Marine Propulsion & Engineering System Flashcards
A carburetor is required to have a safety device called a(an):
backfire flame arrestor
All marine low speed diesel engines are of what design?
four-stroke
Diesel engines are considered safer than gasoline engines because :
the fuel used is less volatile
Exhaust gases in a two-stroke/cycle diesel engine are discharged through :
exhaust ports or valves
If an engine shuts down due to a high jacket water temperature, what action should be taken?
allow engine to cool gradually
One major disadvantage of a low-speed diesel as compared to a steam main-propulsion system is:
a minimum speed for the engines that limits the minimum speed of the vessel
The exhaust pipe shall be kept gas tight throughout its entire length because:
Carbon Monoxide may enter the internal portions of the vessel
What condition will result in the automatic shutdown of a diesel engine?
Low lube oil pressure
The term “separation” as used in oil purification refers to the removal of :
two liquids from each other
Why is it necessary to extend ventilators to the bilges?
to remove fuel vapors which are heavier than air
At a given erosion of piping and machinery will be minimized by utilizing :
superheated steam
A lower edge of a propeller blade when the blade is in a horizontal position and moving downward?
leading edge
The conical steel, or composition cone instaled on a propeller, known as fair waters, provide which of the following benefits?
reduce turbulence
Where a propeller shaft passes through the hull, which of the following will stop water from entering the vessel?
stuffing box
The instrument called the telegraph is used to :
Give signals to and from bridge
When the firing rate of a boiler is reduced, the flow of fuel should be :
reduced before the air flow
The type of chemical that can be used routinely so as to maintain the potable water’s quality of hygiene is:
Chlorine
When a misalignment between the pump and its driving source exceeded that specified by the manufacturer of the pump, the shaft :
bearing will be overloaded and will fail
Which of the listed typeof valves could be damaged if it is used for regulating the flow of fluid through a piping system?
Gate valve
In an AC generator, the voltage induced in the armature windings is maximum when the field poles are :
rotating at a high speed
Why is protection equipment very essential in an electrical distribution system?
all of these are correct
Air that is trapped in the hydraulic fluid of a steering gear system would best be indicated by?
an improper rudder response
Which of the following units of a steering gear system will actuate the steering gear in conjunction with the hydraulic messages served by the telemotor?
ship servomotor
What will happen if one generator driving an engine automatically shuts down if there are two generators in parallel operation?
a circuit breaker will trip on reverse power
With gasoline engines, if a mechanical exhaust system is used, before starting the engine, you should run the exhaust blower at a sufficient time so as to :
ensure at least one complete change of air in the compartments concerned
A megohmeter is an instrument used to test for:
an open field coil
The capacitance is arranged in series on an AC circuit. If the line voltages remain constant, the capacitive reactance value can be varied by changing the :
line frequency
The term “Capacitance” is the property of an electrical circuit that resists or opposes any change in the?
voltage
In order to protect electric generators against any overload, they are fitted :
with fuses or circuit breakers
The basic unit of measurement for inductance is the :
Henry
What is the proper method of applying plastic electrical cable splice?
wind the tape sa that each turn overlaps the turn before it
What could be the purpose of a main switchboard circuit breaker reverse-power trip?
prevent alternator motorization
The precision instrument known as “wheatstone bridge” is used to measure :
Resistance
In order to check the three line fuses of a three-phase system consisting of three-phase motor, you should :
place the starter in the “stop” position
Which instrument may be used to check the resistance of insulation?
Megohmeter
As the amount of moisture content in the atmosphere increases, the difference between the dry-bulb and wet-bulb temperature will :
Decrease
Inside an air-conditioned room, you notice that the people inside are complaining of being too cool, what could be the most probable reason for this?
relative humidity is too low
The term “short cycling” in a refrigeration system means?
compressor stops and starts frequently
The usual characteristic of a refrgerant known as Freon is:
non-toxic
A characterisitc of Freon 12 is :
soluble when mixed with oil at lower viscosity and pour point
This is the ability of an oil to separate cleanly from an oil and water mixture.
demulsibility
The branch of science known as Hydrostatics deals mainly with _______.
fluids at rest
This the amount of heat absorbed by each unit mass of refrigerants as it flows through an evaporator:
Refrigerating
This term indicates the difference between the pressure at a point being measured and that of a perfect vacuum is called ________________ pressure.
Absolute
The energy associated with molecules is known as:
thermal energy
The type of energy that exist within a system as a result of the relative velocities of to or more objects is called:
Kinetic energy
Latent heat of water vapor in the air depends upon the:
Dry-bulb temperature
The ration of the weight of moisture contained in a given volume of air, to the weight of moisture that the same sample would hold if saturated, and expressed in grains is called the:
relative humidity
Whe the air reaches its dew point,therefore it is at its:
highest relative humidity
If there is a constant hissing sound at the thermal expansion valve, what does it means?
lack of refrigerant
What would most satisfactorily lower the humidity of the air being circulated by an air conditioning sytem?
cooling the air to a point below the dew point, then recooling it
A type of stabilizer that usually is fitted at the turn of the bilge and does not project beyond the vertical line from the ship’s side or below the horizontal line of the ship,s bottom.
non-rectangle fin
Sewage treatment systems on board a US inspected ship must be approved by which authority?
U.S. Coast Guard
The flame screens installed on a sewage tank vents prevents explosion by:
dissipating the heat of fire
This is the process of separation of the more volatile parts of petroleum oil from those less volatile by vaporization and subsequent condensation.
Distillation process
This is a hydraulic accumulator that is designed to _____.
store fluid under presure
If a hydraulic pump is operated at maximum efficiency, will it be a cause to overheat?
pumps internal slippage when excessive will cause it to overheat
The oil levels in a hydraulic system reservoirs should be maintained at a recommended level in order to:
all of these are correct
Which power source will actuate a solenoid valve?
electric current
Why do you think Dcseries motors are used extensively for electric drives on winches?
they are designed to operate ina stalled condition
This the ability of metals to be hammered or rolled out?
malleability
A large, low speed, main propulsion diesel engine is operating at a rated load and speed while the vessel is in a calm seas. As the intensity of the sea increases, the engine speed governor maintains the RPM, with the load indicator showing an increase in load beyond the allowable limits. Which action must be taken next?
decrease the engine RPM
With an internal combustion engine, it converts chemical energy into?
heat energy
The fuel injected into a diesel engine combustion chamber is generally ignited by _____.
heat of compression
If the piston rings are operating, what would you see visually?
shiny face and bottom, black top and back
What is the use of rotating pistons?
reduce piston ring wear
If there is a sudden unloading of a diesel engine, it will cause _____?
overspeed trip
The number of crankshaft revolutions to complete one cycle if it is a two-stroke cycle engine is:
one revolution
The nmostprobable reasonof a sudden drop in compression pressurein one cylinder is?
excessive early fuel injection
The instrument called the pyrometer is used to measures?
exhaust temperature
If you see that a diesel engine is emitting white smoke, it means?
low combustion temperature
The reversing system used on a 2-stroke cycle forted engine is:
rotating camshaft
The dirty F.O. strainer could be determined by?
decreasing pressure drop cross the strainer
If temperature of fuel decreases, which of the following will increase? I. Pour Point II. Viscosity
II only
If you have discovered a leak in the gasoling line to the engine, the best thing to do is?
close the fuel valve at the tank
The most practical method of detecting fuel oil injection to a cylinder of a running engine is:
chaecking the exhaust temperature regularly
If a lubricating oil is thinning out of high temperatures and thickening at low teemperature, it will have :
low viscosity index
Steam does work in an engine or turbine, it expands and :
decreases in superheat
Which is NOT a function of the steam drum of a marine water-tube boiler?
collects steam exhausted from the turbines
Stern tube and strut bearings lined with hardwood or rubber composition materials are lubricated with ?
saltwater
That type of the propeller, wherein blades are integral with the hub, the propeller is called:
solid propeller
What is the element that responds to the signal from the detecting element and gives a signal representing the controlled condition?
measuring element
On board tanker vessels, which type ofg valve is most commonly used in conjunction with hydraulically actuated control?
butterfly valve
The rudder stock in an electrohydraulic steering system is limited by:
a differential gear
The Coast Guard regulations require steering gear systems to be equipped with a means of steadying the rudder in an emergency. This can be accomplished by:
suitable arrangement of stop valves from the rams in the hydraulic piping
The meghometer is also connected to each end of an individual motor winding, a low ohm reading means :
good continuity
The instrument called an ohmeter is used to measure:
circuit continuity
To protect against overheating, circuits are fitted with:
circuit breaker
One ton per cubic meter represents:
mass density
The leads connected from a megohmeter are atteached to the leads of an AC motor field coil. A reading of infinity is obtained by indicatinga (an):
open field coil
What is the function of lubricating oil?
reduce the accumulation of harmful detergents
What is that expression re;ated to the cross-sectional area of shipboard electrical conductors?
millimeters
The rate of flow of electrical currents through a conductor is measured in:
amperes
Electrical power is expressed in:
watts
If the length of a wire is halved and the cross-sectional area is doubled, the resistance will be:
quartered
053101 If the piston stroke of a diesel engine is 10 1/2 inches and the speed of the crankshaft is 720 RPM, what is the average piston speed?
1260 feet/minute
What is the average piston speed if the piston stroke of a diesel engine is 10.5 inches and the speed of the crankshaft is 720 RPM?
1260 feet/minute
What is the average piston speed of a five cylinder low speed engine which has a bore of 29.5 inches, a stroke of 63 inches, and a rated speed of 123 RPM?
1291 ft/min
A five cylinder low speed engine has a bore of 29 1/2 inches, a stroke of 63 inches, and a rated speed of 123 RPM. What is the average piston speed?
1291 ft/min
Between cylinders of a V-16 four-stroke cycle diesel engine, the firing interval is _______.
45.00’
What is the firing interval between cylinders of a V-16 four-stroke cycle diesel engine?
45.00’
What is the average piston speed of an engine with a 12 inch stroke operating at 900 RPM?
450 ft/min
Calculate the average piston speed of an engine with a 12 inch stroke operating at 900 RPM.
450 ft/min
Which cylinder liner surface condition indicates proper lubrication?
A bright appearance
Which of the following cylinder liner surface condition indicates proper lubrication?
A bright appearance
Modern marine diesel engines having mechanical fuel injection operate on a combustion cycle which is __________.
a combination of constant volume and constant pressure
