Planning and design of facilities for ships to discharge or receive cargo and passengers.
REQUIREMENTS OF A GOOD HARBOR
Classification of Harbor
Classification of breakwaters:
VISHNU VIJAYANHOD-Department Of Civil Engineering um Baselios Mathews II College of Engineering
3. REQUIREMENTS OF A GOOD HARBOR:
– THE DEPTH OF A HARBOR SHOULD BE SUFFICIENT
FOR EVERY TYPE OF VISITING SHIPS.
– THE BOTTOM OF HARBOR SHOULD PROVIDE SECURED
ANCHORAGE TO HOLD THE SHIPS AGAINST HIGH
– TO PREVENT DESTRUCTIVE WAVE ACTION, BREAK
WATER ARE PROVIDED.
– THE ENTRANCE OF A HARBOR SHOULD BE WIDE
ENOUGH TO PROVIDE THE EASY PASSAGE OF SHIPS.
10. HARBOR OF REFUGE:
• The harbor used for ships in storms or
Good anchorage and safe and easy access
from the sea.
e.g: DOVER IN ENGLAND
11. COMMERCIAL HARBOR:
Facilities for loading and
unloading of cargo are
IT MAY BE ,
1. Part of bigger complex
2. Independent unit or single
3. Terminal as oil terminal, coal
19. Size of harbor
• Size of harbor depends on number and size of ships
likely to use the harbor at one time.
• The harbor entrance should be designed and located for
quick and easy navigation ships.
• It should be narrow enough not expose the harbor to
the effect of the stormy area.
• Maximum dimension up to 180 M have been adopted.
• Modern ships 275 m to 300 m long
• 30- 40 m wide. maneuvering4/28/2020 19
20. Size determined by
• Accommodation required
• Convenience for maneuvering and navigation
• Adaptability to natural features
21. Entrance width
• Narrow Entrance will protect the interior
• In artificial harbor break water protects the
high intensity of waves from sea.
• Waves from out side harbor setup diminutive
waves inside the harbor depending on the
22. Stevens Formula For Entrance width
• Empirical formula suggested by Stevenson with a
limited application is some times used.
• h =
− 0.027 4 𝐷 (1+
• H : height of unrestricted wave at the entrance
• l=width of entrance mouth in M
• L= Width of harbor in M
• h=reduced ht of diminutive wave inside
• This formula applicable to a well protected harbor by a
vertical sea wall ,distance of 15 m
23. Shape of harbor
• principle to follow for deciding shape.
• Protect harbor from sea waves , one of the
pier head project little beyond others.
• Inside the pier heads, the width should widen
• General shape obtained by a series of straight
length and no re-entrants angle should be
24. Harbor Depth
• Depth generally determined by the following
• D= D1+
• D1= Draft of the largest ship to be
• D2= allowance for squat of the moving ship.
• H = height of storm waves
• Maximum harbor depth= loaded draft +1.2 for
bottom soft rock. 1.8 for hard rock.
25. Site selection
1.Availability of cheap land and construction
2. Transport and communication facilities
3. Natural protection from winds and waves
4. Industrial development of the locality
5. Sea-bed subsoil and foundation conditions
6. Traffic potentiality of harbor
7. Availability of electrical energy and fresh water
8. Favorable marine conditions
9. Defense and strategic aspects
• Wind : Air in motion is known as wind.
• Direction and speed should taken from the
which the wind blow.
• Speed of wind expressed as knots.
• 1 knots = 1.852 kmph.
• The alternate rising and falling of the sea,
usually twice in each lunar day at a particular
place, due to the attraction of the moon and
29. A lunar day
• A lunar day is the period of time it takes for
the Earth's Moon to complete one full
rotation on its axis with respect to the Sun
• The winds cause waves on the surface of the
ocean (and on lakes).
• The wind transfers some of its energy to the
water, through friction between the air
molecules and the water molecules.
• Stronger winds (like storm surges) cause
31. HEIGHT AND LENGTH OF WAVES
• A crest is the point on a wave with
the maximum value or upward
displacement within a cycle..
• A trough is the opposite of a crest,
so the minimum or lowest point in
• Fetch, area of ocean or lake
surface over which the wind blows
in an essentially constant direction,
thus generating waves. The term
also is used for fetch length (KM),
which is the horizontal distance
over which wave-generating winds
32. • HEIGHT OF THE WAVE IN METERS = 0.34 𝐹
• F Is the fetch in km.(Stevenson formula)
33. WAVE ACTION
• A sea wave when braking
against in a obstacle or
marine structure which
produce various force.
• Air compression
• Water harmer
34. coastal current
• Long shore currents are
generated when a "train"
of waves reach
the coastline and release
bursts of energy.
• which runs parallel to the
shoreline. This type
of current is called a
“long shore current.”
35. Littoral drift
Longshore drift is a geographical
process that consists of the
transportation of sediments (clay, silt,
sand and shingle) along a coast at an
angle to the shoreline, which is
dependent on prevailing wind
direction, swash and backwash.
This process occurs in the littoral zone,
and in or close to the surf zone. The
process is also known as littoral
drift, longshore current or longshore
36. Break water
• The protective barrier
constructed to enclose
harbors and to keep the
The structure constructed to
protect harbor from storm
They are generally stone
Through this shelter, to manipulate the littoral/sand transport
conditions and thereby to trap some sand entrance inside the
37. Design of breakwaters:
Following information should he collected before
the design of a breakwater:
1.Character of coastal currents
2.Cost and availability of materials of construction
3.Directions and force of prevailing winds
4.Nature of the bottom or foundation
5.Probable maximum height, force and intensity of
38. Classification of breakwaters:
• Breakwaters are classified mainly into three
A) Rubble Mound Breakwaters
B) Vertical-wall breakwaters
C) Floating breakwaters
39. Rubble Mound Breakwaters
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
40. Rubble Mound Breakwaters
• A breakwater constructed by a heterogeneous
assemblage of natural rubble or undressed stone.
• When water depths are large Rubble Break Water
may be uneconomical in view of huge volume of
• Built up to water depth of 50m.
• Not suitable when space is a problem. If the
harbor side may have to be used for berthing of
ships, the RBW with its sloping faces is not
suitable for berthing.
• These type of breakwaters dissipate the incident
wave energy by forcing them to break on a slope
and thus do not produce appreciable reflection.4/28/2020 40
41. STRUCTURAL COMPONENT
1) Constructed by natural rubble or
2) Comparatively safe.
3) Has a broad base which helps in
distributing the load on a wider area.
4) Consists of central portion called core,
protective cover called Armour layer and
in between is the under layer.
43. ADVANTAGES OF RMBW
• Use of natural material
• Reduces material cost
• Use of small construction equipment
• Less environmental impact
• Most widely used in Indian ports
• Easy to construct
• Failure is mainly due to poor interlocking
capacity between individual blocks
• Unavailability of large size natural rocks leads to
artificial armour blocks .
44. Vertical-wall breakwaters
• A breakwater formed by the construction in a
regular and systematic manner of a vertical wall
of masonry concrete blocks or mass concrete,
with vertical and seaward face.
• Reflect the incident waves without dissipating
much wave energy.
• Normally it is constructed in locations where the
depth of the sea is greater than twice the design
45. ADVANTAGES OVER RBW
• saving in material due to smaller body width.
• Rapidity in construction.
• Non availability of large quantities of stones.
• Occupies less space.
47. Disadvantages of vertical wall break
• Sea bottom has to be leveled and prepared for
placements of large blocks or caissons.
• Foundations made of fine sand may cause erosion and
• Erosion may cause tilting or displacement of large
• Difficult and expensive to repair.
• Building of caissons and launching or towing them into
position require special land and water areas beside
involvement of heavy construction equipment.
• Require form work, quality concrete, skilled labour,
batching plants and floating crafts.
48. FLOATING BREAKWATER
• A removable breakwater constructed by caissons or
pontoons with valves for trimming whilst afloat and
for sinking when is position and pump connections for
refloating, moored to the sea bed.
• inexpensive, easily moved from site to site, often very
• ineffective to long waves, must be anchored.