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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?:
In an automatic temperature control system, operating with a PID controller, which of the following settings or parameter adjustments may result in system oscillation?:
Which ideal heat engine cycle is the vapour-compression refrigeration system based on?:
The first step in completing an SSA is to:
Master of every ship must provide:
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?:
When starting three phase induction motors which of the following starting methods will immediately apply rated voltage to the machine?:
Some vessels have a central hydraulic system consisting of a number of hydraulic power packs for driving cargo pumps, deck machinery, ship’s cranes, etc. Which parameter is normally used to automatically bring the power packs on and off line to match operational demand?:
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:
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?:
How long after starting a refrigeration compressor should the oil separator return valve be opened?:
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.:
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?:
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?:
In the diagram below we want to verify the resistance of the PT100 sensor fitted with compensation. What is the correct calculation?:
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?:
Which of the 4 alternatives shows a NPN bipolar transistor?:
The range of a transducer is 0-200 bar and the output signal is 4-20 mA. What is the output signal when the process value is 100 bar?:
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?:
What is the normal slow down/shutdown temperature for the jacket cooling water outlet from a diesel engine cylinder?:
Select, from the options given, the one most likely to result in a sudden reduction in main diesel engine operating speed during normal operation:
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?:
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?:
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?:
The diagram shows a thyristor (SCR) with a Resistor and Capacitor (R and C). The RC network shown, performs which of the following applications?:
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?:
What do you understand by the term Maximum Continuous Rating, MCR, of a diesel engine?:
What would be a typical setting for the overspeed trip to operate and shut down the engine on a medium speed diesel engine?:
Which statement about the use of profiling onboard a ship is true?:
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?:
In a PID controller it is possible to change the setting of the Proportional band (P), the Reset time (I) and the Rate time (D). Please indicate which curve shows the typical response to a step change in input, if the setting of the reset time is too small.:
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?:
In terms of automated control systems, what is typical for a continuous control system?:
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?:
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?:
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?:
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?:
What function is this circuit performing?:
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.:
Which of the following symptoms would indicate that the filter drier in a refrigeration circuit has become blocked?:
What is usually the effect on G when the ship is damaged with water ingress?:
A High Breaking Capacity fuse found in a Main High Voltage Switchboard will typically have fault level rating of?:
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?:
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?:
What would the results of a TAN test, carried out on lubricating oil samples from a diesel engine, indicate?:
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?:
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?:
When considering instrumentation systems,what is the meaning of the expression “dead- band”?:
Which electronic component or system is this graphical symbol illustrating:
Which of the below structures of bulk carriers are considered critical?:
What is the bias value used for in a controller?:
Onboard training should be organised in such a way that:
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?:
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?:
What type of dynamic forces may cause indent in plating on forecastle deck and main deck in way of pillars inside forecastle?:
What does the term “stoichiometric mixture” mean when used in relation to combustion of hydrocarbon fuels?:
A 3-phase cage rotor induction motor requires protection by a time delay overload trip. What is the reason for this?:
For a ship operating or calling in US waters, COTP can request (OPA-90)?:
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?:
Which of the following terms is used to describe a thermodynamic process in which no heat transfer into or out of the system occurs?:
The main propulsion diesel engine is normally started by direct admission of compressed air. Which one of the following statements is correct?:
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?:
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?:
Which of the following is the minimum acceptable value of insulation resistance for High Voltage equipment?:
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?:
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?:
A transformer overheats while taking a shore supply. Which is the likely cause?:
Which one of the following items has to be included in an abandon ship drill according to SOLAS regulations?:
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?:
A High Breaking Capacity fuse found in a Main High Voltage Switchboard will typically have fault level rating of?:
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?:
The turbocharger on a diesel engine is surging. Which one of the following options would be the most likely cause?:
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?:
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.:
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?:
How is the prime mover load normally kept to a minimum when starting up an electric driven reciprocating type air compressor?:
What does the term “stoichiometric mixture” mean when used in relation to combustion of hydrocarbon fuels?:
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?:
When selecting switchgear to work with High Voltage it is important to use an appropriate arcing medium. What is meant by arcing medium?:
Which of the following would be considered pollution, when discharged overboard, under the US water pollution laws?: