Module 3

Onboard Equipment on a Ship

Engine Room (ER)

MARINE ENGINEER

Anybody who wants to be a Marine Engineer must be ready and prepared to spend a long period in training. Practical training is of crucial importance because the sea environment is very demanding. Sea training is not easy, although it only takes place when a candidate has sufficient knowledge already. A cadet engineer has to learn new skills and put them into practice. For instance, he learns how to do machine repairs like opening up different bearings, tube sleeves, and rusty items like nuts and bolts, as well as cleaning valves and changing filters.

 

The successful candidate may be awarded a diploma and will then be able to work on ships as a qualified Marine Engineer class four. Then after some time spent working on ships, he can sit for competency certificates as a class-two Marine Engineer. Again, after some time at sea, he can sit for the class-one certificate of competency, which qualifies him to take up the job of the Chief Engineer on board a ship.

 

A marine engineer can be called a ship mechanic, a ship machinist, a ship engine operator, or a ship engine room attendant.

Ships Propulsion Systems

The main engine of a ship is connected to its propeller with the help of a shaft. This whole system, along with other vital machineries is known as the ship propulsion system. The type of propulsion system used in a ship depends on several factors such as speed, power, ship type etc.

Since the time man started using ships, various types of propulsion systems have been used depending on the ship’s requirement. In this article, we will try to have a brief overview of the kind of propulsion systems that are available in the market and their selection procedure according to the requirement.

Marine engines

There are four main types of marine engines:

  • Diesel engine

  • Steam turbine

  • Gas turbine

  • Marine nuclear plant

Each engine has its own particular application.

Diesel engine

The diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber during the final stage of compression.

It is similar to that used in a bus. Its power is expressed as brake horsepower (bhp). This is the power put out by the engine.

The power output of a modern marine diesel engine is about 40,000 brake hoursepower. This is now expressed in kilowatts.

Diesel engine

The diesel engine has the highest thermal efficiency of any regular internal or external combustion engine due to its very high compression ratio.

Internal combustion engine is an engine in which the combustion of a fuel (normally a fossil fuel) occurs with an oxidizer (usually air) in a combustion chamber. In an internal combustion engine the expansion of the high-temperature and pressure gases produced by combustion applies direct force to some component of the engine, such as pistons, turbine blades, or a nozzle. This force moves the component over a distance, generating useful mechanical energy.

Low speed engine.

Diesel engines are manufactured in two stroke and four stroke versions.

Steam Turbines

Steam turbines are high pressure steam is directed into a series of blades or vanes attached to a shaft, causing it to rotate. This rotary motion is transferred to the propeller shaft by gears.

Steam is produced by boiling water in a boiler, which is fired by oil.

Recent developments in steam turbines which have reduced fuel consumption and raised power output have made them more attractive as an alternative to diesel power ships.

Gas Turbines

A gas turbine engine is a very light and easily removed for maintenance.

Energy is added to the gas stream in the combustor, where fuel is mixed with air and ignited. In the high pressure environment of the combustor, combustion of the fuel increases the temperature. The products of the combustion are forced into the turbine section. There, the high velocity and volume of the gas flow is directed through a nozzle over the turbine's blades, spinning the turbine which powers the compressor and, for some turbines, drives their mechanical output. The energy given up to the turbine comes from the reduction in the temperature of the exhaust gas.

It is also suitable for complete automation.

Nuclear power engine

Nuclear power engine in ships has mainly been confined to naval vessels, particularly submarines.

But this form of power will be used more in merchant ships as oil fuels become more expansive. A nuclear-powered ship differs from a conventional turbine ship in that it uses the energy released by the decay of radioactive fuel to generate steam. The steam is used to turn a shaft via a tubine in the conventional way.

SHAFT

A shaft is a revolving rod that transmits motion or power: usually used of axial rotation.

Axial- rotary motion of an object around its own axis;

Auxiliary Equipment

Marine Auxiliary Systems

As the name itself suggests, auxiliary systems are there to fulfil several other requirements on board marine vessels apart from propulsion, which is of course the main function.

Despite the importance of the main ship diesel engines, it does not require much intuition to realize that only providing motive power for the ship is not sufficient. The marine vessels have lots of other requirements which make them a complete self sustaining unit in the middle of the sea. Some of these requirements include electric power.

Power is required for lighting purposes in the accommodation and other areas, and also to operate the various machineries on deck and in the ship’s engine room.

The term “marine auxiliary systems” mainly refers to the auxiliary engines or generators that generate electrical energy for consumption on board.

However the term is also used in the broader sense to denote other equally important machineries and equipment, without which the ship will not be in a position to operate normally. These could include some of the following:

  • Motors & pumps

  • Boiler

  • Inert Gas plant

  • Deck cranes

  • Mooring Winches and Windlass 

  • Simple Centrifuges for Oil Purification

  • Boiler make-up water treatment plant and storage

  • Fuel preparation system

  • Generator cooling

  • Generator high voltage system

  • Monitoring and alarm system

  • Battery supplied emergency lighting and communication

Auxiliary Equipment

Auxiliary engines or generators which are one of the most prominent components of the marine auxiliary systems list, are interesting piece of machinery having their own cooling system, fuel system, lubrication system and so forth. Since one or more generators keep running continuously except during black out or dry-dock, they often demand routine maintenance as well as emergency breakdown repairs.

Boilers are important since steam is required for several purposes on board ships. So are the Inert Gas generators which are used to maintain inert atmospheres in cargo tanks which carrying such a cargo.

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