50 TOP Docks and Harbour Engineering Multiple choice Questions and Answers pdf download

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1. 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 are true and R is the correct explanation of A.
b) Both A and R are 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.
Ans: a

2. 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
Ans: d

Docks and Harbour Engineering MCQs

3. 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
Ans: d

4. 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
Ans: d

5. Dead weight tonnage of a ship
i)    varies with latitude and season
ii)   is more than displacement tonnage
iii)  is the difference between displacement load and displacement light Of these statements
a) i) and ii) are correct
b) ii) and iii) are correct
c) i) and iii) are correct
d) Only iii) is correct
Ans: c

6. 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
Ans: c

7. As per Stevenson's empirical formula, the approximate value of the height of the wave in metres is given by
a) 0.34 VF
b) 0.5 VF
c) 1.5 VF
d) 3.4 VF
where F is the fetch in km.
Ans: a

8. As per Berlin's formula, the length of wave in metres is given by
a) 1.3412
b) 1.5612
c) 1.7412
d) 1.9412
where 't' is the period in seconds for two successive waves to pass the same section.
Ans: b


9. 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 are true and R is correct explanation of A.
b) Both A and R are 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.
Ans: a

10.   Consider the following statements in regard to Beaufort scale for wind speeds,
(i)   The Beaufort number ranges from 1 to 12.
(ii)  Higher Beaufort number indicates higher speed of wind,
(iii) Beaufort number for calm is smallest and for hurricane is highest Of these 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
Ans: b

11. 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
Ans: c

12. In a two lane channel, bottom width of channel is given by
a) Manoeuvring lane + 2 x Bank clearance lane
b) 2 x Manoeuvring lane + 2 x Bank clearance lane
c) 2 x Manoeuvring lane + 2 x Bank clearance lane + ship clearance lane
d) Manoeuvring lane +   2 x Bank clearance lane + ship clearance lane
Ans: c

13.     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
Ans: a

14. 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 cons-truction, the work is not interrupted even during stormy weather.
Ans: b

15. 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 are true and R is the correct explanation of A.
b) Both A and R are 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.
Ans: a

16. The most popular method of construction of wall breakwaters is
a) Barge method
b) Staging method
c) Low level method
d) none of the above
Ans:

17. 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
Ans: d

18. 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
Ans: b

19. 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
Ans: d

20. If H is the height of the wave expected, then the height of the breakwater is generally taken as
a) 1.2 H to 1.25 H above the datum
b) 1.2 H to 1.25 H above the low water level
c) 1.2 H to 1.25 H above the high water level
d) 1.2 H to 1.25 H above the mean sea level
Ans: c

21. Assertion A : Basin walls have to be of much grater 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 are true and R is the correct explanation of A.
b) Both A and R are 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.
Ans: a

22. In multiple point mooring system, vessel is secured to minimum of
a) two points
b) four points
c) six points
d) eight points
Ans: b

23. By increasing the rise of lockgates,
(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
Ans: a

24. Which of the following is a fixed type mooring accessory ?
a) bollard
b) buoys
c) cables
d) anchors
Ans: a

25. 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
Ans: a

26. 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
Ans: b

27. 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
Ans: b

28. 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
Ans: b

29. 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
Ans: d

30. Assertion A : Large size stones are required in stone revetment in shore protection.
Reason R : Resistance of stone to wave force is proportional to its volume and wave force is proportional to the exposed area of the stone.
Select your answer based on the coding system given below.
a) Both A and R are true and R is the correct explanation of A.
b) Both A and R are true but R is not a correct explanation of A.
c) A is true but R is false.
d) A is false but R is true.
Ans: a

31.      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
Ans: c

32.    Which of the following structures protects the shore by trapping of littoral drift?
a) groynes
b) sea walls
c) revetments
d) moles
Ans: a

33. 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
Ans: c

34. 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
Ans: a

35. 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
Ans: d

36. 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 a 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
Ans: d

37. 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
Ans: c

Latest Docks and Harbour Engineering Objective type Questions for freshers

TOP 30 Harbour Engineering Interview Questions and Answers pdf free download

Real Time Harbour Engineering Interview Questions and Answers PDF

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1. Explain About Harbours?
Harbours:  A harbour can be defined as a sheltered area of the sea in which vessels could be launched, built or taken for repair; or could seek refuge in time of storm; or provide for loading and unloading of cargo and passengers.Harbours are broadly classified as:
 Natural harbours.
 Semi-natural harbours.
 Artificial harbours.

2. Explain About Natural Harbours?
Natural harbours:
Natural formations affording safe discharge facilities for ships on sea coasts, in the form of creeks and basins, are called natural harbours. With the rapid development of navies engaged either in commerce or war,improved accommodation and facilities for repairs, storage of cargo and connected amenities had to be provided in natural harbours.
The size and draft of present day vessels have necessitated the works improvement for natural harbours.
The factors such as local geographical features, growth of population, development of the area, etc. have made the natural harbours big and attractive. Bombay and Kandla are, examples of natural harbours

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3. Explain About Semi-natural Harbours?
Semi-natural harbours: This type of harbour is protected on sides by headlands protection and it requires man-made protection only at the entrance. Vishakhapatnam is a semi-natural harbour.

4. Explain Artificial Harbours?
Artificial harbours:
Where such natural facilities are not available, countries having a seaboard had to create or construct such shelters making use of engineering skill and methods, and such harbours are called artificial or man-made harbours.
Madras is an artificial harbour.
Thus, a naval vessel could obtain shelter during bad weather within a tract or area of water close to the shore, providing a good hold for anchoring, protected by natural or artificial harbour walls against the fury of storms.

5. What Is Natural Roadsteads And Artificial Roadsteads?
Natural roadsteads:  A deep navigable channel with a protective natural bank or shoal to seaward is a good example of a natural roadstead. A confined area naturally enclosed by islands as in a creek if available is known as a circumscribed natural roadstead.
Artificial roadsteads:  These may be created suitably by constructing a breakwater or wall parallel to the coast or curvilinear from the coast


6. What Is The Accessibility And Size Of Harbours?
Accessibility and size of harbours :
Accessibility depends on the location of the harbours.
The harbour entrance should be designed and located for quick easy negotiation by ships, overtaken by storms.
At the same time, it should be narrow enough not to expose the harbour to the effects of the stormy sea.
Maximum dimensions upto 180 have been adopted
The entrance is generally placed of the sea, with a passage to the interior of the harbour so arranged as to minimize the effect of rough seas.
Thus; the size is determined by:
Accommodation required.
Convenience for maneuvering and navigation.
Adaptability to natural features.

7. How Do We Do Site Selection For A Harbour?
The guiding factors which play a great role in choice of site for a harbour are as follows :
Availability of cheap land and construction materials.
Transport and communication facilities.
Natural protection from winds and waves.
Industrial development of the locality.
Sea-bed subsoil and foundation conditions.
Traffic potentiality of harbour.
Availability of electrical energy and fresh water.
Favorable marine conditions.
Defence and strategic aspects.

8. Explain How The Shape Of A Harbour Should Be?
The following principles should be kept in mind:
In order to protect the harbour from the sea waves, one of the pier heads should project a little beyond the other.
Inside the pier heads, the width should widen very rapidly.
The general shape of the harbours should be obtained by a series of straight lengths and no re-entrant angle should be allowed.

9. Explain About Harbour Planning?
It is necessary to carry out a thorough survey of the neighbourhood including the foreshore and the depths of water in the vicinity
The borings on land should also be made so as to know the probable subsurface conditions on land. It will be helpful in locating the harbour works correctly.
The nature of the harbour, whether sheltered or not, should be studied.
The existence of sea insect undermine the foundations should be noted.
The problem of silting or erosion of coastline should be carefully studied.
The natural metrological phenomenoa should be studied at site especially with respect to frequency of storms, rainfall, range of tides, maximum and, minimum temperature and of winds, humidity, direction and velocity of currents, etc.

10. Explain About Ports And Classification Of Ports?
Ports:  The term port is used to indicate a harbour where terminal facilities, such a stores, landing of passengers and cargo, etc. are added to it.  Thus, a harbour consists of the waterways and channels as far as the pier head lines and a port includes everything on the landward side of those lines i.e. piers, slips, wharves, sheds, tracks, handling equipment, etc.
Classification of ports: Depending upon the location, the ports can be classified as;
Canal ports.
River ports.
Sea ports.

11. Explain The Requirement For Port Design?
Port design: The design of a port should be made while keeping in mind the following requirements:
 The entrance channel should be such that the ships can come in and go out easily.
 The ships should be able to turn in the basin itself.
 The alignment of quays should be such that the ships can come along side easily even when there is an on-shore wind.
 The width behind the quay should be sufficient to deal with the goods.
 There should be enough provision for railway tracks to take care for loading and unloading of cargo.

12. What Are The Requirements For Good Port Design?
It should be centrally situated for the hinterland. For a port, the hinterland is that part of the country behind it which can be served with economy and efficiency by the port.
 It should get good tonnage i .e. charge per tonne of cargo handled by it.
 It should have good communication with the rest of country.
 It should be populous
 It should be advance in culture, trade and industry.
 It should be a place of defence and for resisting the sea-borne invasion
 It should command valuable and extensive trade.
 It should be capable of easy, smooth and economic development.
 It should afford shelter to all ships and at all seasons of the years
 It should provide the maximum facilities to all the visiting ships including the servicing of ships.

13. Explain About Tides And Waves?
Tides:  Tides on the coast-line are caused by the sun and moon.  The effect of tides is to artificially raise and lower the mean sea level during certain stated periods.  This apparent variation of mean sea level is known as the tidal range.

Spring tides and Neap tides:  At new and full moon or rather a day or two after (or twice in each lunar month), the tides rise higher and fall lower than at other times and these are called Spring tides.  Also one or two days after the moon is in her quarter i.e. about seven days from new and full moons (twice in a lunar month), the tides rise and fall less than at other times and are then called neap tides.

Waves and wind:  The ‘sea wave’ is by far the most powerful force acting on harbour barriers and against which the engineer has to contend.  The wave has the impulse of a huge battering ram and equipped with the point of a pick axe and chisel edge”.  It is the most in compressible natural phenomena.  The formation of storm waves takes place in the open sea due to the action of wind.

Water waves are of two kinds:

Waves of oscillation
Waves of translation;
 The former are stationary, while the latter possess forward motion.  But all translatory waves originally start as waves of oscillation and, become translatory by further wind action.  The harbour engineer’s main concern is the translatory wave.

14. What Is Breakwater And Explain Its Alignment?
Breakwaters:  The protective barrier constructed to enclose harbours and to keep the harbour waters undisturbed by the effect of heavy and strong seas are called breakwaters.
Alignment:  A good alignment for a breakwater is to have straight converging arms so that the angle of inter section does not exceed 60 degrees.  It is desirable to avoid straight parallel or diverging arms running out to sea.

15. Explain The Design Of Breakwaters?
Design of breakwaters:
Following information should he collected before the design of a breakwater:
Character of coastal currents
Cost and availability of materials of construction
Directions and force of prevailing winds
Nature of the bottom or foundation
Probable maximum height, force and intensity of waves. !
The three important rules to be observed in the design of a breakwater are as under:
The design should be based on the extreme phenomena of the wind and waves, and not on the mean or the average.
The height of the wave should he determined by Using the equation H = 034¥Fand the height of wall should be decided accordingly by making sufficient allowance for freeboard.
It should be seen that the material in the foundation is not subject to scour.

16. Explain The Detrimental Forces Acting On Breakwaters?
Detrimental forces acting on breakwaters:

Hydrostatic force:
This force reduces the apparent weight and hence, the marine structures suffer these losses to a great extent unless the foundations are absolutely impervious.
External forces:
The intensity of external forces, especially wind and wave action, is enormous.
The power of wind produces vibrations in the masonry structure and weakens the different courses of masonry.
In a similar way, the wave when it recedes induces ‘suction action and it results in the erosion of the foundation unless it is made safe and secure.

17. Explain The Classification Of Breakwaters?
Breakwaters are classified mainly into three types:
 Heap or mound breakwater.
 Mound with superstructure.
 Upright wall breakwater.

18. Explain Heap Or Mound Breakwater?
Heap or mound breakwater :
It is a heterogeneous assemblage of natural rubble, undressed stone blocks, rip rap, supplemented in many cases by artificial blocks of huge bulk and weight, the whole being deposited without any regard to bond or bedding.
This is the simplest type and is constructed by tipping or dumping of rubble stones into the sea till the heap or mound emerges out of the water, the mound being consolidated and its side slopes regulated by the action of the waves.
The quantity of rubble depends upon the depth, rise of tides and waves and exposure.
On exposed sites, the waves gradually drag down the mound, giving it a flat slope on the sea face.
As far as possible, such flattening has to he protected.
The disturbing action of the waves is the most between the high and low water levels.
Consequently, all protective methods are adopted above the low water level.
Protection is also very necessary to the top of the mound and outer or exposed face.

19. What Are Wharves?
Wharves:  Platforms or landing places are necessary for ships to come, close enough to the shore, for purposes of embarkation, disembarkation, etc. at the same time.  These platform locations should give sufficient depth of water for the ship to float.  Such platforms are, called wharves.
They are built out into or on to. the water
Thus, a wharf affords a working platform alongside the ship in continuity of the shore.
A wharf is quay but the term wharf is generally used for an open structure of piles or posts with bracings, jutting from the shore towards the sea.
A wharf may be a sheet pile wall or it may consist of a piled projection with or without artificial retention of soil some distance behind or it may be a gravity wall.
Wharves may either be parallel to the shore and abutting against it or they may project into the water either at right angles or oblique to the shore.
The former type is adopted at places where depth of water is sufficient for the ships to berth, say 10 m to 12 m
The latter type is adopted at places where depth of water near the shore is not enough for the ships to enter safely.
The level of wharf should be above the high water level. But at the same time, it should be economical to load the vessels when the water level is low.
Wharf should act as a unit when there is an impact from any vessel.
Hence, it should be properly braced and bolted. It is desirable to provide rounded corners for wharves which art likely to be used by large vessels.
Such a construction will result in a smooth entry of vessels into the slips

20. What Are Piers?
Piers :
The structures which are built perpendicular or oblique to the shore of a river or sea are known as piers.
In the sea the piers are constructed where the sea is not deep and the natural harbour is not convenient for allowing the ships to berth adjacent to the shore.
In many cases, the piers are constructed with piles, columns and braces leaving good space for the ocean current to flow without causing any obstruction.
The dimensions of a pier should be worked out very carefully.
Its length should be sufficient to accommodate the longest ship likely to take its advantage.
In other words, it should project beyond the bow or stern of the ship so as to
protect its hull. Its width should be sufficient to satisfy its utility.
It can be stated that the pier should be of sufficient width to allow easy unloading of cargo without any undue delay.

21. What Is Quays?
Quays : Wharves along and parallel to the’ shore, are generally called quays and their protection walls are called quay walls

22. Explain The Design Process Of Quay Walls?
They are built to retain and protect the embankment or filling:
Factors affecting the design are as follows
Character of foundation;
Pressure due to water that finds its way to the real of the wall;
Effect of buoyancy for the portion of the wall submerged;
Earth pressure at rear;
Weight of the wall itself;
live load of vehicles passing on the platform at the rear;
dead load of the goods stored on the platform;
force of impact of vessels; etc.
 Quay wails are designed similar to retaining walls; But on the water side, they are subject to varying water pressure (owing to level variations due to tides), and on the land side, earth and contained water pressures, with proper allowances for surcharge.

23. Explain About Jetties?
Jetties :  These are the structures in the form of piled projections and they are built out from the shore to deep water and they may be constructed either for a navigable river or in the sea.
In rivers, the jetties divert the current away from the river bank and thus, the scouring action is prevented.
As the current is diverted to deep waters, the navigation is also controlled.
In the sea, the jetties are pr at places where harbour entrance is affected by littoral drift or the sea is shallow for a long distance.
Thus, they extend from the shore to the deep sea to receive the ships.
In a limiting sense, a jetty is defined as a narrow structure projecting from the shore into water with berths on one or both sides and sometimes at the end also.
 Jetties are exposed to severe wave action and their structural design is similar to that of breakwater.
However, the designed standards may be released to a certain extent due to the fact that the jetties are usually built normal to the most dangerous wave front.
The impact caused by the berthing ships will depend on the skill of the berthing officer, local condition of currents, wind, etc.
The berthing velocity depends upon the condition of approach, wind, etc. and it decreases with the increase in the size of the ships

24. What Is A Fender?
Fender :    The cushion which is provided on the face of jetty for ships to come in contact is known as fender.
It is provided for various forms and is made of different materials.
The common material used as fender for jetties is the framework of timber pile driven into the sea bed at a short distance from the jetty and filling the space with coiled rope, springs, rubber, buffers, etc.
The fender system controls the relative motion between dock and ship caused by wind and waves.
Hence, it also prevents the paint of ships being damaged.
For the purpose of classification, the fenders can be classified in the following four categories:

Rubbing strips.
Timber grill.
Gravity-type fendering system.
Rubber tendering.

25. Explain About Rubbing Strips?
Rubbing strips: In its simplest form, the fender system adopted for small vessels consists of rubbing strips of timber, coir padding or used rubber tyres  It is also convenient to use pneumatic inflated tyres, either by suspending them or installing them at right angles to jetty face.  The inflated big-size tyres are useful to transfer cargo between mother ship and daughter ships.  The pneumatic rubber fenders are very useful for transferring cargo from ship to ship of big sizes.

26. Explain About Timber Grill?
Timber grill:  This system consists merely of vertical and horizontal timber members fixed to the face piles.  This is a simple form of fender and to make it more effective, energy fender piles may be driven along the jetty face with cushion or spring inserted between them.

27. Explain Gravity-type Fendering System?
Gravity-type fendering system:  As the ships grew in size, this s came into force and in its simplest form, it consists of a weighty fender which is raised up when there is an impact of the berthing ship and thus, the initial energy of shock, is absorbed.

28. What Is Rubber Tendering?
Rubber tendering:  Due to the development of rubber technology and with, further growth in ship size, rubber fendering is preferred at present.  The shapes of rubber fenders may be cylindrical, square, V-shape or cell type.

29. Explain About Signals?
Signals: The approach channel of a modern port should be clearly defined o demarcated by the provision of suitable signals.

Thus, signals will be required at the following places:

 Light ships have to be provided at important changes in the direction of the route of ships.
 Lighted beacons are to be fixed on river banks
 Buoys are required at entrance channels to ports
 Requirements of a signal :

It should be conspicuously visible, from a long distance.
It should not vary in character and should be positively recognizable.
It should be simple for identification.

30. What Are The Types Of Signals?
Types of signals: The signals are broadly divided into the following three categories

Light signals
Fog signals
Audible signals.
The first classification of light signals is very important. Fog signals and audible signals are occasionally used. 

Latest Harbour Engineering Interview Questions for freshers and Experienced pdf

30 TOP Docks and Harbour Engineering Interview Questions and Answers pdf download

Real Time Dock and Harbour Engineering Interview Questions and Answers PDF

=> Also Read Docks and Harbour Engineering MCQs

1. Explain About Harbours?
Harbours:  A harbour can be defined as a sheltered area of the sea in which vessels could be launched, built or taken for repair; or could seek refuge in time of storm; or provide for loading and unloading of cargo and passengers.Harbours are broadly classified as:
 Natural harbours.
 Semi-natural harbours.
 Artificial harbours.

2. Explain About Natural Harbours?
Natural harbours:
Natural formations affording safe discharge facilities for ships on sea coasts, in the form of creeks and basins, are called natural harbours. With the rapid development of navies engaged either in commerce or war,improved accommodation and facilities for repairs, storage of cargo and connected amenities had to be provided in natural harbours.
The size and draft of present day vessels have necessitated the works improvement for natural harbours.
The factors such as local geographical features, growth of population, development of the area, etc. have made the natural harbours big and attractive. Bombay and Kandla are, examples of natural harbours

Dock and Harbour Engineering Interview Questions

3. Explain About Semi-natural Harbours?
Semi-natural harbours: This type of harbour is protected on sides by headlands protection and it requires man-made protection only at the entrance. Vishakhapatnam is a semi-natural harbour.

4. Explain Artificial Harbours?
Artificial harbours:
Where such natural facilities are not available, countries having a seaboard had to create or construct such shelters making use of engineering skill and methods, and such harbours are called artificial or man-made harbours.
Madras is an artificial harbour. 
Thus, a naval vessel could obtain shelter during bad weather within a tract or area of water close to the shore, providing a good hold for anchoring, protected by natural or artificial harbour walls against the fury of storms.

5. What Is Natural Roadsteads And Artificial Roadsteads?
Natural roadsteads:  A deep navigable channel with a protective natural bank or shoal to seaward is a good example of a natural roadstead. A confined area naturally enclosed by islands as in a creek if available is known as a circumscribed natural roadstead.
Artificial roadsteads:  These may be created suitably by constructing a breakwater or wall parallel to the coast or curvilinear from the coast

6. What Is The Accessibility And Size Of Harbours?
Accessibility and size of harbours :
Accessibility depends on the location of the harbours.
The harbour entrance should be designed and located for quick easy negotiation by ships, overtaken by storms.
At the same time, it should be narrow enough not to expose the harbour to the effects of the stormy sea.
Maximum dimensions upto 180 have been adopted
The entrance is generally placed of the sea, with a passage to the interior of the harbour so arranged as to minimize the effect of rough seas.
Thus; the size is determined by:
Accommodation required.
Convenience for maneuvering and navigation.
Adaptability to natural features.

7. How Do We Do Site Selection For A Harbour?
The guiding factors which play a great role in choice of site for a harbour are as follows :
Availability of cheap land and construction materials.
Transport and communication facilities.
Natural protection from winds and waves.
Industrial development of the locality.
Sea-bed subsoil and foundation conditions.
Traffic potentiality of harbour.
Availability of electrical energy and fresh water.
Favorable marine conditions.
Defence and strategic aspects.

8. Explain How The Shape Of A Harbour Should Be?
The following principles should be kept in mind:
In order to protect the harbour from the sea waves, one of the pier heads should project a little beyond the other.
Inside the pier heads, the width should widen very rapidly.
The general shape of the harbours should be obtained by a series of straight lengths and no re-entrant angle should be allowed.

9. Explain About Harbour Planning?
It is necessary to carry out a thorough survey of the neighbourhood including the foreshore and the depths of water in the vicinity
The borings on land should also be made so as to know the probable subsurface conditions on land. It will be helpful in locating the harbour works correctly.
The nature of the harbour, whether sheltered or not, should be studied.
The existence of sea insect undermine the foundations should be noted.
The problem of silting or erosion of coastline should be carefully studied.
The natural metrological phenomenoa should be studied at site especially with respect to frequency of storms, rainfall, range of tides, maximum and, minimum temperature and of winds, humidity, direction and velocity of currents, etc.

10. Explain About Ports And Classification Of Ports?
Ports:  The term port is used to indicate a harbour where terminal facilities, such a stores, landing of passengers and cargo, etc. are added to it.  Thus, a harbour consists of the waterways and channels as far as the pier head lines and a port includes everything on the landward side of those lines i.e. piers, slips, wharves, sheds, tracks, handling equipment, etc.
Classification of ports: Depending upon the location, the ports can be classified as;
Canal ports.
River ports.
Sea ports.

11. Explain The Requirement For Port Design?
Port design: The design of a port should be made while keeping in mind the following requirements:
 The entrance channel should be such that the ships can come in and go out easily.
 The ships should be able to turn in the basin itself.
 The alignment of quays should be such that the ships can come along side easily even when there is an on-shore wind.
 The width behind the quay should be sufficient to deal with the goods.
 There should be enough provision for railway tracks to take care for loading and unloading of cargo.

12. What Are The Requirements For Good Port Design?
It should be centrally situated for the hinterland. For a port, the hinterland is that part of the country behind it which can be served with economy and efficiency by the port.
 It should get good tonnage i .e. charge per tonne of cargo handled by it.
 It should have good communication with the rest of country.
 It should be populous
 It should be advance in culture, trade and industry.
 It should be a place of defence and for resisting the sea-borne invasion
 It should command valuable and extensive trade.
 It should be capable of easy, smooth and economic development.
 It should afford shelter to all ships and at all seasons of the years
 It should provide the maximum facilities to all the visiting ships including the servicing of ships.

13. Explain About Tides And Waves?
Tides:  Tides on the coast-line are caused by the sun and moon.  The effect of tides is to artificially raise and lower the mean sea level during certain stated periods.  This apparent variation of mean sea level is known as the tidal range.

Spring tides and Neap tides:  At new and full moon or rather a day or two after (or twice in each lunar month), the tides rise higher and fall lower than at other times and these are called Spring tides.  Also one or two days after the moon is in her quarter i.e. about seven days from new and full moons (twice in a lunar month), the tides rise and fall less than at other times and are then called neap tides.

Waves and wind:  The ‘sea wave’ is by far the most powerful force acting on harbour barriers and against which the engineer has to contend.  The wave has the impulse of a huge battering ram and equipped with the point of a pick axe and chisel edge”.  It is the most in compressible natural phenomena.  The formation of storm waves takes place in the open sea due to the action of wind.

Water waves are of two kinds:

Waves of oscillation
Waves of translation;
 The former are stationary, while the latter possess forward motion.  But all translatory waves originally start as waves of oscillation and, become translatory by further wind action.  The harbour engineer’s main concern is the translatory wave.

14. What Is Breakwater And Explain Its Alignment?
Breakwaters:  The protective barrier constructed to enclose harbours and to keep the harbour waters undisturbed by the effect of heavy and strong seas are called breakwaters.
Alignment:  A good alignment for a breakwater is to have straight converging arms so that the angle of inter section does not exceed 60 degrees.  It is desirable to avoid straight parallel or diverging arms running out to sea.

15. Explain The Design Of Breakwaters?
Design of breakwaters:
Following information should he collected before the design of a breakwater:
Character of coastal currents
Cost and availability of materials of construction
Directions and force of prevailing winds
Nature of the bottom or foundation
Probable maximum height, force and intensity of waves. !
The three important rules to be observed in the design of a breakwater are as under:
The design should be based on the extreme phenomena of the wind and waves, and not on the mean or the average.
The height of the wave should he determined by Using the equation H = 034¥Fand the height of wall should be decided accordingly by making sufficient allowance for freeboard.
It should be seen that the material in the foundation is not subject to scour.

16. Explain The Detrimental Forces Acting On Breakwaters?
Detrimental forces acting on breakwaters:

Hydrostatic force:
This force reduces the apparent weight and hence, the marine structures suffer these losses to a great extent unless the foundations are absolutely impervious.
External forces:
The intensity of external forces, especially wind and wave action, is enormous.
The power of wind produces vibrations in the masonry structure and weakens the different courses of masonry.
In a similar way, the wave when it recedes induces ‘suction action and it results in the erosion of the foundation unless it is made safe and secure.

17. Explain The Classification Of Breakwaters?
Breakwaters are classified mainly into three types:
 Heap or mound breakwater.
 Mound with superstructure.
 Upright wall breakwater.

18. Explain Heap Or Mound Breakwater?
Heap or mound breakwater :
It is a heterogeneous assemblage of natural rubble, undressed stone blocks, rip rap, supplemented in many cases by artificial blocks of huge bulk and weight, the whole being deposited without any regard to bond or bedding.
This is the simplest type and is constructed by tipping or dumping of rubble stones into the sea till the heap or mound emerges out of the water, the mound being consolidated and its side slopes regulated by the action of the waves.
The quantity of rubble depends upon the depth, rise of tides and waves and exposure.
On exposed sites, the waves gradually drag down the mound, giving it a flat slope on the sea face.
As far as possible, such flattening has to he protected.
The disturbing action of the waves is the most between the high and low water levels.
Consequently, all protective methods are adopted above the low water level.
Protection is also very necessary to the top of the mound and outer or exposed face.

19. What Are Wharves?
Wharves:  Platforms or landing places are necessary for ships to come, close enough to the shore, for purposes of embarkation, disembarkation, etc. at the same time.  These platform locations should give sufficient depth of water for the ship to float.  Such platforms are, called wharves.
They are built out into or on to. the water
Thus, a wharf affords a working platform alongside the ship in continuity of the shore.
A wharf is quay but the term wharf is generally used for an open structure of piles or posts with bracings, jutting from the shore towards the sea.
A wharf may be a sheet pile wall or it may consist of a piled projection with or without artificial retention of soil some distance behind or it may be a gravity wall.
Wharves may either be parallel to the shore and abutting against it or they may project into the water either at right angles or oblique to the shore.
The former type is adopted at places where depth of water is sufficient for the ships to berth, say 10 m to 12 m
The latter type is adopted at places where depth of water near the shore is not enough for the ships to enter safely.
The level of wharf should be above the high water level. But at the same time, it should be economical to load the vessels when the water level is low.
Wharf should act as a unit when there is an impact from any vessel.
Hence, it should be properly braced and bolted. It is desirable to provide rounded corners for wharves which art likely to be used by large vessels.
Such a construction will result in a smooth entry of vessels into the slips

20. What Are Piers?
Piers :
The structures which are built perpendicular or oblique to the shore of a river or sea are known as piers.
In the sea the piers are constructed where the sea is not deep and the natural harbour is not convenient for allowing the ships to berth adjacent to the shore.
In many cases, the piers are constructed with piles, columns and braces leaving good space for the ocean current to flow without causing any obstruction.
The dimensions of a pier should be worked out very carefully.
Its length should be sufficient to accommodate the longest ship likely to take its advantage.
In other words, it should project beyond the bow or stern of the ship so as to
protect its hull. Its width should be sufficient to satisfy its utility.
It can be stated that the pier should be of sufficient width to allow easy unloading of cargo without any undue delay.

21. What Is Quays?
Quays : Wharves along and parallel to the’ shore, are generally called quays and their protection walls are called quay walls

22. Explain The Design Process Of Quay Walls?
They are built to retain and protect the embankment or filling:
Factors affecting the design are as follows
Character of foundation;
Pressure due to water that finds its way to the real of the wall;
Effect of buoyancy for the portion of the wall submerged;
Earth pressure at rear;
Weight of the wall itself;
live load of vehicles passing on the platform at the rear;
dead load of the goods stored on the platform;
force of impact of vessels; etc.
 Quay wails are designed similar to retaining walls; But on the water side, they are subject to varying water pressure (owing to level variations due to tides), and on the land side, earth and contained water pressures, with proper allowances for surcharge.

23. Explain About Jetties?
Jetties :  These are the structures in the form of piled projections and they are built out from the shore to deep water and they may be constructed either for a navigable river or in the sea.
In rivers, the jetties divert the current away from the river bank and thus, the scouring action is prevented.
As the current is diverted to deep waters, the navigation is also controlled.
In the sea, the jetties are pr at places where harbour entrance is affected by littoral drift or the sea is shallow for a long distance.
Thus, they extend from the shore to the deep sea to receive the ships.
In a limiting sense, a jetty is defined as a narrow structure projecting from the shore into water with berths on one or both sides and sometimes at the end also.
 Jetties are exposed to severe wave action and their structural design is similar to that of breakwater.
However, the designed standards may be released to a certain extent due to the fact that the jetties are usually built normal to the most dangerous wave front.
The impact caused by the berthing ships will depend on the skill of the berthing officer, local condition of currents, wind, etc.
The berthing velocity depends upon the condition of approach, wind, etc. and it decreases with the increase in the size of the ships

24. What Is A Fender?
Fender :    The cushion which is provided on the face of jetty for ships to come in contact is known as fender.
It is provided for various forms and is made of different materials.
The common material used as fender for jetties is the framework of timber pile driven into the sea bed at a short distance from the jetty and filling the space with coiled rope, springs, rubber, buffers, etc.
The fender system controls the relative motion between dock and ship caused by wind and waves.
Hence, it also prevents the paint of ships being damaged.
For the purpose of classification, the fenders can be classified in the following four categories:

Rubbing strips.
Timber grill.
Gravity-type fendering system.
Rubber tendering.

25. Explain About Rubbing Strips?
Rubbing strips: In its simplest form, the fender system adopted for small vessels consists of rubbing strips of timber, coir padding or used rubber tyres  It is also convenient to use pneumatic inflated tyres, either by suspending them or installing them at right angles to jetty face.  The inflated big-size tyres are useful to transfer cargo between mother ship and daughter ships.  The pneumatic rubber fenders are very useful for transferring cargo from ship to ship of big sizes.

26. Explain About Timber Grill?
Timber grill:  This system consists merely of vertical and horizontal timber members fixed to the face piles.  This is a simple form of fender and to make it more effective, energy fender piles may be driven along the jetty face with cushion or spring inserted between them.

27. Explain Gravity-type Fendering System?
Gravity-type fendering system:  As the ships grew in size, this s came into force and in its simplest form, it consists of a weighty fender which is raised up when there is an impact of the berthing ship and thus, the initial energy of shock, is absorbed.

28. What Is Rubber Tendering?
Rubber tendering:  Due to the development of rubber technology and with, further growth in ship size, rubber fendering is preferred at present.  The shapes of rubber fenders may be cylindrical, square, V-shape or cell type.

29. Explain About Signals?
Signals: The approach channel of a modern port should be clearly defined o demarcated by the provision of suitable signals.

Thus, signals will be required at the following places:
 Light ships have to be provided at important changes in the direction of the route of ships.
 Lighted beacons are to be fixed on river banks
 Buoys are required at entrance channels to ports

Requirements of a signal :
It should be conspicuously visible, from a long distance.
It should not vary in character and should be positively recognizable.
It should be simple for identification.

30. What Are The Types Of Signals?
Types of signals: The signals are broadly divided into the following three categories
Light signals
Fog signals
Audible signals.
The first classification of light signals is very important. Fog signals and audible signals are occasionally used. 

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