were asked in the Class 4B exam of MMD . This is the part 4 of
series dealing with the Marine engineering knowledge. Answer to these questions
will be available shortly. It is very important to have a look of the
questions that are asked in the previous year’s exam papers. If you have any
suggestions related to these questions, please write in the comment box below
this article. Previous year MMD exam papers are available for other subjects
also in our site.
Marine engineering knowledge for Class 4B MMD exam
a letter to the company Technical Manager stating with reasons why the fuel
bunkered in the last port is of very poor quality.
Short notes on the following:
air starting valves
any turbo-charging system based on the pulse or constant pressure systems.
rolling of a vessel.
of reducing roll in a vessel.
Make a diagrammatic sketch of a jacket cooling water
system as applied to a group of medium speed auxiliary diesel engines. Indicate
the temperatures and pressures in the system. Describe in particular the flow
of water from entry to the engine to outlet from the engine and sketch the more
important joints in the system.
used in exhaust gas boilers.
TWO reasons why a tube is condemned.
how it is replaced by a spare tube.
Suggest with reasons the possible consequences of allowing an exhaust
gas boiler to run dry during full power
operation of the main engine
reference to air compressors state why:
volume should be as small as possible,
lubrication should be minimal,
filters should be cleaned regularly,
delivery spring loaded plate valves are use.
dirty atomizer sprayer plate in the burner of an auxiliary boiler, would be
indicated by ____________.
carbon on the register doors
a dazzling white atomizer flame
fluctuating pressure in the windbox
an unevenly shaped burner flame
highest pressure in any closed diesel engine freshwater cooling system is at the
jacket water outlet
expansion tank inlet
heat exchanger inlet
cooling water pump outlet
the following statements describes the function of an alarm annunciator on an
engine room alarm panel?
An alarm condition causes a light and siren to come on
which remain on until the machinery is secured.
A flashing light comes on, followed by an audible
alarm. When an alarm acknowledge button is depressed, the audible alarm is
silenced and light stays on.
An alarm condition gives an audible and visual alarm
signal, both of which are secured when the alarm acknowledge button is
An alarm condition causes a flashing light to come on,
followed by an audible alarm. When the alarm acknowledge button is depressed,
the warning light is extinguished.
of the main shafting between engine and propeller causes bearing overloads and
the difficulties associated with checking shaft alignment and the reasons why
results are unreliable due to external factors.
with a simple sketch how a bearing load is assessed.
controlling the viscosity of the fuel oil to the injectors.
are auxiliary engine-starting air valves connected and operated? What attention
do they require?
reference to heat exchangers state why:
preferable to brazing;
preferable to using ferrules and grommets.
reference to fuel cam design state:-
dwell is sometimes incorporated.
purpose of reduce width on certain sections of the cam.
governs the spring force?
a system of feed water treatment suitable for an auxiliary boiler and explain
the test on the boiler water, which are necessary to ensure that the condition
of the water is satisfactory.
The diameters of crankshaft and intermediate shaft
bearings are different, and in old engines there may also be differences in the
crankshaft journals. How is the axial center-line of the various bearings found
when taking measurements to establish the true shafting line?
Enumerate the properties desirable in a crankcase
lubricating oil suitable for use in a trunk piston engine and describe a system
for purifying the oil. State how and why the system is operated.
and describe a crankcase oil mist detector system and state the conditions,
which will actuate the alarm.
how readings of cylinder liner wear are taken and indicate the form in which
the measurements are recorded for reference. Explain why limits are imposed on
the maximum wear of cylinder liners and state the possible effects on engine
operation if these limits are exceeded.
Discuss the importance- of correct cylinder lubrication in a large
Diesel engine, explaining the possible consequences of both over- and
Sketch and describe systems using loop and uniflow scavenging. What is
meant by scavenge efficiency ?
What modification of the fuel injection and atomising arrangements may
be found necessary when oil having a high viscosity, such as boiler oil, is
used for fuel?
Describe, with the aid of sketches, the construction of the cross head
guides and columns for a any large 2 stroke slow speed main propulsion engine.
Sketch and describe automatic devices for the under mentioned duties:
Discuss the causes, possible associated hazards and lowering of thermal
efficiency consequent on poor combustion in a Diesel engine cylinder.
Illustrate your answer by means of indicator cards.
The amount of oil atomized by the return flow variable
capacity atomizer, used with some automatically fired boilers, is controlled by
amount of air admitted to the atomizer
oil pressure in the oil return line
quantity of oil delivered by the service pump
proportioning device in the atomizer fuel valve
A diesel engine should not be operated at low loads for
long periods of time because
heavy carbon deposits will buildup on the valves and in
fuel dilution is increased at low load
exhaust valves may be damaged
all of the above
The major cause of fuel pump and injection system
problems is _____________.
kinked fuel lines
excessive engine vibration
dirty fuel oil filter element can be detected by ________.
visual inspection of the element
the pressure drop across the filter
high fuel oil tank temperature
increase flow rate from the filter
A main engine liner which was recently overhauled and
its sealing rings renewed, started leaking during the voyage. Write a letter to
the owners suggesting what you propose to do in the next port, to ensure that
such a problem does not reoccur again.
the main engine lubricating oil system of a large 2 stroke marine diesel engine
and state the L.O. safety devices on the system.
with reason the essential requirement for unattended machinery spaces(UMS).
Describe briefly the operation of an electrical or hydraulic main engine
the type described indicate how failure can occur and the action to be taken if
immediate correction cannot be achieved and the engine must be operated.
speaking the foundation of a reciprocating engine must perform three function
the weight of the engine.
the engine in proper alignment with the driven mechanism.
vibrations produced by unbalanced forces due to reciprocating and revolving
to perform all these functions. Suggest any other function, you think it,
performs other than the ones stated above.
the concept of pH and the significance of its value in boiler water chemical
reasons, what could cause the pH value in boiler water to reduce:
Rapidly over a short period of time
Gradually over a long period of time.
what can be done to continue operation with a turbo-charger having water
leakage into the exhaust gas space.
a simple cross-section through a single stage jacket cooling water centrifugal
pump with a fully shrouded single entry impeller; name the components of the
pump and indicate the direction of fluid
diesel driven life boat engine simply refuses to start after running
perfectly for a period of half an hour
just before you prepare it to restart again. State just 4 checks you would make
to confirm the cause of this problem.
leakage and premature failure of valve packing is a result of ____________.
opening a valve too quickly
jamming a valve in the closed position
low pressure fluid flow through the pipeline
a scored valve stem
A large marine diesel main propulsion engines, speed
fluctuates all the time during the voyage. Give a report (in about 200 words)
to the chief engineer explaining the observation of various engine parameters,
during the voyage which could be indication of some fault, causing engine speed
Sketch an Main engine starting air system, used for
a large 2 stroke slow speed engine naming the various components, and fittings
in the system.
rise in pressure during combustion accompanied by knocking of the unit or detonation usually occurs
the pressure rise after ignition of fuel charge.
fuel charge is about to ignite.
the unit reaches peak pressure and before ignition of fuel charge.
the combustion process.
requirements which a fuel injection system must fulfil are ________________
of small amount of fuel oil.
quality of fuel injection
the fuel injection
distribution of the fuel in the combustion space.
it is appropriate or not.
diesel engine, air movements inside a combustion chamber is very important.
Generally speaking, air movement helps
optimising liner lubrication
If any point you perceive is false, state why is it so.
engine under load continuously fluctuates even with a steady load. The fault
you diagnose could be owing to
servicing of the governor in the last port.
fuel injectors done in the last decarbonisation
obviate the problem
inspection undertaken with respect to your ships main propulsion engines during a one-day stoppage at a
foreign port after a long period of continuous running.
emergency generator simply refuses to start after running perfectly for a period of half an hour just before you
prepare it to restart again. State just 4 checks you would make to confirm the
cause of this problem.
manifold of one of the generators
engines under load turns red hot. There is no lagging on the manifold. What
efforts would you make to cool down the manifold? State clearly what could be
the causes for such an occurrence.
Explain the possible reasons
for excessive lubricating oil consumption in an auxiliary Diesel engine and
state the danger, which may be associated with this defect.