Docks and Harbor Model(1st)

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

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(i) and (iii) are correct
(i) and (ii) are correct
(ii) and (iv) are correct
(iii) and (iv) are correct

Select the incorrect statement.

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

Which of the following is a fixed type mooring accessory ?

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cables
bollard
buoys
anchors

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

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Free-board
Draft
Beam
Depth

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

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(i) and (iii) are correct
(ii) and (iii) are correct
(i), (ii) and (iii) are correct
(i) and (ii) are correct

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

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Fetch
Swell
Surf
Clapotis

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

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4 m
5 m
2.5 m
7 m

The most popular method of construction of wall breakwaters is

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none of the above
Barge method
Low level method
Staging method

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.

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Both A and R are true but R is not a correct explanation of A.
A is true but R is false.
A is false but R is true.
Both A and R are true and R is the correct explanation of A.

A ship is berthed in a chamber and lifted by principles of buoyancy Such a chamber is called.

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Floating dock
Wet dock
Refuge dock
Dry dock

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:

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A is false but R is true.
A is true but R is false.
Both A and R are true and R is correct explanation of A.
Both A and R are true but R is not the correct explanation of A.

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

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sea wall with concave face
vertical sea wall
sea wall with batter
stepped sea wall

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

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Only (iii) is correct
Only (ii) is correct
(i) and (iii) are correct
(i) and (ii) are correct

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

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1.5612
1.7412
1.9412
1.3412

As per Stevenson’s empirical formula, the approximate value of the height of the wave in metres is given by (where F is the fetch in km.)

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3.4 VF
0.5 VF
0.34 VF
1.5 VF

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

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5/8
3/16
3/8
5/16

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:

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A is true but R is false.
Both A and R are true and R is the correct explanation of A.
Both A and R are true but R is not the correct explanation of A.
A is false but R is true.

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

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(i) and (iii) are correct
(i) and (ii) are correct
(ii) and (iii) are correct
Only (iii) is correct

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

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one – tenth highest waves
one – fourth highest waves
one – third highest waves
one – fifth highest waves

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

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When the dock is empty with the ship of maximum tonnage
When the dock is full of water
When the dock is empty
When the dock is dry and is under construction

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

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(i), (ii) and (iii) are correct
(ii) and (iii) are correct
(i) and (iii) are correct
(i) and (ii) are correct

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

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2.0 L
1.5 L
4.0 L
1 L

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

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0.6 Hs and 1.67 Hs
0.6 Hs and 1.87 Hs
1.27 Hs and 1.87 Hs
1.27 Hs and 1.67 Hs

As compared to wall type breakwater, mound type breakwater

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Requires low maintenance cost
Results in less damage due to gradual failure
Requires skilled labor
Requires less material

Which of the following are repair docks ?

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marine railways, dry docks, floating docks, wet docks
wet docks, floating docks, lift docks, marine railways
wet docks, lift docks, marine railways, dry docks
dry docks, wet docks, floating docks, lift docks

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

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Maximum rise
Maximum range
Mean rise
Mean range

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:

1 Mark(s)

Both A and R are true but R is not the correct explanation of A.
A is false but R is true.
Both A and R are true and R is the correct explanation of A.
A is true but R is false.

If H is the height of the wave expected, then the height of the breakwater is generally taken as

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1.2 H to 1.25 H above the low water level
1.2 H to 1.25 H above the datum
1.2 H to 1.25 H above the high water level
1.2 H to 1.25 H above the mean sea level

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

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Manoeuvring lane + (2 × Bank clearance lane)
(2 × Manoeuvring lane) + (2 × Bank clearance lane + ship clearance lane)
(2 × Manoeuvring lane) + (2 × Bank clearance lane)
Manoeuvring lane + (2 × Bank clearance lane) + ship clearance lane

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

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6.8 m
8.169 m
9.144 m
2.073 m

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

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Sea walls, bulk heads and revetments
Sea walls, revetments and groynes
Sea walls, bulk heads and groynes
Bulk heads, revetments and groynes

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

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Two points
Eight points
Six points
Four points

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

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groynes
moles
revetments
sea walls

Minimum width of ship clearance shall be (where “B” is beam of the design vessel)

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50 m
B or 30 m
1.5 B
1.5 B or 50 m

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:

1 Mark(s)

A is false but R is true.
Both A and R are true and R is the correct explanation of A.
A is true but R is false.
Both A and R are true but R is not correct explanation of A.

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

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The length of design vessel + 10% clearance between adjacent vessels
The length of design vessel + 20% clearance between adjacent vessels
Twice the length of design vessel
The length of design vessel

A ship strikes the berth generally at an angle

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30° with the face of the dock
10° with the face of the dock
45° with the face of the dock
90° with the face of the dock

Docks and Harbor Model(1st) : Question 1 of 37