1. SHIP TECHNOLOGY
LGB 11503
......SyllabusLGB 11503-Ship Technology SLT.doc
Lecturer:
......Lesson PlanStandard QA Lesson Plan auzuddin Ayob
F Ship Technology LGB11503 SLT.doc
B. Eng Marine Eng;
M. Eng Materials Sc & Eng
3. SECTION 1- TOPIC 1
The principal oceanographic characteristics that make up the
marine environment and their relevance to the design,
construction, operation and maintenance of marine vessels.
– Oceanography in relation to ships / shipping activities
– The nature of wind, wind description, wind measurement, wind around
coast line and the regular global wind.
– The nature of waves and swells and their principal effects on ships.
– The nature of tides, current and iceberg and their effects on ships and
maritime activities.
– The six dimension of movement of a floating body and the design of a
floating vehicle
– The cause, effect and prevention of corrosion in the maritime
environment.
– Type of marine industries and trade
4. Introduction
OCEANOGRAPHY IN RELATION TO
SHIPS / SHIPPING ACTIVITIES
Ship is any large floating vessel capable of crossing open
waters (i.e. ocean) and carrying materials and goods from
one port to another port. In modern times it usually denotes
a vessel of more than 500 tons of displacement.
5. Oceanography also called oceanology or marine
science, is the branch of Earth Sciences that studies the
Earth's oceans and seas. It covers a wide range of topics,
including marine organisms and ecosystem dynamics; ocean
currents, waves, and geophysical fluid dynamics; plate
tectonics and the geology of the sea floor.
6. Ships
Ships are a vital element in the modern world. They still carry some 95
per cent of trade. In 1994 there were more than 80,000 ships each with
a gross tonnage of 100 or more, representing a gross tonnage of over
450 million in total. Although aircraft have displaced the transatlantic
liners, ships still carry large numbers of people on pleasure cruises and
on the multiplicity of ferries operating in all areas of the globe. Ships,
and other marine structures, are needed to exploit the riches of the
deep.
7. Ships- continued
Although one of the oldest forms of transport, ships, their equipment and
their function, are subject to constant evolution. Changes are driven by
changing patterns of world trade, by social pressures, by technological
improvements in materials, construction techniques and control systems,
and by pressure of economics. As an example, technology now provides
the ability to build much larger, faster ships and these are adopted to gain
the economic advantages those features can confer.
MS Oasis of the Seas, the world's largest passenger ship, was built
by South Korean-owned shipbuilding group STX Europe.
10. Sect. 1 ME
Lesson Plan No 1- Wind
What Is Wind?; Effect of wind on ship and wave
characteristics.
The wind is a large-scale movement of air caused by
differences in atmospheric pressure between localities.
Air under high pressure moves toward areas of low
pressure. The greater the difference in pressure, the faster
the air flows.
Strong winds can add to the resistance a ship
experiences and make manoeuvring difficult. Beam wind
will make a ship heel and create waves.
The wave characteristics depend upon the strength of
wind, its duration and the distance over which it acts, which
is called its fetch.
11. Sect. 1 ME
Describing Wind :
• Wind is described with direction and speed.
• The direction of the wind is expressed as the direction from
which the wind is blowing.
• Winds have different levels of speed, such as “breeze” and
“gale”, depending on how fast they blow.
The strength of a wind is classified in broad terms by the
Beaufort Wind Scale (Fig.1). The wind velocity varies with
height. Beaufort wind speeds are based on the wind speed
at a height of 6m.
12. Devised by British Rear-Admiral, Sir Francis Beaufort in 1805 based on observations of the effects of the wind
Beaufort Wind Speed Wave
WMO*
Number Height Effects observed on the sea
knots mph description
(force) (feet)
0 under 1 under 1 - Calm Sea is like a mirror
1 1-3 1-3 0.25 Light air Ripples with appearance of scales; no foam crests
2 4-6 4-7 0.5 - 1 Light breeze Small wavelets; crests of glassy appearance, not breaking
3 7 - 10 8 - 12 2-3 Gentle breeze Large wavelets; crests begin to break; scattered whitecaps
4 11-16 13-18 3½ - 5 Moderate
Small waves, becoming longer; numerous whitecaps
breeze
5 17-21 19-24 6-8 Fresh breeze Moderate waves, taking longer form; many whitecaps; some
spray
6 22-27 25-31 9½-13 Strong breeze Larger waves forming; whitecaps everywhere; more spray
7 28-33 32-38 13½-19 Near gale Sea heaps up; white foam from breaking waves begins to be
blown in streaks
8 34-40 39-46 18-25 Gale Moderately high waves of greater length; edges of crests
begin to break into spindrift; foam is blown in well-
marked streaks
9 41-47 47-54 23-32 Strong gale High waves; sea begins to roll; dense streaks of foam; spray
may begin to reduce visibility
10 48-55 55-63 29-41 Storm Very high waves with overhanging crests; sea takes white
appearance as foam is blown in very dense streaks;
rolling is heavy and visibility is reduced
11 56-63 64-72 37-52 Violent storm Exceptionally high waves; sea covered with white foam
patches; visibility further reduced
12 64 and 73 and 45 and Hurricane Air filled with foam; sea completely white with driving spray;
over over over visibility greatly reduced
Fig. 1 Beaufort Wind Scale ( note :1 knots = 1.852 kmph)
17. Sect. 1 ME
Beaufort Scale
• The scale is primarily used at sea, but it useful to anyone
interested in the weather.
• In 1805, Admiral Sir Francis Beaufort (of the British
Navy) devised the following scale of wind velocity.
• The numbers are arranged in sequential order, with a low
value zero to a high value of twelve.
18. Sect. 1 ME
Wind Measurement
Wind velocities are measured in a horizontal plane, although a definite
vertical gust component exists. The term ‘velocity’ indicates direction and
speed, although not all wind velocities measure in both quantities. An
anemometer is used to measure speed and the direction of the wind.
A hemispherical cup anemometer of the type invented in
1846 by John Thomas Romney Robinson
19. Sect. 1 ME
Wind Measurement - continued
Winds are named in accordance with the direction from
which they are blowing. E.g. a southerly wind is blowing
from the south.
Wind direction is measured in a clockwise direction from
North, either in 360o, eg. spanning 45o, 22.5o or 11.25o.
Fig. 2 Wind Direction
North West Wind South Wind
20. Wind and Wave characteristics.
The winds affect the maintenance and decay of wave
systems as well as their generation. Waves are built by the
surface friction between the wind and the water or sea.
A short, sharp blow will cause steep, but shallow waves
known colloquially as a chop.
A wind of longer duration will build up longer, larger waves
that are less steep and less inclined to break.
There are three basic wind forms experienced around
coastline; frontal wind, pressure wind and land and sea
breezes.
21. Sect. 1 ME
Frontal Wind
This can be the most severe of all, although it usually doesn’t last long.
Associated mostly with the onset of a cold front, this wind will blow very
hard and very strong initially and come in with a sudden impact. But it will
blow itself out very quickly, the worst often being over in less than an hour.
If the cold front is severe, there is usually prior warning in the form of sky
signs. A build up of cumulonimbus clouds, often with lightning and thunder,
appears in the Southern and Western skies.
Just prior to the onset of the storm, when the sky will probably resemble a
boiling cauldron of grey to black cloud, the wind will die right away. This is
the proverbial calm before the storm, because within minutes the frontal
wind will race down in a line across the water, at speeds probably
somewhere between 40 and 60 knots. Temperature will drop considerably
as the cold air comes in, there may be rain, hail, lightning and thunder, and
the wind will blow hard for probably 20 minutes to half an hour before it
begins to ease. It will probably blow itself out within the hour.
22. FRONTAL WIND
cold front
warm front
Frontal wedging: When a warm air mass and a cold air mass collide, you get a front.
Remember how low-pressure warm air rises and cold high-pressure air moves into its place?
The same reaction happens here, except the two forces slam into each other. The cold air
forms a wedge underneath the warm air, allowing it to basically ride up into the troposphere
on its back and generate rain clouds. There are four main kinds of fronts, classified by airflow
momentum. In a warm front, a warm air mass moves into a cold air mass. In a cold front, the
opposite occurs. In a stationary front, neither air mass advances. Think of it as two fronts
bumping into each other by accident. In an occluded front, a cold front overtakes a moving
warm front, like an army swarming over a fleeing enemy.
23. Sect. 1 ME
Pressure Winds
Formed by the circulation of air around pressure systems, these are the
most common winds of our everyday life. They are fairly predictable in
that they rotate around high and low pressure systems.
On the weather map the isobars, or lines of pressure, indicate their
direction and approximate intensity:
• winds circulating clockwise around a high-pressure system in the
Northern Hemisphere.
• winds circulating anti-clockwise around a low-pressure system in the
Northern Hemisphere.
• vice versa in the Southern Hemisphere.
Northern Hemisphere
Isobars
24. Sect. 1 ME
Pressure Winds- continued
The high-pressure system is usually the gentle one, while the low
pressure brings unpleasant winds. As with the other winds, both are
unpredictable and often the area between a high and low-pressure centre
is squeezed to create a sort of wind race or channel through which the
wind increases speed considerably.
This is indicated on the weather map by the closeness of the isobar lines.
The spacing of the isobars is the indication of the gradient of the pressure
and thus the speed of the wind. The closer together the isobars, the
stronger the wind. Unlike frontal winds, the pressure winds do not come in
with a great slam. They are probably more dangerous to offshore boats
because they blow steadily and consistently for long periods and thus
build up heavy and dangerous seas. They are more predictable as they
have a steady increase in wind speed over a period of hours rather than
arriving with the sudden impact of the frontal winds.
25. The following weather map is from Australia and shows high and low
pressure air masses with a front moving across the bottom of the country.
There are strong winds (isobars close together) around the coast but not in
the middle of the continent, which is typical for this large land mass.
27. Sect. 1 ME
Land and Sea Breezes
In tropical and sub-tropical regions, land and sea breezes occur
daily. The land breeze can be virtually ignored since it is quite a
gentle offshore zephyr.
Refer to online guide – Forces and Winds
http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/land/crc.rxml
28. Sect. 1 ME
A: Sea breeze, B: Land breeze
Lake - Sea breeze and atmospheric depth
A sea-breeze (or onshore breeze) is a wind from the sea that develops over land near
coasts. It is formed by increasing temperature differences between the land and water
which create a pressure minimum over the land due to its relative warmth and forces
higher pressure, cooler air from the sea to move inland. Generally, air temperature gets
cooler relative to nearby locations as one moves closer to a large body of water.[1]
29. Sect. 1 ME
Wind Vectors
Wind Vectors indicate wind direction and speed. The black arrows
plotted on this image are wind vectors. These vectors indicate
direction and intensity of the wind. The vectors point in the direction to
which the wind is blowing and in this image, winds are primarily
blowing from west to east. Intensity of the wind is conveyed through
the size of the vector. The longer the arrows, the stronger the winds.
Atmospheric Pressure
Refer to online guide:
http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/prs/def.rxml
30. Sect. 1 ME
Global Winds
There are regular winds around the world. Some blow the same way all
year round such as the “Roaring Forties” south of Australia. Others
change their direction depending upon the season. These winds are
very strong and are collectively called trade winds because they have
been used by trading ships for thousands of years.
In the days of sailing ships, winds were essential, and sailing with the
wind behind you was much quicker and easier than trying to sail into a
strong head wind.
The same principal still applies today even though the engine driven
ships do not rely on wind power. However modern ships are so large
and have such high square profiles that strong winds have a huge effect
on fuel consumption and time taken for a trip. This affects the costs of
the journey and in an industry where profit is all important, it is
fundamental for all ship owners and masters to be aware of the global
winds.
31. This creates cell-like patterns of wind around the world, as seen
in the diagram to the left.
However, winds do not simply blow in straight lines from north to
south. Instead, they are bent by the spinning of the Earth:
to the right north of the equator, and
to the left in the south.
32. Wind is a vital resource. It turns generators that power cities, provides opportunities
for sport, and is affects commerce as ships sail from port to port. Understanding the
global wind patterns can be both advantageous and necessary for industry that
depend on the wind's energy. To understand the global wind patterns it is best to first
view the Earth as a fixed (non rotating) planet.
view the Earth as a
fixed (non rotating)
planet
33. The global wind pattern is also known as the "general
circulation" and the surface winds of each hemisphere
are divided into three wind belts:
•Polar Easterlies: From 60-90 degrees latitude.
•Prevailing Westerlies: From 30-60 degrees latitude (aka
Westerlies).
•Tropical Easterlies: From 0-30 degrees latitude (aka
Trade Winds).
view the Earth as a
rotating) planet.
34. Sect. 1 ME
Lesson Plan No 2- Wave
Waves
Seawater is effectively incompressible so its density does not
vary with depth as such. The density of water varies with
temperature and salinity; as does its kinematic viscosity. The
density of seawater increases with increasing salinity.
The term 'sea waves' is applied to waves generated locally by a
wind. When waves travel out of the generation area they are
called swell waves. Waves carry energy and are random in
height, length, and direction. The wave form depends upon depth
of water, current and local geographical features.
All deep sea waves follow the same shape regardless of other
differences. That shape is a trochoid. A trochoid is defined as the
curve traced by a point fixed on a circle as the circle rolls along a
straight line. The standard wave form is a trochoidal wave and it
is used for all naval architecture and ship structure calculations.
35. Sect. 1 ME
Trochoidal Wave Form
The waves travel is not due to bodily movement of the whole mass
of water, but is simply constant rotation of points in circles in definite
positions. This motion applies to every particle in the wave, and is
the reason why any floating platform can be unstable.
36. Sect. 1 ME
Waves - continued
The following definitions are used in describing a wave:
Speed or Velocity (V)
usually expressed in knots is the speed at which individual waves
travel.
Length (L)
is the horizontal distance between successive crests or successive
troughs.
Period or Time (T)
expressed in seconds is the time interval required for the passage of
successive crests or successive troughs past given point.
Height (H)
is the vertical distance between the top of a crest and the bottom of a
trough.
37. Temperature, Density and Kinematic Viscosity Sect. 1 ME
Temperature Density (kg/m3) Kinematic Viscosity
o
C (m2/sX106)
The appearance of a rough
Fresh Salt Fresh water Salt
water water water sea holds little promise that
0 999.8 1028.0 1.787 1.828
the effect of waves on the
10 999.6 1026.9 1.306 1.354
behaviour of a ship can be
20 998.1 1024.7 1.004 1.054
predicted with any degree of
30 995.6 1021.7 0.801 0.849
certainty.
There are two very important
Code Description of sea Wave height (m)
effects causing this problem,
0 Calm (glassy) 0.00 one, that waves cause a ship
1 Calm (rippled) 0.00-0.10 to roll and pitch and the other,
2 Smooth (wavelets) 0.10-0.50 that waves break on board.
3 Slight 0.50-1.25 These will affect ship motions,
4 Moderate 1.25-2.50 shipping water, structural
loading and loss of ship
5 Rough 2.50-4.00
speed.
6 Very rough 4.00-6.00
7 High 6.00-9.00
8 Very high 9.00-14.00
9 Phenomenal >14.00
38. Sect. 1 ME
Lesson Plan No 3- Tides, Current and
Iceberg
Tides
Tide is a flow of a large mass of the sea due to a rise in sea level, which is
caused by the gravitational effect of the sun and the moon on the earth.
The moon exerts about twice the pull of the sun since it is so much nearer
to the earth. The amount of attraction varies inversely as the square of the
distance, and the moon attracts the part of the earth, which is nearest to it
more strongly than the parts, which are farthest away.
When the earth, sun and moon are in line their combined pull produces
the largest movement of the water, the spring tides. When the three
bodies are at right angles this gives the smallest movement, the neap
tides. This happen fortnightly intervals.
39. Spring tide
Spring tides occur when the
sun and moon are directly in
line with the earth and their
gravitational pulls reinforce
each other.
The exceptionally high and low tides
that occur at the time of the new moon
or the full moon when the sun, moon,
and earth are approximately aligned.
40. Neap tide
A tide that occurs when the difference between high
and low tide is least; the lowest level of high tide.
Neap tide comes twice a month, in the first and third
quarters of the moon.
41. Sect. 1 ME
The earth rotates on its axis once in 24 hours and each meridian turn
comes opposite the moon, so that in each rotation of 24 hours there are 2
high and 2 low tides with roughly six hours between a high tide and the
next low.
This periodic rise and fall of the ocean waters is most noticeable on shores
which shelve gradually and expose a wide expanse of beach between high
and low water tide levels. The influence varies directly as the mass and
inversely as the cube of the distance.
Large differences in tidal range occur at different locations along the ocean
coast due to:
• secondary tidal waves set up by the primary tidal waves
• the mass of water moving around the earth
• the depth of shoaling water
• the configuration of the coast.
42. The effects of tides on maritime activity include:
• It may only be possible to exit and enter estuaries or bays at a
certain time.
For example, a large ship can only enter a port at high tide.
• Launching times.
• The maximum load the ship can carry.
• Fishing - because fish follow the current and tides.
• Design of the waterline of the ship.
• High tides needed to clear bars, reefs etc under water.
43. Sect. 1 ME
Current
A current is defined as a body of water moving in a certain
direction. Currents, like tides, are controlled by the
gravitational forces of the moon and the sun. In summer
some currents will flow in one direction, then in winter they
will flow the opposite direction.
Throughout the worlds oceans, there are a number of
significant currents which have been used by ships for
thousands of years. Vikings and ancient greeks knew the
times of year to travel with the currents and make their
sailing/rowing much easier. Modern ship owners use the
same information to allow for more economical travel.
Fishermen throughout time have also used the currents for
their benefit. Fish, large and small, follow the currents as
their food sources are also carried along by the currents.
44. Sect. 1 ME
Icebergs
The immersed volume of an iceberg is always greater than
the volume above the water and increases with the age of
the ice. Only 10% of the real size can be seen on the surface
of the water and the other part remains under surface of
water.
The effects of iceberg on maritime activity include:
• Sea level / tides – the melted ice will increase the sea
volume so the sea level will increase flooding the low
area nearby.
• Sea road – usually the ship will use the safest way to
travel.
• Material used for ship’s hull – thicker plate metal used
for ship’s hull.
• Type of ship – there are icebreaker ships to break the
iceberg to ease the ship’s passage.
45. Sect. 1 ME
Lesson Plan No 4- The six Dimension of
movement of a floating body
• Heave
• Yaw
• Pitch
• Sway
• Roll
• Surge
(Relevance of oceanography characteristics i.e wave, wind, current, etc. to ship behavior)
46. Hogging &
Sagging
When the vessel is suspended between the crests of a wave equal to its own
length, and then; when the vessel is suspended on just one crest at midships.
In the first case the hull will tend to sag and this is known as the sagging
condition. In the second case, the hull tends to hog and this is known as the
hogging condition.
47. Diagram showing the
wreck of the Malaysian
ship Selendang Ayu,
and the double-bottom
tank leaks
The ship which is always
crossing the oceans will
encounter bad weather,
rough sea with big waves
and experienced hogging
and sagging. Due to the Aerial view of Selendang Ayu, broken in half off Unalaska Island.
weight of cargo onboard
the process of hogging
and sagging will make the
hull of ship crack at the
joining part and
eventually the ship will be
broken into two parts.
48. Sect. 1 ME
Design of Floating Vehicles
The major requirements of the design of a floating vehicle
are;
• Most importantly being afloat.
• Structurally withstand the forces of the ocean.
• Enable cargoes, passengers and crews to be carried
safely.
• Enable it to operate efficiently and economically.
• Provide satisfactory conditions for habitation.
(Relevance of oceanography characteristics i.e sea, wave, wind to ship design)
49. Lesson Plan No 5- Corrosion
Introduction
All materials including metals deteriorate. Some deteriorate
faster than others, while some deteriorate more than others.
This gradual process of deterioration or degradation is called
corrosion and it affects the metals used in ship construction.
All metals will corrode on contact with water and air. Effective
coating and minimisation strategies are essential to the
shipbuilding industry and the effective life-span of the
components they manufacture.
The reduction or minimisation of corrosion is of vitally
significant in determining the potential life span and suitability
of materials to be used for shipbuilding, outfitting requirements
and structural applications.
50.
51. Sect. 1 ME
The cause, effect and prevention of corrosion in the
maritime environment .
What is Corrosion
Corrosion can be defined as ‘the destruction of metal by
chemical or electrochemical reaction within its
environment’. Also, it can be defined as ‘the conversion of
metallic iron to a mixture of oxides and other compounds,
resulting in a change in appearance and reducing its
strength’.
To reduce the waste of materials by corrosion, the correct
materials must be selected, and protection and corrosion
control is needed.
52. Sect. 1 ME
The Cause of Corrosion
The basic cause of corrosion is that all metals are inherently unstable. They
seek self-destruction by reacting with their environment, forming metal
compounds to obtain the stable state of low free energy. This is the state of
metal found in nature. This instability will demand the metal to return to the
combined state. The rate at which they seek self-destruction will depend on
the environment. The result is corrosion product known as rust.
Basically, metals and compounds in the environment can react with each
other to form another compound of much lower free energy. This
interaction is very likely to take place since systems universally tend to
seek a low-energy situation.
reduction oxidation
Metallic mineral → Metal → Corrosion
products
(extraction) (corrosion)
The above diagram is the simplification of the process, which converts metallic
compounds or minerals to metal, and back to metallic compounds as corrosion
products.
53. Sect. 1 ME
The Cause of Corrosion in the Marine Environment
In a marine environment, the main factor that influences corrosion is
the environment itself.
There are several causes of corrosion in the marine environment, such
as:
• aqueous corrosion in which the metals in contact with sea water
• atmospheric corrosion of metals exposed on or near coastlines
• hot salt corrosion in engines operating at sea or taking in salt-
laden air.
Corrosion by seawater or aqueous corrosion, is an electrochemical
process. All metals and alloys, when in contact with seawater, have a
specific electrical potential (corrosion potential) at a specific level of
acidity or alkalinity in the water.
Marine vessels are exposed to the atmosphere, fresh water and
seawater. In each of this element of the environment, there exist a
large range of conditions, which may be corrosive.
54. Sect. 1 ME
Atmosphere
In the atmosphere there will be some trace of water in the form of water
vapour. This would lead to condensation that will produce droplets of
water or a continuous film in the case of extreme humidity. Metals will
react with condensations and form corrosion product.
Aqueous Corrosion
Any kind of water (domestic and industrial) can give rise to corrosion.
The same process as described previously will occur if metal and water
come into direct contact .
Seawater
Salt corrosion is mainly encountered in marine environments. Seawater
contains a wide range of salts for example, sodium chloride, magnesium
fluorides and calcium bromides. Because of the high chloride content,
seawater corrodes most metals. The salt content also gives rise to higher
electric conductivity than fresh water.
55. Corrosion process- electrochemical process
The corrosion process is an electrochemical process which
begins when the metal reacts to its environment and its atoms
are exposed to the moisture filled atmosphere, giving up
electrons and releasing positively charged ions into the
moisture filled solution which become electrically conductive,
and is called an electrolyte. The point of corrosion is called an
Anode.
56. Sect. 1 ME
Corrosion process- Galvanic Corrosion
Corrosion is the chemical breakdown of the surface of
the metal, with consequent loss in thickness and
strength. Galvanic corrosion is very much like corrosion
in the marine environment, but bear in mind that
corrosion can also take place if only one metal is
present.
When two different metals are electrically connected,
an electric potential exists between them. In the
diagram, the two metals are copper and steel.
Seawater will act as electrolyte in this process.
Because of the electric potential, base metal, in this
case the steel, tends to release its electron and
become an ion. The electron will travel to the cathode
or the noble metal. The conventional current will flow
the other way round the circuit. At the cathode, the
electrons ionise oxygen and water molecules and
which become hydroxyl ions. The cathode will be
protected from corrosion.
Electro-chemical corrosion involving wet
As the process continues, steel will continuously corrosion (Galvanic Corrosion)
breakdown into ions that will change its thickness and (Galvanic corrosion is a common
hence strength. This process will continue until the problem when dissimilar metals
potential between the metals is no longer capable of are immersed in seawater in a
ionising the base metal and corrosion stops. marine environment, and an
electrical connection is made)
60. Sect. 1 ME
The prevention of corrosion in the marine environment
There are several ways in which corrosion can be prevented and controlled. In
general, the first level of protection is control of the metal - which means the use of
the correct metal for the job. The second level is control of the environment; either by
modification or exclusion from contact with the metal.
The final control is through the design – avoiding designs in which the kinetics of
attack on one metal is stimulated by another and avoidance of design, which lead to
localized attack, impingement and cavitation etc.
Corrosion prevention methods used in seawater include:
• methods based on protective coatings (isolation from seawater)
• impressed voltage or coupling to sacrificial anode (changing the potential of
the metal)
• passivation of metal (using corrosion inhibitors) -hard non-reactive surface film
• changing the pH of the local environment (using chemical)
• methods based on modification of metal or change to more corrosion resistant
material.
Most corrosion-resistant metals rely on hard non-reactive surface of oxide film to
provide protection against corrosion (passivation of metal) .If the oxide is slightly
adherent, stable and self-healing, as on many stainless steels and titanium, then the
metal will be highly resistant to corrosion. If the film is loose, powdery, easily
damaged and non-self repairing, such as rust on steel, then corrosion will continue
unchecked. Even so, the most stable oxides may be attacked when aggressive
concentrations of hydrochloric acid are formed in chloride environments.
61. Cathodic Protection - sacrificial anode
In the example above, zinc plates are used to induce sacrificial corrosion of the “
below the waterline” components such as hull, stern, propeller and rudder areas.
63. Protective Coatings of marine structures - Metallic coatings
Electroless Plating, Hot Dip Galvanizing, Anodising, Painting
etc.
64. Sect. 2 ME
Lesson Plan No 6- Marine Industries
Merchant Industry
Transport of Raw Materials:
• Oil- Crude oil is transported by sea in oil tankers
• Iron Ore- Iron ore is transported by ship in the form of crushed
rock. It stows at about 0.4 – 0.5 m3/tonne and is one of the densest
materials carried by ship.
• Coal - Coal stows at about 1.2 – 1.4 m3/tonne and is carried
mainly in bulk carriers of more than 40,000 dwt.
• Bauxite- Bauxite stows at about 0.7 – 1.1 m3/tonne and is carried
usually in medium size carriers or multi-deck cargo vessels.
Transport of Manufactured Goods:
Steel, Engineering Components, Electrical and Electronic
Components,
65. Sect. 2 ME
Trade
International trade evolved from the need for different
countries to import and export various goods.
Approximately three quarters of the world’s trade is moved
by sea transport.
There is no country in the world that is totally self sufficient,
they all import something.
Some countries, such as Japan, Singapore, Brunei and
Papua New Guinea are highly dependent on imported
goods.
66. Sect. 2 ME
Trade Route
• Route 1 – Blue – Atlantic and Indian Oceans - Europe, around Cape of Good
Hope (Sth. Africa), around Australia (anti-clockwise), Japan.
• Route 2 – Red – Atlantic and Pacific Oceans – Europe, around Cape Horn
(Argentina), Japan
• Route 3 – Green – Atlantic and Pacific Oceans – Europe, Panama Canal, Japan
• Route 4 – Pink – Atlantic Ocean, Red Sea and Pacific Ocean – Europe, Red Sea,
Suez Canal (Egypt), India, Asia, Japan
• Route 5 – Blue Dash – Atlantic Ocean – Europe, United States of America
• Route 6 – Blue Dash – Pacific Ocean – United States of America, Japan
67. Sect. 2 ME
Examples of trade by sea:
Raw Material From To
Iron ore South Africa Australia Japan
Scandinavia USA
USA Europe
Grain Canada Malaysia
Australia
South America
Oil Malaysia USA
Timber Indonesia Japan
USA Australia
Scandinavia
Coal South Africa England
Eastern Europe Malaysia
USA Western Europe
Australia Japan
68. Sect. 2 ME
The Fishing Industry
The fishing industry provides an important protein-rich source of food for
many populations in the world. This is due to the fact that ¾ of the land of
the world is surrounded by sea making fish readily available.
The major Malaysian fishing areas are: Endau, Mersing, Penarik Village,
Merchong Village, Pulau Perak, Pulau Labuan, Pulau Mabul, Seas off
Kota Kinabalu, Kudat, Miri, Tanjung Karang, Sungai Besar, Bagan Datoh,
Lumut and Penang.
There are four main countries that have relatively large fishing fleets:
Japan
Norway
Indonesia
California(a state of America) - product from deep sea.
69. Sect. 2 ME
The Naval Defence Industry
Naval Defence vehicles are needed for:
• Defence for countries
• Defence and protection of main trade routes from the pirates,
which rob the merchant ships.
• Protection for fishing vessels from pirates
• Prevention of fishing vessels trespassing and crossing the
country’s fishing border.
• Protection of offshore rigs and oil platforms.
70. Sect. 2 ME
Oil & Gas Industry
Oil drilling rigs and supply platforms rigs
Drilling for oil in the sea became a commercial necessity as the land supplies of oil
became restricted. Drilling ships and rigs firstly sunk bores to establish the supply. The
drilling platform does not sit on the seabed but floats on submerged tanks at the end of
legs at each corner of the platform.
Propellers all around the rig connect to satellite positioning equipment keep the ship
above the bore hole to an accuracy of a few meters. Although in heavy seas drilling must
be stopped.
When the rig is drilling in a water level of several hundred meters this would be
considered a very accurate positioning system. When oil has been located the well head
must be tapped to allow the drilling rig to move on.
This is done by capping the well head on the sea bed with a device known as a
Christmas tree. The Christmas tree is simply a manifold with several valves constructed
of stainless steel
Oil Production Platform
The oil production platform simply contains pumps and tanks for removing the oil to
tankers or monitoring flow through a pipeline to shore. The production platform has
accommodation for the crews who are flown on and off as tours of duty are completed.
