LDD 10102 Secewewrewtion 1 Marine Environment Rev SHO

8/12/2019 LDD 10102 Secewewrewtion 1 Marine Environment Rev SHO

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INTRODUCTION TO SHIP TECHNOLOGY

LDD 10102

L ectur er:


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REMEMBER TO WRITE THEIMPORTANTANT NOTES


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SECTION 1- TOPIC 1

The principal oceanographic characteristics that make up the marineenvironment 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 coastline 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 maritimeactivities.

The six dimension of movement of a floating body and the design of a floatingvehicleType of marine industries and trade


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In t roduc t ionOCEANOGRAPHY IN RELATION TO SHIPS /

SHIPPING ACTIVITIESShip 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 morethan 500 tons of displacement.


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Oceanography also called oceanology or marinescience, is the branch of Earth Sciences that studies theEarth's oceans and seas. It covers a wide range of topics,including marine organisms and ecosystem dynamics; oceancurrents, waves, and geophysical fluid dynamics; platetectonics and the geology of the sea floor.


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Ships

Ships are a vital element in the modern world. They still carry some 95per 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 over450 million in total. Although aircraft have displaced the transatlanticliners, ships still carry large numbers of people on pleasure cruises andon 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.


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Although one of the oldest forms of transport, ships, their equipment andtheir function, are subject to constant evolution. Changes are driven bychanging patterns of world trade, by social pressures, by technologicalimprovements in materials, construction techniques and control systems,and by pressure of economics. As an example, technology now providesthe ability to build much larger, faster ships and these are adopted to gainthe economic advantages those features can confer.

Ships- continued

MS Oasis of the Seas , the world's largest passenger ship , was builtby South Korean-owned shipbuilding group STX Europe .
http://en.wikipedia.org/wiki/MS_Oasis_of_the_Seashttp://en.wikipedia.org/wiki/Passenger_shiphttp://en.wikipedia.org/wiki/STX_Europehttp://en.wikipedia.org/wiki/STX_Europehttp://en.wikipedia.org/wiki/Passenger_shiphttp://en.wikipedia.org/wiki/MS_Oasis_of_the_Seas


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75% Of Earth Is CoveredBy Sea


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Lesson Plan No 1- Wind

What Is Wind?; Effect of wind on ship and wave.

The wind is a large-scale movement of air caused bydifferences in atmospheric pressure between localities. Air under high pressure moves toward areas of lowpressure. The greater the difference in pressure, the fasterthe 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 ofwind, its duration and the distance over which it acts, whichis called its fetch.

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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 withheight. Beaufort wind speeds are based on the wind speedat a height of 6m.

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BeaufortNumber(force)

Wind Speed WaveHeight(feet)

WMO*description

Effects observed on the seaknots mph

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 3 - 5 Moderatebreeze

Small waves, becoming longer; numerous whitecaps

5 17-21 19-24 6 - 8 Fresh breeze Moderate waves, taking longer form; many whitecaps; somespray

6 22-27 25-31 9-13 Strong breeze Larger waves forming; whitecaps everywhere; more spray7 28-33 32-38 13-19 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 crestsbegin 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; spraymay begin to reduce visibility

10 48-55 55-63 29-41 Storm Very high waves with overhanging crests; sea takes whiteappearance 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 foampatches; visibility further reduced

12 64 andover

73 andover

45 andover

Hurricane Air filled with foam; sea completely white with driving spray;visibility greatly reduced

Fig. 1 Beaufort Wind Scale

Devised by Brit is h Rear-Adm iral , Sir Francis B eaufort in 1805 based on o bservation s of the effects of the win d

( note :1 knots = 1.852 kmph)


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Storm Violent storm

Gale Strong gale


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Beaufort Scale

The scale is primarily used at sea, but it useful to anyoneinterested 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 lowvalue zero to a high value of twelve.

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Wind Measurement Wind velocities are measured in a horizontal plane, although a definite verticalgust component exists. The term velocity indicates direction and speed,although not all wind velocities measure in both quantities. An anemomete r isused to measure speed and the direction of the wind.

A hemispherical cup anemometer of the type invented in1846 by John Thomas Romney Robinson

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http://en.wikipedia.org/wiki/John_Thomas_Romney_Robinsonhttp://en.wikipedia.org/wiki/John_Thomas_Romney_Robinson


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Wind Measurement - continued

Winds are named in accordance with the direction fromwhich they are blowing. E.g. a southerly wind is blowingfrom the south .

Wind direction is measured in a clockwise direction fromNorth, either in 360 o, eg. spanning 45 o, 22.5 o or 11.25 o.

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North West Wind South Wind

Fig. 2 Wind Direction


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The winds affect the maintenance and decay of wavesystems as well as their generation. Waves are built by thesurface friction between the wind and the water or sea.

A short, sharp blow will cause steep, but shallow wavesknown colloquially as a chop .

A wind of longer duration will build up longer, larger wavesthat are less steep and less inclined to break.

There are three basic wind forms experienced aroundcoastline ; frontal wind, pressure wind and land and seabreezes.

Wind and Wave characteristics.

FRONTAL WIND


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cold front

FRONTAL WIND

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 airforms a wedge underneath the warm air, allowing it to basically ride up into the troposphereon its back and generate rain cloud s. There are four main kinds of fronts, classified by airflowmomentum. In a warm front , a warm air mass moves into a cold air mass. In a cold front , theopposite occurs. In a stationary front , neither air mass advances. Think of it as two frontsbumping into each other by accident. In an occluded front , a cold front overtakes a movingwarm front, like an army swarming over a fleeing enemy.

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Pressure Winds

Formed by the circulation of air around pressure systems, these are themost 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 theirdirection and approximate intensity:

winds circulating clockwise around a high-pressure system in theNorthern Hemisphere. winds circulating anti-clockwise around a low-pressure system in theNorthern Hemisphere. vice versa in the Southern Hemisphere.

Northern HemisphereIsobars

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The following weather map is from Australia and shows high and lowpressure air masses with a front moving across the bottom of the country.There are strong winds (isobars close together) around the coast but not inthe middle of the continent, which is typical for this large land mass.


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Weather Report (Sattelite Image)

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Land and Sea Breezes

In tropical and sub-tropical regions, land and sea breezes occurdaily. The land breeze can be virtually ignored since it is quite agentle offshore zephyr.Refer to online guide Forces and Winds http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/land/crc.rxml

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http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/land/crc.rxmlhttp://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/land/crc.rxmlhttp://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/land/crc.rxmlhttp://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/land/crc.rxml


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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 nearcoasts. It is formed by increasing temperature differences between the land and waterwhich create a pressure minimum over the land due to its relative warmth and forceshigher pressure, cooler air from the sea to move inland. Generally, air temperature getscooler relative to nearby locations as one moves closer to a large body of water. [1]

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http://en.wikipedia.org/wiki/Windhttp://en.wikipedia.org/wiki/Sea_breezehttp://en.wikipedia.org/wiki/Sea_breezehttp://en.wikipedia.org/wiki/Windhttp://en.wikipedia.org/wiki/File:LAKE_BREEZE.gifhttp://en.wikipedia.org/wiki/File:Diagrama_de_formacion_de_la_brisa-breeze.png


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Global Winds

There are regular winds around the world. Some blow the same way allyear round such as the Roaring Forties south of Australia. Others

change their direction depending upon the season. These winds are verystrong and are collectively called trade winds because they have beenused 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 astrong head wind.

The same principal still applies today even though the engine drivenships do not rely on wind power. However modern ships are so large andhave such high square profiles that strong winds have a huge effect onfuel 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 fundamentalfor all ship owners and masters to be aware of the global winds.


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This creates cell-like patterns of wind around the world, as seenin the diagram to the left.

However, winds do not simply blow in straight lines from north tosouth. Instead, they are bent by the spinning of the Earth:

to the right north of the equator, andto the left in the south.


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Wind is a vital resource. It turns generators that power cities, provides opportunitiesfor sport, and is affects commerce as ships sail from port to port. Understanding theglobal 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 firstview the Earth as a fixed (non rotating) planet.

view the Earth as a

fixed (non rotating)planet


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The global wind pattern is also known as the "generalcirculation" and the surface winds of each hemisphereare 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.

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Lesson Plan No 2- WaveWaves

Seawater is effectively incompressible so its density does notvary with depth as such. The density of water varies withtemperature and salinity; as does its kinematic viscosity. Thedensity of seawater increases with increasing salinity.

The term 'sea waves' is applied to waves generated locally by awind. When waves travel out of the generation area they arecalled swell waves . Waves carry energy and are random inheight, length, and direction. The wave form depends upon depthof water, current and local geographical features .

All deep sea waves follow the same shape regardless of otherdifferences. That shape is a trochoid . A trochoid is defined as thecurve traced by a point fixed on a circle as the circle rolls along astraight line . The standard wave form is a trochoidal wave and itis used for all naval architecture and ship structure calculations.

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Trochoidal Wave Form

The waves travel is not due to bodily movement of the whole massof water, but is simply constant rotation of points in circles in definitepositions. This motion applies to every particle in the wave, and isthe reason why any floating platform can be unstable.

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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 successivetroughs.

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 atrough.

Temperature, Density and Kinematic Viscosity Sect. 1 ME


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TemperatureoC

Density (kg/m 3) Kinematic Viscosity(m 2/sX10 6)

Freshwater

Saltwater

Fresh water Saltwater

0 999.8 1028.0 1.787 1.828

10 999.6 1026.9 1.306 1.354

20 998.1 1024.7 1.004 1.054

30 995.6 1021.7 0.801 0.849

Code Description of sea Wave height (m)

0 Calm (glassy) 0.00

1 Calm (rippled) 0.00-0.10

2 Smooth (wavelets) 0.10-0.50

3 Slight 0.50-1.25

4 Moderate 1.25-2.50

5 Rough 2.50-4.00

6 Very rough 4.00-6.00

7 High 6.00-9.00

8 Very high 9.00-14.00

9 Phenomenal >14.00

The appearance of a roughsea holds little promise that

the effect of waves on thebehaviour of a ship can bepredicted with any degree ofcertainty.

There are two very important

effects causing this problem,one, that waves cause a shipto roll and pitch and the other,that waves break on board.

These will affect ship motions,shipping water, structuralloading and loss of shipspeed.

Temperature, Density and Kinematic Viscosity

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Tides

Tide is a flow of a large mass of the sea due to a rise in sea level, which iscaused 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 nearerto 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 itmore strongly than the parts, which are farthest away.

When the earth, sun and moon are in line their combined pull producesthe largest movement of the water, the spring tides. When the three

bodies are at right angles this gives the smallest movement, the neaptides. This happen fortnightly intervals.

Lesson Plan No 3- Tides, Current and

Iceberg

d


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Spring tide

Spring tides occur when thesun and moon are directly in

line with the earth and theirgravitational pulls reinforceeach other.

The exceptionally high and low tidesthat occur at the time of the new moonor the full moon when the sun, moon,and earth are approximately aligned.


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Neap tide

A tide that occurs when the difference between highand 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.


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The effects of tides on maritime activity include:

It may only be possible to exit and enter estuaries or bays at acertain 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.

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Current

A current is defined as a body of water moving in a certaindirection. Currents, like tides, are controlled by thegravitational forces of the moon and the sun. In summersome currents will flow in one direction, then in winter theywill flow the opposite direction.

Throughout the worlds oceans, there are a number ofsignificant currents which have been used by ships forthousands of years. Vikings and ancient greeks knew thetimes of year to travel with the currents and make theirsailing/rowing much easier. Modern ship owners use thesame information to allow for more economical travel.

Fishermen throughout time have also used the currents fortheir benefit. Fish, large and small, follow the currents astheir food sources are also carried along by the currents.

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Icebergs

The immersed volume of an iceberg is always greater than

the volume above the water and increases with the age ofthe ice. Only 10% of the real size can be seen on the surfaceof the water and the other part remains under surface ofwater.

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 lowarea nearby.

Sea road usually the ship will use the safest way totravel. Material used for ships hull thicker plate metal used

for ships hull. Type of ship there are icebreaker ships to break the

iceberg to ease the ships passage.

Lesson Plan No 4- The six Dimension of Sect. 1 ME


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Lesson Plan No 4- The six Dimension ofmovement of a floating body

Heave

Yaw

Pitch

Sway

Roll

Surge(Relevance of oceanography characteristics i.e wave, wind to ship behavior)


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When the vessel is suspended between the crests of a wave equal to its ownlength, 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 thehogging condition.

Hogging &

Sagging


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Diagram showing thewreck of the Selendang

Ayu, and the double-bottom tank leaks

The ship which is alwayscrossing the oceans willencounter bad weather,rough sea with big wavesand experienced hoggingand sagging. Due to theweight of cargo onboard

the process of hoggingand sagging will make thehull of ship crack at the

joining part andeventually the ship will bebroken into two parts.

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Design of Floating Vehicles

The major requirements of the design of a floating vehicleare;

Most importantly being afloat.

Structurally withstand the forces of the ocean.

Enable cargoes, passengers and crews to be carriedsafely.

Enable it to operate efficiently and economically.

Provide satisfactory conditions for habitation.

(Relevance of oceanography characteristics i.e sea, wave, wind to ship design)

Lesson Plan No 5- Corrosion


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All materials including metals deteriorate. Some deteriorate faster than others,while some deteriorate more than others. This gradual process of deteriorationor degradation is called corrosion and it affects the metals used in shipconstruction. All metals will corrode on contact with water and air. Effective coating andminimisation strategies are essential to the shipbuilding industry and theeffective 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, outfittingrequirements and structural applications.

Lesson Plan No 5 Corrosion

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The cause, effect and prevention of corrosion in themaritime environment .

Corrosion

Corrosion can be defined as the destruction of metal bychemical or electrochemical reaction within its

environment. Also, it can be defined as the conversion ofmetallic iron to a mixture of oxides and other compounds,resulting in a change in appearance and reducing itsstrength.

To reduce the waste of materials by corrosion, the correctmaterials must be selected, and protection and corrosioncontrol is needed.


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In the example above, zinc plates are used to induce sacrificial corrosion of the

below the waterline components such as hull, stern and rudder areas.

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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. Itstows at about 0.4 0.5 m3/tonne and is one of the densest materialscarried by ship.

Coal - Coal stows at about 1.2 1.4 m3/tonne and is carried mainly inbulk carriers of more than 40,000 dwt.

Bauxite- Bauxite stows at about 0.7 1.1 m3/tonne and is carried usuallyin medium size carriers or multi-deck cargo vessels.

Transport of Manufactured Goods:Steel, Engineering Components, Electrical and Electronic Components,

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Trade

International trade evolved from the need for differentcountries to import and export various goods.

Approximately three quarters of the worlds 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 andPapua New Guinea are highly dependent on importedgoods.

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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

Trade Route

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Examples of trade by sea:

Raw Material From To

Iron ore South Africa AustraliaScandinaviaUSA

JapanUSAEurope

Grain Canada Australia

South America

Malaysia

Oil Malaysia USA

Timber IndonesiaUSAScandinavia

Japan Australia

Coal South AfricaEastern EuropeUSA

Australia

EnglandMalaysiaWestern EuropeJapan

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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 of the land ofthe 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 offKota Kinabalu, Kudat, Miri, Tanjung Karang, Sungai Besar, Bagan Datoh,Lumut and Penang.

There are four main countries that have relatively large fishing fleets:JapanNorwayIndonesiaCalifornia(a state of America) - product from deep sea.

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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 thecountrys fishing border.

Protection of offshore rigs and oil platforms.

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Oil drilling rigs and supply platforms rigs

Drilling for oil in the sea became a commercial necessity as the land supplies of oilbecame 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 oflegs at each corner of the platform.

Propellers all around the rig connect to satellite positioning equipment keep the shipabove the bore hole to an accuracy of a few meters. Although in heavy seas drilling mustbe stopped.When the rig is drilling in a water level of several hundred meters this would beconsidered a very accurate positioning system. When oil has been located the well headmust 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 aChristmas tree. The Christmas tree is simply a manifold with several valves constructedof stainless steel

Oil Production Platform

The oil production platform simply contains pumps and tanks for removing the oil totankers or monitoring flow through a pipeline to shore The production platform has

LDD 10102 Secewewrewtion 1 Marine Environment Rev SHO

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