DDE – Unlimited HP, Revision & Practice Exams

What statement is true concerning the arrangement of line shaft bearing housings?

1. Line shaft bearing housings are typically single-piece pedestal type bearing housings.
2. Line shaft bearing housings are typically single-piece flange type bearing housings.
3. Line shaft bearing housings are typically split half flange type bearing housings.
4. Line shaft bearing housings are typically split half pedestal type bearing housings. ✓

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

1. bees wax
2. distilled water
3. the same refrigerant as the system ✓
4. mercuric sulfate

The BTU value of fuel oil is determined by a/an __________.

1. hydrometer
2. calorimeter ✓
3. viscosimeter
4. open cup test

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.

The purpose of the metal spray rub coating on the rotor and stator casing of an axial-type compressor is which of the following?

1. ensure protection for the gearbox adapter when removing or replacing the bearings
2. control air flow through the compressor
3. provide close vane to rotor and blade to stator case clearances ✓
4. seal the circumferential dovetails

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.

What is the term used to describe the stationary vanes preceding the first stage of an axial compressor?

1. Variable stator vanes.
2. Inlet guide vanes. ✓
3. First stage stator vanes.
4. Variable inlet vanes.

Why are loose-fitting blades used on the first several stages of large axial compressors?

1. To compensate for a malfunctioning compressor support bearing.
2. To compensate for the abrasive action of the blade tips.
3. To minimize vibration while the engine is passing through critical speed ranges. ✓
4. To maintain close tolerances in the compressor.

A centrifugal flow gas turbine uses what type of combustion chamber?

1. can ✓
2. annular
3. can-annular
4. double-annular

The three most common types of combustors used in gas turbine engines are which of the following?

1. can, derivative, and can-derivative.
2. can, angular, and can-angular.
3. can, annular, and can-annular. ✓
4. can, vortex, and can-vortex.

The turbine nozzles convert heat and pressure energy to velocity energy by means of which of the following?

1. Deflection process.
2. Convergent process. ✓
3. Divergent process.
4. Convergent-Divergent process.

What are the two principal functions of the turbine nozzle guide vanes?

1. Convert the potential energy of the hot gases into heat energy and direct the flow of gases to the turbine rotor blades.
2. Convert the heat energy of the hot gases into potential energy and direct the flow of gases to the turbine rotor blades.
3. Convert the heat energy of the hot gases into potential energy and direct the flow of gases to the compressor rotor blades.
4. Convert the heat energy of the hot gases into kinetic energy and direct the flow of gases to the turbine rotor blades. ✓

Which of the following is an advantage of a single-shaft gas turbine engine compared to a split-shaft gas turbine engine?

1. Reversible
2. Fewer moving parts ✓
3. Lower starting torque
4. Better fuel economy

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 ✓

A simple precaution to reduce the possibility of accidental fires in the paint locker, is to __________.

1. label the fixed firefighting system
2. store paint cans on metal shelves only
3. not allow oily rags to accumulate in the space ✓
4. place a portable fire extinguisher immediately outside the locker

The longer an oil fire is permitted to burn, the __________.

1. easier it is to control
2. easier it is to extinguish
3. harder it is to extinguish ✓
4. less chance there is of reignition

One of the main concerns when fighting a galley fire is __________.

1. contaminating food with extinguishing agent
2. spreading of fire through the engineering space
3. the igniting of a grease fire in the range hood ventilation system ✓
4. the loss of stability

When a vessel is inclined, the tendency for it to return to its original position is caused by the __________.

1. movement of the center of gravity
2. movement of the center of buoyancy toward the low side of the vessel ✓
3. increased free surface in the buoyant wedge
4. upward movement of the center of flotation

Adverse effects due to free surface will result when __________.

1. the vessel's draft is increased, thus increasing the vessel's wetted surface area
2. a portion of liquid is removed from a full tank ✓
3. the vessel is trimmed by the stern
4. the vessel's draft is decreased exposing more surface area to the wind and current

Modern ships use multiple computers arranged in a client/server network to perform various shipboard functions. What type of computer network would most likely be used aboard ship?

1. Wireless local area network
2. Wireless wide area network
3. Wired wide area network
4. Wired local area network ✓

Under unusual circumstances, it may be required to operate a ship's service generator above its rated kVA. What supplemental casualty control action will be required?

1. While maintaining the rated system frequency, lower the operating voltage to at least 5% below the rated system voltage.
2. Increase the cooling water flow, while maintaining air temperatures above the dew point to avoid any condensation. ✓
3. While maintaining the rated system voltage, lower the operating frequency to at least 5% below the rated system frequency.
4. Increase the cooling water flow, while maintaining air temperatures below the dew point for increased cooling effect.

Before any auxiliary diesel engine hydraulic starting system is opened for servicing or repair, you must __________.

1. Place all control levers in the "HOLD" position
2. Ensure that the hydraulic fluid reservoir is full
3. Block all hydraulic hoses using high-pressure covers
4. Bleed off all hydraulic pressure from the system ✓

If an auxiliary diesel engine equipped with an electric starting system cranks very slowly after repeated attempts to start, the cause could be a/an __________.

1. Low lube oil viscosity
2. Low compression pressure
3. Ring gear with broken teeth
4. Overheated motor windings ✓

Which of the components listed are interchangeable between different backpack self-contained breathing apparatus produced by various manufacturers?

1. The facepiece
2. The regulator
3. The air cylinder ✓
4. All of the above

The hand brake of a lifeboat winch is __________.

1. manually disengaged when hoisting a boat
2. applied by dropping the counterweighted lever ✓
3. controlled by the centrifugal brake mechanism
4. automatically engaged if lowering speed is excessive

The canopy of your life raft should __________.

1. go into place as the raft is inflated ✓
2. be put up after everyone is aboard
3. be put up only in severe weather
4. be used as a sail if the wind is blowing

A reciprocating refrigeration compressor may be tested for leaking discharge valves by stopping the compressor, turning the discharge service valve all the way in, and then turning the compressor over by hand. If the discharge valves are leaking, the high-side pressure gauge will show pressures which react in which way?

1. decreasing with each stroke
2. decreasing to a vacuum
3. rising and falling with each stroke ✓
4. increasing with each stroke

When pumping down an air conditioning system to test the low-pressure cut-out switch, assuming that the compressor is running, what should be done to initiate the test?

1. stop the compressor
2. secure the condenser
3. stop the circulating pump
4. close the "king" valve ✓

The action necessary to use the steering gear room trick wheel when transferring the steering control from the wheelhouse to local control is to __________.

1. Align the trick wheel to the rudder angle position before engaging ✓
2. Set the six-way control valve in the trick wheel position
3. Open the power transfer switch before engaging the trick wheel
4. Always place the rudder in the amidships position to engage the trick wheel

A device used to hold open the refrigeration compressor suction valve during starting to reduce the compression load is called what?

1. relief valve
2. discharge line bypass
3. suction line bypass
4. cylinder unloader ✓

A vessel is in compliance with federal regulations regarding the discharge of sewage by __________.

1. treating sewage in an approved system
2. holding all sewage onboard
3. pumping the sewage ashore to an approved container
4. all of the above ✓

Which of the procedures or conditions listed could result in damaging a transistor beyond repair?

1. Providing insufficient voltage to the input circuit.
2. Installing a transistor whose current rating exceeds the design circuit current.
3. Providing incorrect polarity to the collector circuit. ✓
4. Applying silicone grease between the heat sink and the transistor mounting.

What is an ammeter used to measure?

1. continuity
2. current ✓
3. resistance
4. voltage

When configuring a digital multimeter as an ohmmeter, what will MOST likely be displayed on the screen when the test leads are shorted together?

1. A reading of "OL" ohms will be displayed.
2. A reading of residual test lead and internal resistance will be displayed (typically .2 to .5 ohms).
3. A reading of 0 ohms will be displayed.
4. B or C could be correct depending upon the digital multimeter. ✓

When a battery-operated megohmmeter (insulation tester) is used to perform a dielectric absorption test, the resistance is measured and recorded from each conductor to ground each minute for 10 consecutive minutes. What condition accounts for a gradual rise in resistance each successive minute?

1. The insulation has direct continuity with ground.
2. The insulation is in good condition. ✓
3. The insulation is cracked and otherwise deteriorated.
4. The insulation is contaminated with moisture.

As the electrolyte level in the cells of a lead-acid battery evaporates over time, what will tend to happen to the specific gravity of the electrolyte in the cells as the level drops due to evaporation?

1. The specific gravity of the electrolyte will increase as only the water will evaporate from the electrolyte solution. ✓
2. Although the specific gravity will change due to evaporation, there is no predictable tendency either way.
3. The specific gravity of the electrolyte will remain unchanged as both the water and sulfuric acid will evaporate from the electrolyte solution.
4. The specific gravity of the electrolyte will decrease as only the sulfuric acid will evaporate from the electrolyte solution.

How can the loss of residual magnetism in an alternator with a brushless excitation system be corrected?

1. using a storage battery or battery charger to "flash" the field ✓
2. running the generator at normal speed with the field rheostat fully counterclockwise
3. allowing the generator to run at 10% of normal speed for 5 minutes
4. running the rotor in the opposite direction for 5 minutes

What type of AC motor would use a rheostat in the rotor circuit to vary the speed of the motor?

1. wound-rotor induction motor ✓
2. synchronous motor
3. regenerative braking motor
4. squirrel-cage induction motor

What is the function of the movable cams in a master-switch winch motor drum controller?

1. maintain resistance contacts in clean condition
2. limit the amount of load put on the motor
3. regulate the speed of the motor ✓
4. insulate the operating handle

A boiler safety valve must be capable of __________.

1. Closing with a chattering motion to free scale deposits from the seats
2. Opening gradually above a designated pressure
3. Remaining open until all pressure in the steam drum is relieved
4. Remaining open until a preset pressure drop occurs ✓

Many steam plants are designed so that diesel oil can be provided to the burners when __________.

1. Lighting off a cold ship ✓
2. A heavy fuel must be blended
3. Overload capacity is required
4. Heavy smoking persists

When raising steam on a cold boiler under normal conditions, you should always __________.

1. Take 24 hours to raise steam
2. Use a large orifice burner sprayer plate to start
3. Raise steam within one hour or less
4. Use a small orifice burner sprayer plate to start ✓

The boiler water gauge glasses should be blown down __________.

1. twice each day on the midnight and afternoon watches
2. when the boiler water level changes in a steaming boiler
3. every 12 hours of steady boiler steaming operation
4. when you are in doubt about the water level ✓

In the boiler steam and water system, pressure is highest in the __________.

1. dry pipe
2. mud drum
3. feed line ✓
4. steam stop

Because of the pressure drop existing across each diaphragm, the flow of steam between the nozzle diaphragm and the rotor of the turbine is held to a minimum by __________.

1. a fluid seal
2. a labyrinth packing ring ✓
3. deflector rings
4. a Babbitt liner

Large temperature and pressure drops which occur in the first stage of a combination impulse and reaction turbine are caused by steam passing through __________.

1. a single row of blades more than once
2. one or more velocity-compounded impulse stages at the high-pressure end of the turbine ✓
3. a nozzle diaphragm in the low-pressure end of the turbine
4. a dummy piston and cylinder to offset axial thrust

For the successful operation of a reverse osmosis freshwater generator, why is the high-pressure pump required to operate in the 750 to 1200 psig range for a discharge pressure?

1. To overcome the pore size of the semi-permeable membrane.
2. To overcome the osmotic pressure generated by the difference in solution concentrations. ✓
3. To successfully force the salt water through the pre-filter (or pre-filters).
4. To successfully force the salt water through the chemical pre-treatment device.

Prior to starting a main propulsion diesel 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?

1. When the oil level rises to the ADD mark on the side of the dipstick marked ENGINE STOPPED and OIL COLD.
2. When the oil level rises to the FULL mark on the side of the dipstick marked ENGINE STOPPED and OIL COLD. ✓
3. When the oil level rises to a level well above the FULL mark on the side of the dipstick marked ENGINE STOPPED and OIL COLD.
4. When the oil level rises to the between the ADD and FULL marks on the side of the dipstick marked ENGINE STOPPED and OIL COLD.

When checking the cylinder jacket water cooling expansion tank level on a main propulsion diesel engine on your towing vessel while underway on a coast-wise voyage, what should be the expansion tank level?

1. The level should be in the upper part of the sight glass when the engine is at operating temperature. ✓
2. The level should be out of sight high in the sight glass when the engine is at operating temperature.
3. The level should be in the lower part of the sight glass when the engine is at operating temperature.
4. The actual level is unimportant as long as it is visible in the sight glass when the engine is at operating temperature.

You are analyzing the data used for trend analysis for a two-stroke main propulsion diesel engine on your river push boat. Although the engine has yet to experience a safety shutdown on high crankcase pressure, over time the crankcase pressure (which normally runs in a vacuum) has gradually become less negative. Which of the following failures would most likely be responsible for this condition?

1. Burned cylinder exhaust valve
2. Dribbling injector needle valve
3. Worn piston compression rings ✓
4. Leaking crankcase handhole cover

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?

1. When the oil level rises to the between the ADD and FULL marks on the dipstick.
2. When the oil level rises to the FULL mark on the dipstick. ✓
3. When the oil level rises to the ADD mark on the dipstick.
4. When the oil level rises to a level well above the FULL mark on the dipstick.

You have just replaced a mechanically operated unit injector on a two-stroke cycle auxiliary diesel engine's #1 cylinder on your river push boat. You are using an injector timing tool to set the injector follower height. To do this you must ensure that the fuel cam follower is riding on the fuel cam base circle. Which of the following statements represents the best assurance that the crankshaft is properly positioned?

1. The crankshaft should be barred in the direction of rotation until the #1 cylinder's intake valves are fully closed.
2. The crankshaft should be barred in the direction of rotation until the #1 cylinder's exhaust valves are fully opened. ✓
3. The crankshaft should be barred in the direction of rotation until the #1 cylinder's exhaust valves are fully closed.
4. The crankshaft should be barred in the direction of rotation until the #1 cylinder's intake valves are fully opened.

An engine that emits black smoke through the stack may indicate a misfiring cylinder. Assume that the auxiliary diesel engines on your articulated tug-barge unit have a fuel injection system that permits the injectors to be disabled for troubleshooting purposes by loosening the high-pressure fuel injection line fitting at the injector nozzle while the engine is running and noting the response of the engine in terms emission of black smoke. Which of the following statements is true?

1. After disabling the injector of a given cylinder, if the engine previously producing a clear exhaust now produces black smoke, this indicates that the cylinder associated with the disabled injector is misfiring.
2. After disabling the injector of a given cylinder, if the engine previously producing black smoke now produces a clear stack, this indicates that the cylinder associated with the disabled injector is misfiring. ✓
3. After disabling the injector of a given cylinder, if the engine previously producing black smoke now produces even denser black smoke, this indicates that the cylinder associated with the disabled injector is misfiring.
4. After disabling the injector of a given cylinder, if the engine previously producing black smoke continues to produce equally dense black smoke, this indicates that the cylinder associated with the disabled injector is misfiring.

The main propulsion diesel engines used to power the ship-docking tug to which you are assigned are started with vane-type air-starting motors designed to operate at 250 psig. The in-line lubricator should provide 3 drops of oil per cranking minute, as long as the in-line lubricator oil viscosity is as specified. If the start air pressure is within the normal range and the oil viscosity is correct, but the oil injection rate is only 1 drop per minute, what should be done?

1. The starting air pressure supplied to the air-starting motors should be increased.
2. The in-line lubricator oil injection metering needle valve should be further closed.
3. The oil in the in-line lubricator should be replaced with oil of lower viscosity than specified.
4. The in-line lubricator oil injection metering needle valve should be further opened. ✓

When interpreting the engine lube oil supply header pressures for the main engines on your river push boat, what statement is true assuming that the lube oil pump is engine-driven?

1. As the lube oil temperature increases, the supply header pressure tends to decrease, and as the engine rpm increases, the supply header pressure tends to increase. ✓
2. As the lube oil temperature increases, the supply header pressure tends to increase, and as the engine rpm increases, the supply header pressure tends to decrease.
3. As the lube oil temperature increases, the supply header pressure tends to increase, and as the engine rpm increases, the supply header pressure tends to increase.
4. As the lube oil temperature increases, the supply header pressure tends to decrease, and as the engine rpm increases, the supply header pressure tends to decrease.

The diesel fuels burned in auxiliary and main diesel engines of tugboats operating in harbor areas are required to meet certain specifications. Among these are limits of certain contaminants to limit atmospheric emissions to acceptable levels. Which of the following soluble contaminants is applicable?

1. Asphaltenes
2. Sulfur ✓
3. Total sediment
4. Water

The main engines on the harbor tug to which you are assigned are fitted with duplex secondary spin-on fuel filters. Concerning the selector handle, what statement is true?

1. The selector handle is normally placed in the "BOTH" position regardless of the load or rpm on the engine in order to be able to double the fuel handling throughput at any load or rpm and allow the engine speed to be changed without worrying about the selector handle position.
2. The selector handle is placed in the "BOTH" position when the engine is running at low load or rpm. When the engine is running at high load or rpm, the selector handle is placed in either the "1" or "2" position depending upon which filter element is clean.
3. The selector handle is placed in either position the "1" or "2" position regardless of the load or rpm on the engine. The selector handle is temporarily placed in the "BOTH" position only when transitioning from a restricted filter element over to a clean filter element. ✓
4. The selector handle is placed in the "BOTH" position when the engine is running at high load or rpm to accommodate higher fuel delivery requirements. When the engine is running at low load or rpm, the selector handle is placed in either the "1" or "2" position.