long enough for most solids to settle ✓
4. only after bypassing the low-pressure pressuretrol

Why is the cycle efficiency higher in the intercooled-recuperated cycle as compared to a simple cycle gas turbine? Illustration GT-0026

1. The intercooler serves to reduce the required high-pressure compressor power while the recuperator utilizes waste heat from the exhaust to decrease required fuel to achieve the turbine inlet temperature. ✓
2. The intercooler serves to increase the required high-pressure compressor power while the recuperator utilizes waste heat from the exhaust to increase turbine inlet temperature.
3. The intercooler serves to reduce the required high-pressure compressor power while the recuperator utilizes waste heat from the exhaust to decrease turbine inlet temperature.
4. The intercooler serves to increase the required high-pressure compressor power while the recuperator utilizes waste heat from the exhaust to decrease turbine inlet temperature.

The two basic types of compressors used in gas turbine engines are which of the following?

1. Axial and lobe.
2. Centrifugal and axial. ✓
3. Axial and reciprocating.
4. Centrifugal and reciprocating.

What is the disadvantage of a dual-entry centrifugal compressor compared to a single-entry centrifugal compressor?

1. The dual-entry compressor utilizes a more complicated inlet ducting. ✓
2. The dual-entry compressor is larger in diameter.
3. The dual-entry compressor rotates at slower speeds.
4. The dual-entry compressor has a greater efficiency.

Which of the following terms refers to axial compressor stator blades?

1. Roots
2. Nozzles
3. Shrouds
4. Vanes ✓

How do the high-velocity high-temperature gases cause the gas turbine rotor to rotate?

1. By increasing the velocity of the gases.
2. By transferring velocity energy and thermal energy to the turbine blades. ✓
3. By converting the high-velocity gas to low-velocity gas.
4. By creating a low-pressure area before the rotor.

The turbine nozzle blades convert the combustion gases heat and pressure energy into what form of energy?

1. Thermal
2. Kinetic ✓
3. Chemical
4. Electrical

Accelerating the compressor to the self-sustaining speed of the engine is the function of which of the following components?

1. Compressor extension shaft
2. Starter ✓
3. PT shaft
4. Mechanical drive shaft

What is the power source for the ignition exciter of a gas turbine engine?

1. Four lead-acid batteries
2. Ship's 400 Hz system
3. Ship's 28 volt DC system
4. Ship's 115 volt AC system ✓

The main lubrication system utilized by the gas turbine engine shown in the illustration is what type? Illustration GT-0017

1. Oil mist recovery sump
2. Dry sump ✓
3. Common drain sump
4. Wet sump

As shown in the illustration, what is the purpose of pressurizing the main bearing lube oil sumps on a typical marine gas turbine? Illustration GT-0023

1. Assists in cooling the lube oil.
2. Minimizes oil leakage from the rotor shaft. ✓
3. Increases lube oil penetration.
4. Provides uniform lube oil distribution around the bearing.

The fuel oil system of a gas turbine engine provides all EXCEPT which of the following?

1. Acts as a hydraulic medium to actuate the fuel control
2. Controls the angle of the variable stator vanes
3. Provides accurately metered fuel for combustion
4. Acts as a cooling medium for the lube oil cooler ✓

The only hand tools that should be used on gas turbine engines are chrome plated, nickel plated, or which of the following?

1. Cadmium plated
2. Unplated ✓
3. Silver plated
4. Bronze plated

The two main types of compressor stall are known as what?

1. Flame out and inlet temperature stall
2. Rapid rise and temperature inversion
3. Overspeed and overload stall
4. Steady state and transient ✓

What is the primary purpose of the diffuser and distributor on the GE LM2500 gas turbine?

1. To provide even temperature distribution at the compressor
2. To provide uniform air flow to the combustor ✓
3. To provide uniform air flow to the turbine
4. To provide uniform air flow to the compressor

The gas generator section of the GE LM2500 gas turbine is composed of all of the following components EXCEPT which of the following?

1. Bellmouth
2. FOD screen
3. Two-stage HP turbine
4. Six-stage LP turbine ✓

In accordance with 46 CFR, life jackets should be stowed in __________.

1. The forepeaks
2. The pumproom
3. Readily accessible spaces ✓
4. Locked watertight containers

Which of the gases listed is the poisonous gas most likely to be found in a closed compartment involved in a fire?

1. Nitrogen
2. Hydrogen
3. Carbon dioxide
4. Carbon monoxide ✓

A fire that has developed in a pile of rubber gasket material would be classified as a __________.

1. Class "A" ✓
2. Class "B"
3. Class "C"
4. Class "D"

A fire in a pile of dunnage would be classified as a __________.

1. class "A" ✓
2. class "B"
3. class "C"
4. class "D"

The most effective method of extinguishing a class "A" fire is by __________.

1. blanketing and smothering
2. using a sodium based dry chemical
3. quenching and cooling ✓
4. using non-conducting extinguishers

Combustible gas indicators incorporate the use of a/an __________.

1. Inflatable bag
2. Vapor-detecting carbon compound
3. Wheatstone bridge ✓
4. Sensitive liquid chemical

When checking the level of a volatile liquid in a tank on the weather deck of a tank vessel, you should position yourself __________.

1. at a right angle to the wind direction ✓
2. on the windward side of the opening
3. on the leeward side of the opening
4. so that the obstruction of your body will protect you from the fumes

An LNG carrier has an approved type of gas detecting system to detect methane leaks. What area(s) would this be NOT used in?

1. Barrier spaces
2. Boiler burner supply piping
3. Cargo handling rooms
4. Habitability Spaces ✓

In accordance with 33 CFR Subchapter O (Pollution), the overall responsibility in maintaining the Oil Record Book is given to the __________.

1. Chief mate
2. Cargo engineer
3. Master ✓
4. Chief engineer

Stability is determined principally by the relationship of the center of gravity and the __________.

1. aft perpendicular
2. center of buoyancy ✓
3. keel
4. center of flotation

What is the definition of the stability symbol “CL”?

1. Center of longitudinal force
2. A vertical plane through centerline ✓
3. Center of load
4. Center of load displacement

In the absence of external forces, adding weight to one side of a floating vessel, will cause the vessel to __________.

1. trim to the side opposite TCG until all moments are equal
2. list until the center of buoyancy is aligned vertically with the center of gravity ✓
3. heel until the angle of loll is reached
4. decrease draft at the center of flotation

A vessel having a concentration of weight toward the top of the vessel is said to be __________.

1. stiff
2. buoyant
3. tender ✓
4. neutral

The horizontal fore and aft movement of a vessel is called __________.

1. yaw
2. heave
3. surge ✓
4. sway

In accordance with 33 CFR Subchapter O (Pollution), the definition of graywater includes drainage from which of the following?

1. Dishwashers ✓
2. Toilets
3. Hospital sinks
4. Cargo spaces

Release of refrigerant to the atmosphere during the process of purging of air and non-condensable gases can be kept to a permissible minimum by what action?

1. purging through the top of the receiver rather than the top of the condenser
2. purging through the discharge service valve rather than the top of the condenser
3. purging through a dehydrator
4. cracking the purge valve briefly and allowing the refrigerant to re-settle between purges ✓

Concerning the charging of refrigerant into a vapor compression refrigerating system, which of the following is true?

1. when charging as a liquid it should be to the high side only ✓
2. when charging as a liquid it should be to the low side only
3. when charging as a vapor it should be directly to the receiver only
4. when charging as a liquid it may be to the low or high side

Standard filter/driers used in many commercial type refrigeration units may contain what type of substance?

1. activated alumina or silica gel desiccant beads ✓
2. activated charcoal
3. alcohol based liquid drying agents
4. any of the above may be used

If a reciprocating air compressor has cylinder suction or discharge valves that fail to properly seat, what statement is true concerning the result?

1. The compressor would have longer running periods at higher displacement capacity between operating cycles.
2. The compressor would have longer running periods at lower displacement capacity between operating cycles. ✓
3. The compressor would have shorter running periods at lower displacement capacity between operating cycles.
4. The compressor would have shorter running periods at higher displacement capacity between operating cycles.

In the presence of an open flame or hot surfaces, chlorinated fluorocarbon refrigerants decompose and form what chemical substance?

1. water vapor
2. phosgene gas ✓
3. carbon monoxide
4. petroleum crystals

In a closed-loop process control system, what term is used to describe the action of measuring the difference between the actual result and the desired result and using that difference to drive the actual result toward the desired result?

1. Deadband
2. Gain
3. Instability
4. Feedback ✓

When an electricity generating plant features shaft-driven generators, what type of propulsor would be the most practicable for main propulsion?

1. Fixed-pitch propeller
2. Tandem propeller
3. Detachable-blade (built-up) propeller
4. Controllable-pitch propeller ✓