shanghai revision questions - imla¼Žnone of the angular velocity in both azimuth and tilt of the...

《航海仪器》英文习题集

Revision Questions in Support of the Subject of Shipborne Navigational Aids

including Gyrocompass, Echosounder, Speedlog and

Magnetic Compass

陈宇里编

Developed by: CHEN YULI

Communication and Navigation Section

Merchant Marine College of Shanghai Maritime University

Shanghai Maritime University

目录

Chapter 1 The Ship’s Gyrocompass ...........................................................1

Chapter 2 The Ship’s Echosounder...........................................................20

Chapter 3 The Ship’s Speedlog.................................................................26

Chapter 4 The Ship’s Magnetic Compass.................................................33

Keys for Reference ...................................................................................50


1

Chapter 1 The Ship’s Gyrocompass

I. Choose one of the most appropriate choices to complete the question. 1. The precession of a three-freedom gyroscope rotating with rapid velocity is depicted as

_______.

A． when applies an external force, the angular momentum end of the gyroscope turns to the

direction of the external force by the shortest path

B． when applies an external torque, the angular momentum end of the gyroscope turns to

the direction of the external force by the shortest path

C． when applies an external torque, the angular momentum end of the gyroscope turns to

the direction of the external torque by the shortest path

D． when applies an external torque, the spinning axis of the gyroscope is able to

automatically seek and settle down the true north

2. A balancable gyroscope means _______.

A． a three-freedom gyroscope whose gravity center coincides with its geometrical center

B． a three-freedom gyroscope whose spinning axis may point any direction in space

C． a three-freedom gyroscope without any application of external torque

D． a three-freedom gyroscope whose gravity center does not coincide with its geometrical

center

3. A pendulous gyrcoscope means _______.

A．a three-freedom gyroscope whose gravity center coincides with its geometrical center

B．a three-freedom gyroscope whose spinning axis may point any direction in space

C．a three-freedom gyroscope without any application of external torque

D．a three-freedom gyroscope whose gravity center does not coincide with its geometrical

center

4. A free gyrcoscope means _______.

A．a three-freedom gyroscope whose gravity center coincides with its geometrical center

B．a three-freedom gyroscope whose spinning axis may point any direction in space

C．a three-freedom gyroscope on which is without any application of external torque

D．a three-freedom gyroscope whose gravity center does not coincide with its geometrical

center

5. The gyroscope in engineering term is defined as _______.

A．the rapidly-rotating symmetrical rigid object together with its suspension assembly

B．the general description of the rotor as well as its suspension assembly

C．the three-freedom balanceable gyroscope

D．the rapidly-rotating three-freedom gyroscope

6. The gyroscopic rigidity is expressed as _______.

A．the spinning axis of a rapidly-rotating free gyroscope has a tendency of remaining the

original direction in terrestrial space

B．the angular momentum end of the spinning axis of a rapidly-rotating free gyroscope turns

to the end the external torque

C．the spinning axis of a rapidly-rotating free gyroscope has a tendency of remaining the


2

original direction in celestial space

D．the spinning axis of a rapidly-rotating free gyroscope has a tendency of remaining the

original direction referring to the mounting base

7. When a three-freedom gyroscope rotates rapidly, its spinning axis remains _______; if an

external torque is applied on its vertical axis, the spinning axis will _______.

A．unchanged in celestial space; produce the precession

B．unchanged in terrestrial space; produce the precession

C．unchanged in celestial space; remain unmoved

D．in the meridian plane; settle down the true north

8. When an external torque is applied on the direction vertical to the spinning axis, the axis will

precess and the precession angular velocity is _______.

A．proportional to the external torque and the angular momentum

B．inversely proportional to the external torque and the angular momentum

C．proportional to the external torque but inversely proportional to the angular momentum

D．inversely proportional to the external torque but proportional to the angular momentum

9. Suppose the angular momentum of the spinning axis of a free gyroscope is pointing to the

true north, the northern end of the spinning axis will move _______if an external torque is

applied on the west direction of the horizontal axis of the spinning axis.

A．horizontally and eastwards

B．horizontally and westwards

C．vertically and upwards

D．vertically and downwards

10. The root reason which causes the free gyroscope unable to settle down in the meridian plane

is _______.

A．the vertical component of the angular velocity of the earth’s rotation

B．the horizontal component of the angular velocity of the earth’s rotation

C．the gyroscopic precession

D．the self-weight of the gyroscope

11. In the northern hemisphere, the spinning axis of the free gyroscope having the apparent

movement to the eastern side of the meridian plane is caused by _______.

A． the angular velocity of the earth’s revolution

B． the horizontal component of the angular velocity of the earth’s rotation

C． the vertical component of the angular velocity of the earth’s rotation

D． the angular velocity of the rapidly-rotating gyroscope

12. When the free gyroscope is moving apparently to the horizontal plane, its precession angular

velocity is related to _______.

A． the geographical latitude

B． the azimuth of the spinning axis

C． the angular velocity of the earth’s rotation

D． the tilt angle of the spinning axis

13. In the northern hemisphere, when the spinning axis is moving apparently, then _______.

A． the angular velocity of the apparent movement is equal to the angular velocity of the

earth’s rotation

B． the northern end of the spinning axis is deviating eastwards from the meridian plane and


3

moving upwards from the horizontal plane

C． the northern end of the spinning axis is deviating westwards from the meridian plane

and moving downwards from the horizontal plane

D． the northern end of the spinning axis is horizontally rotating 360 degrees per day

14. At the equator, if the spinning axis of a gyroscope is remaining in the meridian plane, this

axis will _______ as the earth is rotating on.

A． deviate eastwards from the meridian plane

B． deviate westwards from the meridian plane

C． always remain in the meridian plane

D． remain a tilt angle from the horizontal plane

15. The spinning axis of a gyroscope will remain stationary if the condition of _______ is met.

A． none of the angular velocity in azimuth of the spinning axis

B．none of the angular velocity in tilt of the spinning axis

C．none of the angular velocity in both azimuth and tilt of the spinning axis

D．none of the angular velocity of the absolute movement in space of the spinning axis

16. The trace of the spinning axis of a gyroscope under the influence of both the earth’s rotation

and the controlling torque is _______.

A．undamped ellipse

B．undamped circle

C．undamped hyperbola

D．undamped spiral circle

17. The purpose applied the controlling torque on the gyroscope is _______.

A．to compensate the apparent movement in tilt of the spinning axis

B．to eliminate the latitude error

C．to compensate the apparent movement in azimuth of the spinning axis

D．to eliminate the speed error

18. The spinning axis of a gyroscope will enable the perfomance of _______when a controlling

torque is applied.

A．remaining stationary in space

B．seeking the true north

C．settling the true north

D．compensating the latitude error

19. If the structure parameters of a gyrocompass remain constant, the controlling torque is related

to _______.

A．the latitude

B．the azimuth

C．the tilt

D．the angular momentum

20. The movement trace of the spinning axis of a gyroscope is _______ when a gyrocompass is

starting up.

A．an equiangular spiral curve

B．a damped exponential curve

C．an elliptical curve

D．a circular curve


4

21. The damping factor of a gyrocompass normally varies from _______.

A．1-2

B．2.5-4

C．5-8

D．8-10

22. If the structural parameters and the ship’s position of a pendulous gyrocompass remain

constant, a gyrocompass, the spinning axis trace of an undamped ellipse will have _______.

A．the eccentricity unchanged

B．the eccentricity changed at random

C．the horizontal axis increased but the vertical axis decreased

D．both the horizontal and vertical axes decreased

23. In the northern hemisphere, the settled position of the spinning axis northern end of the

bottom-heavy gyrocompass is _______.

A．in the meridian plane and above the horizontal plane

B．in the meridian plane and beneath the horizontal plane

C．on the east of the meridian plane and above the horizontal plane

D．on the west of the meridian plane and beneath the horizontal plane

24. If the azimuth of the tilt of a gyroscope is 5° and -5°, respectively, then the current position of

its spinning axis can be concluded _______.

A．on the east of the meridian plane and above the horizontal plane

B．on the east of the meridian plane and beneath the horizontal plane

C．on the west of the meridian plane and above the horizontal plane


25. The crucial principle of turning a free gyroscope into a gyrocompass is _______.

A．to compensate the earth’s revolution

B．to compensate the apparent movement of the spinning axis created by the vertical

component of the angular velocity of the earth’s rotation

C．to compensate the apparent movement of the spinning axis created by the horizontal

component of the angular velocity of the earth’s rotation

D．to compensate the gyroscopic precession

26. To turn a free gyroscope into a pendulous gyrocompass, _________ should be exerted.

A．the precessing torque and the stabilizing torque

B．the controlling torque and the stabilizing torque

C．the precessing torque and the damping torque

D．the controlling torque and the damping torque

27. When the northern end of the spinning axis of a top-heavy gyrocompass is moving toward

the horizontal plane, the damping torque will _______.

A．courage this movement

B．discourage this movement

C．not have any influence on this movement

D．none of all above

28. Which of the following gyrocompass applies the damping in tilt by attaching an iron weight

on the west of the sensitive element? _______

A．Anschütz Type 22


5

B．Sperry Type MK37

C．Navigation Type II

D．Arma-Brown Type 10

29. In the northern hemisphere, the reason that the spinning axis is above the horizontal plane

when a gyrocompass settles down is to _______.

A．produce the controlling torque

B．produce the damping torque

C．produce angular momentum

D．compensate the rolling error

30. When the structural parameters of a gyrocompass remain constant and its time period of an

undamped ellipse is equal to 84.4min, the corresponding latitude is termed as _______.

A．the standard latitude

B．the design latitude

C．the middle latitude

D．the fixed latitude

31. The damping factor of a gyrocompass presents the time period as the spinning axis is moving

dampedly _______.

A．in respect of the azimuth

B．in respect the tilt

C．in respect of excessive liquid angle

D．at a latitude

32. The Schuler Tuning denotes that a gyrocompass does not suffer from the first type of ballistic

error provided that the time period of an undamped ellipse of the gyrocompass is equal to

_______.

A．46.4min

B．90.4min

C．84.4min

D．64.4min

33. Among the following series of gyrocompasses, _______adopts the damping in azimuth;

_______ adopts the damping in tilt.

A．Arma-Brown; Anschütz

B．Sperry; Arma-Brown

C．Arma-Brown; Sperry

D．Anschütz; Sperry and Arma-Brown

34. The production of the controlling torque of Anschütz series gyrocompass is achieved by

_______.

A．vertically lowering the gravity center of the gyrosphere from the geometrical center of the

gyrosphere

B．attaching a fluid ballilistic pots along the north-south direction above the balanceable

gyroscope

C．the electrically-operated pendulum

D．vertically lowering the gravity center of the gyroscope from the geometrical center of the

gyroscope

35. The angular momentum of a bottom-heavy gyrocompass and a top-heavy gyrocompass is


6

settling _______ and _______, respectively.

A．northwards, northwards

B．southwards, southwards

C．northwards, southwards

D．southwards, northwards

36. For Sperry Type MK 37 gyrocompass, supporting the sensitive element is achieved by

_______.

A．the combination of the suspension iron wires and the horizontal bearing

B．the combination of the fluorocarbon oil and the suspension iron wires

C．the compound liquid of the distilled water, the glycerin and the benzoic acid

D．the combination of the floating by the liquid and the suspension bearing

37. After compensating the speed error via the external method for the Sperry Type MK 37

gyrocompass, the spinning axis of the gyrocompass remains ______ in terms of the azimuth.

A．in the meridian plane

B．in the horizontal plane

C．a deviation from the horizontal plane

D．a deviation from the meridian plane

38. In compliance with the requirements of the relevant Standards, the lasting time of a marine

gyrocompass from the startup to the settling down should not more than _______.

A．3hours

B．6hours

C．1.5hours

D．8hours

39. In order to enable the spinning axis of Sperry Type MK 37 gyrocompass to swing to the

settling position after the damping movement, a damping iron weight should be attached on

_______.

A．the west of the follow-up element

B．the west of the sensitive element

C．the east of the follow-up element

D．the east of the sensitive element

40. Which of the following factors are irrelated to the speed error of a marine gyrocompass?

_______.

A．the course and the speed

B．the earth’s radius and the latitude

C．the angular velocity of the earth’s rotation

D．the angular momentum of the gyroscope

41. The heading transmission accuracy of a stepper system applied on a Sperry Type 37

gyrocompass is equal to________ degree.

A．1/6

B．5/6

C．1.0

D．1.5

42. After compensating the speed error via the internal method for a gyrocompass, the spinning

axis of the gyrocompass remains ______ in terms of the azimuth.


7

A．in the geographical meridian plane

B. in the magnetic meridian plane

C．the deviation from the meridian plane

D．the deviation from the horizontal plane

43. The production of the controlling torque of Arma-Brown series gyrocompass is achieved by

______．

A．vertically lowering the gravity center of the gyrosphere from the geometrical center of the

gyrosphere

B．attaching a fluid ballistic pots along the north-south direction above the balanceable

gyroscope

C．the electrically-operated pendulum

D．attaching an iron weight on the west of the sensitive element

44. The purpose of the electrically-operated pendulum of Arma-Brown series gyrocompass is to

______.

A．detect the azimuth and the tilt of the spinning axis of the gyrosphere

B．compensate the latitude error

C．supply the gyromotor with the three-phase electricity

D．transmit the heading information to the repeaters

45. The element to detect the follow-up signal in the Arma-Brown series gyrocompass is ______.

A．the Whestone Signal Bridge

B．the E-shaped transformer

C．the 8-shaped coil and the electro-magnet

D．the electrically-operated pendulum

46. When starting up a Sperry Type 37 gyrocompass, the Mode is switched on the SLEW and

operating the SLEW joystick to control the rotation of the scale card. The purpose of this

operation is to ________before the gyromotor starts rotating.

A．make the lubber line settling the ship’s true heading

B．compensate the lubber error

C．make the lubber line settling the true north

D．compensate the rolling error

47. The gyrocompass which the gyrosphere is supported by the combination of the spiral iron

wire and the floating of the liquid is ______.

A．Arma-Brown Type 10

B．Sperry Type 37

C．Sperry Type 37 and Arma-Brown Type 10

D．Anschütz Type 22

48. The ship sailing in the status of ______ will not suffer from the ballistic error.

A．both changing speed and altering course

B．constant speed and altering course

C．changing speed and constant course

D．constant speed and course

49. The element of detecting the follow-up signal used by the Sperry Type 37 gyrocompass is

______.

A．the E-shaped transformer


8

B．the Wheatstone Signal Bridge

C．the sensitive coil and electro-magnet

D．the synchro receiver

50. The transmission system of the Sperry Type 37 gyrocompass is _______.

A．the alternative synchro system

B．the photoelectric stepper system

C．the contacting stepper system

D．the photoelectric synchro system

51. The settling position of the spinning axis of a top-heavy gyrocompass located on the southern

hemisphere is ______.

A．on the east of the meridian plane and above the horizontal plane

B．on the east of the meridian plane and beneath the horizontal plane

C．on the west of the meridian plane and above the horizontal plane


52. The purpose of the Arma-Brown Type 10 gyrocompass using two independent follow-up

system is to detect ______.

A．the tank’s deviation from the position

B．the tank’s deviation from the gyrosphere

C．the gyrosphere’s deviation from the position

D．the gyrosphere’s deviation from the celestial space

53. Normally, readjusting the speed and latitude correctors of a gyrocompass is based on ______.

A．the ship’s current speed and latitude

B．one knot change of ship’s speed and one degree alternation of ship’s course

C．at most five knots change of ship’s speed and five degrees alternation of ship’s course

D．the seafarer’s common practice

54. The lubber error of a marine gyrocompass signifies ______.

A．the heading reading error

B．the error caused by the spinning axis deviation from the true north

C．the error caused by the spinning axis deviation from the compass north

D．the error caused by the spinning axis deviation from the horizontal plane

55. The Anschütz series gyrocompass does not suffer from the latitude error due to the adoption

of ______.

A．vertically lowering the gravity center of the gyrosphere

B．the dual spinners

C．the damping method in tilt

D．the damping method in azimuth

56. When a ship is changing the speed or altering the course, due to the influence of the inertia

moment, the error caused by the spinning axis’s deviation from _______is so-called _______.

A．the true north; the speed error

B．the true north; the rolling error

C．the settling position; the ballistic error

D．the settling position; the latitude error

57. The marine gyrocompass lubber line means the error of _______caused by the compass

lubber line _______with the ship’s fore and aft line.


9

A．the deviation from the true north; parallel

B．the deviation from the true north; unparallel

C．reading; parallel

D．reading; unparallel

58. The first type of the ballistic error of a marine gyrocompass is caused by ______.

A．the inertia moment applied on the gravity controlling torque device of the gyrocompass

B．the inertia moment applied on the damping torque device of the gyrocompass

C．the inertia moment applied on the geometrical center of the gyrocompass

D．the ship’s rolling

59. The pendulous gyrocompass will not suffer from the first type of ballistic error provided that

the ship’s sailing latitude is ______.

A．more than the design latitude

B．less than the design latitude

C．equal to the design latitude

D．around the equator

60. The influence of the inertia moment will disappear in______after the ship’s manoeuvring.

A．0.5 hour

B．1.0 hour

C．3.0 hours

D．5.0 hours

61. The purpose adopting the dual spinners for the Anschütz series gyrocompass is to

compensate ______.

A．the latitude error

B．the first type of the ballistic error

C．the rolling error

D．the speed error

62. When starting up the Arma-Brown Type 10 gyrocompass, the purpose of operating the knobs

of “AZ”, “TILT” and the button of “SLEW RATE” is to ______.

A．eliminate both the latitude error and the speed error

B．eliminate the rolling error

C．enable the gyrocompass to work in the status of the bearing gyroscope

D．reduce the settling time period

63. Which of the following statements regarding the gyrocompass error is incorrect? ______.

A．Damping in tilt will produce the latitude error.

B．The speed error is not related to the ship’s position.

C．The settling position of the spinning axis of a gyrocompass will remain unchanged

provided that the speed error is compensated by using the external method.

D．The first type of the ballistic error will disappear in 1 hour after the ship’s manoeuvring.

64. The gyrocompass speed error will become the maximum when the ship sails on the course of

______.

A．045 and 225

B．090 and 270

C．000 and 180

D．135 and 315


10

65. The gyrocompass speed error is irrelated to _______.

A．the speed

B．the course

C．the ship’s position

D．the gyrocompass structural parameters

66. The gyrocompass speed error is to _______the compass structure and _______to the latitude

direction.

A．related; related

B．related; irrelated

C．irrelated; irrelated

D．irrelated; related

67. After 10min of starting the Arma-Brown Type 10 gyrocompass, the follow-up system will be

in work _______.

A．automatically

B．manually

C．after starting the follow-up switch


68. For a Sperry Type 37 gyrocompass, the follow-up signal is produced and transmitted by

_______.

A．the Whetstone Signal Bridge

B．the 8-shaped coil and the electro-magnet

C．the E-shape transformer and the pick-off coil

D．the electrically-operated pendulum

69. When the ship is sailing beyond the design latitude, the change of the ballistic error will

_______.

A．increase

B．decrease

C．remain constant

D．depend on the compass structure

70. As shown in the Figure, OXYZ means the free gyrocompass coordinate system, arrow R

means the rotating direction of the gyro rotor with high speed.

Suppose the initial direction of the spinning axis is matched with the

positive direction of the OX axis. If an external force F is vertically

and upwards applied on the positive direction of the OX axis, then

the direction of the precession angular velocity of the angular

momentum end of the spinning axis is on _______.

A．the positive direction of the OY axis

B．the negative direction of the OY axis

C．the positive direction of the OZ axis

D．the negative direction of the OZ axis

71. As shown in the Figure, OXYZ means the free gyrocompass

coordinate system, arrow R means the rotating direction of the gyro

rotor with high speed. Suppose the initial direction of the spinning

axis is matched with the positive direction of the OX axis. If an


11

external force F is vertically and upwards applied on the positive direction of the OX axis,

then the precession direction of the angular momentum end of the spinning axis is on

_______.

A．the positive direction of the OY axis

B．the negative direction of the OY axis

C．the positive direction of the OZ axis

D．the negative direction of the OZ axis

72. Suppose the equation of the gyroscope spinning axis is ,

where: H represents the angular momentum of the spinning axis, My represents the external

torque applied on the OY axis, MZ represents the external torque applied on the OZ axis, ω1

represents the horizontal component of the earth’s angular velocity, ω2 represents the vertical

component of the earth’s angular velocity, α represents the azimuth of the spinning axis,

represents the tilt of the spinning axis.

Then, the OZ axis’s component of the angular velocity regarding the gyroscope spinning axis

related to the terrestrial coordinate system is represented by _______.

A．

B．ω2

C．

D．-ω1α







Then, the OY axis’s component of the angular velocity regarding the gyroscope spinning axis

related to the terrestrial coordinate system is represented by _______.

A．

B．ω2

C．

D．-ω1α





z

y

MH

MH

)(

)(

1

2

z

y

MH

MH

)(

)(

1

2

z

y

MH

MH

)(

)(

1

2


12



Then, the OY axis’s component of the angular velocity regarding the gyroscope spinning axis

related to the celestial coordinate system is represented by _______.

A．

B．ω2

C．

D．-ω1α







Then, the OZ axis’s component of the angular velocity regarding the gyroscope spinning axis

related to the celestial coordinate system is represented by _______.

A．

B．ω2

C．

D．-ω1α

76. As shown in the Figure, suppose MM’ represents the meridian plane, HH’ represents the

horizontal plane, now apply a controlling torque on the horizontal axis of the a free

gyroscope located at the equator, then trace of the northern end of the spinning axis of this

gyroscope is _______。

A. B.

C. D．

77. The Figure shows the moving trace of the spinning

axis of a free gyroscope located in the southern

hemisphere whose the horizontal axis and the

vertical axis are applied the controlling torque and

the damping torque, respectively, where MM’

represents the meridian plane and HH’ represents the horizontal plane. Suppose u3 represents

z

y

MH

MH

)(

)(

1

2


13

the linear velocity of the spinning axis created by the damping torque, then the direction of u3

of the Point P shown in the Figure is _______。

A．easterly

B．westerly

C．upward

D．downward


axis of a free gyroscope located in the southern

hemisphere whose the horizontal axis and the

vertical axis are applied the controlling torque and

the damping torque, respectively, where MM’ represents the meridian plane and HH’

represents the horizontal plane. Suppose u2 represents the linear velocity of the spinning axis

created by the damping torque, then the direction of u2 of the Point P shown in the Figure is

_______。

A．easterly

B．westerly

C．upward

D．downward


axis of a free gyroscope located in the northern

hemisphere whose the horizontal axis is applied

the controlling torque and the damping torque,

where MM’ represents the meridian plane and HH’ represents the horizontal plane. Suppose

u2 represents the linear velocity of the spinning axis created by the damping torque, then the

direction of u2 of the Point P shown in the Figure is _______。

A．easterly

B．westerly

C．upward

D．downward


axis of a free gyroscope located in the northern

hemisphere whose the horizontal axis is applied the

controlling torque and the damping torque, where

MM’ represents the meridian plane and HH’ represents the horizontal plane. Suppose u3

represents the linear velocity of the spinning axis created by the damping torque, then the

direction of u3 of the Point P shown in the Figure is _______。

A．easterly

B．westerly

C．upward

D．downward

81. Suppose a ship fitted a Sperry Type MK37VT gyrocompass is stably sailing in the calm

waters of the southern hemisphere with the constant speed and course. The gyrocompass

error is measured as 1.°2E. If all external signals are normally input into the gyrocompass,

then this gyrocompass error is comprised by _______.


14

①the latitude error ②the speed error ③the ballistic error ④the rolling error ⑤the lubber

error

A．①②

B．①②④

C．①②③④

D．⑤

82. When the lighting point displayed on the digital monitor screen of the Anschütz Type 22

gyrocompass will disappear after starting up the gyrocompass 3 hours, this means the current

heading accuracy is _______.

A．<=1°

B．<=2°

C．<=4°

D．<=5°

83. The supporting liquid of Anschütz Type 22 gyrocompass should be changed at the interval of

______.

A．12 months

B．18 months

C．36 months

D．48 months

84. There is/are_______electrode(s) existing on the surface of the gyrosphere of the Anschütz

Type 22 gyrocompass.

A．1

B．2

C．3

D．4

85. ______are designed to provide the gyromotor with three-phase electricity in the Anschütz

Type 22 gyrocompass.

A．The top electrode and the bottom electrode

B．The top electrode and the middle electrode

C．The top electrode, the bottom electrode and the middle electrode

D．The top electrode, the bottom electrode, the middle electrode and the follow-up electrode

86. The follow-up functionality of the Anschütz Type 22 gyrocompass is achieved by _______.

A．the top electrode

B．the bottom elelctrode

C．the middle electrode

D．the top electrode, the bottom electrode and the middle electrode

87. The gyrosphere of the Anschütz Type 22 gyrocompass is filled with the gas of _______.

A．hydrogen

B．oxygen

C．nitrogen

D．helium

88. The method of stabilize the gyrosphere of the Anschütz Type 22 gyrocompass is _______.

A．the combination of the floating of the liquid and the electro-magnetic force

B．the combination of the floating of the liquid and the supporting bear


15

C．the combination of the floating of the liquid and the suspension iron wire

D．the combination of the floating of the liquid and the circulation of the liquid

89. The normal working temperature of the supporting liquid in the Anschütz Type 22

gyrocompass is _______.

A．52±3℃

B．45±3℃

C．45℃

D．50℃

90. The follow-up system of the Anschütz Type 22 gyrocompass will start to work when the

temperature of the supporting liquid reaches _______.

A．45℃

B．49℃

C．52℃

D．57℃

91. The basic principle of measuring the position of the gyrosphere using in the Anschütz Type

22 gyrocompass is based on _______.

A．the visual observation through the transparent glasses attached on the middle part of the

follow-up sphere

B．the calculation the weight of the supporting liquid

C．the Whetstone Signal Bridge

D．the detection distance between two electrodes

92. The cooling system applied in the Anschütz Type 22 gyrocompass is using _______.

A．the electrical fan

B．the free wind ventilation

C．the water circulation

D．the combination of the electrical fan and the water circulation

93. When the temperature of the supporting liquid of the Anschütz Type 22 gyrocompass reaches

45℃ after starting up, the digital monitor screen will display the ship’s heading followed by

a flashing point. This flashing point means _______.

A．the gyrosphere is seeking the true north

B．the gyrosphere has already settled the true north

C．the three-phase electricity of the gyrosphere is unstable

D．the gyromotor is out of order

94. The indicating light (LED) of the steering repeater of the Anschütz Type 20 gyrocompass

displaying the yellow means

A．the follow-up system does not work and the gyrocompass can not work in normal

condition

B．the gyrocompass has already been settled down, the follow-up system has started, but the

heading is unstable

C．the gyrocompass is working in normal condition

D．the gyrocompass is out of order

95. The indicating light (LED) of the steering repeater of the Anschütz Type 20 gyrocompass

displaying the red means

A．the follow-up system does not work and the gyrocompass can not work in normal


16

condition

B．the gyrocompass has already been settled down, the follow-up system has started, but the

heading is unstable

C．the gyrocompass is working in normal condition

D．the gyrocompass is out of order

96. After starting up the Anschütz Type 22 gyrocompass, what the digital monitor screen shown

is in the Figure, which means ______.

A．the gyrocompass has already been settled down and the ship’s

heading is 38.8°

B．the gyrocompass is still heating the supporting liquid and the temperature of the

supporting liquid is 38.8℃

C．the gyrocompass has already been settled down and the temperature of the supporting

liquid is 38.8℃

D．the gyrocompass is still heating the supporting liquid and the ship’s heading is 38.8°

97. After starting up the Anschütz Type 22 gyrocompass, what the digital monitor screen shown

is in the Figure, which means ______.


heading is 130.5°

B．the gyrocompass is still heating the supporting liquid and the

temperature of the supporting liquid is 130.5℃

C．the gyrocompass is seeking the true north and the ship’s heading is 130.5°

D. the gyrocompass is still heating the supporting liquid and the ship’s heading is 130.5°

98. After starting up the Anschütz Type 22 gyrocompass 3 hours, what the digital monitor screen

shown is in the Figure, which means ______.

A．the gyrocompass has already been settled down (<=2°) and the

ship’s heading is 131.8°





99. After starting up the Anschütz Type 22 gyrocompass 5 hours, what the digital monitor screen

shown is in the Figure, which means ______.


heading is 131.8°





100. The accuracy of the stepper system applied by the Arma-Brown Type 10 gyrocompass is

_______.

A．1/6°

B．1°

C．2°

D．3°


17

101. The dynamically tuned gyroscope is used in _______.

A．the Anschütz Type 22 gyrocompass

B．the Sperry Type MK 37 VT gyrocompass

C．the Arma-Brown Type 10 gyrocompass

D．the Meridian Standard gyrocompass

102. The method of supporting freely the gyrosphere in the Meridian Standard gyrocompass is

_______.

A．the combination of the floating of the liquid and the spiral wire suspension

B．the combination of the floating of the liquid and the supporting bearing

C．the floating of the liquid

D．the combination of two vertical spiral wires and the gimbals

103. The compensation of the rolling error is achieved in the Meridian Standard gyrocompass by

_______.

A．the dual spinners

B．the damping weight attached on the west of the sensitive element

C．the damping the electrically-operated pendulum

D．the liquid pots connected by the tube

104. The accuracy of the stepper system used in the Meridian Standard gyrocompass is _______.

A．1/6°

B．1°

C．2°

D．3°

105. After starting up the Meridian Standard gyrocompass 24 minutes, the gyrocompass indicator

lights will display the green, which means _______.

A．the gyrocompass has completed the self test and started to seek the true north

B．the gyrocompass is conducting the self test

C．the gyrocompass has already been settled down

D．the follow-up of the gyrocompass starts to work

106. Which of the following statements regarding the Directional Gyro mode is incorrect?

_______.

A．The gyrocompass working in DG mode is not able to seek the true north

B．If the ship’s sailing latitude is more than 80°, the DG mode should be used

C．The gyrocompass working in the DG mode is able to compensate both the rolling error

and the ballistic error

D．The error will increase as time goes by when the gyrocompass is working in the DG mode

II. Answer the following questions. 1. Depict a three-freedom gyroscope structure, definition and the basic gyroscopic properties. 2. Depict the apparent rule of the spinning axis of a free gyroscope located on the earth and

explain its physical characteristics. 3. What is the root cause that the free gyroscope located on the earth is not able to settle down

in the meridian plane? 4. State the working principle of the bottom-heavy gyrocompass. 5. State the working principle of the top-heavy gyrocompass. 6. What is the damping factor and the damping time period of a gyrocompass? 7. What’s the latitude error of a gyrocompass and how to compensate it?


18

8. What’s the speed error of a gyrocompass? What factors are contributory to the speed error? How to compensate it?

9. What’s the ballistic error of a gyrocompass? How to compensate it? 10. What’s the condition for the pendulous gyrocompass that will not suffer from the first type of

the ballistic error when ship’s manoeuvring? 11. What’s the rolling error of a gyrocompass? Simply state how the Anschütz series

gyrocompass and the Sperry series gyrocompass compensate this error? 12. What’s the lubber error of a gyrocompass? How to measure and align this error? 13. State the characteristics of the Anschütz series gyrocompass. 14. Fill in the following form regarding the process of making a free gyroscope into a marine

gyrocompass:

15. Fill in the blanks in the following form taking three gyrocompasses of the Anschütz Type 22,

the Sperry Type MK37E and the Arma-Brown MK 10 as examples: Comparison contents Anschütz 22 Sperry MK37E Arma-Brown MK 10

Number of spinner One

Direction of angular

momentum North

Supporting ways for

sensitive element

Both floating and

circulation of liquid

Device of applying

controlling torque Two liquid pots with tube Horizontal spiral wire

Device of applying

damping torque

Two liquid pots with

tube Vertical spiral wire

The earth’s rotation causes the apparent movement of the spinning axis of a free

gyroscope with the property of the gyroscopic inertia:

Move at the northern hemisphere and the horizontal plane;

Move at the northern hemisphere and the horizontal plane;

Use another gyroscopic property: , apply the on the axis;

Then the trace of the spinning axis of the gyroscope is to seek the true north;

Once again use another gyroscopic property: , apply the on the gyro;

For the Anschütz series gyrocompass, apply the damping torque on the axis is

known as the damping in azimuth;

For the Sperry series gyrocompass, apply the damping torque on the axis is

known as the damping in tilt, but the error is produced;

Then the trace of the spinning axis of the gyroscope is to settle the true north.


19

Follow-up system E-shaped transformer

Transmission system Stepper system

Method of compensating

rolling error Damping pendulum

16. The following Figure shows the damping curve of a Anschütz series gyrocompass, then:

(1) What are the damping factor and the damping time period, respectively?

(2) Suppose the initial azimuth of the spinning axis is 81°, then how long will the gyrocompass

take when it has been settled down (azimuth <1°)?


20

Chapter 2 The Ship’s Echosounder

I. Choose one of the most appropriate choices to complete the question. 1. The standard acoustic speed traveling in the seawater for a marine echosounder is designed as

_______ m/s, and this speed is greatest influenced by _______.

A．330, the seawater temperature

B．1500, the seawater salinity

C．330, the seawater salinity

D．1500, the seawater temperature

2. The acoustic speed traveling in the seawater is _______.

A．rising as the rise of the water temperature, pressure and salinity

B．decreasing as the rise of the water temperature, pressure and salinity

C．rising as the rise of the water temperature and pressure, but decreasing as the rise of the

water salinity

D．decreasing as the rise of the water temperature and pressure, but decreasing as the rise of

the water salinity

3. The acoustic speed traveling in the seawater is irrelated to _______.

A．the frequency of the acoustic source

B．the seawater temperature

C．the seawater salinity

D．the seawater hydrostatic pressure

4. The benefit of using the ultrasonic pulse to measure the water depth by the marine

echosounder is _______.

A．the fast traveling speed

B．the low energy attenuation

C．the good restriction for the audio wave

D．the good diffraction ability

5. Both influence from the rise of the seawater pressure and the decrease of the seawater

temperature on the acoustic speed traveling in the seawater as the water depth is rising will

_______.

A．increase the acoustic speed

B．decrease the acoustic speed

C．nearly compensate each other


6. Which kind of the sea bottom characteristics is the poorest reflection source to the ultrasonic

pulse? _______.

A．mud

B．rock

C．gravel

D．sand

7. The measurement depth of a marine echosounder is irrelated to _______.

A．pulse repetition duration


21

B．pulse length

C．transmitting power

D．transmission method

8. Magnetostrictive transducer should be ________ for service after it had been powered off for

ages.

A．stagnated

B．laserized

C．polarized

D．magnetized

9. The surface of the echosounder transducer shall not be painted because the paint would

_______.

A．erode the surface

B．segregate the surface with the seawater

C．produce the air bubbles surrounding the transducer

D．greatly absorb the acoustic energy

10. Which of the following statements regarding the echosounder is incorrect?

A．The minimum depth is dependent upon the pulse length

B．The depth accuracy will be lowered when the ship is sailing in the rough sea and suffering

the severe rolling and pitching.

C．When sounding in the shallow waters, the depth should be measured by the backward

boundary of the signal belt.

D．When the ship has been at anchor for long times, the echosounder may be powered on

once half of a month.

11. The echosounder is able to properly display the water depth provided that the relationship

between the echoes returned time of the maximum range (t) and the pulse repetition duration

(T) is met as _______.

A．t<T

B．t>=T

C．t>2T

D．t=4T

12. The maximum range of a marine echosounder is dependent upon _______.

A．the pulse repetition duration

B．the pulse length

C．the transducer sitting position

D．the pulse trigging method

13. The minimum range of a marine echosounder is dependent upon

A．the pulse repetition duration

B．the transmitting frequency

C．the acoustic speed

D．the pulse length

14. The deviation of the surface of the transducer leveled with the ship’s bottom should not be

more than _______.

A．0.5°

B．1°


22

C．1.5°

D．2°

15. The proper use of the echosounder range is _______ when the channel depth is unknown.

A．to firstly select the deep range then gradually lower the range

B．to firstly select the shallow range then gradually increase the range

C．to firstly select the mid range then alternatively select the deep and shallow ranges

D．to select any range below mid-range

16. A wide echo signal belt may be displayed on the indicator of the echosounder when sounding

in the shallow water, then the depth should be measured base on _______.

A．the forward boundary of the signal belt

B．the middle position of the signal belt

C．the backward boundary of the signal belt

D．any boundary of the signal belt

17. The mechanical echosounder should repress the Zero signal when sounding in _______.

A．the shallow waters

B．the mid-depth waters

C．the deep waters

D．any depth range

18. The reason that the echosounder should not be used when a ship is going astern is that

_______.

A．the ship is suffering the heavy rolling

B．the transducer surface is attached by the dirties

C．the reflection of the sea bottom is reduced

D．there are a lot of air bubbles existing in the seawater

19. When the actual revolution of a time rotor of a mechanical echosounder is more than the

nominal revolution, then _______.

A．the depth will not be indicated

B．the indicated depth will be more than the actual depth

C．the indicated depth will be less than the actual depth

D．the indicated depth will be equal to the actual depth

20. The baseline error of a echosounder is referred to as _______.

A．the error produced by the distance between the transmitting transducer and the receiving

transducer

B．the error produced by the incorrect calculation of the ship’s draft

C．the error produced by the transducer which is not fitted on the ship’s keel.

D．the error produced by the numerous air bubbles in the seawater

21. The echosounder baseline error can be ignored when the water depth is more than _______

meters.

A．5

B．10

C．8

D．15

22. The working principle of the marine echosounder is _______.

A．to measure the water depth by means of the straight line and the good reflection


23

characteristic of the electromagnetic wave traveling in the seawater

B．to measure the water depth by means of the straight line and the good reflection

characteristic of the ultrasonic pulse traveling in the seawater

C．to measure the water depth by means of the measurement of the transmitting frequency

and the receiving frequency on the basis of the characteristic of the different traveling speed of the

ultrasonic pulse in the different water depth

D．to measure the water depth by means of the straight line and the good reflection

characteristic of the audio wave traveling in the seawater

23. The echosounder actually measures the echoed _______of the ultrasonic pulse.

A．speed

B．depth

C．duration

D．distance

24. The echosounder measures the depth between _______ and the sea bottom.

A．the display

B．the surface of the transducer

C．the ship’s draft line

D．the sea surface

25. The wave transmitted by the echosounder is _______.

A．the continuous audio pulse

B．the continuous audio wave

C．the continuous ultrasonic pulse

D．the ultrasonic pulse

26. The time of lighting the “0” on the scale card of a mechanical echosounder means _______.

A．the ultrasonic pulse is starting to transmit

B．the ultrasonic pulse is starting to transmit

C．the ultrasonic pulse reaches the sea bottom

D．the ultrasonic pulse returns the sea surface

27. The display of the marine echosounder shall be _______.

A．graphically recorded

B．digital

C．flashing

D．analogical

28. The marine echosounder shall be able to record the information at least for_______hours.

A．6

B．12

C．24

D．288

29. The marine echosounder shall indicate the water depth at least for _______ minutes.

A．6

B．12

C．15

D．60

30. The device in charge of transmitting the ultrasonic pulse into the seawater in the echosounder


24

is _______.

A．the transmitting oscillator

B．the pulse creator

C．the transmitting transducer

D．the indicator

31. The maximum range of the echosounder is related to _______.

①the transmitting power;②the pulse repetition frequency;③the pulse length.

A．②③

B．①③

C．①②

D．①②③

32. The working frequency of the echosounder is referred to as _______.

A．the pulse repetition frequency

B．the duration of the pulse transmission

C．the pulse transmission numbers per minute

D．the frequency of the transmitting ultrasonic pulse

33. When the depth marker is not clearly displayed on the echosounder indicator, then _______.

A．the range should be changed

B．the illumination should be increased

C．the tune should be increased

D．the gain should be increased

34. The echosounder should not be used when _______.

A．the ship is going ahead

B．the ship is going astern

C．the ship is at anchor

D．the ship is drifting

35. The setting of the dangerous water depth alarm should be based on _______.

A．the ship’ s draft

B．the channel bottom characteristic

C．the ship’s under-keel clearance

D．the ship’s draft, the channel bottom characteristic and the ship’s under-keel clearance

36. For the echosounder which the transmitting transducer and the receiving transducer are

differently located, _______ should be corrected when sounding in the shallow waters.

A．the zero error

B．the baseline error

C．the speed error

D．the error caused by the slope of the sea bottom

37. Suppose the indicated depth is 100 meters when an echosounder is using under the 200-meter

range, then the maximum allowable error for this echosounder is _______ meter.

A．±0.25

B．±0.5

C．±2.5

D．±5.0

38. The indicated depth is _______ the actual depth provided that the actual speed of the


25

ultrasonic pulse traveling in the water is less than the design speed.

A．less than

B．more than

C．equal to


39. Suppose the pulse length of a marine echosounder is 0.4ms, then it means _______.

A．the minimum depth should be more than 0.3 meter

B．the minimum depth should not be more than 0.3 meter

C．the maximum depth should be less than 300 meters

D．the maximum depth should not be less than 300 meters

40. The indicated depth is the actual depth provided that the zero signal of a

mechanical echosounder is lighted earlier.

A．less than

B．more than

C．equal to


41. The echosounder transducer shall be installed on the position of the ship’s bottom .

A．where the engine room, the propellers and the thruster shall be kept away as far as

possible

B．of 1/3 of the ship’s length from the bow

C．between 1/2 to 1/3 of the ship’s length from the bow

D．located before the transducer of the Doppler speedlog but away from the direction of the

transmitting beam

II. Answer the following questions. 1. What factors are contributory to the acoustic velocity traveling in the seawater?

2. Depict the working principle of the echosounder.

3. Draw the configuration of the echosounder and state the function of each component and the

working process.

4. Which factors are contributory to the maximum depth and minimum depth, respectively?

5. What aspects should be taken into considerations when installing the transducer?

6. What kinds of errors are inclusive of the echosounder?

7. State other factors affecting the working of the echosounder.

8. The technical parameters of four ranges of a shipborne echosounder is shown in the

following Form, then

Range Pulse length (ms) Pulse repetition frequency (pulse/min)

1 0.25 750

2 0.38 375

3 1.00 150

4 2.00 75

(1) What are the maximum depth and the minimum depth of this echosounder, respectively?

(2) Suppose this ship is sailing with the even-keel draft of 10 meters in a fairway charted the

sounding of 10.6 meters, which ranges of this echosounder may be selected in order to properly

indicate the measured depth? (NB: The tidal height is ignored.)


26

Chapter 3 The Ship’s Speedlog

I. Choose one of the most appropriate choices to complete the question. 1. Both the Doppler log and the acoustic correlation log are able to work on _______.

A．the athwartship mode and the longitudinal mode

B．the recording display and the lighting display

C．the mechanical mode and the electrical mode

D．the water tracking mode and the sea tracking mode

2. The relative log is to measure the ship’s speed and distance with the reference _______.

A．to the wind and the current

B．through the water

C．through the water and over the ground

D．over the ground

3. Compared with the relative log, the absolute log may _______.

A．be applicable to measure the higher speed

B．measure the speed over the ground

C．sound the depth

D．measure the ship’s athwartship speed

4. Which of kind of the speed logs can measure the ship’s speed under the influence of the wind

rather than the current? _______.

A．the electromagnetic log

B．the absolute log

C．the acoustic correlation log

D．the Doppler log

5. Suppose the ship’s speed is 10kn when sailing in the calm waters. Now the wind speed and

the current speed with the ship are 2kn respectively, then the speed indicated on the

electromagnetic log is _______and the speed over the ground indicated on the Doppler log is

_______.

A．10kn, 12kn

B．12kn, 14kn

C．14kn, 12kn

D．10kn, 14kn

6. Suppose the ship’s speed is 10kn when sailing in the calm waters. Now the wind speed and

the current speed against the ship are 2kn respectively, then the speed indicated on the

relative log is _______and the actual ship’s speed over the ground is _______.

A．10kn, 10kn

B．6kn, 6kn

C．6kn, 8kn

D．8kn, 6kn

7. Both the fore-and-aft speed and the athwartship speed can be measured by _______.

A．the acoustic correlation log

B．the electromagnetic log


27

C．the Doppler log

D．the Doppler log and the acoustic correlation log

8. Which of the following statements is incorrect in terms of the ship’s speedlog? _______.

A．The acoustic correlation log may be an absolute log.

B．The absolute log is a log capable of measuring the speed over the ground.

C．The Doppler log can measure the speed over the ground.

D．The shipborne electromagnetic log can measure the longitudinal speed and the athwartship

speed of the ship.

9. The working principle of the electromagnetic log is to produce the electronic signal of the

ship’s speed by _______.

A．the electromotive force caused by the water current cutting through the magnetic force

lines of the ship’s sensor

B．the Doppler shift of the ultrasonic wave of the ship’s sensor

C．the Doppler shift of the electromagnetic wave of the ship’s sensor

D．the signal delay measured by the ship’ s transducer

10. The electronic signal output by the electromagnetic log’s sensor is_______to the ship’s speed

through water.

A．exponential

B．logarithmic

C．proportional

D．inversely proportional

11. One of the benefits of the acoustic correlation log is that the measurement accuracy is free

from the influence of _______.

A．the sea noise

B．the sea bottom characteristic

C．the energy attenuation

D．the water temperature and the salinity

12. The transmission direction of the ultrasonic pulse from the acoustic correlation is _______.

A．horizontally fore and aft

B．downwards fore and aft

C．vertically upward

D．vertically downward

13. The sensor of the electromagnetic sensor can not be installed on _______ of the echosounder

transducer.

A．the fore part

B．the aft part

C．the left side

D．the right side

14. The Doppler log is working on the Doppler effect to measure the ship’s speed and the

cumulative distance. The Doppler effect denotes that when the transmission and the reception

are approaching each other, the frequency received by the receiver is _______ the frequency

of the transmission source.

A．more than

B．less than


28

C．equal to

D．not affected by

15. The signal output by the ship’s log to the other navigational aids is stipulated by _______.

A．100P/mile

B．200P/mile

C．300P/mile

D．400P/mile

16. The main types of the electromagnetic log’s sensor consist of _______.

A．the tube type and the electromagnetic type

B．the water pressure type and the hydrostatic type

C．the flush type and the tube extension type

D．the magnetostrictive type and the electrostrictive type

17. The ship’s speed measured by the Doppler log is a function of _______.

①the transmitting frequency;②the pulse repetition frequency;③the pulse length;④the

Doppler shift;⑤the acoustic traveling speed

A．①②③

B．①②④

C．①④⑤

D．③④⑤

18. The reason that the direction of the ultrasonic pulse transmitted by the Doppler log is not

vertical with the direction of the ship’s speed is _______.

A．to reduce the pitching error

B．to reduce the rolling and pitching error

C．to facilitate the reception of the returned echo

D．that the horizontal Doppler effect can be produced

19. The purpose of using two acoustic beams of a Doppler log is _______.

A．to measure the ship’s fore-and-aft speed

B．to eliminate the error caused by the change of the acoustic traveling speed

C．to eliminate the error caused by the ship’s rolling and pitching

D．to measure the ship’s athwartship speed

20. The Doppler log should have _______ installed on the ship bottom.

A．the electromagnetic sensor

B．the sound-electricity transducer

C．the electromagnetic wave creator

D．the pressure tube

21. The angle between the horizontal plane and the wave transmission for a Doppler log is

normally _______.

A．30º

B．60º

C．90º

D．180º

22. The measurement accuracy of a Doppler log is about _______.

A．±0.01kn

B．±0.05kn


29

C．±1kn

D．±2kn

23. _______is free from the change of the acoustic traveling speed.

A．The Doppler log

B．The acoustic correlation log

C．The echosounder

D．None of all above

24. Compared with the electromagnetic log, the Doppler log benefits from _______.

A．higher speed measurement accuracy (less than 0.5%)

B．the measurement of the ship’s athwartship speed

C．the measurement of the ship’s speed over ground under the range

D．All above

25. The six-beam speedlog used on the superships can measure the ship’s speed including

_______.

A．the athwartship speed of the bow and the stern, and the fore-and-aft speed

B．the portside speed of the bow and the stern, and the fore-and-aft speed

C．the portside speed and the starboardside speed of the stern, and the fore-and-aft speed

D．the forward speed of the bow, the aftward speed of the stern, and the fore-and-aft speed

26. The acoustic correlation log makes use of the correlation technology to obtain_______to

measure the ship’s speed and the distance.

A．the echo phase difference

B．the echo signal envelope

C．the Doppler shift

D．the electromagnetic wave signal

27. The acoustic correlation log is referred to as the log working on the principle of measuring

_______.

A．the electromotive force

B．the water pressure

C．the Doppler shift

D．the correlation time delay

28. The measurement accuracy of the acoustic correlation log is dependent upon the correlation

time delay and _______.

A．the current speed

B．the ship’s speed

C．the acoustic traveling speed

D．the distance between two transducers

29. The acoustic correlation log is able not only to measure the ship’s speed and the distance, but

also to _______.

A．measure the water depth

B．detect the sea bottom characteristic

C．detect the fish school

D．detect the bearing of the dangerous object

30. The sounding equipment which is able to avoid the measurement error caused by the change

of the acoustic traveling speed is _______.


30

A．the Doppler log

B．the acoustic correlation log

C．the echosounder

D．all above

31. What kinds of the ship’s speed are required to measure the log correction in the water haven?

_______.

A．full ahead

B．half ahead

C．slow ahead

D．all above

32. Which of the following statements is correct regarding the ship’s log? _______.

A．The relative log can reflect the influence of the current to the ship.

B．The absolute log can measure the cumulative distance but the relative log cannot.

C．The absolute log can measure the speed when the ship is going astern but the relative

cannot.

D．The absolute log can reflect the influence of the wind to the ship.

33. The ship’s log which is only able to measure the speed through water is referred to as

_______.

A．the absolute log

B．the relative log

C．the Doppler log

D．the acoustic correlation log

34. The speed measured by the relative log is _______.

A．the speed through water

B．the speed over ground

C．the speed through current

D．the speed to wind

35. The ship’s athwartship speed can be measured by _______.

A．the electromagnetic log

B．the Doppler log

C．the acoustic correlation log

D．B+C

36. The speed and the distance measured by the electromagnetic log are those _______.

A．to the wind and the current

B．through the water

C．over the ground


37. The purpose of the electromagnetic log sensor is to detect the ship’s speed through the water

and output an electronic signal _______.

A．proportional to the speed

B．inversely proportional to the speed

C．proportional or inversely proportional to the speed

D．sinusoidal to the speed

38. The element measuring the ship’s speed in the electromagnetic log is _______.


31

A．the transducer

B．the electromagnetic sensor

C．the pressure tube

D．the photoelectrical sensor

39. The purpose of the Doppler log using two beams is to _______.

A．eliminate the influence caused by the sea bottom characteristic difference

B．repress the sea noise

C．overcome the phenomenon of the energy attenuation

D．to eliminate the influence of the ship’s vertical movement and rolling caused by the seas

40. Which of the following statements is most adequate for the current shipborne Doppler

speedlog? _______.

A．It only measures the speed over the ground.

B．It only measures the speed through the water.

C．It measures the speed over the ground in the shallow waters, but the speed through water

in the deep waters.

D．It measures the speed over the ground in the deep waters, but the speed through water in

the shallow waters.

41. Suppose the tracking depth of the Doppler log and the acoustic correlation log is 200 meters,

when the ship’s is sailing in the waters with the depth more than 200 meters, then the speed

measured by these logs is _______.

A．the absolute speed

B．the relative speed

C．the absolute speed or the relative speed

D．none of any kind of the speed

42. The relation between the ship’s speed v measured by the acoustic correlation log and the

distance between two transducers s as well as the signal time delay r is that _______.

A．the v is proportional to the s and the r

B．the v is inversely proportional to the s and the r

C．the v is proportional to the s but inversely proportional to the r

D．the v is proportional to the r but inversely proportional to the v

43. _______is able to indicate the ship’s speed, distance and the water depth.

A．The electromagnetic log

B．The Doppler log

C．The water pressure log

D．The acoustic correlation log

44. The Figure shows the scenario that a Doppler log system fitted on the ship is transmitting the

ultrasonic pulses, then this kind of the Doppler log system is known as _______.

A．one-element log

B．two-element array log

C．three-element array log

D．four-element array log

II. Answer the following questions. 1. Depict the working principle of the flush type of the electromagnetic log.


32

2. What is the Doppler effect? How the Doppler log uses this effect to measure the speed?

3. Draw the relevant picture and depict the working principle of the two-beam Doppler log.

4. State the category and the purpose of the Doppler log.

5. Draw the relevant picture and depict the working principle of the acoustic correlation log

6. Depict the working process of the acoustic correlation log.

7. Compared with the Doppler log, what are the advantages of the acoustic correlation log?


33

Chapter 4 The Ship’s Magnetic Compass

I. Choose one of the most appropriate choices to complete the question. 1. The deviation of a marine magnetic compass is defined by the horizontal angle

between_______and_______.

A． the true north, the magnetic north

B． the true north, the compass north

C． the magnetic north, the compass north

D． the ship’s lubber line, the compass north

2. The magnetic moment of a magnet is defined by the multiplication between _______ and

_______.

A． the magnetic flux of the like pole, the distance between two ends

B． the magnetic flux of the like pole, the distance between two poles

C． the magnetic field intensity, the distance between two ends

D． the magnetic field intensity, the distance between two poles

3. Compared with the soft iron, the magnetization of the hard iron is _______ but the residual

magnetism is_______.

A． easier, more

B． easier, less

C． harder, more

D． harder, less

4. The total permanent magnetic force at the ship’ s magnetic compass may be broken into three

components mutually vertical apart, as known as _______.

A．P，Q，R

B．P，fz，R

C．cz，Q，R

D．P，Q，kz

5. _______denotes the ship’s permanent magnetic force pointing to the ship’s bow.

A．P

B．Q

C．R

D．fz

6. _______denotes the ship’s permanent magnetic force pointing to the ship’s portside.

A．-P

B．-Q

C．+R

D．+fz

7. The ship’s permanent magnetic force is related to _______.

A．the ship’s position

B．the ship’s course

C．the ship’s speed

D．the installation position of the magnetic compass onboard


34

8. The magnetic flux in the northern magnetic pole and the southern magnetic pole are defined

as _______ and _______, respectively.

A．negative, positive

B．positive, negative

C．negative, negative

D．positive, positive

9. The lines of the terrestrial magnetic force surrounding the earth’ s space is running _______.

A．from the north to the south

B．from the south to the north

C．from the magnetic poles to the magnetic equator

D．form the magnetic equator to the magnetic poles

10. The curve connecting all points with the equivalent dip is so-called _______.

A．the magnetic equator

B．the magnetic latitude

C．the magnetic longitude

D．the isogone

11. The magnetic equator is referred to as the curve connecting all points that _______.

A．the variation is null

B．the dip is null

C．the horizontal terrestrial magnetic force is null

D．are coincided with the geographical equator

12. The horizontal terrestrial magnetic force is null at _______, while the vertical terrestrial

magnetic force is null at _______.

A．the magnetic poles, the magnetic poles

B．the magnetic equator, the magnetic equator

C．the magnetic poles, the magnetic equator

D．the magnetic equator, the magnetic poles

13. The southern magnetic pole is annually _______.

A．changed slowly

B．changed obviously

C．fixed

D．changed at random

14. The magnetic dip is referred to as the angle between the lines of the terrestrial magnetic force

and _______.

A．the local magnetic meridian line

B．the local geographical meridian line

C．the local horizontal plane

D．the local vertical plane

15. The directive force of a marine magnetic compass is referred to as _______.

A． the horizontal component of the terrestrial magnetic force

B． the vertical component of the terrestrial magnetic force

C． the ship’s permanent magnetic force

D． the ship’s induced magnetic force

16. The directive force will be maximum when the magnetic compass is located at _______.


35

A．the northern hemisphere

B．the southern hemisphere

C．the magnetic equator

D．the magnetic poles

17. The magnetic compass is not able to direct the magnetic north at the magnetic equator due to

_______.

A．the strong vertical component of the terrestrial magnetic force

B．the null of the vertical component of the terrestrial magnetic force

C．the strong horizontal component of the terrestrial magnetic force

D．the null of the horizontal component of the terrestrial magnetic force

18. Besides the ship’s position, the magnetic compass is also related to _______.

A．the ship’s magnetism

B．the ship’s course


D．the date

19. The magnetic compass fitted on the iron-made ship board will suffer from _______ due to

the influence under the permanent magnetism and the induced magnetism.

A．the variation

B．the compass error

C．the deviation

D．the error

20. The magnetic compass will not suffer from the deviation when _______.

A．the iron-made is in the dry dock

B．fitted on the wood-made ship board

C．fitted on the newly iron-made ship board

D．fitted on the iron-made fishing vessel board

21. The spare magnet bars should be stored onboard by _______.

A．attracting the like poles

B．attracting the unlike poles

C．the mean of the poles at random

D．the mean of the single magnet bar

22. _______ are referred to as the three elements of the terrestrial magnetism.

A．The variation, the deviation and the directive force

B．The dip, the deviation and the directive force

C．The variation, the dip and the directive force

D．The variation, the dip and the deviation

23. That the magnetic moment of a magnetic compass becomes weaker will cause _______.

A．the increase of the card swinging angle but the decrease of the swinging period

B．the decrease of the card swinging angle but the increase of the swinging period

C．the increase of the card swinging angle but the increase of the swinging period

D．the decrease of the card swinging angle but the decrease of the swinging period

24. The magnetic compass fitted on the wood-made ship board processes _______.

A．the deviation but is free from the variation

B．the variation but is free from the deviation


36

C．both the deviation and the variation

D．the null of the compass error

25. When a magnetic compass is fitted on the ship board, the quantity and the direction of all soft

iron coefficients remain _______.

A．unchanged

B．changed with the ship’s position

C．unchanged for the direction, but changed for the quantity with the ship’s position

D．unchanged for the quantity, but changed for the direction with the ship’s course

26. Which of the following alphabetic symbol is not used to represent one of nine soft irons on a

marine magnetic compass? _______.

A．a

B．g

C．i

D．k

27. The directive force of a magnetic compass on an iron-made ship board is _______that on the

shore.

A．less than

B．more than

C．equal to

D．undetermined to

28. The coefficient of the magnetic compass is only related to _______.

A．the ship’s course

B．the ship’s position


D．the soft iron coefficients of a and e

29. The deviation curve caused by the permanent magnetic force P along with the ship’s fore and

aft direction is _______ varying with the ship’s magnetic course.

A．a sine curve

B．a cosine curve

C．a tangent curve

D．a spiral curve

30. The deviation curve caused by the permanent magnetic force Q along with the ship’s

athwartship direction is _______ varying with the ship’s magnetic course.

A．a sine curve

B．a cosine curve

C．a tangent curve

D．a spiral curve

31. The deviation curve caused by the vertical soft iron (-c) is _______ varying with the ship’s

magnetic course.

A．a sine curve

B．a cosine curve

C．a tangent curve

D．a spiral curve

32. The deviation curve caused by the vertical soft iron (-a) is _______ varying with the ship’s


37

double magnetic course.

A．a sine curve

B．a cosine curve

C．a tangent curve

D．a spiral curve

33. The deviation curve caused by the athwartship soft iron (-e) is _______ varying with the

ship’s double magnetic course.

A．a sine curve

B．a cosine curve

C．a tangent curve

D．a spiral curve

34. For a magnetic compass installed in the ship’s fore and aft plane, the deviation coefficients of

_______ are negligible or of the null.

A．A and B

B．B and D

C．C and D

D．A and E

35. The half deviation remained in the process of the compass deviation correction is caused by

_______.

A．the induced magnetism in asymmetrical arrangements of longitudinal and athwartship soft

irons

B．the induced magnetism in asymmetrical arrangements of longitudinal and vertical soft

irons

C．the induced magnetism in asymmetrical arrangements of longitudinal and athwartship hard

irons

D．the induced magnetism in asymmetrical arrangements of longitudinal and vertical hard

irons

36. The curve connecting all points of the equal variation on the chart or the map is so-called

_______.

A．the variation curve

B．the isogone

C．the curve of the magnetic force

D．the curve of the equal magnetic force

37. The magnetic compass binnacle is made of _______.

A．the iron and the bronze

B．the bronze or the aluminum

C．the steel and the iron

D．the iron-nickel alloy

38. The main purpose of the magnetic compass card is to _______.

A．hold the liquid

B．store the correctors

C．direct the course

D．take the bearing

39. The element of directing the course in the magnetic compass is_______.


38

A．the compass binnacle

B．the compass card

C．the compass bowl

D．the compass buoyant chamber

40. The layout of the magnetic needles attached on the magnetic compass card should

be_______the NS axis of the compass card.

A．parallel with

B．vertical with

C．symmetrically parallel with

D．symmetrically vertical with

41. The main purpose of the floater in a magnetic compass bowl is to _______.

A．increase the compass card magnetism

B．increase the compass card rotation moment

C．increase the compass card buoyancy

D．compensate the reading error due to the rolling

42. The purposes of the liquid in the bowl of a magnetic compass do not include _______.

A．the friction reduction between the needle and the cap

B．the contribution to the directive ability due to the damping

C．the avoidance of the vibration

D．the increase of the magnetic moment

43. The purpose that the ethyl alcohol is included in the compound liquid in the bowl of the

magnetic compass is to _______.

A．dilute the liquid

B．lower the density of the liquid

C．lower the freezing point of the liquid

D．disinfect the liquid

44. The specific proportions of the distilled water and the ethanol indigents included in the liquid

in the bowl of the magnetic compass are _______, respectively.

A．45％, 55％

B．55％, 45％

C．50％, 50％

D．35％, 65％

45. _______may be used as the supporting liquid in the bowl of the ship’s magnetic compass.

A．The liquid of mixing 45％ of the distilled water and 55％ of the ethanol

B．The liquid of mixing 50％ of the distilled water and 40％ of the ethanol

C．The kerosene

D．The gasoline

46. The lubber line of a magnetic compass should be fully _______the ship’s fore and aft line

otherwise the residual deviation will increase.

A．parallel with

B．coincided with

C．crossed with

D．vertical with

47. The magnets stored in the vertical round tube or vertical rectangular box are known as


39

_______.

A．the vertical induced magnet bars and the Flinder’s bars

B．the vertical induced magnet bars and the soft iron bars

C．the Flinder’s bars or the soft iron bars

D．the vertical induced magnet bars, the Flinder’s bars or the soft iron bars

48. The deviation correctors installed on the both sides of the compass binnacle are known

as_______for the correction of _______

A．the soft iron spheres, the quadrantal deviation

B．the Flinder’s bars, the semicircular deviation

C．the vertical induced magnet bars, the heeling deviation

D．the horizontal induced magnet bars, the semicircular deviation

49. The “0” marking on the compass card of a magnetic compass fitted on a iron-made ship

onboard denotes _______.

A．the ship’s bow

B．the true north

C．the magnetic north

D．the compass north

50. A small liquid magnetic compass fitted on the lifeboat should consist of the complete

supporting frame and the oil lamp. The quantity of the lamp oil is required to be consumed at

least _______.

A．2 hours

B．4 hours

C．6 hours

D．10 hours

51. The main purpose of checking the half time period of swinging the compass card is to

_______.

A．check the quantity of the friction between the magnetic needles and the cap

B．check the quantity of the compass card magnetism

C．check the quantity of the rotation moment of the compass card

D．check the quantity of the buoyancy of the compass card

52. If the constant (fixed) deviation is negligible, the ship’s deviation should be corrected

provided that the standard compass deviation is more than _______, and the steering compass

deviation is more than _______.

A．±1º, ±3º

B．±3º, ±5º

C．±5º, ±3º

D．±5º, ±1º

53. The method for checking the sensitivity of the compass card is to observe if the card can

return to its original position after using the small magnet to swing the card 2º～3º of the port

and starboard side. This method should be conducted when _______.

A．the ship is berthed along the wharf

B．the onboard machineries and the onshore machineries are not working

C．the deviation is not very large

D．all above


40

54. The method for checking the sensitivity of the compass card is to observe if the card can

return to its original position after using the iron bars or the small magnets to swing the card

2º～3º of the starboard side. This method should be conducted when the ship _______.

A．is underway

B．is at anchor

C．is berthed along the wharf

D．is drifting

55. When checking the soft iron deviation correctors, they are required that _______.

A．no permanent magnetism exists

B．the permanent magnetism exists

C．a small amount of the permanent magnetism exists

D．no induced magnetism exists

56. What the half time period of swinging the compass card is more than the nominal time period

means _______.

A．the magnetism of the compass needles is rather strong

B．the magnetism of the compass needles is becoming weaker

C．the needles of the compass card is rather sensitive

D．the compass liquid is deteriorated

57. The method of checking the half time period of swinging the compass card is to check

whether _______ is required

A．the magnetic moment of the compass card needles

B．the sensitivity of the compass card

C．the horizon of the compass card

D．the quantity of the compass liquid

58. What the half time period of swinging the compass card is much more than the nominal time

period means _______.

A．the magnetic force of the compass card is rather strong

B．the magnetic force of the compass card is becoming weaker

C．there are air bubbles existing in the compass bowl

D．the magnetic needles attached on the compass card are seriously worn and torn

59. The ship’s bow should be steered at the direction of_______to check if there is the permanent

magnetism exists in the soft iron spheres fitted on the compass binnacle.

A．the north

B．the south

C．the east or the west

D．the intercardinal course

60. The root cause to create the compass deviation is _______.

A．the ship’s induced magnetism

B．the terrestrial magnetism

C．the ship’s permanent magnetism

D．the ship’s induced and permanent magnetism

61. The reason to cause the change of the compass deviation is _______.

A．the change of both the ship’s magnetism and the terrestrial magnetism

B．that the azimuth device has errors


41

C．by using the spare compass

D．the liquid is reducing or the air bubbles is existing in the compass bowl

62. The reason that the compass deviation varies with the ship’s course is that _______.

A．the observation is inaccurate

B．the compass structure has defection

C．the terrestrial magnetic field the ship’s located is abnormal

D．there are different functional relationship between various deviation forces and the

compass course

63. The vertical correctors stored in the bronze-made tube beneath the compass bowl are

_______for the corrections of the ship’s _______.

A．the hard iron correctors, semicircular deviation

B．the hard iron correctors, heeling deviation

C．the soft iron correctors, heeling deviation

D．the soft iron correctors, quadrantal deviation

64. The fore-and-aft correctors horizontally stored in the compass bowl are_______for the

corrections of the compass’s _______.

A．the hard irons, semicircular deviation force

B．the hard irons, quadrantal deviation force

C．the soft irons, semicircular deviation force

D．the soft irons, quadrantal deviation force

65. The athwartship correctors horizontally stored in the compass bowl are_______for the

corrections of _______.

A．the hard irons, the ship’s fore-and-aft permanent magnetic force

B．the hard irons, the athwartship permanent magnetic force

C．the soft irons, the ship’s fore-and-aft permanent magnetic force

D．the soft irons, the ship’s athwartship permanent magnetic force

66. After completing the compass deviation adjustment, the residual deviation on the direction of

_______ should be observed in order to develop the compass deviation table.

A．four cardinal courses

B．four intercardinal courses

C．four cardinal courses and four intercardinal courses

D．every 15º

67. If the deviations’ difference between the calculation from the deviation table and the

observation from the ship’s swing is more than _______, that means there is an obvious error

existing in the calculation or the observation.

A．±0.5 º

B．±1.0 º

C．±1.5 º

D．±2.0 º

68. Suppose the standard compass course is 100 º, the deviation of the standard compass is -1º,

the steering compass course is 105 º, then the deviation of the steering compass is _______by

comparing the standard with the steering.

A．+4 º

B．+5 º


42

C．+6 º

D．-6 º

69. Suppose the bearing of a leading light is measured as 287º by the magnetic compass when the

ship is passing the light, the true bearing of this light is 293º taken from the chart, and the

variation is determined as -1º, then the deviation of this magnetic compass is _______

A．+5 º

B．+6 º

C．-6 º

D．+7 º

70. When using the sun’s azimuth to measure the magnetic compass deviation, the sun’s height is

preferable to be limited as less than _______.

A．30 º

B．45 º

C．60 º

D．90 º

71. To develop the deviation curve after completing the deviation correction, it is required that

the quantity of the deviation is small and the curve is _______, otherwise there is an error

existing in the deviation correction or calculation.

A．smooth

B．a straight line

C．a sine curve

D．a regular polygonal line

72. The compass card is suffering from the rolling with the ship’s rolling when the ship is sailing

in the rough seas because _______is not accurately eliminated.

A．the hard semicircular deviation

B．the quadrantal deviation

C．the heeling deviation

D．the soft semicircular deviation

73. The methods measuring the ship’s compass deviation involve the use of _______.

A．the course comparison

B．the leading light

C．the celestial objects(the sun)

D．all above

74. When using the sun’s azimuth to measure the compass deviation, the deviation could include

the error due to the influence of _______ if the sun’s rather high.

A．the rapid change of the sun’s azimuth

B．the inclination of the compass card

C．A or B

D．the lubber error

75. When the air bubbles are found in the compass bowl, _______.

A．the liquid should be timely refilled because the air bubbles could influence the compass

operation

B．the liquid should be refilled until much more air bubbles are found

C．the air bubbles are unnecessary to be removed


43

D．the compass cannot work normally

76. The international signal flags of _______should be hoisted onboard when the ship is

swinging for measuring and correcting the deviation.

A．HB

B．BQ

C．OQ

D．TE

77. To improve the bearing accuracy when using the leading lights to measure the compass

deviation, the distance between the ship and the fore light should be controlled

about_______times of the distance between the fore and aft lights.

A．3-5

B．1-2

C．10-15

D．more than 10

78. To improve the deviation accuracy when using the comparison between the gyrocompass

course and the magnetic compass course to determine the deviation, _______.

A．both courses should be observed simultaneously

B．the gyrocompass course should be firstly observed followed by the observation of the

magnetic compass course

C．the magnetic compass course should be firstly observed followed by the observation of the

gyrocompass course

D．A or B or C

79. The sequence of eliminating the deviation for a new magnetic compass is normally_______.

A．the semicircular deviation, the heeling deviation, the quadrantal deviation

B．the heeling deviation, the semicircular deviation, the quadrantal deviation

C．the heeling deviation, the approximate elimination of the quadrantal deviation, the

semicircular deviation, the quadrantal deviation

D．the approximate eliminations of the quadrantal deviation and the sub-semicircular

deviation, the accurate eliminations of the heeling deviation, the semicircular deviation and the

quadrantal deviation

80. The principle of the deviation correction is to compensate the corresponding ship’s magnetic

force by using the deviation correction force with _______.

A．the equal quantity, the opposite direction and the same characteristic

B．the equal quantity, the opposite direction and the opposite characteristic

C．the opposite quantity, the opposite direction and the same characteristic

D．the equal quantity, the same direction and the same characteristic

81. The angle between the magnetic north and the compass north is known as _______.

A．the deviation

B．the compass error

C．the variation

D．the compass course

82. The deviation of a magnetic compass fitted on the iron-made ship board is related to

_______.

A．the ship’s position and course


44

B．the ship’s position and variation

C．the ship’s size, course and speed

D．the ship’s position and date

83. The compass binnacle should not be made of _______.

A．bronze

B．aluminum

C．iron

D．wood

84. Suppose the standard compass course is 094º, the deviation of this standard compass is -1º,

when the steering compass course is 100º, then the deviation of this steering compass is

_______.

A．+5º

B．-5º

C．+6º

D．-7º

85. The standard magnetic compass should be fitted_______.

A．at any location onboard

B．in the ship’s fore and aft plane

C．in the plane parallel with the ship’s fore and aft plane

D．in the bridge

86. The deviation of the ship’s magnetic compass should at least be measured and corrected once

at the interval of _______ as per the requirement.

A．one year

B．two years

C．three years

D．four years

87. Suppose the true bearing of a lighthouse is 100º, the local variation is 7ºW, and the compass

bearing of this lighthouse by using the magnetic compass is measured as 95º, then the

deviation of this compass course is _______.

A．8ºE

B．8ºW

C．2ºE

D．2ºW

88. Which are the following conditions that the ship should swing to measure and correct the

deviation of the magnetic compass?

① the ship’s superstructure is obviously changed after repairing the ship;② the ship

encounters the severe collision;③the air bubbles are found in the bowl;④the magnetic compass is

moved backwards one meter when repairing the ship;⑤after loading the magnetic cargo or using

the electromagnetic crane for the cargo loading;⑥using the spare bowl.

A．①②④⑤

B．①②③④⑤

C．①②④⑤⑥

D．③④⑤⑥


45

89. ①②③④ shown in the Figure represent four different deviation correctors fitted in the

magnetic compass, respectively, then the corrector used for

correcting the quadrantal deviation is represented by

_______。

A．①

B．②

C．③

D．④

90. ①②③④ shown in the Figure represent four different

deviation correctors fitted in the magnetic compass,

respectively, then the corrector used for correcting the

deviation caused by the soft iron c is represented by

_______。

A．①

B．②

C．③

D．④

91. ①②③④ shown in the Figure represent four different deviation correctors fitted in the

magnetic compass, respectively, then the corrector used for

correcting the heeling deviation is represented by _______。

A．①

B．②

C．③

D．④

92. ①②③④ shown in the Figure represent four different

deviation correctors fitted in the magnetic compass,

respectively, then the corrector used for correcting the

semicircular deviation is represented by _______。

A．①

B．②

C．③

D．④

93. When a ship is conducting the deviation correction, suppose the ship’s sailing on the east

course, and the current deviation is measured as the easterly deviation, then the red pole of

the magnet bars to be added in the compass should be directed to _______.


B．the ship’s stern

C．the ship’s portside

D．the ship’s starboardside


course, and the current deviation is measured as the westerly deviation, then the red pole of





46



95. When a ship is conducting the deviation correction, suppose the ship’s sailing on the west
















the magnet bars directed to the ship’s bow should be moved _______.

A．upwards

B．downwards

C．to the portside

D．to the starboardside




A．upwards

B．downwards

C．to the portside





A．upwards

B．downwards

C．to the portside





A．upwards

B．downwards

C．to the portside



47

101. When a ship is conducting the deviation correction, suppose the ship’s sailing on the north





C．the portside

D．the starboardside






C．the portside


103. When a ship is conducting the deviation correction, suppose the ship’s sailing on the south





C．the portside







C．the portside




the magnet bars directed to the ship’s starboardside should be moved _______.

A．upwards

B．downwards

C．to the portside





A．upwards

B．downwards

C．to the portside





48


A．upwards

B．downwards

C．to the portside





A．upwards

B．downwards

C．to the portside


109. When a ship is conducting the deviation correction, suppose the ship’s sailing on the

north-east course, and the current deviation is measured as the easterly deviation, then two

soft iron spheres (slices) should be moved _______.

A．closely

B．far

C．unchanged



north-east course, and the current deviation is measured as the westerly deviation, then two


A．closely

B．far

C．unchanged



south-east course, and the current deviation is measured as the easterly deviation, then two


A．closely

B．far

C．unchanged



south-east course, and the current deviation is measured as the westerly deviation, then two


A．closely

B．far

C．unchanged


113. The international signal flags of _______should be hoisted onboard when the ship is

swinging for measuring and correcting the deviation.


49

A．

B．

C．

D．

114. As shown in the Figure, L represents the distance between two lights (★), then the area

represented by _______ is preferable by using this leading

lights to measure the ship’s compass deviation.

A．（1）

B．（2）

C．（3）

D．（4）

II. Answer the following questions. 1. What’s the variation, the magnetic equator and three

elements of the terrestrial magnetism? 2. Simply state the reason of producing the heeling deviation

and the method to correct it. 3. Simply depict the principle and the procedure of correcting

the semicircular deviation and the quadrantal deviation. 4. What are the conditions that the ship is required to conduct the deviation correction? 5. Simply state the preparations when the ship’s ready to swing to correct the deviation. 6. What is the sequence of the deviation correction? 7. Simply depict the pithy formula used in the corrections of the semicircular deviation and the

quadrantal deviation. 8. Why does the residual deviation on the eight compass courses need be measured after

completing the deviation correction? 9. What are the methods to measure the compass deviation? 10. How to determine the quality of the compass deviation curve? 11. Simply state the category and the purpose of the magnetic compass. 12. Simply state the basic structure of the compass bowl. 13. Simply state the category and the purpose of the magnetic compass deviation correctors. 14. Simply state operational method of the azimuth device. 15. How to check the sensitivity and the magnetism quantity of the compass card? 16. Simply state the magnetic compass maintenance and the operational cautions. 17. Simply depict the reason producing the air bubbles in the compass bowl and the correction

method.

LL

2L

3L

5L

(1)(2

)(3)

(4 )Shanghai Maritime University

50

Keys for Reference

Chapter 1 The Ship’s Gyrocompass

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

C A D C A C A C B A C A B C C

16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

A C B C A B A B C B D A B A B

31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

A C D A C D D B B D A A C A C

46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

A A D A B D B C A D C D A C B

61 62 63 64 65 66 67 68 69 70 71 72 73 74 75

C D B C D D A C D D B A C D B

76 77 78 79 80 81 82 83 84 85 86 87 88 89 90

B C A B B D B B C A C D D D A

91 92 93 94 95 96 97 98 99 100 101 102 103 104 105

D D A B D B C A A B D D C A C

106

C

Chapter 2 The Ship’s Echosounder

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

D A A C C A D D D C A A D A A

16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

A A D C A A B C B D A A B C C

31 32 33 34 35 36 37 38 39 40 41

C D D B D B D B A A A

Chapter 3 The Ship’s Speedlog

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

D B B A B D D D A C D D A A B

16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

C C D C B B A B D A A D D A B

31 32 33 34 35 36 37 38 39 40 41 42 43 44

D D B A D B A B D C B C D B

Chapter 4 The Ship’s Magnetic Compass

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

C B C A A B D B B B B C A C A

16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

C D D C B B C B B A C A A A B

31 32 33 34 35 36 37 38 39 40 41 42 43 44 45


51

A A A D A B B C B C C D C B C

46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

B C A D D B B D C A B A B D D

61 62 63 64 65 66 67 68 69 70 71 72 73 74 75

A D B A B C A D D A A C D C A

76 77 78 79 80 81 82 83 84 85 86 87 88 89 90

C A A D A A A C D B A C A A C

91 92 93 94 95 96 97 98 99 100 101 102 103 104 105

B D A B B A A B B A D C C D A

106 107 108 109 110 111 112 113 114

B B A A B B A D D


shanghai revision questions - imla¼Žnone of the angular velocity in both azimuth and tilt of the...

Documents