Le test comprend 80 questions aléatoires.
Total de questions sur ce sujet : 84
How long after starting a refrigeration compressor should the oil separator return valve be opened?
It should be opened only when the crankcase oil level is low.
It should be opened once the oil separator unit has warmed up.
It should be opened one minute after start up.
It should be opened before start up.
Marine diesel engines are normally provided with automatic protection devices which operate in the event of abnormal conditions arising. Why would medium speed engines used for main propulsion normally only automatically slow down for certain abnormal conditions but automatically shut down for the same conditions when used to drive an alternator?
Sudden total loss of propulsive power may seriously endanger the vessel. This is a greater risk than engine damage.
Since the engine used for propulsion would usually be bigger the sudden stop would generate greater thermal stress which may damage the engine.
Since the engine used for propulsion would usually be bigger the sudden stop would generate greater thermal stress which may damage the engine.
How is the prime mover load normally kept to a minimum when starting up an electric driven reciprocating type air compressor?
By using an unloading device to keep the compressor suction valves open until the machine is up to speed.
By keeping the main discharge valve closed until the machine is up to speed.
By keeping the second stage drain valve open until the machine is up to speed.
By using an unloading device to keep the compressor delivery valves open until the machine is up to speed.
Medium and high speed diesel engines used for electrical generation duties on board ship have overspeed protection devices fitted to protect the engine in case the electrical generator trips while carrying high loads. Why are these devices necessary?
To stop the engine before any serious damage occurs to the electrical components due to excess voltage and frequency.
To stop the engine before any serious damage occurs due to excess inertial loads.
To stop the engine before any serious damage occurs due to rapidly changing thermal loads.
The turbocharger on a diesel engine is surging. Which one of the following options would be the most likely cause?
Dirty scavenging air cooler on the air side.
The lubrication oil pump is malfunctioning.
Worn out bearings on the turbocharger.
What does the term “stoichiometric mixture” mean when used in relation to combustion of hydrocarbon fuels?
An ideal mixture of fuel and air in which all of the fuel and oxygen in the mixture are consumed during combustion.
A ideal mixture of fuel and air in which all of the oxygen in the air in the mixture is consumed during combustion.
An ideal mixture of fuel and air in which all of the fuel in the mixture is consumed during combustion with a minimum of excess air.
The first step in completing an SSA is to:
Develop an onboard security survey checklist.
Create a list of potential motives for security incidents against your ship.
Identify the key shipboard operations, systems, areas and personnel that are critical to protect.
List the existing security measures.
The operation of a diesel engine is controlled by a mechanical-hydraulic, compensated speed sensing governor. How will the governor control be affected if the compensation needle valve is closed in and the engine load changes?
Engine speed control will be sluggish.
The governor will hunt resulting in erratic engine speed control.
A change in load will not affect a speed sensing governor.
In terms of automated control systems, what is typical for a continuous control system?
The control valve will always be changing position.
It is not possible to have a stable process.
The output signal is equal to the input signal.
It is possible to predict the control mathematically.
A transformer is rated at 22 kVA, 440/220 Volts, 60 Hz, is used to step down the voltage to a lighting system. The low tension voltage is to be kept constant at 220 Volts. What load impedance connected to the low-tension side will cause the transformer to be fully loaded?
What do you understand by the term Maximum Continuous Rating, MCR, of a diesel engine?
The maximum cylinder pressure that the engine can operate at continuosly.
The maximum load that the engine can operate at continuosly.
The maximum speed that the engine can operate at continuously.
HEL-H is the abbreviation of a heavy helicopter radius of action for rescue purposes. What do you think the radius and evacuating capacity of the helicopter is?
500 nm and capacity for evacuating more than 25 persons.
100 nm and capacity for evacuating more than 10 persons.
200 nm and capacity for evacuating more then 15 persons.
A compressed air supply system has two automatically controlled air compressors. When demand is high both compressors are needed to meet the delivery requirements. What is the best method for controlling the compressors to meet a varying, but intermittent demand?
Sequential start initiated by pressure switches set at different switching pressures.
Start and stop of the compressors controlled by timer switches.
Continuous running of both compressors and the use of unloading devices.
Onboard training should be organised in such a way that:
Each crew member is trained individually.
It is an integral part of the overall training plan.
It does not contravene with the rest hours of the crew.
Select, from the options given, the one most likely to result in a sudden reduction in main diesel engine operating speed during normal operation:
Fuel oil pipes or filters becoming fouled.
Loss of signal to engine governor.
The temperature control for the central cooling system low temperature circuit has failed and a new 3 term controller is to be fitted. Which of the given options would be the correct method of setting up the controller?
All three actions should be set simultaneously.
Set the proportional action first.
Set the integral action first.
Set the derivative action first.
A low exhaust temperature in one cylinder of a diesel engine is noticed during routine checks. Which of the options given is the most likely cause of this?
Charge air pressure is too high.
Problem with the fuel quality or supply to the engine.
Injection valve opening pressure is too low.
Some of the nozzle holes of the fuel injection valve are blocked.
Some ships generate electrical power at 440 Volts, but then step up this voltage to supply specific electrical equipment. One common example, may be to feed a large bow thruster. Why is this done?
The shipyard could not purchase High Voltage generating plant at the time of manufacture, so they used what was available at the time.
A large bow thruster will draw very large currents at low voltage. Being typically remote from the generator, significant voltage drops would occur at low voltage.
Manufacturers can supply High Voltage bow thrusters at less cost, and the power factor is improved.
The instrument air system is suffering from excess water carry over to the instrument air lines. The air intake to the compressor has very high humidity. Which of the actions given in the options will most likely result in reducing this problem?
Increase the cooling water flow through the compressor intercooler and aftercooler.
Use an additional coalescer filter in the inlet to the instrument air filter system.
Shorten the time between automatic receiver drain blow downs.
Reduce the superheat setting on the instrument air refrigeration/dryer unit.
For a ship operating or calling in US waters, COTP can request (OPA-90)?
Participation in all announced drills.
Unannounced drills at any time.
Maximum two drills a year.
Maximum one drill a year.
A U tube manometer is used to measure the pressure delivered by a ventilation fan. Following replacement of the fan by a larger unit with a higher delivery rate and pressure the liquid is blown out of the open end of the manometer. Which of the options given will allow the manometer to be used to measure the delivery pressure of the larger fan?
Refill the manometer with liquid with a higher density.
Refill the manometer with liquid with a higher viscosity.
Refill the manometer with a reduced the amount of liquid.
Prior to removing the access doors to a pressure vessel for internal maintenance it should be ensured that all pressure has been relieved. As well as a zero indication on a pressure gauge which other measure, from the options given should be taken to confirm this prior to commencing the work?
Open the drain valve and when the outflow stops slacken off the drain valve flange bolts and “crack” open the flange in case the drain is blocked.
Open the drain valve while pressure still shows on the gauge and to check it is clear. Outflow should cease as the pressure gauge reaches zero.
Open the drain valve when the gauge reads zero to check that there is no outflow.
Worn piston rings are allowing a small amount of piston blow-by on a 2-stroke main diesel engine cylinder, but due to the circumstances, it is not possible to stop and do a piston overhaul. What is the correct, temporary action to take?
Increase the cylinder oil rate to neutralise the corrosive action of the combustion products or change to a more alkaline cylinder oil.
Increase cylinder oil feed rate slightly and monitor the scavenge space drains.
Continue to operate the engine as normal.
The charge air pressure supplied to a diesel engine, which is normally 2,0 bar, is reduced to 1,5 bar. What will be the likely effect on the engine operation?
The performance of the engine will be reduced noticeably.
The performance of the engine will be similar to normal conditions.
The turbochargers cooling water flow will increase.
What is the bias value used for in a controller?
It is used to adjust a controller’s proportional response to error
It is used to remove steady state error at a reference set point.
What would be a typical setting for the overspeed trip to operate and shut down the engine on a medium speed diesel engine?
15 % above engine rated speed.
1 % above engine rated speed.
25 % above engine rated speed.
5 % above engine rated speed.
A 3-phase cage rotor induction motor requires protection by a time delay overload trip. What is the reason for this?
It will allow for inrush current or motor specific faults.
It will tolerate fault conditions during start up.
When starting air is applied to a diesel engine the engine fails to turn over but is seen to oscillate back and forth. What is the most likely cause of this problem?
An interlock is blocking the air to the starting air distributor.
The automatic valve has failed to open.
One or more cylinder air start valves are stuck open.
Which of the below structures of bulk carriers are considered critical?
Longitudinal deck plating outside hatches.
Upper and lower connection of main side frames.
Which electronic component or system is this graphical symbol illustrating:
3-phase sine-wave generator.
A heat exchanger of the tube and shell type is used for cooling lubricating oil with seawater as the secondary fluid. Which of the options would indicate that the tube stack was becoming fouled (scaled or coked) rather than blocked?
A reduced temperature difference between the seawater inlet and outlet and also between the lubricating oil inlet and outlet.
An increase in the temperature difference between the seawater inlet and outlet and a reduced temperature difference between the lubricating oil inlet and outlet.
A reduced temperature difference between the seawater inlet and outlet and an increase in the temperature difference between the lubricating oil inlet and outlet.
In the diagram below we want to verify the resistance of the PT100 sensor fitted with compensation. What is the correct calculation?
What is usually the effect on G when the ship is damaged with water ingress?
It first rises and then lowers.
Which of the following symptoms would indicate that the filter drier in a refrigeration circuit has become blocked?
A hammering noise from the drier.
A large temperature drop across the drier.
A pressure rise before the drier.
Two identical medium speed engines are connected through clutches and a reduction gearbox to a single controllable pitch propeller. It is noted during normal operation that the load sharing between the engines is uneven with one engine taking a greater proportion of the load as the total load increases even though they are equally loaded at low load. Select from the options given the most likely cause of this problem.
The clutch on one engine is slipping.
The fuel filters in the supply line for one of the engines are blocked.
The governor droop settings are incorrectly set and are not matched.
One of the engines is running faster than the other at high loads.
The muster list shall show the duties assigned to the different members of the crew. Which of the given duties necessarily have to be included in the muster list?
Type of fires that can be encountered on board.
Preparation and starting of emergency generator.
Preparation and launching of survival crafts.
The piston rod of a large two stroke diesel engine has been damaged and is heavily scored in way of the piston rod gland (stuffing box). It has been decided that it is economically viable to recondition the rod at a shoreside facility. Select, from the options given, the most suitable repair method that should be used?
Recondition the rod by build up using electric arc welding and surface grinding.
Recondition the rod by machining away the score marks and fit undersize rings to the stuffing box.
Recondition the rod by surface grinding and build up using plasma spraying with metal similar to the original.
When starting three phase induction motors which of the following starting methods will immediately apply rated voltage to the machine?
Which of the following is the minimum acceptable value of insulation resistance for High Voltage equipment?
After a couple of hours of operation the failure alarm sounds for a heavy fuel oil purifier which is operating on a timed automatic sludge cycle. Upon investigation the purifier is found to be running slowly and when opened up the casing and sludge outlet is heavily fouled with sludge in contact with the bowl. From the options given what is the most likely cause of this problem?
The heavy fuel is unstable leading to excessive high viscosity sludge formation.
The clutch for the drive shaft is worn and slipping.
The purifier bowl has not closed properly.
The dirty oil throughput is excessive.
This circuit shows a transformer with two windings, N (1) = 2 000 and N (2) = 1 000 turns, on a common magnetic circuit. Assume that there are no energy losses in the transformer itself. Calculate the output voltage V (2) when the input voltage is V (1) = 100 Volt.
What is the normal slow down/shutdown temperature for the jacket cooling water outlet from a diesel engine cylinder?
A transformer, rated at 22 kVA, 440/220 Volts, 60 Hz, is used to step down the voltage for a lighting system. The low tension voltage is to be kept constant at 220 Volts. What load impedance connected to the low-tension side will cause the transformer to be fully loaded?
Maintenance is to be carried out on a diesel engine. How long after stopping the engine should the cooling water and lubricating oil be kept circulating in order to avoid any undue thermal stress from residual heat?
10 minutes is sufficient.
This circuit consists of a voltage source V, a change-over switch S, a resistor R and a capacitor C. The voltage/time figures 1 to 4 show changes in the voltage V(C) when the switch S is suddenly shifted from position 1 to 2 at time t = 0. Only one of the diagrams is correct. Which?
A High Breaking Capacity fuse found in a Main High Voltage Switchboard will typically have fault level rating of?
Part of the outer surface of a refrigeration compressor crankcase and the refrigerant return line near the compressor ice up heavily during normal operation. Which of the options given is the most likely cause of this problem?
The seawater flow control valve for the condenser is faulty allowing insufficient cooling water flow.
The superheat control setting for the thermostatic expansion valve is set too low.
The filter drier unit in the liquid line is partly blocked.
The oil separator is not functioning correctly and is allowing lubricating oil to pass into the system.
The operation of a diesel engine is controlled by a mechanical-hydraulic, compensated speed sensing governor. How will the governor control be affected if the compensation needle valve is closed in and the engine load changes?
Altering the compensation needle valve has no effect on speed control.
A change in load will not affect a speed sensing governor.
Engine speed control will be sluggish.
The governor will hunt resulting in erratic engine speed control.
The charge air pressure supplied to a diesel engine, which is normally 2,0 bar, is reduced to 1,5 bar. What will be the likely effect on the engine operation?
The cylinder cooling water flow will increase.
The performance of the engine will be reduced noticeably.
The performance of the engine will be similar to normal conditions.
The turbochargers cooling water flow will increase.
In the event of a diesel engine crankcase explosion which of the safety devices fitted to the engine is designed to minimise the risk of a secondary explosion?
Main bearing temperature monitoring equipment.
Crankcase oil mist detector.
Crankcase extraction fan.
Crankcase relief valves/doors.
A medium speed diesel engine, operating with a pulse turbocharging system, has been adjusted to have good power balance. What would the cylinder exhaust gas temperatures, relative to each other, be expected to be?
All cylinder exhaust temperatures should be equal if the cylinder power balance is correct.
Which of the following would be considered pollution, when discharged overboard, under the US water pollution laws?
A medium speed diesel engine is used to drive a controllable pitch propeller through a suitable clutch and reduction gearbox. What should the propeller blade attitude normally be after the engine is started and before the clutch can be engaged?
The blades should be in the zero thrust position.
The blades should be in the full astern position.
The blades should be in the full ahead position.
The blades should be in the zero pitch position.
Which one of the following items has to be included in an abandon ship drill according to SOLAS regulations?
Checking that life-jackets are correctly donned.
Starting and operating radio life-saving appliances.
Launching and recovery of a survival craft.
Manoeuvring the lifeboat in the water.
What type of dynamic forces may cause indent in plating on forecastle deck and main deck in way of pillars inside forecastle?
Slamming in way of flat bottom forward of light draught.
Forces created by waves on the forecastle.
Pressure forces caused by green water on deck.
When selecting switchgear to work with High Voltage it is important to use an appropriate arcing medium. What is meant by arcing medium?
The way in which the contacts separate as the switchgear operates.
The gas or vapour which will minimise creation of an electric arc as contacts open.
Equipment which communicates information about the arcing.
A material which assists a welding process.
New MARPOL regulations came into effect from July 93 stating that the previous instantaneous rate of discharge of oil content (60 litters per nautical mile) was changed to:
20 litters per nautical mile.
30 litters per nautical mile.
25 litters per nautical mile.
What would the results of a TAN test, carried out on lubricating oil samples from a diesel engine, indicate?
A measure of the organic acids in the lubricating oil.
A measure of the of organic and inorganic acids in the lubricating oil.
A measure of the remaining alkalinity in the lubricating oil.
Which of the 4 alternatives shows a NPN bipolar transistor?
The main propulsion diesel engine is normally started by direct admission of compressed air. Which one of the following statements is correct?
The starting air admission should continue until the engine has fired.
A heavily leaking starting air valve may cause an explosion in the starting air pipe system.
Slow turning should be set to operate automatically at finish with engines to allow the engine to cool down evenly.
When trying to reverse a large slow speed diesel engine in the astern direction it cannot be turned on air even though it will start in the ahead direction. What is the likely cause of this problem?
The start is blocked because the air distributor has not moved to the astern position.
One of the cylinder air start valves has stuck open.
The reversing servo for the fuel pumps has stuck in the ahead position.
Which of the following options is the most likely to result in the maximum cylinder pressure for all cylinders on a diesel engine to be lower than normal?
Camshaft timing advanced.
During maintenance work on the main engine a problem arises regarding the lifting of a main component in that the manufacturer’s instructions ado not apply to the engine as fitted and present a hazard. In which of the information/record sources given in the options, is it most important to record the information relating to this anomaly?
Engine room planned maintenance schedule.
ISM procedures in the ship’s safety manual.
How often should the lifeboat wire falls be turned and renewed?
Turned at intervals of not more than 30 months and renewed every 5 years.
Turned every 2 years and renewed every 4 years.
Turned every 30 months and needs only to be renewed if the wire is in poor condition.
The torsion meter for the main propeller shaft is reading high. The torque is sensed using the angle of twist principle with two clamp rings attached to the shaft at a fixed distance, with stationary proximity switches for measuring the angle of twist and also shaft speed fixed to a rigid stool. What is the most likely cause of the high reading?
Axial slip of one of the clamp rings to bring them closer together.
Axial slip of one of the clamp rings to move them further apart.
Circumferential slip of the forward clamp ring in the opposite direction to shaft rotation.
Circumferential slip of the after clamp ring in the opposite direction to shaft rotation.
A transformer overheats while taking a shore supply. Which is the likely cause?
In an automatic temperature control system, operating with a PID controller, which of the following settings or parameter adjustments may result in system oscillation?
A High Breaking Capacity fuse found in a Main High Voltage Switchboard will typically have fault level rating of?
A viscosity controller for the main diesel engine fuel oil supply is giving poor control resulting in the viscosity of the fuel oil being too low at the engine. Which of the defects given in the options is likely to be the cause of this problem?
Capillary tube in the viscometer is blocked giving high differential pressure at the DP cell.
The air supply pressure to the controller for controlling the steam valve for steam to the fuel heater is too low.
The bellows in the DP cell is ruptured giving no differential pressure signal.
The drive for the internal sample pump for the viscometer has sheared.
When considering instrumentation systems,what is the meaning of the expression “dead- band”?
The controller will enter “sleep mode”.
It will take some time before the controller will react to a change.
The controller will not react to a process change in this range.
It will is not respond to adjustment of set-point.
Which of the following terms is used to describe a thermodynamic process in which no heat transfer into or out of the system occurs?
What does the term “stoichiometric mixture” mean when used in relation to combustion of hydrocarbon fuels?
An ideal mixture of fuel and air in which all of the fuel and oxygen in the mixture are consumed during combustion.
A ideal mixture of fuel and air in which all of the oxygen in the air in the mixture is consumed during combustion.
An ideal mixture of fuel and air in which all of the fuel in the mixture is consumed during combustion with a minimum of excess air.
Master of every ship must provide:
The training during crews working hours only.
Proper rest to the crew after each training programme.
Facilities to conduct training whenever required by the training officer.
A link between the shipboard training officer and the company training officer ashore.
What function is this circuit performing?
Which statement about the use of profiling onboard a ship is true?
A random selection process must be established.
Profilers need at least half an hour to gather the information they need.
Only visitors can be profiled.
Detection equipment can be used in place of profiling.
A combustible gas indicator of the catalytic filament type is used to check the atmosphere in an enclosed space onboard ship. When taking readings in a fuel tank which has been emptied for cleaning the meter reading initially rises and then falls back to zero. What is the likely defect, if any, in the instrument when this type of behaviour is displayed?
The sampling pump is faulty.
The filament has burnt out.
The filament is contaminated due to too high a concentration of hydrocarbons.
During inspection and calibration of a cylinder unit, the liner is found to be worn in a cloverleaf pattern with maximum wear midway between the lubrication points. What action is necessary to rectify the problem?
Reduce the jacket cooling water temperature to avoid thermal stress of the cylinder liner.
Increase the cylinder oil rate to neutralise the corrosive action of the combustion products or change to a more alkaline cylinder oil.
Contact engine maker for advice.
Decrease jacket cooling water temperature to avoid heat stress.
Many large, slow speed diesel engines have direct oil cooling of the piston crowns provided. An automatic slow down and alarm are sometimes fitted to protect against failure of this system. Which parameter is usually used to initiate this slow down?
Low pressure in the cooling oil return line.
Low flow or no flow in the cooling oil return line.
High temperature of the piston crown.
A two step controller (open/close) has failed and the only available spare controller is a P+I controller. Select, from the options given, how the P+I controller could be set up to achieve approximate two step control.
Set the proportional band to maximum width and the integral action to maximum (repeat per minute).
Set the proportional band to minimum width and the integral action to maximum (repeats per minute).
Set the proportional band to minimum width and the integral action to maximum (repeats per minute).
The diagram shows a thyristor (SCR) with a Resistor and Capacitor (R and C). The RC network shown, performs which of the following applications?
Divert fast voltage spikes which may lead to uncontrolled switch on.
Provide voltage smoothing for SCR power supply.
Allow bypass route for AC signals.