Multiple Choice Questions and Answers on Docks and Harbour Engineering

01. Which of the following conditions of loading imposes the greatest load on the foundation in case of dry docks?

(A) When the dock is empty
(B) When the dock is empty with the ship of maximum tonnage
(C) When the dock is full of water
(D) When the dock is dry and is under construction

Answer: Option C

02. Which of the following structures are constructed parallel to shore line to develop a demarcating line between land area and water area?

(A) Sea walls, bulk heads and groynes
(B) Sea walls, bulk heads and revetments
(C) Sea walls, revetments and groynes
(D) Bulk heads, revetments and groynes

Answer: Option B

03. In multiple point mooring system, vessel is secured to minimum of

(A) Two points
(B) Four points
(C) Six points
(D) Eight points

Answer: Option B

04. As compared to wall type breakwater, mound type breakwater

(A) Requires skilled labour
(B) Requires low maintenance cost
(C) Requires less material
(D) Results in less damage due to gradual failure

Answer: Option D

05. In a two lane channel, bottom width of channel is given by

(A) Manoeuvring lane + (2 × Bank clearance lane)
(B) (2 × Manoeuvring lane) + (2 × Bank clearance lane)
(C) (2 × Manoeuvring lane) + (2 × Bank clearance lane + ship clearance lane)
(D) Manoeuvring lane + (2 × Bank clearance lane) + ship clearance lane

Answer: Option C

06. In basins subjected to strong winds and tide, the length of the berthing area should not be less than

(A) The length of design vessel
(B) The length of design vessel + 10% clearance between adjacent vessels
(C) The length of design vessel + 20% clearance between adjacent vessels
(D) Twice the length of design vessel

Answer: Option C

07. A ship strikes the berth generally at an angle

(A) 90° with the face of the dock
(B) 45° with the face of the dock
(C) 30° with the face of the dock
(D) 10° with the face of the dock

Answer: Option D

08. If ‘Hs’ is the significant wave height, then the average wave height and highest wave height respectively are given by

(A) 0.6 Hs and 1.67 Hs
(B) 0.6 Hs and 1.87 Hs
(C) 1.27 Hs and 1.87 Hs
(D) 1.27 Hs and 1.67 Hs

Answer: Option B

09. The difference in height between highest high water and lowest low water is called

(A) Mean range
(B) Maximum range
(C) Maximum rise
(D) Mean rise

Answer: Option B

10. When a ship floats at its designed water line, the vertical distance from water line to the bottom of the ship is known as

(A) Beam
(B) Depth
(C) Freeboard
(D) Draft

Answer: Option D

11. By increasing the rise of lock-gates, (i) The length of the lock gate will increase (ii) Transverse stress due to water pressure on the gate will increase (iii) Compressive force on the gate will increase Of these statements

(A) (i) and (ii) are correct
(B) (i) and (iii) are correct
(C) Only (ii) is correct
(D) Only (iii) is correct

Answer: Option A

12. For designing the dock, the proportion of ship load assumed to be borne by keel blocks is

(A) 5/8
(B) 3/8
(C) 3/16
(D) 5/16

Answer: Option A

13. As per Berlin’s formula, the length of wave in metres is given by (Where ‘t’ is the period in seconds for two successive waves to pass the same section.)

(A) 1.3412
(B) 1.5612
(C) 1.7412
(D) 1.9412

Answer: Option B

14. When a wave strikes a vertical breakwater in deep water, it is reflected back and on meeting another advancing wave of similar amplitude merges and rises vertically in a wall of water. This phenomenon is called

(A) Surf
(B) Clapotis
(C) Fetch
(D) Swell

Answer: Option B

15. Select the incorrect statement.

(A) The progress of work in low level method of mound construction is very slow
(B) Barge method of mound construction is economical
(C) In low level method of mound construction, the area of working is limited
(D) In staging method of mound construction, the work is not interrupted even during stormy weather

Answer: Option B

16. Pick up the correct statement from the following:

(A) The regular periodic rise and fall of the surface of the sea, is called tide
(B) The average difference in water level between high tide and low tide at a place, is called tidal range
(C) The movement of water caused by the action of tide, is called a tidal current
(D) All of the above

Answer: Option D

17. The significant wave height is defined is the average height of the

(A) One-third highest waves
(B) One-fourth highest waves
(C) One-fifth highest waves
(D) One-tenth highest waves

Answer: Option A

18. The fixed mooring does not require

(A) Mooring post
(B) Bollard
(C) Anchors
(D) Capstan

Answer: Option C

19. A ship is berthed in a chamber and lifted by principles of buoyancy, such a chamber is called.

(A) Dry dock
(B) Wet dock
(C) Floating dock
(D) Refuge dock

Answer: Option C

20. Due to the impact of water wave on a sea shore structure

(A) Hydrostatic pressure coupled with a strong momentary impact is caused
(B) Vibrations are subjected
(C) Internal pressure is developed
(D) All of the above

Answer: Option D

21. Assertion A: Intervention of undulations in the sea bed reduces the depth of wave at the section. Reason R: No wave can have a height greater than the depth of water through which it passes Select your answer based on the coding system given below:

(A) Both A and R is true and R is correct explanation of A
(B) Both A and R is true but R is not the correct explanation of A
(C) A is true but R is false
(D) A is false but R is true

Answer: Option A

22. Surf zone is:

(A) The fathom line of 10 m depth
(B) The fathom line of 5 m depth
(C) The swell of the sea breaking on the shore or reefs
(D) The coast line attacked by the waves

Answer: Option C

23. Assertion A: Basin walls have to be of much greater height than dock walls. Reason R: Tidal basins are subject to fluctuations of levels due to tidal variations Select your answer based on the coding system given below:

(A) Both A and R is true and R is the correct explanation of A
(B) Both A and R is true but R is not correct explanation of A
(C) A is true but R is false
(D) A is false but R is true

Answer: Option A

24. Pick up the correct statement from the following:

(A) A harbour without any port complex, is called a refuge harbour
(B) A harbour used for fishery, is called fishery harbour
(C) The terminal building of a commercial harbour consists of an administrative block, customs clearance and ware-houses
(D) All the above

Answer: Option D

25. Which of the following structures protects the shore by trapping of littoral drift?

(A) Groynes
(B) Sea walls
(C) Revetments
(D) Moles

Answer: Option A

26. Pick up the correct statement from the following:

(A) The tides at any place occur a little less than 1 hour later, each succeeding day
(B) The influence of the earth’s gravity alone produces level-tidal less sea
(C) The spinning force is maximum at the equator and zero at the poles
(D) All of the above

Answer: Option D

27. The minimum diameter of turning besin, where ships turn by going ahead and without tug assistance should be

(A) L
(B) 1.5 L
(C) 2.0 L
(D) 4.0 L

Where ‘L’ is the length of the largest ship to use the port

Answer: Option D

28. Pick up the correct statement from the following:

(A) The maritime structures should be designed to withstand wave motion of air
(B) The wind vortex results in conical depression in the air surface
(C) A tube of air rotating at hundreds of kilometres per hour forms a tornado
(D) All of the above

Answer: Option D

29. At a given port, the fetch is 400 nautical miles, the maximum height of storm wave will be

(A) 2.073 m
(B) 8.169 m
(C) 9.144 m
(D) 6.8 m

Answer: Option C

30. Pick up the correct statement from the following:

(A) Spring tides are caused at new and full moon
(B) Neap tides are caused when the moon is in her quarters
(C) Spring tides are roughly twice the height of neap tides
(D) All of the above

Answer: Option D

31. Which of the following is a fixed type mooring accessory?

(A) Bollard
(B) Buoys
(C) Cables
(D) Anchors

Answer: Option A

32. According to the recommendations of International Navigational Congress in 1912, the ratio of length to width at the entrance for cargo vessels is

(A) 5.5 and 6.0 to 1
(B) 6.2 and 6.8 to 1
(C) 7.4 and 7.8 to 1
(D) 8.2 and 8.5 to 1

Answer: Option C

33. Consider the following statements. (i) Fender is the cushion provided on the face of the jetty for ships to come in contact, (ii) Slip is the space of water area between two adjacent piers where ships are berthed, (iii) Pier head is a structure constructed near the tip of break water near the harbour entrance. Of the statements

(A) (i) and (ii) are correct
(B) (ii) and (iii) are correct
(C) (i) and (iii) are correct
(D) (i), (ii) and (iii) are correct

Answer: Option D

34. Pick up the correct statement from the following:

(A) For nautical purposes, low water level is generally referred to by the navigators
(B) The depth of the bed of the sea from the surface of water is called sounding
(C) The contour lines on the bed of a water body are called fathoms
(D) All the above

Answer: Option D

35. The maximum harbour depth below lowest low water is generally equal to (i) Loaded draft +1.2 m when bottom is rock (ii) Loaded draft +1.8 m when bottom is soft (iii) Loaded draft +1.2 m when bottom is soft (iv) Loaded draft +1.8 m when bottom is rock Of these statements

(A) (i) and (ii) are correct
(B) (i) and (iii) are correct
(C) (ii) and (iv) are correct
(D) (iii) and (iv) are correct

Answer: Option D

36. If F is the fetch, the straight line distance of open water available in kilometres, the height of the wave in metres is

(A) 0.15 √F
(B) 0.20 √F
(C) 0.28 √F
(D) 0.34 √F

Answer: Option D

37. Minimum width of ship clearance shall be

(A) B or 30 m
(B) 1.5 B or 50 m
(C) 1.5 B
(D) 50 m

Where ‘B’ is beam of the design vessel

Answer: Option A

38. Which one of the following statements is correct?

(A) The soundings are made with respect to the mean low water
(B) The soundings which are below the datum are written in black on the map
(C) The spot heights of the features above datum are written in red on the map
(D) All the above

Answer: Option D

39. Which of the following are repair docks?

(A) Marine railways, dry docks, floating docks, wet docks
(B) Dry docks, wet docks, floating docks, lift docks
(C) Wet docks, floating docks, lift docks, marine railways
(D) Wet docks, lift docks, marine railways, dry docks

Answer: Option C

40. The smoothened surface of the front face of the guay walls, is known as fending which is made of

(A) Granite stone
(B) Timber
(C) Steel
(D) All the above

Answer: Option D

41. Assertion A: Depth and width required at the entrance to a harbour are more than those required in the channel. Reason R: The entrance to a harbour is usually more exposed to waves as compared to the harbour itself. Select your answer based on the coding system given below:

(A) Both A and R is true and R is the correct explanation of A
(B) Both A and R is true but R is not the correct explanation of A
(C) A is true but R is false
(D) A is false but R is true

Answer: Option A

42. Pick up the incorrect statement from the following: In a dry dock block made of hard wood,

(A) Spacing of the blocks is 1.35 m
(B) The lowest block is 1.8 m long 40 cm × 40 cm in cross-section
(C) The middle block is 1.6 m long 40 cm × 40 cm in cross-section
(D) None of these

Answer: Option D

43. Which one of the following lines is used for tying a ship with a dock?

(A) Bow line
(B) Stern line
(C) Spring line
(D) All of these

Answer: Option D

44. In a wet dock system,

(A) Minimum required depth of water for the vessels is maintained (B) Entrance locks are provided with massive gates
(C) The cost of construction is quite heavy
(D) All the above

Answer: Option D

45. Assertion A: Marine structures are made specially bulky and strong. Reason R: Sea insects result in undermining of the hardest and the soundest building material Select your answer based on the coding system given below:

(A) Both A and R is true and R is the correct explanation of A
(B) Both A and R is true but R is not the correct explanation of A
(C) A is true but R is false
(D) A is false but R is true

Answer: Option A

46. The floating mooring does not require

(A) Cables
(B) Anchors
(C) Bollard
(D) Buoy

Answer: Option C

47. A dock:

(A) Is a marine structure for berthing of vessels for loading and unloading cargo and passengers
(B) Is provided with a dock gate
(C) Is provided with an arrangement to pump out water when required
(D) All the above

Answer: Option D

48. Which of the following type of sea walls results in greatest protection of shore structures?

(A) Vertical sea wall
(B) Sea wall with batter
(C) Stepped sea wall

(D) Sea wall with concave face

Answer: Option D

49. Pick up the correct statement from the following:

(A) An artificial barrier which makes the enclosed area safe for anchorage of ships, is known as break water
(B) The break water whose inside is used as a platform for loading and unloading is called a mole
(C) The length of the quay wall is governed by the length of the largest vessel likely to be berthed
(D) All the above

Answer: Option D

50. If the maximum spring rise is 2 m and height of the waves expected is 4 m , then the breakwater height above the datum will be

(A) 2.5 m
(B) 4 m
(C) 5 m
(D) 7 m

Answer: Option D