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Кораблестроение, океанотехника и системотехника

объектов морской инфраструктуры» (только для профиля

океанотехника и системотехника объектов морской инфраструктуры)

Marine Engines

There are four main types of marine engines: the diesel engine, the steam

turbine, the gas turbine and the marine nuclear plant. Each type of the engines has

particular application.

The diesel engine is a form of internal combustion engine in which the

power is developed by the piston in the cylinder. But some power is lost due to

friction in the cylinder. Most large merchant vessels are powered by medium-speed

diesel engines; they are cheaper, smaller in size and weight.

In steam turbines high pressure steam is directed into blades of the shaft,

rotates the shaft; the rotary motion is transferred to the propeller shaft. Steam is

produced by boiling water in a boiler. Steam turbines are more often used in ships,

especially in container ships.

Gas turbines use gas to turn a shaft. A gas turbine engine is very light and

easily removed for maintenance. Gas turbines can be completely automated.

Nuclear power in ships is mainly used in icebreakers. A ship uses the energy

released by the decay of radioactive fuel to generate steam. The steam is used to

turn a shaft via a turbine.

Repair

Repair is fixing any sort of mechanical or electrical device if it has got out of

order or broken. It is performing the routine actions which keep the device in

working order or prevent trouble in maintenance. After repair the device must

perform the required function properly.

The repair actions include the combination of all technical, administrative

and supervision actions, tests, measurements, replacements, adjustments and

inspection. It means that any machinery is repaired up to such condition that it may

be continuously used.

In marine practice it is very often necessary to repair some machinery on

board ship. But very complicated machinery, lack of necessary spare parts, absence

of highly-qualified specialists makes repair difficult for ship’s engineers; besides

most types of repairs are very costly.

Examples of repairs which can be carried out on board ship are main engine

piston, crankcase bearing overhauls, pump and auxiliary machinery overhauls. But

all the parameters must be checked to prevent any possible breakdowns after

repair. Tests and trials should be carried out to check the quality of work, newly

installed equipment, materials and systems.

Cooling System

Cooling is a method of heat removal from components. Cooling of the diesel

engine is very important and necessary due to high temperatures and friction

between moving parts of the engine. The main function of the cooling system is to

carry away the hat, to reduce wear, and thermal deformation. The engine parts that

require cooling are the cylinder, the piston, the exhaust manifold, fuel valves,

crosshead guides, etc.

The cooling medium can be fresh water, sea water, oil and air. The most

often used cooling system is enclosed fresh water system. In this case the engine

room is almost free from corrosive and dirty sea water. Fresh water does not form

scale but it is very costly.

Sea water is free of charge and may be discharged into the sea. But it

contains a lot of minerals, forms deposits and causes corrosion, so it should be well

filtered. Oil as a coolant has a lot of advantages. It reduces engine noise, has

purifying and lubrication functions. But oil absorbs less heat than water. Air as a

coolant is free of charge but a great amount of air is needed to cool a small surface.

Кораблестроение, океанотехника и системотехника

объектов морской инфраструктуры» (только для профиля

кораблестроение)

Container Ships

Container ships are cargo ships that carry all cargo in containers, it is called

containerization. Container ships are all purpose-built and are second only to crude

oil tankers as the biggest cargo ships on the oceans. Container ships are designed in

such a way that no space is wasted. Large container ships are built in Demark,

South Korea, Japan.

Their capacity is measured in TEUs (Twenty-foot equivalent units). This is

the number of 20-foot containers that a vessel can carry. The majority of containers

used today are 40 feet in length. Container ships now carry up to 12,000 containers

on a voyage. Container ships mostly do not carry their own loading gear; loading

and unloading can only be done at ports with the necessary cranes.

There is no way to know the contents of each container. There must be as

little vibration of the loaded container as possible. Thus the operator has to be well-

qualified and experienced to operate the crane efficiently.

In open sea, storms can cause the loss of containers. The great value of cargo

on these vessels makes them a target for pirates.

Shipbuilding

Shipbuilding is a construction of ships. It normally takes place in a

specialized facility known as a shipyard.

The profession of a shipbuilder dates back to ancient times. The early

Egyptians knew how to assemble planks of wood into a watertight hull. Their ships

had a single mast with a single square sail. These ships could also be oar propelled.

The Greek ships had much more oars for additional speed; their ships were of a

light construction.

In the 12th century northern European ships began to be built with a rudder.

Later the above water hull for additional stability and techniques for strengthening

the internal frame were developed.

The demand for ships capable of operating safely in the open ocean led to

documentation of design and construction practice. Thus the field of naval

architecture appeared. But construction techniques changed slowly. Iron was

gradually adopted in ships. In the 19th century steel replaced iron, wood continued

to be used for decks. Modern ships have been produced of welded steel with good

properties.

Double Hull

A double hull is a ship hull design and construction method where the

bottom and sides of the ship have two complete layers of watertight hull surface.

One outer layer is a normal hull of the ship and the second inner hull forms an

architectural barrier to sea water in case the outer hull is damaged and leaks.

The space between the two hull layers is often used as storage tanks for fuel

or ballast water. Double hulls are more effective safety measure than the double

bottom. Double hulls are significantly safer than single hulls. In case of grounding

or other underwater damage, the damage is limited to flooding the bottom

compartment and the main occupied areas remain safe.

Double hulls and bottoms are required in all passenger ships, as well as oil

tankers to prevent or reduce oil spill in to the sea. A double hull also strengthens all

the structure of the ship.

But the double hull increases the risk of corrosion in the double hull and it is

very dangerous for the crew to inspect those areas. Besides there can be explosive

accidents in the double hull.

Строительство»

Marine Structures

A port must include convenient and compact means for landing, loading and

discharging of goods and embarkation of passengers. A dock, a wharf or a quay, a

pier or a jetty and many other features are marine structures.

A dock is constructed to handle passengers or general cargo or a

combination of both. It may be required to handle a specific type of cargo,

particularly bulk cargo such as oil, ore, cement, grain, fertilizers. Constructing a

dock it is necessary to take into consideration some factors: whether a temporary or

a permanent installation is required, the size of ships to use a dock, the direction of

waves and wind, soil conditions and others. There are wet docks, artificial basins

for vessels, and dry docks, when the basin is pumped out.

In many locations the ground may be low and marshy and it is necessary to

fill it in. It is done by dredging the adjacent waterway, creating a navigable canal.

A pier or jetty is a dock which projects into water; sometimes it is called a mole.

Piers provide berths on both sides doubling the berthing space for the same length

of a wharf. New quays and wharves should be designed with regard to the nature

of cargo and passenger traffic.

Port Protection

Sea-going ships can use inland waterways but a river has to be widened and

deepened, its banks must be protected so that they do not wash away and block the

river and river ports with mud. It is necessary to maintain the depth of water in the

basins by dredging otherwise the port would become silted.

Seasonal changes of water discharge in rivers make navigation

unpredictable. Insufficient water depths, variability of precipitation and

evaporation cannot support navigation of any significance.

Particular problem for the inland waterway network and ports arises from

floods. Serious bank erosion takes place causing widening of the original section of

rivers and canals and their silting. Floods threaten the stability of the flood banks

and make navigation difficult because of uncertain depths in rivers and canals.

To the banks subjected to wave action traditional of lining is used. It consists

of stone blocks on the slope above water supported by a row of piles at navigation

level and loose stone below water.

Sometimes dams and barriers are constructed to reduce the height of floods

and to control the flow of water in rivers. Earth dams are mostly often used

because they are considered to be permanent and require practically no

maintenance. The type and height of a dam depend on geology and configuration

of the site.

General Cargo Terminals

Bulk shipping terminals, including berths for tankers, vary with the type of

material and machinery and other facilities required for the particular cargo to be

handled.

As for general cargo terminals they are quite conventional and have changed

little over years. Nowadays they are larger and have wider aprons resulted from

usage of various trucks, portal cranes, railroad lanes for cargo handling. Larger

ships of greater tonnage, more capacious storage areas and transit sheds require

longer and wider piers and wharves.

General cargo terminals must be wide enough to accommodate ships of great

size and to provide space for ships’ maneuvering in and out of the inside berth with

the assistance of a tug.

Transit sheds of general cargo terminals provide temporary storage for (1)

goods discharged from vessels and awaiting clearance through customs and

distribution to warehouses on points of destination and (2) goods arriving by land

and awaiting export. Most terminals along the inland waterways have railroad and

highway connections to facilitate the delivery of cargo.

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