QUESTION BANK GENERAL ENGINEERING KNOWLEDGE PART-4

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Q a) Describe an automatic self de-sludging centrifuge suitable for dealing with fuel of density up to 1010 kg/m3 at 150 deg. C.

b) Explain how the centrifuge described in (a) is able to remove water from the fuel which has a density that is higher than that of water & state factors that may assist the operation.

c) As a 2/E, write down the start-up procedure for the centrifuge described in (a) for the benefit of your staff.

d) State how the problem of the catalytic fines in fuel oil may be dealt with.

Q With reference to oil / water separators:

a) Describe, will the help of a sketch, the circuit for an interface detector.

b) Explain the consequences if the interface position is incorrect.

c) Enumerate the various possibilities by which the oil/water interface can be described.

Q With reference to the oily water separators:-

a) Describes with the help of a sketch, the working of such a separator,

b) Explain the consequence if the interface detector position is incorrect.

c) Enumerate the various possibilities by which oil / water interface can be described.

Q Discuss with reasons one statement that is not correct regarding oily water separators:

a) Test cocks are situated to locate the oil water interface

b) Separation rate is inconsequential

c) Overboard discharge is inconsequential

d) Rise in the temperature assist in the separation process

e) Rate of separation is unrestricted

Q With reference to oil monitoring of bilge and tanker ballast discharges:

a) Describe with the help of a sketch, the general arrangements of an oil monitoring system

b) State the inputs that are recorded

c) Explain the difficulties faced with the efficient operation of the oil monitoring.

Q With reference to electro-hydraulic steering gears:

a) Explain in terms of the control parlance the function of the Hunting gear.

b) Explain the result if the standby pumping unit is motored.

c) State 2  methods employed to avert the standby hydraulic pump being motored by the operating unit.

Q a) Describe with the help of sketches, where necessary a vane type steering gear showing how the weight of the rudder & stock are carried and the arrangement that allow for wear down.

b) State how the vanes described in (a) are secured & the method of sealing the edges.

c) State how, if necessary the steering gear is locked for the rudder maintenance.

Q a) Sketch a 4-ram steering gear arrangement capable of 100% redundancy

b) Describe the operation of the arrangement sketched in (a).

Q With reference to hydraulic steering gears, sketch & describe each of the following:

a) Single failure concept

b) 100 percent redundancy

Q A rudder of a vessel requires extensive welding repairs and as 2/E you are requested to supervise.

a) Suggest a suitable type of the welding process

b) State, with reasons, 4 common welding defects

c) State what tests may be carried out before returning the rudder to service

Q With respect to the steering gear, answer the following:

a) Explain with a diagram, a fail safe steering gear suitable for use on a tanker of more than(>) 100,000 T dwt.

b) Explain the sequence of the events that take place when an oil leak takes place in one of the hydraulic pipe lines.

Q Examine in detail 3 frequently encountered reasons for loss of the steering systems. State how failure is inhibited in the design, operation & maintenance of the steering gear systems. Describe how a vessel may make port upon irreparable failure of the steering telemotor.

Q a) Draw a diagram of a 4 ram hydraulic steering gear showing:

i. Pump isolating valves

ii. Relief/shock valves

iii. By pass valve

b) Explain the operation of the system sketched in (a)

c) Indicate in the diagram in (a) the valve position for the operation of the system when one pump is isolated & the unit is operating on two rams only.

Q Sketch & describe an electro hydraulic stabilizer, explaining how it restrains the rolling action of a vessel in a heavy seaway. What structural parts of the vessel are most affected by this restraint?

Q Describe how you would remove air from a telemotor system. What are the dangers of the air in a telemotor system?

Q a) Sketch & describe a four ram hydraulic steering gears

b) Explain the operations, that are necessary to enable & system to operate on two rams only.

Q a) State why fixed pitch propellers have a poor efficiency when going astern.

b) With reference to controllable pitch propellers state:

i. Why is it preferable that the main servomotor should be housed in the propeller hub rather than in the shafting forward of the propeller shaft?

ii. What regular maintenance & checks should be carried out to assure maximum reliability of the gear at all times?

Q With regards to main transmission shaft flange coupling arrangements:

a) Sketch a hollow type coupling bolt & the hydraulic head/nut & loading rod which are used to fit it.

b) Describe how the bolt is fitted

c) State the advantage of the hollow coupling bolt as compared to the traditional type of coupling bolt.

Q Sketch a sealing arrangement for an oil lubricated stern tube; &

a) Identify the common form of the seal failure?

b) State how oil loss due to seal failure can be restricted whist on passage?

c) What material is used for the sealing ring & propeller shaft liner?

Q With reference to sleeved keyless propeller assemblies:

a) i. State, with the reasons, the metals used in the manufacture of the sleeve & tail end shaft;

ii. State the type & thickness of material used to bond the sleeve to the propeller boss.

b) When removing the propeller from the tail end shaft, state why the following procedures are not recommended:

i. Application of push off force by means of the wedges or jacks & draw off force by strong back.

ii. Expansion of propeller boss by concentrated local heating with gas torches.

c) State the correct procedure for the removal of the propeller from the tail end shaft.

Q a) Describe a transverse bow thruster unit using a controllable pitch propeller. Mention should be made of how it is supported & how the strength of the thrust & reverse thrust are achieved.

b) State with reasons, a suitable prime mover for the controllable pitch propeller.

c) State whether the thrust unit delivers a relatively low pressure head with high volume output or high pressure head with the low volume output.

Q Explain how the ingress of sea water is prevented in an oil lubricated stem bearing system. Should the system fail, describe the corrective action possible whilst the vessel is afloat. State why two stern bearing oil header tanks are installed in some instances?

Q a) Sketch a section through a keyless sleeved propeller.

b) i. State the advantages of using the keyless sleeved propeller.

ii. State with the reasons, which metal sleeve should be made for contact with the forged mild steel tail shaft.

c) State the materials used to bond the sleeve to the propeller & the general thickness of the bonding material.

Q Identify the chief causes of “overheating” in tunnel bearings & of “vibration” in main shafting. Explain why the seating of the engine room amidships improves these tendencies. State how overheating & vibration may be reduced or eliminated.

Q a. Describe a transverse “bow thruster” unit. Mention should be made of where it is fitted, how the propeller hub with shafts & internal bevel gear drive are generally supported & how the manoeuvring oil is conveyed to the propeller main servo-motor. Also mention how strength thrust & reverse thrust are achieved.

b) Give reasons why the standard constant speed non-reversing type electric motor is preferred as the prime mover rather than a diesel engine.

Q a) Sketch an arrangement of propeller & stem tube in which the tube is filled with oil and suggest a method of repair when rubbing surfaces of the oil seal gets badly worn out.

b) State the defects that you would look for when the shaft is withdrawn in the dry dock.

Q a) Explain why, in spite of accurate alignment under static conditions, use of the flexible couplings & copious supply of lubricant, main reduction gearing is still subject to pitting, scuffing & other tooth damages.

b) Discuss the significance of the viscosity in relation to the function of marine turbine oils as used in the main propulsion installations, stating how the viscosity is controlled & what could cause it to change in service.

Q With respect to energy efficient running of ships, comment on optimization of propeller-hull interface, flow devices & improvement of propulsion efficiency.

Q You have been appointed as 2/E to a new vessel that experiences severe aft end vibration. The problem is thought to emanate from the propeller. The company, which is inexperienced in the operation of the ships, request you to investigate the problem. Describe the cause of the vibration & suggest remedies including the selection of a new propeller with a different number of blades?

Q Sketch & describe a fluid coupling as used with a prime mover. Why are these couplings fitted?

Q a) Sketch & describe a Pilgrim Nut for securing a propeller to the screw shaft. Describe how this device is used to loosen the propeller on the shaft when removal or inspection becomes necessary.

b) Give 4 reasons why this method is considered to be superior to all other methods.

Q With reference to keyless propellers

a) Make a sketch showing how a propeller is mounted using the Pilgrim method.

b) Explain the advantages of Pilgrim method.

Q With reference to the carriage and pumping of liquefied gas cargo:

a) Sketch a suitable pumping system labelling the component parts

b) State:

i. Why submerged hydraulically driven pumps are not used

ii. How overheating of the pump drive shaft bearings is avoided

c) State, how the risk of fire & explosion in cargo tanks is obviated both in the loaded & discharged condition.

Q With respect to tankers describes:

a) How a pump room is ventilated

b) How cargo tanks are ventilated

c) Cargo tank protection as per SOLAS 1974

d) Additional alarms provided for the inert gas systems of the ‘inert gas generator type.

e) The main problem of carrying liquefied natural gas.

f) How the boil off from liquefied natural gas is handled.

Q During routine soundings it is found that leakage into a cofferdam is occurring from an adjacent deep cargo oil tank. As 2/E state the procedure for directing safe entry by the engine room staff to ascertain the cause of the leakage. If the leakage persists discuss each of the following options as a possible remedy:

i. Leave the cofferdam to flood with oil

ii. Flood the cofferdam with sea water

iii. Seal the Cofferdam and pressurize with air

iv. Pump the leakage to bunker tanks.

Q a) State the advantages of using steam turbine propulsion power for vessels carrying L.N.G. Cargo.

b) With regard to the use of L.N.G. cargo as boiler fuel explain:

i. The safety precautions relating to the gas pipeline supplying the boiler and burning the gas in the boiler,

ii. The means of getting rid of “excess gases” during loading or discharge.

Q a) Sketch and describe a cargo space inert gas system producing washed gas from either a main boiler or from an independent gas generator module?

b) Why is the inert gas producing system you have described not suitable for machinery space fixed fire fighting system?

c) What percentage by volume of the following products of combustion would you expect with good combustion in the system that you have described:- oxygen, carbon monoxide, nitrogen, un-burnt hydrocarbons, oxide of nitrogen?

d) What are the procedures for cargo tank purging and/or gas freeing?

Q a) i. Sketch a combustion gas system, suitable for inerting the cargo spaces of a vessel.

ii. Describe the operation of this system.

b) State the percentage analysis by volume of the inert gas generated by the system in (a).

Q With reference to Liquefied Natural Gas Carriers (LNG), explain the inspection you will carry out on the following equipment’s:

a) LNG Vaporizer

b) Re-gasification plant

c) Cargo pumps

d) Emergency discharge pumps.

Q a) Sketch and describe an inert gas system either from a main boiler or from an independent gas generator module.

b) Elaborate the alarms and cut outs incorporated in the system to prevent any accident.

c) Explain the various protections for the cargo tanks with respect to pressure/vacuum build up inside the tanks.

Q a) What gases are present in oil tanks after pumping out? How would you remove these gases and what are the dangers of these gases.

b) What is the chemical composition of coal? Give the average calorific value of coal. Describe the chemical process when coal is burned in air?

Q Describe the in water survey to classification society requirements of the external underwater structure of a very large crude carrier.

Q How does the cargo pumping system of a product carrier differ from that of an oil tanker? Sketch the cargo pumping system of a product carrier?

Q Sketch and describe the operation of a reliquefication plant for an LPG carrier. Enumerate the precautions and observations to be carried out before starting, during running and after stopping the reliquefication plant?

Q A ship is engaged in filling double-bottom and deep thanks with fuel. Explain and describe:

a) The dangers implicit in the operation.

b) The precautions that must he observed.

c) The legal requirements that must be adhered to.