57539881 marine engineering third class study guide and training manual

7/31/2019 57539881 Marine Engineering Third Class Study Guide and Training Manual

1/68

The Sea Cadets

MARINE ENGINEERING

THIRD CLASS

STUDY GUIDE AND TRAINING MANUAL

Issue 1

SCTC GANNET

August 2001


2/68

Marine Engineering Third Class Study Guide and Training Manual

- 2 -

This page is deliberately blank


3/68


4/68


- 4 -



5/68


- 5 -

CONTENTS

SYLLABUS SUBJECT PAGE

REFERENCE

3 ME 1 Health and Safety - General 7

3 ME 2 Health and Safety - Workshop 15

3 ME 3 Introduction to Marine Engineering 21

3 ME 4 Engine Construction 27

3 ME 5 Engine Cycles 33

3 ME 6 Mechanical Systems 41

3 ME 7 Electrical System 47

3 ME 8 Basic Electrical Knowledge 51

3 ME 9 Power Generation 55

3 ME 10 Tools and Fasteners 59

Progress Chart 67


6/68


- 6 -



7/68


8/68


- 8 -

Unit Fire appliances

There may be several types of appliances in your unit, all should be in working order

and comply with current safety standards. Each appliance should be used as directed.

Type Use Colour

(a) Water Wood, paper, textiles. Red

Not on electrical fires.

(b) AFFF Foam Wood, paper, textiles Cream

and flammable liquids.

Not on electrical fires.

(c) Dry Powder General, oil and Blue

electrical.

(d) CO2 Electrical and Black

flammable liquids.

Potential Hazards

There are three types of hazards associated with all engines:-

a) Mechanical Fuels, Oils, spillages and fires.

b) Electrical Shock, burns, arcing and fires.

c) General Rotating machinery, noise and exhaust fumes.

Personal Safety Rules

All accidents must be reported to the instructor immediately.

Any fuel/oil must be washed from eyes instantly, using an eye-wash bottle orfresh tap water.

Oil/fuel spillages are to be mopped up immediately.

Overalls are to be worn when in an engineering environment.

Protective footwear is to be worn in an engineering environment.

Ear defenders are to be used when engines are running.

Barrier cream is to be used before working with machinery.

Wash thoroughly before eating, drinking or using the toilet.

Do not skylark when working with or near to engines or machinery.

Jewellery or items that may get caught in machinery are not to be worn.

Keep away from engine exhaust fumes and hot parts of the engine.


9/68


- 9 -

Fire Drill

These will be explained by your instructors and should be fully understood as your

life may depend on it.

a) They will include fire exits and what to do in case of a fire and where tomuster when you are clear of the fire.

b) Emergency drills will include the various ways in which to safely shut down

an engine. This will be covered before you start the practical projects.

Health and Safety Declaration

This is a form declaring that you have understood the health and safety instructions

given to you by your instructor. All Cadets and Staff including instructors are to sign

this declaration at the start of any Marine Engineering course.

This is an example of a Health and Safety declaration.

I hereby declare that I have been informed of the above hazards by the Course

Marine Engineering Instructor, and agree to abide by the conditions and limitations

imposed as a result of them, during my course. Furthermore, I have been informed of

the emergency procedures to be followed in the event of a Fire, Emergency

evacuation and personal injury or dangerous occurrence.

Date Name Rank/Rate Signature Course Remarks


10/68


- 10 -



11/68


- 11 -

The Sea Cadets

Declaration of Health and Safety Induction

I hereby declare that I have been informed of the above hazards by the CourseMarine Engineering Instructor, and agree to abide by the conditions andlimitations imposed as a result of them, during my course. Furthermore, I havebeen informed of the emergency procedures to be followed in the event of a Fire,

Emergency evacuation and personal injury or dangerous occurrence.

Date Name Rank/Rate Signature Course Remarks


12/68


13/68


14/68


- 14 -



15/68


- 15 -

Health and Safety - Workshop

3 ME 2

Emergency procedures and equipment

Fire Drill and Unit layout - Revise your units fire drill and the layout of your unit.

This is necessary as every one needs to know the layout of the building so that they

can find their way out when blinded by smoke or when in the dark. Locate the Glow

signs and the stowage of your fire fighting equipment in your unit. Find your muster

point and remember it.

First Aid Kits and Eye wash bottles - Using a First Aid kit discuss the contents and

where the first aid kits and eyewash bottles are located in the building and on your

motor boat (if applicable).

Personal protective equipment

These consist of the following:-

(a) Hard Hat Understand that webbing spreads the impact over the whole head

rather than the point of impact. There is also a date system for use,

Unapproved stickers or paint/inks must not be used.

(b) Safety Glasses Worn if there is a slight possibility of eye damage - as a

precautionary measure. For use when working at a work bench or on an

engine.

(c) Ear Defenders Various types, ear-muff type, clip-on, and small plugs

inserted in ear, to reduce danger of exposure to high level noise.

(d) Goggles Used where the possibility of eye damage is increased. They will

absorb impact and give all round protection when handling dangerous fluids.

(e) Face Mask Various types for dust and partial fume removal, they can be

throw-away or re-useable types.

(f) Overalls Various different types, must be washed regularly and instructions

followed. Some may be flame retardant and used for special tasks. Disposable

overalls give little protection and should only be used as a last resort.

(g) Gloves Various types for hand and lower arm protection.

(h) Boots Various types. Most have protective toe and heel guards fitted. Many

are resistant to oils and acids. They should have a non-slip sole for working in

engine rooms and with oily machinery.


16/68


- 16 -

Avoiding hazards in the workshop environment

Fuel and electrical fires can be started by poor maintenance, carelessness and not

following safety guidelines. By following these guidelines, risks to Staff and Cadets

can be minimised.

Stow fuel using a safety type of canister and away from heat.

Petrol fumes will ignite more easily than diesel fumes.

Oils, greases and fuels are slippery and spills must be cleaned up immediately.

No Smoking or Naked Lights rules must be observed and correct extinguishers are

at hand when working in an engineering environment.

Tidiness is next to godliness no rags or other flammable materials are to be leftloafing.

Fumes can kill, particularly engine fumes from the exhaust. Do not operate

engines inside buildings as exhaust gasses will quickly fill a poorly ventilated

room. Any accident, however small must be reported and recorded.

Never work on live equipment. Disconnect electrical supplies before working.

Batteries are to be well ventilated when charging.

Keep water away from electrical components.

Know how to stop a machine before you start it!

Never reach across rotating or moving machinery.

Only properly installed machinery is to be run.

Use the appropriate Personal Protective Equipment for the job in hand.

Use ear defenders when operating machinery.

Wash thoroughly before eating and drinking or using the heads.

Use barrier cream on your hands prior to working.

No jewellery is to be worn when in a workshop environment or operating

machinery.

No skylarking, as this often leads to accidents.

Never lift heavy weights or engines without supervision and the correctequipment.

Electrical hazards Electricity is dangerous, it can kill or injure!

(a) Electric Shock caused by electricity flowing through the body, which

in turn affects the control of the muscles, it can stop the heart and leadto death.

Do not touch the casualty, until he/she is isolated from the power.

Isolate the power supply and summon help.

Carry out first aid if qualified.

(b) Electrical Burns Severe burns are caused at the point of contact with

the electrical source.

(c) Electric sparking and Fires sparks can jump across air gaps, fires can

be caused by overheating of cables, poor insulation or by nearbyflammable materials.


17/68


- 17 -

Hazards associated with all engines are:

We can reduce these potential hazards but we cannot totally eliminate them. Many of

these hazards can be reduced by sensible behaviour and by following basic safety

rules.

Engine Fuel By their very nature, fuel and oils catch fire very easily. Care is to be

taken to ensure that any leaks are dealt with as soon as they occur, and that all

spillages are cleared away as a matter of urgency.

Rotating Machinery This should always be protected by guards where possible.

Never remove a guard whilst a machine is running. Never run a machine without a

guard in place. Never lean over a running engine.

Oil and Personal Hygiene The term mineral oil covers a large range of fuels, oilsand lubricating oils. Prolonged contact with certain oils may lead to swellings and

sores which are slow to heal and could be cancerous. The use of barrier creams or

gloves will prevent this occurring. If in doubt seek medical attention.

Noise The internal combustion engine generates noise at a pitch and a volume which

is detrimental to hearing. Prolonged exposure to noise from a running diesel engine

can lead to permanent damage to hearing and possible deafness. Ear Defenders or Ear

Plugs are to be worn at all times when in the vicinity of running engines.

Reporting of accidents

It mandatory that all accidents are reported to your instructor. This is a legal and a

SCC requirement. Accidents are to be recorded in the Unit accident book and the

Commanding Officer informed.


18/68


- 18 -



19/68


- 19 -

Questions : 3 ME 2

1. What are the 4 main hazards associated with running engines?

2. Name 5 personal safety rules.

3. What is the Emergency Drill for your unit?

4. Where and why do you report an accident?

Cadet Objectives

Know how to reduce the risk of personal accidents (both mechanical

and electrical).

Identify the various items of personal protective equipment, and know

when and how they should be worn.

Course Notes

___________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________


20/68


- 20 -



21/68


- 21 -

Introduction to Marine Engineering

3 ME 3

History of the internal combustion engine

During the 19th

century the steam reciprocating engine was developed. These were

crude engines which had poor efficiency, were temperamental and used a lot of

labour. By the late 1880s they were widely used in transport on land and sea and in

industry. The power was introduced into the engine in the form of steam which

necessitated the use of a boiler and auxiliary pumps, requiring a lot of space.

At this time scientists and engineers throughout Europe were obsessed with the idea

of power that could be created within the cylinder itself. If this could be achieved thesteam power unit could be dispensed with. Many problems faced these men, changes

in design to withstand the high temperatures and pressures inside the cylinder;

suitable fuels to bring about the power required and countless others. Working

independently and yet with a common aim these men gradually found the answer to

their problems and by 1900 had succeeded. Research followed two definite lines of

thought and from these the Spark Ignition Engine and the Compression Ignition

Engine were designed.

Development of the internal combustion engine

1770 First steam carriage Cagnot, French. It kept turning over at corners.

1794 Crude Gas Engine Robert Steel, English.

1801 Gas Engine from wood Lebon dHumberstien, French. Basic 2 stroke.

1805 First Internal Combustion Engine vehicle. Voltaic spark, kick open exhaust

Issac de Rivaz, Swiss.

1826 Forty litre Gas Engine. Poor power/weight ratio David Gordon.

1858 First proper 2 stroke. Coal gas using platinum spark plug Joseph Lenoir

Belgium.

1877 Niklaus Otto tried to patent the 4 stroke but Karl Benz fought the patent, and

in 1886 the patent was made invalid and Benz was in charge of the 4-stroke

development. The actual designer of the 4 stroke was Ottos Chief Engineer

Gotlieb Daimler. (Hence the Daimler cycle).

1884 Engines were mass produced by Benz.

1892 Rudolph Diesel designed a heat engine. (Compression Ignition Engine).

1897 First Great British Diesel Engine Mirlees.

1900 Engines followed two paths Spark Ignition Engine (SIE) and Compression

Ignition Engine (CIE).


22/68


- 22 -

The different types of engine

Steam Engines These can be reciprocating or rotary (turbine). They require a boiler

and auxiliary pumps to provide the power, and could be described as external

combustion engines, taking up much more space than internal combustion engines.

Gas Turbines- These are high powered, expensive and are used to power modern

major warships, trains and aircraft. They are not piston engines and are not covered by

the course.

Internal Combustion Piston Engines (ICPE) This term covers both the Spark

Ignition Engine and the Compression Ignition Engine.

Spark Ignition Engine (SIE) In the spark ignition engine an easily vaporised fuel,

normally petrol is mixed with air and is ignited by an electric spark at the end of the

compression stroke. This is the basic motor car engine or outboard motor.

Compression Ignition Engine (CIE) In this engine a fuel of a much higher flash

point is used, giving a much higher safety factor. The fuel is ignited by the high

temperature of the air at the end of the compression stroke. When the air is

compressed in the cylinder, by the piston, to several hundred degrees, fuel is injected

as a fine spray into the cylinder. This engine is the basic diesel engine fitted in some

cars, vans, lorries and most small boats.

Diesel engines are used because they are economical, self contained and are more

efficient than petrol engines, are generally cheaper to maintain, and their fuel is lesshazardous than petrol.

Internal Combustion Piston Engines

Spark Ignition Engines (Petrol) Compression Ignition Engines

(Diesel)

Steam Engines Gas Turbines

HEAT ENGINES


23/68


- 23 -

Types of movement

There are two types of movement that can transmit power reciprocating and rotary.

They transmit power from the piston through the engine to the shaft and propeller.

Reciprocating Movement - Movement in up and down motion. An example is the

piston moving from the top of the cylinder to the bottom of the cylinder.

Rotary Movement Movement in a circular motion. An example is a propeller shaft.

In a piston engine, both rotary and reciprocating movements are used to convert

power from the engine to the propeller.

Main components of a basic piston engine

Engines may vary considerably but the majority incorporate the components listed

below. These components will be covered in more detail in the next Section, 3ME4 -

Engine Construction.

1. Cylinder block and crankcase. The unit forms the principal part of the

engine. It may be cast as a single unit, or the cylinders may be detachable from

the crankcase.

2. Cylinder head. The head, usually detachable, is bolted to the cylinder block

and forms a gas tight and water tight lid on each cylinder.

3. Sump. This is a light casing fitted to the underside of the crankcase to

contain the lubricating oil.

4. Piston. The piston is a sliding fit in the cylinder bore. It is fitted with piston

rings to prevent gas leakage past the piston. The top of the piston is known as

the crown. The lower part, which acts as the guide is called the piston skirt.

5. Connecting rod. The connecting rod is attached to the piston at one end by a

gudgeon pin which is fitted to the piston. This is known as the Little End. The

bottom end of the connecting rod is attached to the crankshaft, at the Big EndBearing.

6. Crankshaft. The crankshaft is carried in main bearings which are part of the

crankcase casting. It converts the reciprocating movement of the piston to

more useful rotary movement.

7. Flywheel. Most internal combustion piston engines have a heavy flywheel to

carry the engine over the non-power strokes, particularly in the four-stroke

engine where there is only one power stroke in four on each piston. The

flywheel is attached to the crankshaft, and is outside the crankcase.


24/68


- 24 -

8. Valves. The valves are usually fitted in the cylinder head, and are called

overhead valves. When open they allow the passage of Air, Fuel, and Exhaust

gas, when shut they seal the cylinder.

9. Camshaft. Each valve is lifted by a cam, which is pear shaped and machined

in an angular position on the camshaft so that it will lift the valve for thecorrect period.

10. Rocker gear. Overhead valves are operated by rockers with one end of each

rocker bearing on the cam or push rod, and the other end on the valve stem.


25/68


- 25 -

Questions : 3 ME 3

1. Who invented the Compression Ignition Engine?

2. What do the letters SIE and CIE stand for?

3. Explain the different types of movement in the piston engine.

4. What is a disadvantage of a steam engine?

5. Name two advantages of a diesel engine.

Cadet Objectives

Describe the main differences between petrol and diesel engines.

Course Notes

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________


26/68


- 26 -



27/68


- 27 -

Engine Construction

3 ME 4

General Arrangement of a Diesel Engine

Diesel engines have an infinite number of jobs to carry out and are, therefore, of many

various shapes and sizes. From simple single cylinder engines to multi-cylinder

engines however, the basic components remain the same.


28/68


- 28 -

The main components

Engines may vary considerably but the majority incorporate the components listed

below.

1. Cylinder block and crankcase. The unit forms the principal part of theengine. It may be cast as a single unit, or the cylinders may be detachable from

the crankcase. A water cooling space is included in the cylinder block. Small

air cooled engines have fins to provide a large surface area for the cooling air.

2. Cylinder head. The head, usually detachable, is bolted to the cylinder block.

In some small two-stroke engines, however the cylinder head is part of the

cylinder and can not be detached. A water cooling space in the head

communicates with the water cooling passages in the cylinder block. Air

cooled types incorporate fins, as in the cylinder block.

2. Sump. This is a light casing fitted to the underside of the crankcase to

contain the lubricating oil. This is normally OMD (oil mineral detergent), or a

commercial equivalent.

3. Piston. The piston is a sliding fit in the cylinder bore. It is fitted with piston

rings to prevent gas leakage past the piston. The top of the piston is known as

the crown. The lower part, which acts as the guide is called the piston skirt.

Compression rings are fitted to maintain a seal between the piston and the

cylinder wall and an oil control (scraper) ring removes excess oil from the

cylinder wall.

4. Connecting rod. The connecting rod is attached to the piston at one end by a

gudgeon pin which is fitted to the piston. A bush in the end of the connecting

rod provides a bearing surface. This is called the small end bearing. The

bottom end of the connecting rod is attached to the crankshaft, with a halved

bearing and bottom cap securely bolted to the connecting rod. This is called

the big end bearing.

5. Crankshaft. The crankshaft is carried in main bearings which are part of the

crankcase casting, with halved bearing shells and bottom caps securely bolted

to the crankcase.

6. Flywheel. Most internal combustion piston engines have a heavy flywheel to

carry the engine over the non-power strokes, particularly in the four-stroke

engine where there is only one power stroke in four on each piston. The

flywheel is attached to the crankshaft, and is outside the crankcase, but

sometimes it is enclosed by the clutch case, or the reversing gear case. The

flywheel usually incorporates a toothed ring into which the engine starter

pinion engages to start the engine.

7. Valves. The valves fitted to all four-stroke engines and some to two-stroke

engines are mushroom-shaped. They have a long stem, over which a spring is

installed to hold the valve on the seating. The valves are usually fitted in thecylinder head, these are called overhead valves.


29/68


- 29 -

Engine components cont

8. Camshaft. Each valve is lifted by a cam, which is pear shaped and machined

in an angular position on the camshaft so that it will lift the valve for the

correct period. The camshaft may lie above the cylinder head, when it is called

an overhead camshaft, or alongside the crankshaft with push rods to lift thevalves if they are of the overhead type.

9. Rocker gear. Overhead valves are operated by rockers with one end of each

rocker bearing on the cam or push rod, and the other end on the valve stem.

Side valves are usually placed immediately above the cams so that the rockers

are not required.

10. Tappets. All valve gear is fitted with tappets, a form of set screw and lock-

nut, which may be fitted to the rockers, the push rods, or the tappet spindle for

side valve engines. The tappets are adjusted to give a slight clearance for

expansion between the tappet and the valve stem. This clearance is alwaysstated for inlet and exhaust valves of each engine.

OVERHEAD VALVE GEAR


30/68


- 30 -

11. Timing gear. The camshaft must be accurately timed to the crankshaft so that

the valves will open when required and for the correct period. The timing gear

consists of gear wheels usually mounted at the front end of the crankcase and

enclosed by a timing case. The gear wheels are marked to show the correct

setting.

12. Fuel pump and injectors. The fuel injection pump may be fitted on the side

of the engine, or an individual fuel injection pump may be fitted alongside

each cylinder. The pump is driven by the timing gear so that fuel is injected

into each cylinder at the correct time. Each cylinder head is fitted with an

injector, which consists of a non-return valve and a nozzle which produces a

fine spray of fuel into the cylinder. The speed of the engine is varied by a

governor which controls the quantity of fuel discharged by the fuel pump.

13. Joints/Gaskets. These are fitted to prevent the leakage of oil, gas or water.

The cylinder head gasket is normally made from copper and compressed fibre,whilst other joints are of treated paper or metal-to-metal with joining

compound between the mating faces.


31/68


- 31 -

Questions : 3 ME 4

1. What is a camshaft?

2. What is a crankshaft?

3. Name the two bearings associated with the connecting rod.

4. What is the purpose of the flywheel and what is the starter ring for?

5. Name two parts of a piston.

6. On a six cylinder diesel engine how many injectors are fitted?

7. Show your instructor the main parts of the diesel engine on your units diesel,

or on a diagram of a diesel engine.

Cadet Objectives

1. Identify all major components and understand their purpose.

2. Know the function of a gasket.

Course Notes

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________


32/68


- 32 -



33/68


- 33 -

Engine Cycles

3 ME 5

The Four Stroke Cycle

The four-stroke cycle is so called because there are four distinct parts to each

complete cycle. The cycle keeps the piston moving upwards and downwards and the

crankshaft revolving, and the sequence is as follows:

The Induction Stroke The piston is moving down the cylinder and sucking in clean

air through the air inlet filter, down through the inlet manifold and into the cylinder,

via the inlet valve. The inlet valve has opened for this specific operation and closes

when the piston is at the bottom and the cylinder is full of clean air.


34/68


- 34 -

The Compression Stroke The piston is now moving back up the cylinder, both the

inlet valve and the exhaust valve are shut and no air can escape. The air is now being

compressed (compression) and as this occurs it heats up. When the piston is at the top

of the stroke and the air is at its most compressed state, diesel fuel is injected into the

cylinder as a high-pressure spray.


35/68


- 35 -

The Power stroke The fuel and air mixture compressed within the cylinder, burn

rapidly and expand, driving and forcing the piston down, producing the power.


36/68


- 36 -

The Exhaust stroke The piston travels back up the cylinder pushing all spent gases

out of the opened exhaust valve, which closes when the piston reaches the top of its

travel. The inlet valve then opens as the cycle starts again.

The power produced is, in part, directly related to the volume of the cylinders,

although other factors enhance performance. It is the amount of fuel/air burnt that

produces the power.

Combustion (the fire triangle) All internal combustion engines require Heat, Fuel

and Air for combustion. Combustion takes place when energy is released by the

atomising of the fuel under pressure and bringing it into contact with the high

temperature of the compressed air. This mix of fuel, air and heat causes an increase in

temperature and pressure in the top of the cylinder. The ignition and expansion that

occur will push the piston downward.


37/68


- 37 -

The Two Stroke Cycle

The exhaust valve opens much earlier in the power stroke than in the case of the 4-

stroke cycle. With the piston still descending inlet ports cut into the base of the

cylinder walls are uncovered. Air enters the cylinder until the piston again covers the

inlet ports as it ascends. The exhaust valve has by this time closed so that a charge ofair is trapped in the cylinder. The piston continues to rise, compressing air until just

before the top of the stroke when the fuel is injected. The fuel is ignited by the heat of

compression and the burning gases drive the piston down in the power stroke.

NOTE: THE CRANKSHAFT WILL ROTATE TWO REVOLUTIONS TO

COMPLETE ONE FULL CYCLE IN THE 4-STROKE CYCLE AND

ONE REVOLUTION IN THE 2-STROKE CYCLE.


38/68


- 38 -



39/68


- 39 -

Questions : 3 ME 5

1. When the piston moves down during the power stroke is:

a) The exhaust valve open or shut?

b) The inlet valve open or shut?

2. When the piston travels back up the cylinder after the power stroke is:

a) The exhaust valve open or shut?

b) The inlet valve open or shut?

3. How many revolutions will the crankshaft do during one full cycle of a4-stroke cycle engine?

Cadet Objectives

1. Know the three elements of combustion.

2. Know the 2 and 4 stroke cycles.

3. Describe the relative positions of pistons at each stage of the cycle.

Course Notes

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________


40/68


- 40 -



41/68


- 41 -

Mechanical Systems

3 ME 6

Essential Mechanical Systems

Diesel engines have 3 main systems that provide the following functions.

Lubricating oil system to cool and lubricate the moving parts of the engine.

Fuel system to provide clean fuel to the injectors so that it can be burnt to givepower.

Cooling system that will cool the engine and its auxiliary components.

The basic mechanical system

Any basic system has a tank, filter, pump and a method of indicating it is runningcorrectly. Systems have a way of returning excess fluid back to the tank.

Tank Filling

Tank drain

BASIC MECHANICAL SYSTEM

The tank is filled to the correct working level, excess can be drained away. The liquid

is drawn through the filter which removes any debris. The liquid is then pumped up to

pressure using the pump and discharged to the system where it is used. Liquid is then

returned back to the tank and the cycle repeats itself.

When filling any system you must use a correctly labeled container and fill it with the

correct fluid. Oil in to the sump and cooling water into the fresh water header tank.

Tank

Pump

Filter System


42/68


- 42 -

Beware of filling the wrong tank with the wrong fluid. Your instructor will show you

how to replenish correctly all the engine levels.

The system pressure can be monitored using a pressure gauge. Oil, water and fuel

levels are always checked prior to starting the engine.

It is good engineering practice to monitor the conditions of the mechanical systems

regularly for problems such as overheating, lack of cooling or leaks on the various

systems. Learning the components of the engine will help you identify any problems

when the engine is running. Many checks can be done before the engine is started to

ensure your engine will run efficiently.

Lubricating oil system

The lubrication system will supply clean oil under pressure, from the sump to the

engine bearings, gears and rocker gear. Most lubricating oil systems will have an oil

pressure gauge for checking the system pressure. The lubricating oil level is checked

using a dip stick which shows the level in the engine sump. The oil system has a

thermostat to keep the lubricating oil at a constant temperature.

BASIC DIESEL ENGINE LUBRICATION SYSTEM

Oil in

Oi l

pump

Oi lfilter

Top endvalvegearpushrods

Camshaft

Crankshaftbearings

Timing

gears

Sump

Oil pressure

gauge

Di st ick


43/68


- 43 -

Fuel system

Diesel engine fuel systems supplies clean fuel from the fuel tank, through filters to a

lift pump and finally to the injection pump, it is then delivered to the individual

injectors which spray the fuel into the top of the piston. Fuel systems must be keptclean and free of any water, which would otherwise collect at the bottom of the fuel

tank.

BASIC DIESEL ENGINE FUEL SYSTEM

Cooling systems

Diesel engines are cooled by air or by a water cooling system. Air is used to cool the

outer fins of the cylinder head. It is directed over the fins giving a cooling effect.

Most diesel engines are cooled by fresh water which circulates under pressure around

the engine cylinder block and cylinder heads narrow passages, this fresh water is

cooled by pumped sea water which also passes through a fresh water cooler. The fresh

water is maintained at the correct temperature by a thermostat.

WARNING: THERE ARE MANY PARTS ON ENGINES WHICH GET HOT

AS THE ENGINE WARMS UP, CARE SHOULD BE TAKEN TO

KEEP CLEAR OF MOVING AND HOT COMPONENTS. THE

COOLING WATER PIPE WILL GET VERY HOT UNTIL THE

THERMOSTAT VALVE STARTS TO REGULATE THE

ENGINES TEMPERATURE.

Fueltank

Mainfi l ter

Liftpump

Finefi l ter

Injection

pump Injector

Fuel i nLeak off l ines


44/68


- 44 -

Cooling systems (contd)

DIRECT OR RAW WATER COOLING

INDIRECT OR FRESHWATER COOLING

Sea

Cock Strainer Water

pump

Oi l

Cooler

Engine

block

Exhaust

mani fold

Directly attached to the engine

Sea

Cock Strainer Seawater

pump

Oi l

Cooler

Thermostat

Directly attached to the engine

Enginecylinderhead &

block

HeaderTank

&Heat

exchanger

Freshwater

pump

Exhaustmanifold


45/68


- 45 -

Questions : 3 ME 6

1. Name the three main systems fitted to a diesel engine.

2. How would you check the oil level of a diesel engine?

3. What are the main components of any basic system?

4. Why are systems checked before and after starting?

Cadet Objectives

1. Describe the purpose of each of the mechanical systems, and the medium used

by each system.

Course Notes

___________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________


46/68


- 46 -



47/68


- 47 -

Electrical System

3 ME 7

The main electrical system components

Electrical systems fitted in a SCC power boat may vary slightly, but the majority

would include:

(a) Battery - This provides the stored electrical energy for the electrical system. It

is usually a lead/acid type. It will be covered in detail in 3 ME 9.

(b) Starter Motor - This is fitted with a pinion which engages with a toothed rim

on the flywheel to turn the engine. As soon as the engine starts, it over-runs

the pinion and causes it to disengage. The starter can be either a pre-engagedstarter or an inertia type starter motor.

The starter motor is connected to the battery via a switch. When the switch is

closed, current passes to the field coils and causes their soft iron cores to

become magnets, whilst at the same a second magnetic field is formed in the

armature. The interaction between these two magnetic fields causes the

armature to rotate. The shaft on the armature has a mechanism to turn over the

flywheel, such as a solenoid or spring loaded pinion, which then drives the

flywheel. When the engine has started the solenoid/spring mechanism

disengages the pinion from the flywheel.

(c) Alternator/Dynamo - This charges the battery, and is driven by a belt off the

engine. The rotating internal parts generates electricity and send it to the

battery which will continually charge whilst the engine is running. If there is a

heavy demand on the battery, it will discharge its charge, and render the

starting circuit inoperable when the next attempt to start the engine is made. A

small red light or negative indicator on the engine start panel will indicate if

the system is not charging.

(d) Voltage Regulator - This regulates the voltage at 12 volts, and is a usually a

sealed component.

(e) Wiring loom - Electricity is transferred from the different electrical

components through terminals to this loom of insulated wires. The wires are

colour coded to identify which components supply each other. The wiring

loom is earthed at various points to prevent components becoming live, to

reduce the chance of electrocution or electric shock.

(f) Fuses - These protect the various components and electrical circuits from

electrical defects. Fuses are coded by colour and must be the correct size for

the circuit. The different types of Fuse will be covered in Class 2.


48/68


- 48 -

BASIC DIESEL ENGINE ELECTRICAL SYSTEM

Materials used in electrical components

Insulators: Materials which dont allow current to flow freely. (High resistance).

eg. Plastic, wood, air, rubber, glass.

Conductors: Materials which allow current to flow freely. (Low resistance).

eg. Metal, water, carbon.

Starter switch

Bilge pumps &Alarm s stems

Starter motor

Distributionboard

- +Battery

Solenoid

Battery isolatorswitch

Generator Navigationlights, horn,

VHF etc.


49/68


- 49 -

Questions : 3 ME 7

1. What is the source of power for the electrical system?

2. Identify the major electrical components in your unit motor boat

3. Explain why the electrical system uses a dynamo/alternator?

4. What are the dangers of electrical circuits?

5. What is the function of fuses in the electrical system?

Cadet Objectives

Identify all major electrical components and understand their purpose

Provide examples of insulators and conductors

Course Notes

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________


50/68


- 50 -



51/68


- 51 -

Basic Electrical Knowledge

3 ME 8

Simple Circuits

A circuit is the combination of several electrical components that when connected

together and provided with a power source will cause an action of some kind. This

action will be in the form of light, movement, heat or noise.

A basic circuit will comprise of:-

Electrons. Current is the movement of electrons through a material. Before a current

can flow in a conductor there must be an applied voltage. This can be produced by

chemicals, heat, light, friction, pressure and by magnetism. Conventional current flow

is from positive to negative.

Current. Is the movement of free electrons, current is measured in Amps.

Voltage. Voltage is an electromotive force (or potential difference) measured in

volts.

Resistance. Resistance is measured in Ohms and depends on temperature.

Ohms Law. At a constant temperature, the steady current flowing through any

conductor is directly proportional to the potential difference across its ends.

I = V

R

Where I is current (amps)

V is voltage (volts)

R is resistance (ohms)

Your instructor will demonstrate Ohms law and show you how to calculate the

different methods of calculating voltage, current and resistance.

Electrical circuits can be measured using a multimeter which will carry out the

following tests.

a) Continuity.

b) Measure voltage.

c) Measure resistance.

d) Measure current.e) Test a fuse.


52/68


- 52 -

Simple circuits (contd.)

There are two types of electrical circuits, and both are used for different applications.

Series Is when components are connected one after another (similar to Christmas

tree lights) and they all share the current equally. If one of the componentsfail, the circuit will fail.

Example of a circuit in series

Parallel Is where each component has its own circuit, and if one component fails the

others will continue to work.

Example of a circuit in parallel


53/68


- 53 -

Questions : 3 ME 8

1. In which direction does current move?

2. Explain Ohms Law in your own words.

3. What is the difference between series and parallel?

Cadet Objectives

1. Construct a circuit to demonstrate series and parallel connections.

2. Carry out practical measurements of current, voltage and continuity.

3. Demonstrate an understanding of Ohms Law.

Course Notes

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________


54/68


- 54 -



55/68


- 55 -

Power Generation

3 ME 9

Generators

A generator is used to convert mechanical rotating energy into electricity. The

generator is driven by a belt, which connects the engine crankshaft and the generator

rotor. The electricity generated is discharged to the electrical system.

This belt driven rotor is turned within the generator, and is surrounded by opposing

magnets that have been wound with wire. This rotating movement within the

magnetic field generates electricity.

TYPICAL MOTOR BOAT GENERATOR

Electrical current

Electrical current is the movement of electrons through a conductor, they are moved

by an electromotive force (emf), it is measured in volts, this will have been

demonstrated in 3 ME 8 using the multimeter when making electrical circuits.


56/68


- 56 -

Batteries These can be wet, dry or gel type cells.

The wet cell (secondary cell) is a container which has plates of different materials that

are submerged in electrolyte. A chemical reaction takes place between the plates and

positive particles migrate through the electrolyte to the negative plate. A circuit is

made between the plates and this will continue until the electrolyte has beenexpended. This type of battery is normally used for motor boats.

The dry cell (primary cell) is made of a carbon rod surrounded by manganese dioxide

with an electrolyte of ammonium chloride. The cell is sealed and is activated when

connected to a circuit, such as a torch. Different chemicals can be used, but the

principal is the same. The average voltage from the cell is 1.5 volts.

The gel cell is a sealed unit which has been constructed similarly to the wet cell. The

electrolyte is contained within the unit and cannot be opened. The battery will only

last a limited lifetime, where upon the battery has to be replaced. This type of battery

is now fitted in most new cars.

A number of cells connected together in series is called a battery. The usual output

would be 12 volts for a SCC motor boat.

Primary cells cannot be recharged; secondary cells are rechargeable.

Battery Maintenance

WARNING: BATTERY CHARGING OR ANY OTHER FORM OF

BATTERY MAINTENANCE MUST ONLY BE CARRIED OUT UNDERCLOSE ADULT SUPERVISION

When checking batteries, personal protective equipment must be worn. This includes

goggles, gloves and an apron. A battery hydrometer must be used to check the

specific gravity of the battery, for a lead acid type the reading should be 1.230 to

1.260. If using a Nickel cadmium type the reading will be 1.160 to 1.230. A

discharged cell will read 1.18 or less on the hydrometer. The readings should be taken

at a cell temperature of 20 degrees C.

Should the electrolyte need to be replenished, distilled water should be used, and

filled to just above the plates.

Batteries must be charged in a well-ventilated area with the plugs removed from the

top of the battery. There must be No Smoking or naked lights when charging as

batteries discharge hydrogen which is an explosive gas.

Battery terminals should also be checked for tightness and never make contact

between the positive and negative terminals as this will complete a circuit. Battery

terminals should be kept clean and protected with petroleum jelly (Vaseline), to stop

corrosion products building up.


57/68


- 57 -

Questions : 3 ME 9

1. Explain how electricity is generated for a motor boat.

2. What is the difference between a primary cell and a secondary cell?

3. Why must battery charging take place in a well ventilated area?

4. What are the SAFETY rules when working with batteries?

5. Why are battery terminals kept clean and protected?

Cadet Objectives

Describe the various methods of power generation

Demonstrate the use of a hydrometer and personnel protective equipment

when checking the condition of a battery.

Course Notes

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________


58/68


- 58 -



59/68


- 59 -

Tools and Fasteners

3 ME 10

Common Workshop Tools

The following tools and fasteners are an example, you may have others which you use

frequently which are not covered here:.

Check your tools for worn and broken parts, before they are used. An example would

be a hammer that has a broken or damaged shaft, the head securing pin may be

missing or loose. Files and screwdrivers must have handles fitted.

Beware of using excessive force, and the hazards to health when not using the correct

tools.

Understand the correct way to tighten and loosen a nut. Clockwise to tighten and anti-

clockwise to loosen a nut.

Soldering Irons should be used under the supervision of a qualified instructor.

Measuring tools are expensive and should be used with care. Scribers and calipers

should not be used for poking dirt out of holes, or skylarking. They are precision

instruments and should be treated as such.

Multimeters are expensive and should be used with care. Never skylark with this

instrument as used incorrectly it could give you an electric shock.

There are many different types of tools and different types of fasteners, some of

which are listed below:

(a) Spanners Open ended, Ring, Adjustable, Box and

Combination.

(b) Sockets Various sizes, Metric and Imperial.

(c) Screwdrivers Cross-head, Flat-head.

(d) Hammers Mallet, Ball-pein and Claw.

(e) Allen Keys Metric and Imperial.

(f) Pliers Long-nosed, Side-cutting.

(g) Hacksaw Standard and Junior.

(h) Files Half-round, Triangular and Flat.

(i) Fasteners Nuts, Bolts, Washers and Connections.

(j) Soldering Iron Electrical

(l) Multimeter Electrical


60/68


- 60 -

Fasteners and Gaskets

(a) The termination and connection of electrical wiring should be done with pliers

and suitable connections. It is important to prevent loose connections that

could earth or short the electrical circuit, or may even start a fire.

(b) Gaskets are pre-formed or can be made from commercial gasket material.

Most diesel engine gaskets are now compressed fibre and copper, fitted to

prevent the leakage of oil, gas or water. Some joints may be metal-to-metal

with jointing compound between the faces.

(c) Fasteners You should be able to recognise and remove/replace nuts, bolts,

washers, screws, clips, split pins and common fasteners.

When a project has been completed, return

your tools and ensure that the working area is

left in a clean and tidy condition. All surplus

items are to be properly disposed of.


61/68


- 61 -


62/68


- 62 -


63/68


- 63 -


64/68


- 64 -


65/68


- 65 -

Questions : 3 ME 10

1. Describe what checks you would carry out on tools for before using them.

2. Demonstrate how electrical connections are checked for security.

3. Why is it important to use the right tool for the right job?

4. Why is it dangerous to use a file without a correctly fitted handle?

Cadet Objectives

1. Demonstrate an understanding of the correct use of standard mechanical

and electrical tools.

2. Show how awareness of the correct way to loosen and tighten fasteners,

and the likely hazards to health when not using the correct tool.

Course Notes

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

______________________________________________________________________________________________________________________________________________________________________

___________________________________________________________________________________


66/68


- 66 -



67/68


- 67 -

The Sea Cadet Corps

Marine Engineering Specialisation

Progress Chart for Class 3

Lesson Instructor Date

3 ME1

Health & Safety

3 ME 2

H & S - Workshop

3 ME 3

Introduction

3 ME 4

Engine Construction

3 ME 5

Engine Cycles

3 ME 6

Mechanical Systems

3 ME 7

Electrical System

3 ME 8

Basic Electrical

3 ME 9

Power Generation

3 ME 10

Tools & Fasteners

3 ME 11

Practical Projects

Revision period

Examination

Notes:

1. Apply to your ASO(ME) who will supply an authorised examination paper.

2. SCC form T7(MarEng) to be signed by CO and forwarded to ASO(ME) on

completion of the examination.


68/68


57539881 marine engineering third class study guide and training manual

Documents