MARINE ENGINEERING SELF EXAMINER, AUX MACHINERY- CAPT AJIT VADAKAYIL

MARINE ENGINEERING SELF EXAMINER, AUX MACHINERY-  CAPT AJIT VADAKAYIL

The following is a SELF EXAMINER questionnaire .

If you are marine engineer at sea, find out what you are worth.

At sea you are only respected for what you are worth!   A donkey on a throne is still a donkey!!

Grading:

Correct- plus two marks

Wrong - minus one marks

Did not attempt- minus two marks

Time allowed- 60 minutes

If you score less than 20% marks -- you are NOT an engineer.

 

1.   Tubing is sized by

a)allowed working pressure

b)cross-section area

c)nominal inside diameter

d)nominal outside diameter

 2.   In a disc-type lubricating oil purifier,

a)the purifier driving gears are lubricated by the reclaimed oil as it leaves the bowl

b)all dirt and sludge are automatically discharged with the cooling water

c)sealing water must never be supplied until after oil is fed to the unit

d)deterioration of the bowl ring gasket will cause the purifier to lose its water seal

 3.   Which of the following conditions will prevent a shipboard pump from achieving its maximum suction lift?

a)leaks developed in the suction piping

b)friction losses as a result of improperly sized pipe

c)gases or vapors released in the liquid as a result of greater than normal pressure drops

d)all of the above

 

 4.   Which of the following statements represents the basic principle of operation of an electrical salinity indicator?

a)measures the hydrogen ion concentration

b)measures the electrical resistance of the water

c)determines the conductivity of the dissolved oxygen

d)measures the voltage of the chloride ions

5.   The proper oil inlet temperature for centrifuging lube oil should be

a)40-50C

b)55-65C

c)70-80C

d)90-98C

 6.   In pressure measurement, absolute pressure is defined as the difference in pressure between

a)any two pressures measured with respect to a common reference

b)atmospheric pressure and barometric pressure at a given point

c)gage pressure and ambient atmospheric pressure

d)a perfect vacuum and the total pressure at a given point

 

 7.   When a flash type of evaporator is to be secured for an extended period of time, the entire unit should be drained, cleaned, and

a)completely filled with salt water

b)filled with descaling compound

c)tightly closed to exclude air

d)vented to the atmosphere

 8.   Overheating of a hydraulic system may be a result of

a)changing pump discharge pressure in response to normal load variations

b)a high oil level

c)incorrect fluid viscosity

d)continued slow recirculation of the oil

 9.   Which of the following conditions can develop if a valve with a badly scored valve stem is repacked?

a)the valve disc will crack

b)leaking and premature failure of the packing

c)the valve disc will become eroded

d)the valve seat will sustain damage due to fretting

 10.   Mechanical shaft seals used on water service pumps require lubrication of the seal faces to minimize deposits of foreign matter on those surfaces. Which of the following pressures and lubricants are required?

a)water under negative pressure

b)water under positive pressure

c)oil under negative pressure

d)oil under positive pressure

 11.   The dimension of the thinnest hydrodynamic film developed within a full journal bearing, when all other factors remain constant, depends upon the

a)pour point of the lubricant

b)fluidity of the lubricant

c)dielectric strength of the lubricant

d)interfacial tension of the lubricant

 

 12.   If two centrifugal pumps, driven by two independent electric motors, operating at unequal speeds are discharging an inflammable liquid through a common discharge line, the higher speed pump may cause the slower pump to

a)stop

b)turn backward

c)overheat

d)overspeed the driving end

 

13.   Overheating of the oil in a hydraulic system can be caused by

a)continuous, unnecessary, and excessive pump discharge pressure

b)an increase in the number of the hydraulic fluid film layers

c)insufficient external pump slippage

d)fluctuating pump discharge pressure in response to normal load variations

14.   Partially clogged or scored nozzles in a two stage air ejector unit of a flash distilling plant could result in

a)-fluctuating vacuum in the flash chamber

b)flooded seawater feed heater shell

c)high water level in the air ejector after condenser

d)malfunctioning check valve in the air ejector discharge

 

15.   If a centrifugal pump sealing line becomes restricted while operating under a negative suction head (suction lift), the inner end of the stuffing box will be

a)under a vacuum and air will tend to leak into the pump

b)sealed by the fluid being pumped and no leakage will occur

c)under pressure and fluid will tend to leak into the pump

d)sealed by the seal cage or pump lantern ring

 

 16.   A piece is missing from one blade of a four-bladed propeller and could result in

a)accelerated stern bearing wear

b)excessive shaft vibrations

c)unusual noises

d)all of the above

 17  If a centrifugal pump operating with a positive suction head vibrates, or becomes noisy, the cause could be

a)excessive pump speed

b)worn wearing rings

c)air leakage into suction line

d)insufficient venting

 

 18  Which of the following statements represents the proper relative direction of flow through a globe valve?

a)direction of flow through the valve is unimportant

b)direction of flow through the valve depends upon the type of seat design used in the valve

c)direction of flow should be from below the seat

d)direction of flow should be from above the seat

 19  A squealing sound occuring from within an operating reciprocating air compressor is an indication of

a)compressor overload

b)motor overload

c)tight compressor bearings

d)badly leaking unloaders

 

 20  Which of the listed conditions can lead to cavitation in a centrifugal pump?

a)vapor pockets formed in the suction flow stream

b)rough casing volute surfaces

c)worn wearing rings

d)heavy fluid in the flow stream

 21  How is water traveling along the shaft of a centrifugal pump prevented from entering the shaft bearing?

a)shaft seal

b)water flinger

c)drain hole

d)lantern ring

 22  Which of the following descriptions best identifies the operating principle of a flash-type evaporator?

a)sea water is heated to boiling temperature while under a vacuum

b)sea water is passed over heated plates in a thin film

c)heated sea water is injected into a vacuum chamber

d)sea water is forced through a heated eductor

 23  Air leaking into a flash type distilling plant could occur through

a)gasketed joints

b)valve stems

c)gage glass packing

d)all of the above

 24  A reciprocating air compressor is running roughly and vibrating excessively, indicating that the

a)compressor is overloaded

b)motor is overloaded

c)foundation bolts are loose

d)belts are too tight

 25  In a radial piston pump, reversal and control of fluid flow are accomplished by moving the

a)central valve

b)radial plunger

c)floating ring

d)cylinder body

26  One cause of leaky valves in a low pressure air compressor may be attributed to

a)running with an air filter element different from that required by the original manufacturer's specifications

b)excessive operating hours without carrying out preventive maintenance

c)the compressor running too fast

d)excessive discharge pressure

 27  To maintain design discharge pressure from a centrifugal pump, the design clearance must be maintained between the

a)shaft and impeller

b)motor and pump shaft

c)casing and impeller wearing rings

d)lantern ring and impeller

 

 28  Stern tube and strut bearings lined with hardwood or rubber composition materials are lubricated with

a)salt water

b)graphite

c)light lubricating oil

d)heavy lubricating oil

 29  A fluctuating and unsteady vacuum in an evaporator may be caused by

a)wet steam entering the air ejector nozzle

b)pinhole leaks in the evaporator tube nests

c)rapid scaling on the evaporator tube nests

d)high water levels in the last effect

30  The static suction head of a pump is the

a)distance of the suction liquid level above the center line of the pump

b)distance the suction liquid level is below the center line of the pump

c)force necessary to overcome frictional losses in the pump and piping

d)amount in inches of mercury the total suction head is below atmospheric pressure

 31  Which of the problems listed could cause air to blow out through the inlet air filter of a running air compressor?

a)high compression pressure in the cylinder

b)a broken intake valve

c)a dirty inlet filter element

d)an improperly adjusted discharge valve

 32  Expansion of the tube bundle in a shell-and-tube type cooler may be provided for by the

a)packing and lantern rings

b)floating end tube sheet

c)shell foundation bolts

d)directional transverse baffles

 

 33   The pressure produced within the oil wedge of a rotating journal is

a)the same as the pressure in the lubricating system

b)less than the pressure in the lubricating system

c)greater than the pressure in the lubricating system

d)highest at the oil groove location

 

 34  An axial piston pump differs from a radial piston pump as the pistons of an axial piston pump are positioned

a)radially from the shaft

b)parallel to each other and to the shaft

c)parallel to each other  but at a right angle to the shaft

d)at an angle to each other and to the shaft

 

 35  Which of the listed characteristics of lube oil are the most important to the engineer from an operational standpoint?

a)ash content, carbon residue, and gravity

b)viscosity, acidity, and demulsibility

c)pour point, flash point, and precipitation number

d)autoignition point, viscosity index, and and film strength

 36  If the existing vapor pressure is subtracted from the indicated pressure at the pump suction, the remainder is the

a)pump head

b)total suction head

c)discharge head

d)apparent NPSH

 

 37  Which of the following problems may by encountered by using an oil having a viscosity  higher than that specified for an operating hydraulic system?

a)external seal leakage

b)hunting due to fast response

c)hydraulic oil film breakdown

d)increased power consumption

 38  Gate valves should not be used for throttling as

a)the pressure drop will be excessive

b)air binding will develop

c)the installation of an equalizing line will be necessary

d)wire drawing of the disc will result

 39  The purpose of an air compressor unloading device is to

a)drain water from the air receiver

b)drain water from the cylinders

c)delay the compression process until the motor is up to speed

d)check  pump alignment

 

 40  Which of the following statements is correct regarding an oil with a high viscosity index?

a)a large change of viscosity occurs with a minor change in temperature

b)no change in viscosity occurs with any change in temperature

c)very little change in viscosity occurs with a significant change in temperature

d)the viscosity of the oil increases with an increase in temperature

 41  An organic solid lubricant, such as graphite, is suitable as an oil additive when used in

a)machinery bearings subjected to high temperatures

b)antifriction bearings on general service pumps

c)bearings subject to fluctuating loads

d)line shaft bearings

 

 42  Which of the pumping systems listed for use aboard ship will most likely use a propeller type pump?

a)fluid power transmission system

b)main circulating system

c)steering gear system

d)fuel oil service booster system

 43   Which of the following statements is correct concerning the viscosity of lubricating oil?

a)viscosity will increase as temperature increases

b)viscosity is a measure of a fluid's internal resistance to flow

c)viscosity will decrease as temperature decreases

d)viscosity is not dependant on temperature

 44  Which of the listed characteristics of lube oil are the most important to the engineer from an operational standpoint?

a)ash content, carbon residue, and gravity

b)viscosity, acidity, and demulsibility

c)pour point, flash point, and precipitation number

d)autoignition point, viscosity index, and and film strength

 

 45  To maintain the design discharge pressure of a centrifugal pump, the clearance between the

a)impeller and lantern ring is critical

b)impeller and casing wearing rings is critical

c)packing box and packing gland is critical

d)gland seal and packing gland is critical

 46  A reservoir is used in a hydraulic system to

a)store fluid until required by the system

b)provide a place for air to separate out of the fluid

c)provide a place for contaninants to settle out

d)all of the above

47. Jacket cooling FW outlet temp in port should be—

a)70C

b)80C

c)40C

d)45C

48. The maximum practical FW lift of a centrifugal pump is zero when

the water temp is-

a)94C

b)100C

c)70C

d)99C

49. The maximum practical FW lift of a reciprocating pump si zero when the

water temp is—

a)70C

b)99C

c)100C

d)94C

50. To make the stroke of a steam reciprocating pump longer you will—

a)throttle cushion valve

b)throttle sniffle valve

c)open cushion valve

d)reduce steam pressure

51. To reduce the noise made by the valves of reciprocating pump against high back pressure, you will—

a)shut sniffle valve

b)open sniffle valve

c)open cushion valve

d)reduce  steam pressure

52. The steam reciprocating pump makes big sound due to piston hitting the head, the reason could be

a)piston rings worn

b)leaky liquid valves

c)cushion valves too wide open

d)all of the above

53. In a 4 stroke engine the exhaust valves open—

a)on third stroke after BDC

b)on 4^th stroke after BDC

c)on third stroke before BDC

d)on 1^st stroke before BDC

54. The pumping losses of a liquid globe valve is—

a)10 metres of pipe

b)20 metres of pipe

c)30 metres of pipe

d)60 metres of pipe

55)  +2000 mm AQ of PV setting on a chemical tanker is equivalent to

a)2 atmospheres

b)1470 mm HG

c)200 KPa

d)0.2 Kg

56.  To prevent explosion, you must keep-

a)HC > 11%

b)HC< 1.5%

c)O2 < 11.5%

d)any of above

57.  1% LFL is equivalent to-

a)10 ppm

b)100 ppm

c) 1000 ppm

d) 10000 ppm

58.  UFL means –

a)1% HC by volume and 99% air

b)20.8% oxygen in air and 1% HC by volume

c)10% HC by volume and 90% air

d)none of above

59.  Pressure guage pressure is –

a)absolute pressure minus atmospheric pressure

b)absolute pressure plus atmospheric pressure

c)absolute pressure multiplied by atmospheric pressure

d)none of above

60.  One bar pressure is equal to-

a)1.033 kg/ cm2

b)14.5 psi

c)750.2 mm HG

d)all of above

61. An example of a bearing which can take thrust only in one direction is—

a)cylindrical roller

b)needle roller

c)thrust ball

d)tapered roller

62. A backfire valve is usually fitted in a oxy-acy system

a)on the HP side of the regulator

b)on the LP side of the regulator

c)inside the regulator

d)none of the above

63. A backfire valve in a oxy-acy system trips if the reverse flow exceeds

a)0.2 bars

b)0.5 bars

c)0.9 bars

d)1.8 bars

64. Washers used on a acetylene bottle can be made of—

a)copper

b)bronze

c)aluminium

d)zinc

65. Which of the following gases are lighter than air—

a)acetylene

b)nitrogen

c)hydrogen

d)all of above

66. Which of the following gases are heavier than air

a)hydrocarbons

b)oxygen

c)carbon di oxide

d)all of above

67. In a oxy acet system the oxygen consumption is

a)half that of acetylene

b)same as acetylene

c)double that of acetylene

d)1/3 that of acetylene

68. The max outlet pressure of a pressure regulator for acetylene is

a)1.6 bars

b)0.8 bars

c)15 bars

d)0.3 bars

69. The max outlet pressure of a pressure regulator for oxygen is

a)4 bars

b)8  bars

c)20 bars

d)150 bars

70. The inner bore of a oxy-acet torch ejects—

a)acetylene

b)oxygen

c)mix of both gases

d)compressed air

71. The working pressure while cutting a steel plate with a oxy-acy torch is

a)0.3 bars acet / 4.0 bars oxy

b)0.9 bars acet/0.4 bars oxy

c)4 bars acet/ 4 bars oxy

d)0.3 bars acet/ 0.3 bars oxy

72. The working pressure while doing gas welding is—

a)0.3 acetylene/ 4 bars oxy

b)0.3 acet/ 0.3 bars oxy

c)2 bars acet/ 2 bars oxy

d)10 bars acet/ 20 bars oxy

73. In arc welding the safety device reduces the striking voltage to open circuit voltage from—

a)80V to 24V

b)440V to 220V

c)110V to 80V

d)220V to 80V

74. The weight of an empty 40 litre oxygen cylinder is –

a)13 kilos more than an acetylene bottle

b)23 kilos more than an acetylene bottle

c)is same as an acetylene bottle

d)is 13 kilos less than an acetylene bottle

75. To pump out ER bilges overboard—

a)it must pass through 15 ppm ODMCS with alarm and autostop

b)ship must be outside special area.

c)ship must be >12 miles from nearest land

d)all of above 

76. The bacteria which is inside ships sewage system is called

a)aerobic bacteria

b)anaerobic bacteria

c)methanogen bacteria

d)none of above

77. The exhaust temperatures of a 4 stroke engine is ( for same bore/ stroke/ speed )—

a)same as a 2 stroke engine

b)higher than  a 2 stroke engine

c)less than a 2 stroke engine

d)some times less, sometimes more than a 2 stroke engine

78.  Gate valves are never used for

a)sea water

b)steam

c)nitrogen

d)compressed air

79. A valve which opens when the pressure to which it is set is exceeded and closes only after the gas  pressure goes well below (by about 1 bar ) the set pressure is called

a)relief valve

b)blow out valve

c)safety valve

d)purge valve

80. An open cooling system in relation to a closed loop cooling system

a)does not require a heat exchanger

b)has no danger of scale deposits

c)has no danger of galvanic action by sea water

d)all of above

81. Sea water cooling to a diesel engine is continued after stopping a diesel engine for some more time to prevent

a)galvanic corrosion

b)thermal stresses

c)prevent lubricating oil form evaporating on cylinder walls

d)none of above

 

82. Babbitt metal is made out of—

a)tin

b)copper

c)antimony

d)all of above

83. What causes decrease of life of an incinerator refractory

a)high sustained furnace temperature

b)rapid changes in temperature

c)flame impingement

d)all of above

84. Simpsons rules are used to calculate, the following,  between the space enclosed by a straight line and a curve

a)area

b)volume

c)geometrical centre

d)all of above

 

85. The crank angles of a 4 stroke engine are—

a)4 cylinder engine/ 180 degrees

b)3 and 6 cylinder engine/ 120 degrees

c)2 cylinder engine/ 360 degrees

d)all of above are true

86. The TBN for AECC for  same sulphur content in fuel oil is

a)same as for MECC

b)lower than that of MECC

c)greater than that of MECC

d)makes no difference

87. The FW cooling system of AE is given corrosion prevention by

a)zinc rods

b)sodium nitrite

c)sodium hypochlorite

d)hydrazine

88. In a variable displacement axial piston pump

a)when swash plate is perpendicular to the axis of rotation no hyd oil will flow

b)when swash plate is at a sharp angle large volume of hyd oil will flow

c)when changing the angle of swash plate the stroke of the piston can be varied.

d)all of above

89)BOD5 and COD are terms used in relation with

a)fresh water generator

b)boiler

c)purifier

d)none of above

90)soot fires in the boiler and economizer can happen if

a)gas velocity is too low

b)gas temperature on boiler tube surface is too low

c)circ water flow velocity and ratio in the boiler is too low

d)all of above

91)economizer works in the temp region of

a)245 -375 C

b)375- 485 C

c)180- 240 C

d)485- 515 C

92) hydrogen fire in a boiler stack starts at

a)400C

b)500C

c)700C

d)1000C

 

93)the lowest ignition temp of soot with an unburnt oil layer on boiler/ economizer tubes can be at

a)150C

b)300C

c)385C

d)430C

94).In a two stage compressor you will find pistons with different diameters (one is bigger than the other).Which one of the following statements is correct ?

a)The smallest diameter piston is the stage two piston.

b) big piston will deliver dryer air into stage one.

c) big piston will give less oil content in the air.

d)the biggest diameter piston is the stage two piston.

95).What is meant by a two stage compressor ?

a)Air from stage one goes through discharge valves in stage one and through suction valves into stage two. In stage two it will be compressed to high pressure air.

b)the compressed air goes back from stage two and into stage one to get extra pressure before it goes into the starting air bottles.

c)two stage air compressors have the capabillity to compress air in stage one and dry the air in stage two.

d)the two stage air compressor take some air from the surroundings to stage one and compress and some air from the surroundings to stage two and compress.

96).When an air compressor is started , it is important that the "blow off" valves are open.  Why?

a)To ensure that the electric motor will not have a too low  torque during start.

b)To ensure that the compressor does not have any back pressure due to leak suction valve in stage one.

c)To be sure that all pressure valves in the HP line to the starting bottle are open.

d)To ensure that we do not have any water assembly in the cylinders when the compressor start.

97).What do we have to do if the lube oil becomes yellow/white (mixed with water) ?

a)Fill more lube oil to dilute the water contained in the oil.

b)Change the lube oil.

c)Drain the water.

d)Clean the lube oil filter with very short intervals.

 

98).You have  a leaky cylinder ( poor O -rings  on a water cooled compressor).  Where is the leaking water most likely to go  when the compressor is running?

a)Into the crankcase and mix with the lube oil.

b)Into the LP air discharge and mix with the air from the compressor.

c)Into the HP air discharge and mix with the air from the compressor.

d)Out of the suction filter for the HP cylinder.

99).The HP discharge valves sometimes get carbonized in a very short time and continue to do so even  when you change the HP valves very frequently. What might be the reason ?

a)Poor effect from air inlet filter.

b)Too low cooling water temperature.

c)Worn scrapper and piston rings.

d)Water in the lube oil.

100).When an overhaul is completed and the compressor is gonna be started for a test run, it is important that we:

a)check that we have an open discharge line all the way to the pressure bottle.

b)check the direction of rotation.

c)check  that all air consumption are closed during the test run.

d)test run upto maximum pressure of the capacity (100 % load).

101).On the air compressor's crankcase there is a small valve that lets off overpressure. What do we have to do if this valve is letting of pressure and oil moisture ?

a)Block the valve because it pollutes the engine room (block off the valve).

b)Check the clearance in the bearings.

c)Overhaul the compressor unit.

d)Increase the flow of cooling water.

 

ANSWERS:

1-D

2-D

3-D

4-B

5-C

6-D

7-D

8-C

9-B

10-B

11-B

12-C

13-A

14-A

15-A

16-D

17-D

18-C

19-C

20-A

21-B

22-C

23-D

24-C

25-C

26-B

27-C

28-A

29-A

30-A

31-B

32-B

33-C

34-B

35-B

36-D

37-D

38-D

39-C

40-C

41-A

42-B

43-B

44-B

45-B

46-D

47-A

48-A

49-A

50-C

51-B

52-D

53-C

54-D

55-D

56-D

57-B

58-C

59-A

60-D

61-D

62-B

63-B

64-C

65-D

66-D

67-C

68-B

69-B

70-B

71-B

72-B

73-A

74-D

75-A

76-A

77-B

78-B

79-C

80-A

81-C

82-D

83-D

84-D

85-D

86-B

87-B

88-D

89-D

90-D

91-A

92-D

93-A

94-A

95-A

96-D

97-B

98-A

99-C

100-A

101-C

 

CAPT AJIT VADAKAYIL

(29 YEARS IN COMMAND )