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Iveco Marine Service Manual

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MARINE DIESEL ENGINES
INSTALLATION HANDBOOK
TECHNOLOGICAL EXCELLENCE
MARCH 2004
II
Publication IVECO MOTORS edited by: IVECO PowerTrain Advertising & Promotion Pregnana Milanese (MI) www.ivecomotors.com
Printed P3D63Z001 E – March 2004 Edition

CONTENTS

MARCH 2004INTRODUCTION
III
CONTENTS 3
PREMISE V
INTRODUCTION 7
1.1 ENGINE 9
1.2 BOAT 17
ENGINE/BOAT CHOICE FACTORS 23
2.1 GENERAL INFORMATION 25
2.2 USE OF THE BOAT - ENGINE SETTING 25
2.3 ENGINE PERFORMANCE 26
2.4 ENVIRONMENTAL CONDITIONS AND “DERATING” 29
2.5 MECHANICAL AND AUXILIARY COMPONENTS 31
2.6 SPEED AND POWER PERFORMANCE 31
DRIVE 33
3.1 PROPULSION SYSTEMS 35
3.2 PROPELLERS 41
3.3 INVERTER-REDUCER 47
3.4 TORSIONAL VIBRATIONS 49
ENGINE INSTALLATION 51
4.1 TRANSPORTATION 53
4.2 INSTALLATION ON THE HULL 53
4.3 SUSPENSION 53
4.4 TILTING 56
4.5 AXIS LINE ALIGNMENT 57
AIR SUPPLY 59
5.1 SUPPLY AND VENTILATION 61
5.2 ENGINE ROOM VENTILATION 61
5.3 AIR FILTERS 62
FUEL SUPPLY 65
6.1 FUEL CHARACTERISTICS 67
6.2 HYDRAULIC CIRCUIT 67
6.3 RESERVOIR 69
6.4 ENGINE-RESERVOIR PIPES 71
6.5 FUEL FILTERING 72
LUBRICATION 75
7.1 LUBRICANT CHARACTERISTICS 77
7.2 OIL FILTERS 77
7.3 OIL QUANTITY AND LEVEL DIPSTICK 78
7.4 LOW PRESSURE SIGNALLING 78
7.5 PERIODIC CHANGE 78
7.6 ENGINE VENT 79
COOLING 81
8.1 INSTALLATION 83
8.2 PRIMARY CIRCUIT 84
8.3 SECONDARY CIRCUIT 84
8.4 KEEL COOLING 87
8.5
GALVANIC CORROSION PROTECTION
89
DISCHARGE 91
9.1 OVERVIEW 93
9.2 DRY DISCHARGE 93
9.3 MIXED DISCHARGE 94
9.4 SILENCERS 96
9.5 COUNTERPRESSURE 96
Page Page
AUXILIARY SERVICES 99
10.1 OVERVIEW 101
10.2
POWER TAKE-OFF ON THE FLY WHEEL
101
10.3 FRONT PULLEY POWER TAKE-OFF 102
10.4 BUILT-IN POWER TAKE-OFF ON TIMING OR FLYWHEEL HOUSING 103
CONTROLS 105
11.1 OVERVIEW 107
11.2 FUNCTIONS 107
ELECTRICAL INSTALLATION 109
12.1 OVERVIEW 111
12.2 POWER CIRCUIT 111
12.3 WIRING 113
12.4 STORAGE BATTERIES 115
12.5 ENGINE ELECTRICAL CIRCUIT 117
12.6 CAN LINE 117
12.7 INSTRUMENT PANEL 118
12.8 WARNINGS AND PRECAUTIONS 118
GALVANIC CORROSION PROTECTION 119
13.1 OVERVIEW 121
13.2 GROUND CONNEXION 122
13.3 DISPOSABLE ANODES PROTECTION 122
13.4 ISOLATED POLES INSTALLATION 123
CONTROL TEST PROCEDURES 125
14.1 OVERVIEW 127
14.2 STATIC TEST 127
14.3 OPEN SEA TESTS 128
14.4 RECOMMENDED GAUGES 130
MARCH 2004
IV
Page
MARCH 2004
V
Aim of this handbook
This handbook has been written to give you the basic information and instructions for the correct choice and installation of IVECO marine Diesel engines. The get the best performance and longest life from your engine you must install it correctly. The infor­mation about the hulls and the propellers are provided as general guidelines for their applications in relation to the choice and installation of the engine. The content of this publication does not replace the expertise and work of marine designers and engi­neers who have the full responsibility for the choice of the boat engine. Further and more detailed information about the characteristics of IVECO engines can be found in the specific publications. Every information included in this Installation Handbook is correct at the time of approval for printing. IVECO reserves the right to make changes without prior notice, at any time, for technical or commer­cial reasons or possible adaptations to the laws of the different Countries and declines any responsibil­ity for possible errors or omissions.
General installation criteria
As an introduction to this Handbook, reference must be made to the following basic installation criteria:
■ choose the engine which is most suitable for the hull according to the power, torque and rpm
requirements and considering the type of use and the environmental conditions for the engine operation (temperature, humidity, altitude);
■ connect the engine to the driven elements (reducer-inverter, propeller and relevant axis, auxiliary
organs, etc.) in the correct way, bearing in mind the problems linked to the drive and the resulting vibrations;
■ choose the sea water circuit or the possible keel cooling system of the right size;
■ adjust the size of the engine compar tment or the engine room to facilitate access to the engine and
the connected parts, both for ordinary maintenance operations and possible repairing operations;
■ foresee the suitable air intake needed for the engine combustion and fundamental for the engine
room ventilation (clean, fresh, without water);
■ get the fuel system dimensioned and positioned correctly;
■ give the priority to those safety problems concerning the personnel in charge of the engine oper-
ation, such as:
- use of the suitable protections and guards for each exposed moving part (pulleys, shafts, belts, etc.)
- positioning of the tie rods and the controls in an easily accessible area, but safe and protected at the same time
- correct insulation of wires and electrical parts
- suitable protection and insulation of all exhaust pipes.
Laws and regulations
The IVECO marine engines are designed and manufactured in compliance with the laws in force and are approved by the main Classification Bodies. As the subject is particularly complex, it is always necessary to make reference to the specific laws of each country which can regulate the different aspects of this subject in different ways, especially:
■ the limitations to gas and noise emissions
■ the restrictions to the installed power for the operation in dangerous areas
■ the engine characteristics to meet the requirements of particular electrical systems and safety
devices.
PREMISE
Warranty
The choice of a type of engine which is not suitable for the required application and/or the non obser­vance of the installation instructions and the use and maintenance rules can make the warranty void.
Safety precautions
We remind you that IVECO marine engines are designed for professional and sailing applications, and not for sports or competitive purposes for which the warranty decays and the supplier’s responsibility is excluded.
The boat safety always depends on the user’s responsibility and common sense. Keep away from the engine moving and hot parts, and take care when coming closer to the engine to prevent possible injuries due to direct contact with the engine or through clothes, jewels, or other objects.
Use the suitable protection devices when carrying out maintenance operations and engine setting.
Before starting the engine, make sure it is fitted with all the elements foreseen by the manufacturer and the installation; do not start the engine with the lubricating, cooling and fuel circuits closed by plugs or obstructed.
Daily check the complete tightness of fluid circuits, especially those of fuel and lubricants, which may cause fires and thus damage people and things.
Make sure that the different pipes are not in contact with hot surfaces or moving elements.
Disconnect the battery in the event of maintenance operations concerning the electrical system.
Drain the cooling, lubrication and fuel circuits only after the fluids cooled down.The pressurised cap of the water circuit can be opened only after the engine cooled down.
The batteries contain a solution of sulphuric acid which is highly corrosive, therefore they must never be turned upside down and must be handled with great care to prevent the fluid transfer. Make sure the battery compar tment gets the suitable air intake.
The used engine fluids and air, water and oil filters must be suitably preserved and sent to the appro­priate collection centres.
MARCH 2004
VI
SECTION 1
MARCH 2004INTRODUCTION
1.7

INTRODUCTION

Page
1.1 ENGINE 9
Piston displacement 10
Real average pressure 10
Driving torque 10
Power 11
Brake real power 12
Correct power 12
Engine total efficiency 13
Fuel consumption 13
Load factor 14
Engine duration 16
1.2 BOAT 17
Types of hull 18
Displacement 19
Relative speed (Taylor ratio) 20
Power definitions for boat propulsion 21
Protection against galvanic corrosion 22
MARCH 2004 INTRODUCTION
1.8
MARCH 2004INTRODUCTION
1.9
Before analysing the main characteristics of the engine relevant for its choice and suitability for the boat and the connection to the engine elements, we believe it is useful to identify the names of the engine components.
1. Comburent air filter - 2. Suction manifold with electrical pre-heater possibility - 3. Union flange of “Riser” or “stack” for gas exhaust - 4. Lifting eyebolts or grommets - 5.Oil fill-in plug - 6.Coolant
reservoir - 7.Coolant fill-in plug - 8. Exhaust manifold cooled down by coolant fluid - 9.Thermostatic
valve for engine coolant - 10. Pipe exchanger for coolant/water sea - 11. Auxiliar y organ control
pulley - 12. Engine support bracket - 13. Sacrificial anodes - 14. Sea water suction - 15. Lubricating oil
draining plug - 16. Heat exchanger for air/sea water - 17. Sea water pump - 18. Electric starter motor
- 19. Rev reducer for sea water pump - 20. Fuel inlet/outlet pipe unions - 21. Fuel filter -
22. Fuel temperature sensor.
Figure 1
1 76 932 54 4 8
111215 101314
21
20
12
19
18
17
16
22

1.1 ENGINE

Piston displacement
The element which best distinguishes the engine is the “overall piston displacement” which represents the total volume of air moved by the pistons during one complete turn of the drive shaft. It represents also the theoretical quantity of air sucked by the cylinders during 2 revolutions of the drive shaft. It is given by the formula:
in cm
3
, where:
• π : 3.1416
• d : cylinder diameter (bore) in cm
• c : piston travel in cm
• i : n° of engine cylinders
Real average pressure
It is the average value of the pressure inside the cylinders during the different operating phases of the engine. It increases during the combustion phase and decreases during the exhaust and suction phases. It is possible to consider it as an indicator of the engine stress since it represents the work done per displacement unit. The real average pressure generates the driving torque and therefore the engine power:
where:
• N : power [kW]
• p.m.e. : real average pressure [bar]
• V : total piston displacement [dm
3
]
• n : rotation speed [giri/min.]
From it you obtain:
With these formulas you obtain that:
■ the power is the linear function of the real average pressure and of the engine rotation speed;
■ with the same power and the same number of rpm, the engines with a higher piston displacement
are subject to a lower real average pressure
The power needed for a boat propulsion requires, if the operating rpm number is the same, the appro­priate consideration about the engine to be used: an engine with a higher piston displacement is sub­ject to a lighter mechanical load as shown by a lower value of the real average pressure and therefore it will be possible to use it for heavy duties compared to the engine with a lower piston displacement.
Driving torque
It represents the thrust impressed by a piston through the connecting rod on the crank arm of the drive shaft. It can be defined as the “rotating force” available to the engine flywheel; it depends on the real average pressure and is strongly influenced by the volumetric efficiency of the engine, i.e. from its capac­ity to suck as much air as possible. Other important factors to obtain a high driving torque and there­fore power are the correct fuel intake and the perfect injection system setting.
MARCH 2004 INTRODUCTION
1.10
MARCH 2004INTRODUCTION
1.11
The driving torque M depends on the power according to:
where:
• M : driving torque [Nm]
• n : rotation rpm [rad/sec] (1 rev per min = π/30 rad/sec)
• N : power [kW]
The formula shows that with equal power it is possible to install engines with high torque and low rota­tion speeds or vice versa, low torque and high rotation speeds. High rotation speeds can generate a high torque by means of a speed regulator. Figure 2 shows how a revolution reduction ratio of 4:1, obtained by coupling the gear wheels with this ratio, makes the output torque increase by the same value 4.
Power
The air and fuel intake inside the cylinders and then burnt during combustion produces the same heat energy which, translated into pressure and force, passes to the crank mechanisms and then to the engine flywheel in the form of mechanical energy, less thermo-dynamic and friction losses. Such energy referred to the time unit is the power that can be generated by the engine and is expressed by the formula:
where:
• M : driving torque [Nm]
• n : rotation rpm [rad/sec] (1 rev per min = π/30 rad/sec)
• N : power [kW]
Figure 3 illustrates the process which generates power as the product of the torque by the angle speed, corresponding to the work of the time unit referred to the rotating motion.
In addition, we provide the following equivalences:
■ 1 kW = 1.36 CV = 1.34 HP
■ 1 CV = 0.986 HP (unit of British Std. and S.A.E).
Figure 2
d. bore - c. travel - w. angle speed - F. force generated by the real average pressure. - c/2. crank arm.
Brake real power
It is the power measured with the dynamometric brake at the drive shaft (flywheel) during the bench tests. The real power values are considered as indicators of the engine capability of generating power in the temperature, pressure and humidity conditions of the test room where the measurements have been carried out.The resulting power can change according to the environmental and load conditions of the accessories connected to the engine (air filters, silencers, fans, pumps, alternators, compressors, etc.).
Correct power
To make it possible to compare the power values measured on the brake in different environmental and testing conditions, some “test standards” have been issued by the different ruling bodies (ISO, BS, DIN, SAE, etc), whose aim is to establish the suitable correcting factors to be adopted to adjust the dif­ferent power rates.The rules are different, basically for the choice of the number of accessories to be connected to the engine during the test and the different reference environmental conditions. As a result, the measurements carried out on the same engine, on the basis of the different prescriptions given by different rules, lead to different results; therefore, it is possible to compare the engine powers only if measured on the basis of the same rule or by applying the correcting coefficients for the off stan­dard performance. In particular, ISO 3046/1, concerning the definition of powers and the bench testing conditions, estab­lishes and unifies:
■ The test method for the brake net power and the engine equipment during the test (presence of
power-absorbing accessories)
■ The reference environmental conditions: temperature of sucked air 298°K (25°C), ambient pres-
sure 100 kPa (750 mmHg), relative humidity 30% and the correcting formulas
■ The fuel characteristics.
MARCH 2004 INTRODUCTION
1.12
Figure 3
MARCH 2004INTRODUCTION
1.13
In addition, IVECO provides the customers with the technical and commercial documentation concern­ing IVECO engines including the reference to the rules required for the correct choice of the engine.
Figure 4 illustrates the power curves of an IVECO engine.
Engine total efficiency
The engine total efficiency is defined as the relationship between the flywheel work and that corre­sponding to the quantity of the fuel heat energy used to obtain that work. All the technical factors con­tribute to the engine efficiency, from the design to the setting, the maintenance to the fuel quality. The engine efficiency, index of the efficiency of transformation of the fuel energy into mechanical ener­gy, is inversely proportional to the fuel specific consumption: an higher efficiency means a lower fuel consumption required to obtain the power yield.The overall efficiency of a Diesel engine is around 0.4 with a clear loss of 60%.
Fuel consumption
The mechanical energy supplied by the engine is obtained by means of the fuel introduced in the engine itself.There are two definitions for the consumption:
■ specific consumption
■ hourly consumption.
Figure 4
1600 1800 2000 2200 2400 2600 2800 3000 g/min
180
170
160
245
230
215
170
160
150
140
130
120
110
100
90
220
200
180
160
140
120
600
575
550
525
500
60
55
50
Kgm g/CVh
Torque Nm BSFC g/KWh
CV KW
Torque
Power
BSFC
The “specific consumption” represents the quantity of fuel used to obtain a unit of mechanical energy; it is expressed in g/kWh and derives from the formula:
Where L is the volume in cm
3
of the fuel having specific gravity y (in g./ cm3), consumed by the engine
in time t expressed in seconds, while power N (in kW) is supplied at given rpm.
The “hourly consumption” represents the quantity of total fuel used by the engine when supplying a power with value N at constant rpm for 1 hour; it is expressed in kg/h and is derived as follows:
The corresponding value in litres is obtained by dividing the result by the fuel specific gravity; for the diesel fuel y it amounts to 0.83 kg/dm3at ambient temperature.
As the consumption is related to the power supplied by the engine, the evaluations and the com­parisons between hourly consumption rates must be made taking into consideration precise and homogeneous engine operating conditions.
Load factor
It represents the average load in time of the power actually required to an engine, expressed as a per­centage of the value of its maximum power. As it represents the engine heavy duty index, it is a relevant indicator for the choice of the correct engine in relation to its application and use. Analysing the engine “load factor” means evaluating which power levels are required during the different work cycles in relation to its possible use at maximum power.
It is expressed by the following formula:
where :
•P
i
: power absorbed for time t
i
•P
max
: maximum power
• N : number of phases in which the work cycle can be split.
Example of calculation for an application having:
■ Max power 200 kW
■ Working cycle of 12 hours, out of which 3 hours at maximum power and 9 hours at half power
The resulting load factor is:
MARCH 2004 INTRODUCTION
1.14
MARCH 2004INTRODUCTION
1.15
Since there are no established rules for the calculation of the heavy duty rate according to the load fac­tor, it is possible to consider the following elements:
■ Light work load factor below 50%
■ Medium work load factor from 50 to 70%
■ Heavy work load work above 70%
Therefore, the work factor is an index of the work heaviness. The definition of load factor already includes the time parameter. However, it is important to stress the concept of “continuous” work or “intermittent” work (see figure 5):
■ As continuous work it is usually meant the engine constant operation at maximum load (24 hours
a day), with minor load and speed variations, or having no variations at all.
■ As intermittent work it is meant the use of the engine with frequent and substantial load and/or
speed variations.
In the marine sector, for example:
■ The continuous work corresponds to that of work boats
(fishing, tug-boats, ferry-boats).
■ The intermittent work corresponds to that of commercial boats
(coastguard and sea rescue, crew transport, etc.).
Finally, there is the definition of:
■ Pleasure boats (yachts), where the engine use is intermittent and limited to the typical life of yachts,
for which maximum powers higher than the previous cases are accepted.
In this respect, see the power classification included in the technical-commercial documentation of each engine.
The above mentioned points are fundamental for the choice of the engine in terms of piston displace­ment, power, overhaul intervals, engine and transmission foreseeable duration. In particular, it is important to bear in mind that the engine load, i.e. its real average pressure, influences the engine overhaul intervals.
Figure 5
100
90 80 70 60 50 40 30 20 10
0
100 90 80 70 60 50 40 30 20 10 0
Load percentage
Heavy continuous Heavy intermittent Medium variable
A B C
Engine duration
The engine duration is identified by the relevant BE10 and is related to a given Load Factor (L.F.).
Example: BE10 (L.F. - 0.7) = 10.000 h
It shows that 90% of the engines working with a medium load factor of 70% exceed the operation duration of 10,000 h, without actions needed for the removal of their main components.
Each engine family and each setting have been associated to a BE10 and the relevant “load factor”.The values result from the use practical tests and the processing of the different data obtained during the bench tests.
It is possible to foresee the engine duration for a specific setting and “load factor” with a good margin of approximation, on the basis of the following correlation:
Figure 6 illustrates the function linking the Duration with the Load Factor.
CAUTION
The engine duration is closely linked to the correct and precise performance of the maintenance actions foreseen by the manufacturer.
MARCH 2004 INTRODUCTION
1.16
Figure 6
Duration (h)
Engine foreseen duration
Load Factor (L.F.)
1
0,9
0,8
0,7
0,6
0,5
0,4
0,3
0,2
0,1
0
MARCH 2004INTRODUCTION
1.17
The choice of a boat engine and its performance in terms of power needed for reaching a pre-estab­lished speed depend on the marine engineer.
The following data are given just for your information and therefore must be interpreted as such.
Figure 7 illustrates the main geometrical data of a boat.
1. Overall width - 2. Floating width - 3. Overall length - 4. Floating length - 5. Waterline - 6. Keel -
7. Draught.
Some parts of the hull mentioned in this handbook are identified in figure 8.
1. Frame - 2. Limber board - 3. Side keelson - 4. Bilge - 5. Keel.
The definition of “side keelson” is particularly important because the engine lays on them.
Figure 7
Figure 8
1 3
7
4
2
5
6
1
2
4
5
3

1.2 BOAT

Types of hull
Displacing hulls
This type of hull is usually characterised by a round bottom and narrow stern.
During sailing this type of boat maintains the same static trim and does not reduce its draught also when the speed increases. Fishing boats, work boats and ferr y-boats belong to this category.
Semi-displacing hulls
These hulls, rather similar to the previous type, can change their trim during sailing as they lift the stem and, as a result of the incidence of the bottom plane, they can use a small part of the water dynamic pressure, thus obtaining a partial glide. Patrol hulls and cruise hulls belong to this category.
MARCH 2004 INTRODUCTION
1.18
Figure 9
Figure 10
MARCH 2004INTRODUCTION
1.19
Gliding hulls
These hulls, due to the shape of their bottom and the power installed, can reach a gliding trim by exploiting the hydro-dynamic phenomena, starting from an initial displacing condition.
The gliding hulls move the water only when stationary or at low speeds; as soon as the boat speed increases, the floating angle changes and the water pressure lifts the boat stem.The pressure increases with the speed square and at the same time the gliding surface is reduced; the pressure centre moves from the stem to the boat centre of gravity which, at full speed and if correctly balanced, reaches the horizontal trim. Yachts, patrol boats and sea rescue boats belong to this category as they are required high speeds.
Displacement
It is the actual weight of the water moved by the boat fully laden and corresponds to the total weight or mass of the boat fully laden. The displacement is a weight and should not be confused with other terms, such as tonnage, which refer to the volume measurements. When unknown, the displacement of a boat can be calculated by making reference to the boat “block coefficient”. This coefficient, usually referred to with C
b
, represents the relationship between the actual hull volume and that of the parallelepiped, circumscribing the hull and limited by the floating length L, by the float­ing width B and by the waterline D.
Therefore, as:
it is derived that the displacement is (for the sea water):
Displacement W = 1,025 · L · B · D · C
b
• L,B,D,in m.;
• W in metric tons;
• Sea water density 1,025.
or:
with
• L, B, D in feet;
• W in tons.
Figure 11
hull.volume
Displacement.W
The block coefficients are included in the following table:
Type of boat Coefficient C
b
Speedboat hulls with V bottom, gliding 0,30
Hulls for sports fishing with length up to 12 m (40 ft),V bottom 0,35
Pilot boats with length below a 12 m (40 ft) 0,35
Semi-gliding hulls (patrol and cruise boats) 0,40
Displacing hulls for cruise, yachts with sail and auxiliary engine 0,45 - 0,55
Fishing boats 0,50 - 0,55
Heavy duty boats 0,55 - 0,65
Tug-boats 0,60 - 0,75
Powered flatboats 0,70 - 0,95
Relative speed (Taylor ratio)
It is the ratio between the boat speed, expressed in knots, and the square root of the floating
length, expressed in feet. This coefficient is a parameter which makes it possible to compare similar bottoms with the action of waves and therefore their resistance to the hull motion: equal relative speeds correspond to compara­ble waves. Experiments and tests carried out on different types of boats pointed out that there is a limit value to the speed beyond which any further increase requires excessive and expensive power growth.
For displacing hulls, the speed limit is for value ratios around an average of 1.34.
At this speed , the hull generates a wave as long as its floating hull length. Any attempts
to go beyond this speed, by increasing the engine power, make the hull stem lift thus creating expen­sive and very often dangerous sailing conditions. Actually, it rarely happens for bigger merchant ship hulls to exceed value 1 of this ratio , while in smaller hulls it is possible to reach values up to 1.2-1.3.
On semi-displacing hulls, it is possible to gradually obtain growing ratios as the hull
characteristics become more and more similar to the gliding type: 1.7 for fast displacing hulls, from 2.5 to 3 for semi-displacing hulls.
MARCH 2004 INTRODUCTION
1.20
MARCH 2004INTRODUCTION
1.21
For example, if the above mentioned calculation is applied to a hull having floating length L = 25 feet, it results in:
■ Displacing hull, limit value knots
■ Semi-gliding hull, limit speed knots
Values above 3 are for gliding hulls.
Practically, this type of hull, according to the bottom shape, starts to glide at a relative
speed .
It means that a hull with length L=10m (32.8 ft) should have a speed above knots
to be able to glide.
Power definitions for boat propulsion
In the powered boat propulsion system there are different power levels, from the engine up to pro­peller.We think it is advisable to identify them from a qualitative point of view, as follows:
■ BHP (Brake horse power): it is the power available to the engine flywheel as defined by the inter-
national regulations.
■ SHP (shaft horse power): it is the power available to the output shaft of the reducer-inverter; there-
fore after the mechanical losses due to the shaft efficiency.
■ DHP (delivered horse power): it is the power which can be actually used by the propeller, there-
fore after the mechanical losses of the axis line (bearings, stuffing box) and of the reducer-inverter, the power absorption by additional accessories which take power from the engine (not included in the BHP) and the deductions due to the environmental conditions.
■ EHP (effective horse power): it is the propeller net efficiency power which is actually translated into
thrust for the boat motion.
1. EHP - 2. Reducer - 3. Engine - 4. DHP - 5. SHP - 6. BHP.
Figure 12
1
3
2
4 5 6
Protection against galvanic corrosion
The hulls made up of metal are subject to corrosion due to galvanic currents. Therefore, if two different metals come into contact, you are recommended to insulate electrically one of the components. As an alternative, you are advised to apply sacrificial anodes as explained in section
8.5, to which you should make reference for further details about this matter.
MARCH 2004 INTRODUCTION
1.22
SECTION 2
MARCH 2004ENGINE/BOAT CHOICE FACTORS
2.23

ENGINE/BOAT CHOICE FACTORS

Page
2.1 GENERAL INFORMATION 25
2.2 USE OF THE BOAT - ENGINE SETTING 25
Fast short-range yachts 25
Long-range yachts/commercial boats 25
Light service 26
Medium service 26
Continuous service 26
2.3 ENGINE PERFORMANCE 26
2.4 ENVIRONMENTAL CONDITIONS AND “DERATING” 29
Ambient temperature 30
Height 30
Humidity 30
2.5 MECHANICAL AND AUXILIARY COMPONENTS 31
2.6 SPEED AND POWER PERFORMANCE 31
MARCH 2004 ENGINE/BOAT CHOICE FACTORS
2.24
MARCH 2004ENGINE/BOAT CHOICE FACTORS
2.25
The type of boat and its purpose, represented by the load factor and the foreseeable operating time together with the choice of the propeller make it possible to identify the performance required to the engine. As the power data which can be derived from the typical curves are the net ones resulting from the flywheel and referred to particular environmental conditions, in the choice of the engine it is necessary to foresee a sufficient power reserve to compensate for factors such as:
■ The environmental conditions (temperature, height, humidity)
■ The power absorbed by accessories such as pumps, compressors, winches, alternators actuated by
the engine, silencers, additional air filters and mechanical organs between the engine and the pro­peller (inverters, reducers, thrust bearings, supports, axis line)
■ Fuel temperature
■ Insufficient maintenance and lack of regular setting-up
■ Preser vation conditions and efficiency of hull and propeller
2.2 USE OF THE BOAT - ENGINE SETTING
The performance of IVECO marine engines is determined by specific settings for each use mission of the engine/boat. The engine setting is established for each type of engine after exhaustive duration tests carried out at IVECO testing bodies and after practical use on the boats. As a result, the engine power and rotation maximum rates admitted for an application are identified.The engine performance can be derived from the typical curves of the engine which usually include five different types of use.
We remind you that the engines must be used for the purpose to which their setting makes reference; the non observance of this prescription makes the warranty void.
Fast short-range yachts
Boat
Yachts and military boats with gliding hull and high-speed boats or semi-gliding hulls and displacing hulls using the maximum power for short periods alternated with long periods where the speed is below the maximum value. For example, yachts, high-speed boats for military or state bodies.
Engine
Use of the maximum power limited to 10% of the time, cruising speed with engine rpm < 90% of the set rated rpm, use limit 300 hours/year.The definition of setting and use limits for military and state bodies is based on the contractual specifications. Power classification according to ISO 3046-7 (IOFN).
Long-range yachts/commercial boats
Boat
Light boats for recreational, commercial and military use with long-range gliding, semi-gliding and dis­placing hulls and use of maximum power for short periods alternated with long periods where the speed is below the maximum value. For example yachts, charters, boats for light commercial use and long-range boats for military and state bodies.
Engine
Use of the maximum power limited to 10% of the time, cruising speed with engine rpm < 90% of the set rated rpm, use limit 1000 hours/year.The definition of setting and use limits for military and state bodies is based on the contractual specifications. Power classification according to ISO 3046-7 (IOFN).

2.1 GENERAL INFORMATION

Light service
Boat
Light boats for tourist, professional or military use subject to frequent speed variations. For example, yachts, charters, light passenger boats, fast patrol boats, police boats, civil protection boats, rescue boats, special squads.
Engine
Use of the maximum power below 10% of the time, cruising speed with engine rpm < 90% of the set rated rpm, use limit 1500 hours/year.The definition of setting and use limits for military and state bod­ies is based on the contractual specifications. Power classification according to ISO 3046-7 (IOFN).
Medium service
Boat
Boats for commercial, military, work and light fishing use with variable speed. For example, patrols, pilot boats, light fishing boats, seasonal medium-range passenger taxi boats, fire boats.
Engine
Use of the maximum power below 25% of the time, cruising speed with engine rpm < 90% of the set rated rpm, use limit from 1500 to 3000 hours/year.The definition of setting and use limits for military and state bodies is based on the contractual specifications. Power classification according to ISO 3046-7 (IOFN).
Continuous service
Boat
Fishing boats, work and load boats, passenger boats where it is possible to use the maximum power. For example fishing boats, work boats, load boats, tug-boats, passenger boats.
Engine
Maximum usable power up to 100% of the operating time, without limiting the number of hours per year. Power classification according to ISO 3046-7 (IOFN).

2.3 ENGINE PERFORMANCE

The diagram of the typical curves of an engine illustrates the maximum engine power and torque according to the rotation speed and provides the engine specific consumption.The engine power and torque values will be different according to the position of the accelerator lever. On the basis of the power and torque curves, which bound the engine operating range when the accel­erator is in limit switch position, it is possible to derive other important parameters for the choice of the engine:
■ Maximum idling speed (n
v
): it is the maximum rotation reached by the engine without load, with
the accelerator in limit switch position.This limit is set by the speed regulator of the injection pump, or by the engine electronic control system EDC, which limits the fuel inlet to the quantity needed to keep the engine running, thus preventing overspeed.This parameter must be taken into consid­eration for the choice of the engine when there are limitations to the maximum rotation speed bearable by the drive system.
■ Maximum power speed (n
p
): it is the speed where the maximum power is supplied, called also
rated speed. It corresponds to the rotation speed at which the regulator - mechanical or electron­ic - with the accelerator in limit switch position, starts to reduce the fuel inlet to control the speed as the torque required by the engine drops. During the bench tests it is possible to detect the max-
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MARCH 2004ENGINE/BOAT CHOICE FACTORS
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imum power speed by loading the dynamometric brake, starting from the idling maximum speed with the accelerator at limit switch, until the maximum power is detected.
This ratio represents the regulator percentage difference at the rated speed.
The curve linking the maximum power value to the null power at the maximum speed is called gap curve.The gap in IVECO marine engines usually amounts to 10%.
■ Maximum torque speed (n
c
): it is the speed, or speed interval, at which the engine reaches the
maximum torque. It is measured during the above mentioned tests, starting from the maximum power with the accelerator in limit switch position and increasing the load of the dynamometric brake. The higher need for energy makes the engine reduce its running speed in order to obtain the maximum torque.
The maximum torque speed is usually identified as the condition with the lowest specific con­sumption. With a speed ranging between the maximum power value and the maximum torque value the engine has a “stable” behaviour, i.e. it regulates itself to adapt its speed spontaneously to the load changes.
Cs. Specific consumption - N. Power - n. Engine speed - M.Torque - A. Gap curve.
In marine applications, the typical rule for the power absorption is the square/cube rule depending on the propeller; the type of hull used greatly affects this rule: in gliding boats, the hull dynamics makes this rule change to a pattern more similar to that shown in figure 3, where there is a hump corresponding to the power absorbed to reach the gliding position. Therefore, on gliding boats it is necessary to install an engine with a great power and torque also at intermediate speeds.
Figure 1
In addition, it is important to make the right choice to prevent:
■ Requesting a power above the rated one
■ Requesting a power needed for gliding incompatible with the power which can be supplied by
the engine
The wrong design of the propeller substantially reduces the boat performance: in the first case the max­imum speed reached by the engine will be below the rated value and equal to the balance between the engine torque and the propeller resistance. In the second case the time need to reach gliding will be prolonged or it will not be possible to reach glid­ing and the engine maximum speed will be noticeably lower than the rated value (see also Section 3). In both cases we are persuaded that the engine setting is wrong, whereas these conditions are due to a propeller which, with the same rotation speed, has actually been designed for an engine greater than the one installed.
It is possible to avoid the above mentioned cases by following this rule: foresee a maximum speed reached by the engines when sailing with a new boat fully laden 3% above the engine rated speed.
This rule is based on the fact that the power required to the engine increases when the boat is used, because of the weight growth and the presence of incrustation and vegetation under the bottom and on the propeller.
Displacing boats
1.Torque limit curve/real average pressure/input, for the engine - 2. Absorption curve of a propeller
too big for the application - 3. Absorption curve of a propeller with the right size (pattern closer to
the cubic one) - 4. Absorption curve of a propeller too small for the application - 5. Gap curve.
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Figure 2
1
2
3
4
5
M
rpm
MARCH 2004ENGINE/BOAT CHOICE FACTORS
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Gliding boats
1.Torque limit curve/real average pressure/input, for the engine - 2. Absorption curve of a propeller
too big for the application - 3. Absorption curve of a propeller with the right size (pattern between
the cube and square one, except for the gliding phase when the square pattern is exceeded) -
4. Absorption curve of a propeller too small for the application - 5. Gap curve.
2.4 ENVIRONMENTAL CONDITIONS AND “DERATING”
Pressure, temperature and humidity of the air sucked by the engine, different from the reference val­ues, play an important role in the supply of power when they vary substantially and persist in time.They affect the density and therefore the weight of the air getting inside the engine and also the fuel quan­tity regulated by the injection pump, in relation to the quantity of air inlet. “Derating” consists in the adjustment of the injected fuel quantity according to the weight variation of the air sucked by the engine, without affecting the optimum ratio, in the event of excessive air, that the diesel engine needs and to prevent the growth of the combustion temperature and the exhaust smoke. With the engine electronic control (EDC), the adjustment of the injection metering is a function imple­mented by the managing software. For the choice of an engine, it is necessary to consider the environmental factors to ensure that it has a power suitable for the load in real operating conditions.
The engine behaviour in particular environmental conditions can be very different according to ist char­acteristics and fittings:
■ Aspirated, supercharged, supercharged with aftercooler
■ Boosting with and without waste gate or controlled by VGT
■ Injection with mechanical pump or electronic control
Figure 3
1
2
3
4
5
M
rpm
The following section includes some considerations on the engine performance variations according to the environmental conditions. However, IVECO reserves the right, when negotiating the contract, to assess every single application to choose the most suitable engine setting and define the possible “derating”.
Ambient temperature
A high temperature can lead to the engine power reduction, as a result of the air rarefaction, and there­fore generate cooling, lubrication and onboard system operating problems. It can be due to the climate conditions or an insufficient ventilation of the engine room. The power reduction in aspirated engines amounts to 2% every y 5.5 °C increase above the reference temperature of the test rule.
The reduction of power in supercharged engines depends on the work margin of the compressor and the available supercharging pressure and, if present, on the efficiency of the air-water exchanger. It can be null when there is more supercharging pressure and with an air-water exchanger having the right size, or it can be equal to the percentage values mentioned for the aspirated engines.
When the temperature is below the reference value, there is no power reduction. Below certain val­ues, it could be difficult to start the engine or some systems may be faulty.
Height
The engine operation at a high altitude, as a result of the lower atmospheric pressure, can lead to a reduction of the quantity of air sucked and thus to a lower torque and power, compared to the typical engine performance curves. The lower performances depend on the characteristics of the turbocharger, where present, and of the engine setting, i.e. of the air system capacity to compensate for the air rarefaction with a higher volume of air inlet. On aspirated engines there might be, up to 2500 m in height, a power loss of 3.5 % every 300 m of difference in height, while on supercharged engines with turbine fitted with waste gate the power reduction can be between zero and approx. 2.5% every 300 m of difference in height, accord­ing to the size, type and matching of the turbocharger.
For a different adjustment of the quantity of injected fuel, the “derating” becomes necessar y for those applications where the critical height is exceeded for a long time and above which there is no com­pensation for the quantity of air inlet. The derating becomes also necessary as a result of a lower counter-pressure at the exhaust which leads to the turbocharger overspeed conditions and as a result of the reduction of the water boiling temperature caused by a lower atmospheric pressure.
Humidity
The engine setting for its use in conditions of high air humidity does not happen frequently, save for the operation in environments constantly above 60% of the relative humidity, as in Tropical forests. In these cases it can be foreseen that every 10% increase of the relative humidity above 60% there can be a derating of:
■ 0,5% for ambient temperature of 30 °C
■ 1% for ambient temperature of 40 °C
■ 1.5% for ambient temperature of 50 °C
The “derating” is managed by IVECO during the contractual negotiations according to the operating conditions of the boat supplied by the Customer.
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2.5 MECHANICAL AND AUXILIARY COMPONENTS
For the evaluation of the engine installed it is necessary to consider the presence of each component producing power absorption and to know exactly the absorbed powers, as the power taken by auxil­iary components is no longer available for the flywheel. It is also necessary to check that these powers comply with the absorption limits.
Winches, generators, pumps and other elements actuated by power takeoffs generate torque and power absorption from the engine, according to their performance and the moment they are used.
The reducers-inverters, the thrust bearings and the supports for the axis line, between the engine and the propeller, absorb power as a result of the friction during sailing. The absorptions of the reducers-inverters vary according to the type and are included in the 3-5% range. The supports, the axis line and the thrust bearing have an incidence amounting to approx. 1% for each element.
2.6 SPEED AND POWER PERFORMANCE
The designed and/or wished speed cannot disregard the economic and critical speed values.
The forecast of the maximum speed and the speed required by the propeller axis for the different types of hull can be based on the following mathematical methods.
Displacing hulls
The forecast of the maximum boat speed in relation to the engine installed can be obtained through the following admiralship formula.
where
:
• V : Hull speed (Kts)
• SHP :Total installed engine (HP)
• D : Displacement
• C : Admiralship coefficient
- L : Waterline length
- B : Waterline width
Summarising table of C values
L/B 1 2 3 3,5 4 4,5 5 5,5 6 6,5 7
C 20 30 40 47 60 80 90 110 125 145 165
Gliding hulls
The speed of gliding hulls can be obtained through the Equadro formula:
where
:
• V : Hull speed
• SHP : Total installed power (HP)
• D : Displacement with hull fully laden (long tons)
• X : Equadro coefficient:
- X : 2,33 - 2,40 Axis lines and astern feet
- X : 2,24 - 2,30 Surface propellers
- X : 2,12 - 2,15 Competition hulls - Deep V
- X : 2,05 - 2,10 Competition catamarans
The formula does not directly consider the boat length, as the fundamental element for the perfor­mance of the gliding hulls is the weight/power ratio.Anyway, the length is still part of the choice of coef­ficient X, synthesis of the propulsion efficiency of the hull block (L/B).
Semi-displacing hulls
The factors defining the possible performance of semi-displacing hulls (or semi-gliding) are:
■ Reduced buttlock angles (0°<Ab<7°), i.e. the angle between the longitudinal line of the hull bot-
tom and the line parallel to the waterline, on a vertical plane at 1/4 of the floating width in ft (B.L.A.) from the longitudinal centre line of the hull.
■ Reduced values of the displacement/length ratio at floating (20<DL<280)
where
:
• D : Displacement with the hull fully laden (long tons)
• L.L.A. : Length of the waterline (ft)
Finally, the introduction of the DL ratio in the formula enables the calculation of the Taylor coefficient and the related speed:
where:
• V : Hull speed (Kts)
With the semi-gliding trim, the power required to reach such a trim can be calculated through the Barnaby formula:
where:
• SHP :Total installed engine (HP)
• K : Shape coefficient
Summarising table of K value
L.L.A. 20 25 30 35 40 45 50 60 70 75 80
K 2,25 2,4 2,6 2,8 3,03 3,24 3,34 3,73 4,13 4,3 4,45
The above mentioned information regard the boats in perfect maintenance conditions.The bottom and propeller incrustation can substantially reduce the boat performance.
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SECTION 3
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DRIVE

Page
3.1 PROPULSION SYSTEMS 35
Axis line propulsion systems 36
Drive with universal joint shaft 37
Angle drive - V drive 38
Inboard-outboard unit with astern foot 38
“S” drive (sailing boats) 39
Water jet propeller 40
3.2 PROPELLERS 41
Propeller technical characteristics 42
Dimensioning 42
Rotation direction 45
Engine with reversible blades 46
Propulsion with surface propellers 46
3.3 INVERTER-REDUCER 47
Choice 47
Efficiency 47
Lubrication 48
Trailing 48
3.4 TORSIONAL VIBRATIONS 49
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MARCH 2004DRIVE
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The drive in most boats is given by means of an engine consisting of: inverter-reducer, propeller sup­port axis and propeller, sometimes ducted, or in alternative a water jet propeller. The size and position of the compartments available for the engine location lead to a different layouts of the engine. The possible solutions are the following:
Figure 1
AXIS LINE DRIVE
ANGLE DRIVE
INBOARD-OUTBOARD UNIT WITH ASTERN FOOT
WATER JET PROPELLER

3.1 PROPULSION SYSTEMS

Axis line propulsion systems
On inboard applications, the propulsion system consists of an engine, an inverter-reducer, an axis line and a propeller, as in the diagram illustrated in figure 2
The advantages of this system can be summarised as follows:
■ Simplicity and reliability
■ Availability of a wide range of components
■ Compliance with the needs of distributing weights on the boat.
These advantages contrast with the following drawbacks:
■ Limited choice of the engine position which sometimes compels to opt for tilted installations, with
the resulting need for the suitable equipment such as oil sump, cooling circuit, etc.
■ Substantial power loss along the drive because of the axis and propeller inclination
■ Arising of noise and vibration whose solution is rather expensive.
The main solutions for the axis line are:
■ Rigid casing, with propeller axis support at the end. Not suitable for engine installation on elastic
supports
■ With elastic casing, propeller axis supported by a sleeve on the casing inside the hull bottom.
The water tightness at the bottom input is obtained through the stuffing box or, more recently, as a result of the hydrostatic tightness systems.The support bearings, usually made of splined rubber, need water lubrication which can be collected outside with a dynamic intake or derived from the sea water exhaust for the engine cooling. The metal bushing bearing, possibly fitted with the rigid casing, need grease lubrication. The axial thrust transmitted by the propeller in the two directions, i.e. for both travelling directions, is usually supported by the reducer-inverter bearings. If the inverter is not arranged or the thrust is higher than the admitted value, it is compulsory to inser t a thrust bearing between the axis line and the inverter output. It is suggested to use the thrust bearing when, in order to improve comfort, the engine is to be sup­ported with vibration-damping blocks which enable it to move incompatibly with the axis travel; in this case it is absolutely necessary to uncouple the drive and the inverter by means of the suitable joint. When the axis line is too long it is necessary to insert intermediate supports in the right position to prevent dangerous bending of the shaft or irregular reducer inverter overloads.
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Figure 2
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Drive with universal joint shaft
Some installations may need an angle drive or offset drive; the right solution is provided by the univer­sal joint shafts:
■ W layout, angle drive
■ Z layout, offset drive
In the applications with universal joint shafts it is necessary to strictly observe the use and installation instructions provided by the manufacturers to prevent any faults due to the drive supplied with uneven speeds. In this respect, we point out the following basic information.
UNIVERSAL JOINT AXES
A. W layout - B. Z layout (constant velocity).
To obtain constant velocity, i.e. the motion uniformity, it is necessary to use two joints together, making sure that the offset angles are the same (layout B in figure 3). The maximum admissible values for operating angles vary according to the type of joint and the rota­tion speed and cannot exceed the values prescribed by the manufacturer. All the technical information needed for the installation of the universal joint drive shall be supplied by the shaft manufacturer; they are about the joint admissible performance but not about the admissible characteristics of the engine/reducer-inverter bushes and bearings.
Prescriptions:
■ The drive based on shafts fitted with universal joint shall be connected to the engine by means of
the suitable joint with flanged bell on the flywheel housing (see Section 10, paragraph 10.2).
■ It is not possible to apply directly a universal joint on the engine flywheel, save specific approval and
the insertion of the suitable elastic component between the engine flywheel and the shaft. Check the joint weight resting on the flywheel.
■ Check also the twisting and bending moment resting on the reducer-inverter.
Figure 3
A
B
Angle drive - V drive
Due to the size, the weight distribution and the hull structure it could be necessary to install an angle drive. On this type of drive it is important that the supporting plane of the engine on the inverter side is close to the connecting plane between the unit output and the propeller axis support. The “V” drive inverters can be flanged directly on the engine or placed far from it.This second solution is more flexible for the choice of the engine position which can be horizontal, thus improving and opti­mising the use of spaces.When universal joint shafts are used check that there is constant velocity rota­tion and maintain the boss angles admitted by the joint in relation to the inverter flanges. The use of the angled inverter is temporarily limited to the yacht and light commercial boat sector because of its high installation and maintenance costs. Strictly observe the installation rules provided by the inverter manufacturer.
EXAMPLE OF ANGLE DRIVE COUPLED WITH THE ENGINE
BY MEANS OF UNIVERSAL JOINT SHAFT
Inboard-outboard unit with astern foot
ENGINE WITH ASTERN FOOT
MARCH 2004 DRIVE
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Figure 4
Figure 5
MARCH 2004DRIVE
3.39
The advantages offered by this solution are:
■ More habitable space inside the hull
■ Better power efficiency, despite the lower mechanical efficiency, since the propeller axis is parallel
to the travelling speed
■ Good manoeuvrability at high speeds, enabled by the simultaneous rotation of the foot-rudder and
the propeller
■ Possibility of correcting the boat trim as a result of the adjustment of the whole astern foot slant
■ Installation simplicity offered by the lack of the axis line, bottom tightness and tailpieces
■ Noise and vibration problems which can be solved more easily
The drawbacks are the following:
■ Boat design for the installation of the astern foot
■ Poor boat manoeuvrability at low speed
■ Unsuitable use on displacing hulls
“S” drive (sailing boats)
It is a propulsion system for limited powers used as an auxiliary unit on sailing boats.This unit, similar to that with the astern foot, consists of an engine and a drive fitted on the appropriate base support­ed by the hull bottom.The foot is usually fixed and for the route changes it is necessary to use the boat rudder ; in some cases the whole wheel unit carries out the rudder function. The propellers used are usually fitted with foldable blades to reduce the resistance to the sailing progress.
“S” DRIVE
Figure 6
The advantages are:
■ Low level of noise and vibrations
■ Facility of installation for the unit limited size
■ Flexibility in the choice of the position onboard
■ Low resistance to the sailing progress
The drawbacks are:
■ Impossibility of use on boats with deep keel
■ Limited choice of drive and propeller ratios.
Water jet propeller
With this type of propulsion system the thrust action is obtained as a result of the variation of the quan­tity of motion of a water mass at the expense of the energy supplied through a one-stage pump (or more stages), generally of axial type with ducted blades (figure 7). The lack of underwater protruding tailpieces reduces the hull travelling resistance and thus the system is particularly suitable for sailing on shallow waters, with a good operating flexibility and the use in extremely safe conditions both for the damages resulting from any water obstacles and the possible injuries due to the lack of the propeller and the rudder. With this system it is possible to reach high speeds with a particularly good propulsion efficiency and manoeuvrability which gets worse at low speeds. The installation on the hull is relatively easy, but the space need is rather big.
WATER JET PROPELLER DIAGRAM
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Figure 7
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In the project of an engine for marine applications the propeller plays an essential role, comparable to that of the engine. The propeller receives the energy transmitted by the engine, deducted from the drive mechanical losses, and it shall be able to translate this energy into speed for the boat progress. Any propulsion solution different from the above mentioned ones requires a specific propeller.
PROPELLER FOR AXIS LINE
PROPELLER FOR ASTERN FOOT
SURFACE PROPELLER
Figure 8

3.2 PROPELLERS

Propeller technical characteristics
The characteristics defining the efficiency of a propeller are the diameter and the pitch. As to the boat performance, another important characteristic is the slip, defined as the difference between the theo­retical pitch and the real pitch.
Theoretical pitch: it expresses the hypothetical progress of the propeller during a revolution in a solid.
Real pitch: it is the real progress of the propeller during a revolution in the water.
In the event of limited slip, the engine will not reach the maximum rotation speed; in the event of exces­sive slip, the propeller will incur cavitation phenomena. In both cases, the engine performance will be reduced and the engine wear increased.
Average slip values per type of hull
Type of hull Speed (Kts) Slip (%)
Flatboats - Sailing boats <9 45
Heavy duty boats 9 - 15 26
Light duty boats - Cruise boats 15 - 30 24
Fast gliding boats 30 - 45 20
Competition boats with V bottom 45 - 90 10
Competition catamarans >90 7
Dimensioning
The calculation of the operating hull slip is obtained trough the following formula:
where:
• V : Hull speed (Kts)
• P : Propeller pitch (m)
• R : Propeller rotation speed (rpm)
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Figure 9
Real pitch 15 inches
Theoretical pitch 19 inches
Diameter 14 inches
Slip 21%
MARCH 2004DRIVE
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Another important value is the blade area-disc area ratio (As/Ad), i.e. the ratio between the total area developed by the blades and the area corresponding to the circle formed by the propeller rated diam­eter. With the same absorbed power, rotation speed and diameter, this ratio increase contributes to reduce the superficial pressure and therefore the potential cavitation risks.
The propeller dimensioning is extremely important to establish what engine power enables the boat highest speed. It depends on the bottom shape (displacing, gliding, semi-gliding) and on the distribution of the weights onboard.The precise propeller dimensioning in relation to the diameter, the pitch, the number of blades and the speed shall be carried out at the shipyard. On displacing work boats, such as tugs and trawlers, it is better to use propellers with big diameter and low rotation speeds. On gliding boats, such as yachts and patrol boats, it is better to use propellers with small diameter and high rotation speeds. It is suggested to size the propeller for 90% of the rated max­imum power, so that the engine, on a new boat fully laden, can reach a speed above 3% that of the maximum power.This way it will be possible for the engine to reach the maximum power speed when the bottom is dirty.
Propellers with the wrong size do not allow the transfer of the maximum power supplied by the engine.
1. Engine power curve - 2. Propeller absorption curve - 3. Gap curve - 4. Work point with new boat -
5. Point of maximum power to be reached when the boat is laden and the bottom not perfectly clean.
Propellers too small
As the power required is lower than the engine rated power, the work point is to be found on the gap curve. In this case, the engine speed is higher than the rated speed and the power supplied is lower than the maximum one.
Propellers too big
The propeller power absorption is higher than the engine rated power. The engine cannot reach its rated speed and therefore it is overcharged. As a result, black smoke could be emitted at the exhaust and this could lead to long-term engine dam­ages and wear.
Figure 10
1
5
4
3
2
The propeller power is proportional to the value of its cubed rotation speed. We call this relation as the “propeller cube rule”. This relation complies with the resistance progress of displacing hulls. On gliding hulls the pattern of the absorbed power is illustrated in figure 11 which highlights the “hump” representing the transient state from the displacing sailing to the gliding sailing (see also figure 3 of Section 2).
1. Displacing hull - 2. Gliding round hull - 3. Gliding edge hull - 4. Hydrofoil.
As a result, every type of boat requires a propeller which enables the boat performance optimisation. Only after identifying the propeller characteristics and its rotation speed you will have all the data nec­essary for the choice of the inverter-reducer.
Considering the shipyard expertise in the choice of the best technical solutions, we provide herein a reference diagram of the propeller rotation speeds according to the application.
Type of hull Taylor Propeller
ratio rotation speeds
DISPLACING - HEAVY (Tug-boats, Heavy trawling) <1,34 from 250 to 600
DISPLACING - MEDIUM-LIGHT (Light trawling, Fishing, Work boats) <1,56 from 300 to 1000
SEMI-DISPLACING (Passenger’s boats, Patrol boats, Motor-yachts) from 1,57 to 3,5 from 800 to 1800
GLIDING (Yachts, Speedboats, Ferr yboats and Fast patrol boats) >3,5 from 1200 to 3000
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Figure 11
1
2
3
4
(Relative speed)
Hump
(Overall resistance)
0 1 2 3 4 5 6
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Rotation direction
First we must say that in marine propulsion the rotation direction is conventionally referred to the observation from the rear side of the considered object, i.e.:
■ From the flywheel side for the engine
■ From the output shaft for the inverter-reducer
■ From the stern side for the propeller.
According to this rule, the rotation direction of what is observed is defined:
■ Right-hand (left-to-right. clockwise) if it matches with the clock hands,
■ Left-hand (left-handed, anticlockwise/counter-clockwise) if contrary to the above mentioned
movement.
IVECO marine engines are left-handed, therefore this shall be taken into consideration for the choice of the inverter. The rotation direction of the inverter output shaft depends on the type of structure and therefore there is a difference between the models with the same rotation direction of the engine and those contrary to it; most modern inverters-reducers can be used for moving forward and backward without limitations.
To make the boat move forward, the propeller direction must be the same of the inverter output shaft direction. In the applications with one engine, the propeller can be made turn in both directions, even if it is the right propeller to be used more actually (therefore with clockwise rotation at gear forward).The drift effect due to the application of the single-propeller is usually corrected by regulating the rudder.
In the twin-engine applications, this problem is more marked, therefore it is necessary to adopt counter­rotating propellers which, to be more efficient, are to be as follows: right propeller with clockwise rota­tion, left propeller with counter-clockwise rotation. As far as this matter is concerned, you are advised to make reference to the prescriptions and warnings provided in the suitable installation, use and main­tenance handbooks supplied by the manufacturer with every inverter.
NOTE
1) Always check the counter-rotation capacity of the inverter before every installation.
2) It is extremely important to ad just the reverse valve. The lever shall make the whole travel to prevent damaging the clutches.
3) Carefully observe the inverter manufacturer’s prescriptions for its installation.
ROTATION DIRECTION IN THE TWIN-ENGINE APPLICATIONS
1. Left propeller, left-hand rotation - 2. Right propeller, right-hand rotation.
Figure 12
1 2
Engine with reversible blades
In this system the propeller blades hinge on the hub; the blade rotation on their axis is obtained by means of the suitable mechanism in the hub actuated through the propeller hollow supporting shaft (figure 13).The blade rotation is such to reverse the movement forward/backward and to keep at the same time the same engine rotation direction. In this case, the mechanical inverter is no longer necessary, while a reducer may be required.A decou­pling clutch is advisable, even if the engine neutral position can be obtained by putting the propeller blades in neutral position (idle pitch) and with the engine idling. The variable pitch propeller enables the propeller pitch adaptation to the real boat needs, whose speed can be accurately kept under control through the engine accelerator fixed positions, thus improving the fuel consumption rates. The remarkable size of the hub used on this type of propellers prevents their use at high speeds and the extremely high cost limits their diffusion.
ENGINE WITH VARIABLE PITCH PROPELLER
1. Clutch - 2. Propeller pitch control.
Propulsion with surface propellers
The surface propellers, different from the traditional ones, are designed to be operated partially under­water and at high rotation speeds. The whole propulsion system is applied on the hull stern and the propeller axis exceeds the stern line. This solution ensures high performances and is adopted mainly on hulls used for speedboat races or on fast patrol boats. The advantages offered by these propellers are a lack of reduction gears, as the propeller rotation speed is the same of the engine and the friction reduction due to the lack of hull protrusions. One of the limits to their diffusion is the difficulty of building propellers able to bear high stresses at low costs.
DRIVE WITH SURFACE PROPELLERS
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Figure 13
21
Figure 14
MARCH 2004DRIVE
3.47
The use of the inverter-reducer unit sets the correct drive ratio between the engine and the propeller and makes it possible to reverse the boat travelling direction. The main types of inverter-reducer units are equipped with oil bath multi-disc clutches actuated by the oil under pressure and cooled down by an oil-sea water heat exchanger fitted on the inverter or the engine. For low powers, mechanically-operated reducers-inverters are used. The reduction ratio can range between 1:1 and 6:1 according to the type and size of the inverter and its use. The reducer output shaft can be coaxial to the input shaft or offset downwards; there are also versions fitted with the output shaft in angled position which makes it possible to substantially reduce or reset the assembly tilt of the engine, thus making it easier to install it on the hull.
NOTE
Inverters different from those proposed by IVECO shall receive prior approval.
It is extremely important to insert the damper snap joint in the connection between the engine fly­wheel and the inverter input shaft, in order to prevent twisting and overloading the engine shaft end. For this reason, the joints must not only have the suitable flexibility and torsion dampening capability, but also the right axial adaptability and the choice must take into consideration the boat purpose. If at the shipyard it is decided to insert a snap joint between the engine and the propeller suppor ting axis, it must be accurately selected to ensure the transmittability of the power, torque and the axial thrust which is to be transmitted by the axis-propeller. If a separate thrust bearing is used, the snap joint to be inserted shall not bear the thrust and is to be inserted between the reducer and thrust bearing. One of the shipyard tasks is to choose the best solution.
Choice
The choice of the inverter-reducer depends on the type of boat and the performances required.This choice is usually made in agreement with the designer and the boat builder since the type of hull, the scope and the required performances influence the choice of the propeller. The structure of the boat is fundamental for the position of the engine and the axis line just as the choice of the inverter flanged on the engine or separated. The performances required to the inverter, obviously compatible with the above mentioned ones in relation to the engine and its use on pleasure boats, for light commercial service or continuous service depend on the engine power, the type of propeller to be installed and the layout of the engine room. The basic factors to make the right choice are the power/rpm ratio, i.e. the torque transmitted and the maximum operating speed equal to that reachable by the engine. As the reduction ratios are available in discrete succession, but not continuous, it is necessary to evaluate correctly the sizes in order to match engine, inverter-reducer, user.
For the choice of the reducer-inverter it is also impor tant to consider the movement reversal alterna­tion which, if very close, requires the use specific components. For heavy duty applications you are suggested to check the suitability of the thrust bearing installed by factory on the inverter; if necessary, as in the event of high reduction ratios, insert an additional thrust bearing to be dimensioned at the shipyard. The boat thrust bearing is necessary to prevent transmitting vibrations to the boat, when the engine is fitted with flexible supports and the propeller axis is not flexible enough to follow its movements
Efficiency
The mechanical efficiency of the reducer-inverter is an index of how much the output power is lower than the one supplied to it; the efficiency varies according to the type of project and building, in par­ticular if carried out by means of ordinary or epicycloid gearing. The value can vary from 0.89 for the solution with epicycloid gearing at high reduction ratio and high rotation speed, to 0.96 - 0.97 of a direct drive system with straight or helicoid teeth extremely refined and with low rotation speed. The presence of auxiliary power takeoffs on the reducer/multiplier reduces the power transmittable by the output shaft according to what is given to the power takeoffs.

3.3 INVERTER-REDUCER

Lubrication
On small mechanically-operated inverters the lubrication of gears, bearings and connected parts is car­ried out by means of shaking due to the partial soaking of the toothed wheels in the oil contained in the unit box. On hydraulically-operated inverters, the suitable pump pressurises the oil for the clutch control. Thus, it will be possible to have two circuits, one at high pressure for the clutches, the other at low pressure for the normal lubrication and cooling of the par ts as mentioned above.
Filtering usually occurs with a mesh filter used for the oil pump suction; in some case a cartridge filter is used, inserted in the low pressure circuit. The inverters oil is cooled down through the suitable heat exchanger of oil-water type. On mechani­cal inverters for low powers, the heat exchanger may not be necessary as the heat produced is dissi­pated as a result of convection-irradiation through the container fitted with fins.
The oil indicated for mechanically-operated inverters and for epicycloid hydraulic inverters is of type A for automatic drives; on hydraulically-operated inverters it is normally used engine oil with the right SAE gradation, not multigrade. You are recommended to observe the prescriptions given in the reducer use and maintenance hand­books.
Trailing
When it is not possible to decouple the inverter unit from the boat engine it is advisable to check the inverter suitability for the so called “free wheeling” or “trailing”, i.e. the condition in which, with the engine stationary, the boat movement makes the propeller rotate, thus inducing the unit kinematic motion.This situation can occur in the following cases:
■ Towed boat with engine stationary or twin-engine boat (with separate propellers) travelling with
just one engine while the other is stationary;
■ Motorsailers or sailing boat with auxiliary engine stationary during sailing;
■ Boat moored in waters with strong current.
The induced rotation of the propeller axis driving the inverter directly connected to it can damage the inverter if the lubrication is not ensured also in these conditions. Some hydraulically-operated inverters whose oil pump is set in the motion by the secondary shaft do no have limitations from this point of view, while for others, according to the model, a limited time is prescribed for these conditions or it is prescribed to star t the engine for some minutes in order to carry out lubrication. In those cases where the prescriptions are not compatible with the use, it could be necessary to adopt countermeasures such as a locking brake on the propeller suppor ting axis or an auxiliary pump for the lubrication maintenance. A similar result can be obtained if the boat is fitted with a variable pitch propeller, with the blades feath­ered or, as for sailing boats, if the propeller is with foldable blades. Also for this subject refer to inverter-reducer manufacturer’s instructions.
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MARCH 2004DRIVE
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The torsional vibrations usually are not perceived as they do not always come out in the form of noise, anyway they are not less dangerous.They regard those systems made up of shafts and rotating masses with big inertia and can arise when these systems undergo a pulsating twisting moment or anyway vari­able at regular intervals. They consist in flexible angle oscillations of a general section of the system compared to a reference section and overlap with the normal rotating movement. As for linear vibrations, also with the torsional ones, when the frequency is close to or coincides with the system frequency, there is resonance.The resulting effect is an additional torsional stress compared to the regular drive stress, with the possibility of exceeding the stability limits and the resulting breaks due to torsion. At design stage it is necessary to analyse the risks deriving from the critical speeds in order to foresee the required remedies (snap joints, variation of shaft diameter, balancing of rotating masses, etc.). Additional power takeoffs can compromise the torsional balance of the involved parts. The analyses of the torsional vibrations of the whole application shall be carried out by the builder fitter-out. IVECO Technical Bodies can make suggestions about the engine data which are needed for the cal­culation.

3.4 TORSIONAL VIBRATIONS

MARCH 2004 DRIVE
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SECTION 4
MARCH 2004ENGINE INSTALLATION
4.51

ENGINE INSTALLATION

Page
4.1 TRANSPORTATION 53
4.2 INSTALLATION ON THE HULL 53
4.3 SUSPENSION 53
Rigid suspension 54
Flexible suspension 54
4.4 TILTING 56
4.5 AXIS LINE ALIGNMENT 57
Check of concentricity 58
Check of parallelism 58
MARCH 2004 ENGINE INSTALLATION
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MARCH 2004ENGINE INSTALLATION
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4.1 TRANSPORTATION

The transportation of the engine or the whole engine/inverter unit shall be carried out with the suit­able lifting systems by means of grommets (eyebolts) made for this purpose and in a safe way to pre­vent any injuries to the operator and irregular stresses on the unit components. The engine room must be set taking into consideration the operating needs and so that to facilitate maintenance and checks. In addition, it is necessary to ensure the removal of the engine/inverter, of the drive and their parts.

4.2 INSTALLATION ON THE HULL

The installation of the engine-inverter unit on the hull shall be carried out according to the following prescriptions:
■ Distribute the weight of the unit evenly on the boat structures.
■ The basement shall suppor t the reaction torque and the thrust supplied by the propeller.
■ The basement shall resist the bumps and the stresses coming from the propeller and the hull
during sailing.
■ Ensure that the engine is not influenced by the hull settling and the resulting effects on the unit-axis line alignment. The cross and longitudinal rigidity of the basement must be such to prevent the engine unit from having a structural function.
■ Foresee basement suppor ts in a position corresponding to those of the engine and such to enable the use of the fastening bolts.
■ The suppor t must be such to enable the correct hanging of the unit thus preventing the unit from having a structural function, except for the engines adopted for this solution.
■ The basement suppor t height must be compatible with the space occupied by the underlying unit parts and match with the tilted alignment of the engine axis line.This tilt must be compatible with the maximum value admitted for the engine to be installed shown in the specific documentation provided with each engine.

4.3 SUSPENSION

On marine installations two types of suspensions are usually adopted:
■ Rigid suspension
■ Flexible suspension
The engine suspension can be:
■ Placed on six points, two of them used for the inverter.Adopted on heavier and bigger engines and always when the drive element weight does not enable the overhanging assembly. Max suppor t coplanarity is required in case of rigid assembly.
■ Placed on four points. Frequent solution for average sized engines and with the drive elements flanged on the engine itself.This solution is adopted when the drive is placed far from the engine, thus it shall have its own supports.
Rigid suspension
It is not admitted for 3-cylinder engines and 4-cylinder engines without balancing masses.
It is often used on work boats where a lower dampening level of the vibrations and noise coming from the engine and the reducer is usually accepted. It is also recommended for applications on fast boats where structural solidity is favoured instead of comfort, as these boats must bear substantial stresses at high speeds. The engine brackets are directly fastened to the hull basement keelson, taking care to level out the rel­evant supporting planes by placing the suitable steel shims, if needed, to distribute the suppor t evenly and to obtain the correct alignment of the engine-axis line.The brackets and the relevant fasteners must be sufficiently rigid and resistant to bear the inverter thrust on the inverter thrust bearing when the inverter is directly flanged on the engine. The correlations needing the axis line installation are mentioned in Section 3, to which you should make reference.The figure illustrates an example of rigid assembly on four points.
Flexible suspension
It is used when a higher soundproofing and vibration reduction are required; it is imposed for 3-cylin­der engines and 4-cylinder engines without balancing masses. It is installed by placing two flexible elements between the engine brackets and the engine support keel­son.The flexible elements are chosen according to the weight resting on them and the level of required dampening. Take par ticular care in the choice of the suspensions for the applications on fast boats or their use on fully developed sea. In some cases special supports are required. If the engine must bear the propeller thrust, the flexible supports must be able to resist also to the alternate variations of the vertical load (axial for the support) resulting from the reaction torque and the thrust actions in the two propeller directions, operating them in radial direction. Figure 2 illustrates an example of the flexible support adjustable in height, supplied upon request by IVECO for some applications and figure 3 shows an example of installation. The height adjustment shall be carried out according to the specific instructions provided by each sup­port supplier. Generally, the installer is reminded that the height adjustment must be a final alignment operation of the engine-axis line, for the correct load distribution on the supports, to be completed after the preliminary positioning. The engine bracket must be placed as close as possible to the flexible element and never to the thread­ed stem top, to prevent dangerous bending caused by horizontal forces.
MARCH 2004 ENGINE INSTALLATION
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Figure 1
MARCH 2004ENGINE INSTALLATION
4.55
You can implement the following procedure:
■ First adjust value X from 5 to 7 mm by operating nuts “B” and “C”.
■ Fasten the suppor ts on the engine brackets by tightening nut “A “.
■ Place the engine on the keelson and check if there is clearance below the flexible support.
■ If this clearance is below 2 mm it can be eliminated by operating nuts “B” and “A”.
■ If it is above 2 mm it is necessary to insert a plate with the right thickness.
■ Carry out alignment with the suitable concentricity checks of the axis line, possibly after 1 or 2 days
of support settling.
■ Value X shall not be above 10 mm; if it is necessary to fur ther lift the engine suppor t, insert some shims between the flexible support and the keelson.
An important warning to be observed for the installation of flexible suspensions is to foresee the suit­able hoses (fuel, exhaust, etc.) for the engine ser vice connections, advisable also for rigid suspensions. As to the relation among suspension, engine, axis line and the relevant connections we refer to what stated above. In the choice of the most suitable flexible suspension, when not supplied with the engine, the installer shall refer to the indications and suggestions provided by the suspension supplier.
Figure 3
Figure 2
B
C
X
A

4.4 TILTING

The maximum tilting angles are a typical characteristic of each engine family and basically depend on the type of oil sump, the characteristics of the lubrication circuits and the technology of some systems, such as the oil supply to the hydraulic tappet.
For the admitted tilting, refer to the technical documentation provided with each engine. It is preferable to have the engine installed horizontally, as a result of the opportunity given by the inverters with angled output shaft. In no case the maximum values can be exceeded for not compromising the engine lubrication condi­tions and its operation.
α.Tilting angle - 2. Parallel to waterline - 3. Inverter - 4. Stem.
To define the tilting angle it is necessary to consider the three reference conditions illustrated in figure 5 where it is clear that in case 2 the angle reached in a temporary condition is substantially higher than the previous ones.
1. In static conditions, responding to the floating status without motion,
2. In dynamic conditions, temporary
3. In stabilised dynamic conditions
MARCH 2004 ENGINE INSTALLATION
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Figure 4
1
α
2
3
4
MARCH 2004ENGINE INSTALLATION
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In the applications with V-drive or in other special applications it is important not to tilt the engine with the front side down, not to compromise the regular operation of the cooling system, suitably designed for the tilted operation with the engine front part up; on the contrary, there would be water vapor­ization in the cylinder heads and the resulting overheating and damaging of the engine.

4.5 AXIS LINE ALIGNMENT

To prevent the early wear of the drive components and the formation of vibrations, the propeller sup­porting axis, the inverter-reducer and the engine shall be aligned correctly, ensuring the flange paral­lelism and concentricity are within the values admitted by the inverter and drive manufacturer. The final alignment shall be carried out after the boat has been in the water for some days. The hull must be fully laden (full water and fuel reservoirs included) or with corresponding sham load in order to simulate the possible structural deformations deriving from the load and the floating effect. Also with the correct alignment, the use of the boat leads to variations in time due to settling which need the check alignment at least once a year or at every beginning of season.
Figure 5
1
2
3
Check of concentricity
To check concentricity, use a dial gauge fastened on inverter flange with the feeling pin in contact with the flange of the axis line as illustrated in the figure.
Check of parallelism
To check parallelism, use a dial gauge fastened on inverter flange with the feeling pin in contact with the flange of the axis line as illustrated in the figure. To carry out alignment operate the engine supports. At the end of alignment, check that the fastening screws and bolts are well tightened.
NOTE
For particular installations (e.g. the astern foot, etc.) follow the indications of the specific publications of the manufacturer.
You are reminded that the shipyard has the whole responsibility for the alignment operations; any IVECO responsibility is excluded.
MARCH 2004 ENGINE INSTALLATION
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Figure 6
Figure 7
SECTION 5
MARCH 2004AIR SUPPLY
5.59

AIR SUPPLY

Page
5.1 SUPPLY AND VENTILATION 61
5.2 ENGINE ROOM VENTILATION 61
5.3 AIR FILTERS 62
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MARCH 2004AIR SUPPLY
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5.1 SUPPLY AND VENTILATION

The temperature and pressure of the air sucked by the engine influence, as seen before, the engine per­formance and operation. As a result, for the engine correct operation and duration, the designer of the engine room shall:
■ Ensure the correct air flow in the quantity required for the engine combustion.
■ Ensure the suitable ventilation of the environment to dissipate the heat radiated by the engines and
keep the room temperature at acceptable levels.
A temperature too high inside the engine room does not only reduce the engine performance, espe­cially if the engines suck air directly inside it, but it would also create:
■ Difficult environmental conditions for the operators in charge of the duct and the engine main­tenance.
■ Operating problems of the electrical systems inside the engine room which usually have tempera­ture functional limitations.
If the engine sucks air directly from the engine room, it is necessary that the ventilation system enables to keep temperature within acceptable limits and anyway not above 10°-15°C the exceeding of the temperature of the engine room compared to the external environment. The specific publications show the air capacity values for the combustion and ventilation of each engine. The ventilation air capacity values given in the publications are those suggested to limit the tempera­ture increase in the engine room within 15°C. It is the shipyard responsibility to ensure the right air intake in the engine room.

5.2 ENGINE ROOM VENTILATION

The shipyard must ensure an abundant and well distributed ventilation and check, at fitting, that during operation there is not depression in the engine room, thus benefiting the correct functional behaviour and the duration of the engines, and therefore the hull performance. It is not possible to define a specific standard suitable for every engine-hull combination. The solutions to be adopted on a speedboat hull with supercharged engines are different from those needed for a work boat with aspirated engines. On speedboat hulls the ventilation air flow is favoured as a result of the “dynamic” effect of the travel­ling speed; the inlets on the superstructure sides will convey the air to the low side at the front of the engine room, while the area on the top of the rear side the suitable outlet will discharge the hot air. If this flow is not sufficient, when, for example, the air inlets fitted with baffles and protections against the sea water substantially reduce the air intake, it is advisable to use the suitable extractor fans to facil­itate the flow. Similarly, they are useful to limit the temperature increase when the hull is travelling at low speed after long operation with the engines at maximum power. The use of fans is suggested and sometimes is necessary, also for work boats and similar boats which, for their low travelling speed, cannot rely on a significant “dynamic” effect. The complete development of the setting and dimensioning calculation for the ventilation system com­ponents of the engine room, complex because influenced by different parameters, lies outside the pur­pose of this handbook and shall be carried out at the shipyard.
Anyway consider the following general indications:
■ The air inlets, to be dimensioned with the right margin, shall be structured to prevent the sea water
passage, accidental or not, which is particularly dangerous when present in the air of supercharged engines, as the turbochargers would rapidly be damaged, with the related consequences;
■ The ducts and the pipes shall put up the least resistance to the air flow.The curves must be wide
and their number the lowest possible. Avoid localised narrowing.
■ The global pressure drop in air ducts shall not exceed 0.5 - 1 mbar of the air overall intake for ven-
tilation and combustion;
■ Prevent accidental clogging of air ducts to the engine room (air inlets, pipes, etc.) which would lead
to excessive depression in the engine room with the obvious consequences for the engines.
■ The ventilation system adopted must be previously checked on the prototype during specific sea
tests, to verify efficiency and carry out the necessary changes and improvements.The tests shall be carried out with the boat at the maximum speed and the engines at full load and maximum rpm for a sufficiently long time, in order to check that the environmental conditions got stabilised.

5.3 AIR FILTERS

The environment where the marine engine operates does not usually have a high level of dust (< 2 mg/m
3
).
In most cases simplified filters usually fitted on IVECO engines are sufficient.
In particular cases where the environment can be dusty, as on work boats for the transpor t of dusty materials, it is necessary to apply, separated from the engine, more efficient air filters usually adopted on industrial applications. In this case the application must consider the following:
■ The maximum depression allowed by the engine suction (filter total plus pipes) shall not exceed 35
mbar with the new filter and 65 mbar with the dirty filter.These limits are valid both for aspirated and supercharged engines;
■ The connection pipe between the engine and the filter, with the correct diameter complying with
the above mentioned needs, can consist of a metal pipe fitted with rubber sleeve at the end or a rubber hose with steel inserts having the right dustproof ends;
■ Anyway all the joints must be dustproof; it is suggested to use screw steel clamps tightening the
rubber sleeve on the ends of the pipe to be connected;
■ Ensure the maximum cleaning of the pipe inside (no metal scraps, welding remains or other mate-
rial which can be sucked by the engine and therefore damage it);
■ It is advisable to apply the right pressure outlet with the suitable clogging sensor downstream of
the filter.
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MARCH 2004AIR SUPPLY
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AIR FILTER FOR DUSTY ENVIRONMENTS
The purpose of an industrial air filter use is to ensure a more silent suction. Figure 2 illustrates a system with filter-silencer and external air outlet, fitted with the separator against the water inlet, to be set at the shipyard. In this case it will be possible to raise the temperature inside the engine room compared to that outside, provided that it is compatible with the safety limits of the engines and the presence of possible electrical or electronic equipment.
INDICATIVE DIAGRAM OF FILTER SILENCER
AND OUTSIDE AIR INLET WITH WATER SEPARATOR
1. Outside air inlet - 2. Conic connection (typical of aspirated engines) - 3. Filter silencer -
4. Draining holes - 5. Detail of connection with sleeve, clamps and bordered pipes.
NOTE
The design and realisation of the air feed in the engine room is part of the expertise and responsibility of the shipyard.
Figure 2
1
3
2
4
5
Figure 1
MARCH 2004 AIR SUPPLY
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SECTION 6
MARCH 2004FUEL SUPPLY
6.65

FUEL SUPPLY

Page
6.1 FUEL CHARACTERISTICS 67
6.2 HYDRAULIC CIRCUIT 67
6.3 RESERVOIR 69
6.4 ENGINE-RESERVOIR PIPES 71
6.5 FUEL FILTERING 72
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MARCH 2004FUEL SUPPLY
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6.1 FUEL CHARACTERISTICS

The fuel inside the engine fulfils two basic functions:
■ it is used for the thermodynamic transformation of the energy
■ it cools down and lubricates the elements and components of the injection system (pump, injec-
tors, etc.)
The characteristics of the fuel prescribed for IVECO engines comply with UNI EN 590 specifications; they correspond to those of the diesel fuel produced by the most qualified Oil Companies and dis­tributed at filling stations.

6.2 HYDRAULIC CIRCUIT

The fuel circuit function is to supply the right quantity of fuel to the engine injection system. The fuel has to be clean and not polluted with remains and water and it is necessary to drain off the fuel sur­plus from the reservoir. A fuel circuit accurately designed and correctly implemented is fundamental for the regular engine operation, in particular at start up.
The design and implementation of the whole system are part of the expertise and responsibility of the shipyard.
The fuel circuits required for IVECO engines are characterised by the use of different injection systems, as illustrated in the following figures:
CIRCUIT FOR TRADITIONAL MECHANICAL PUMP
Figure 1
CIRCUIT FOR COMMON RAIL SYSTEM (CP1)
CIRCUIT FOR COMMON RAIL SYSTEM (CP3)
MARCH 2004 FUEL SUPPLY
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Figure 2
Figure 3
MARCH 2004FUEL SUPPLY
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CIRCUIT FOR PUMP INJECTOR SYSTEM (EUI)
Because of the different performances of the injections system, the fuel pressures, temperatures and capacities have specific values; therefore, you are suggested to see the installation diagrams of each engine for the prescriptions concerning each different system.
For the correct and regular fuel supply, it is absolutely necessary that all the circuit components, espe­cially those depending on the fitter-out such reservoir, cocks, pipes, additional filters and other, are installed accurately and the whole circuit is perfectly waterproof. The presence of air in the circuit reduces its quickness at start up and generates engine irregularities. The fuel leaks are a potential fire danger, for this reason it is particularly important to obser ve fire pre­vention rules.

6.3 RESERVOIR

The shape and characteristics of the reser voir usually depend on its position on the boat and on the sailing autonomy, according to the engine adopted. In order to safeguard the boat and the fuel circuit components, it is necessary to observe the following warnings:
■ The structure must be such to resist the boat bumps at sailing
■ If it is long and low it is advisable to apply breakwater baffles inside.
■ It must be placed far from heat sources, at a limited distance and at the same engine level. If the
reservoir is fitted higher than the engine, foresee the addition of two valves on the suction and return pipes.The valves shall be kept closed for stops above 24 hours, in order to prevent the pos­sible fuel flowing back to the engine.
■ Foresee the suitable filler with mesh filter to stop bigger impurities.
■ Foresee a fuel cock applied next to the reser voir on the fuel pipe and in an accessible position.
■ The sucker shall be at no less than 20 mm above the reservoir bottom.
■ The suction and return pipes shall be at about 30 cm to prevent the fuel flowing back affecting
suction.
■ The suction pipe shall be fitted with a pre-filter able to strain deposits bigger than 0.5 mm and such to prevent the air from getting inside the circuit.
Figure 4
■ It shall be made with materials able to resist chemical agents and hot fuel for the whole boat life.
Metal reservoirs protected through zinc-coating or copper-coating galvanic treatments are not suit­able to contain “diesel fuel” as the sulphur in the fuel can generate chemical reactions, thus pro­ducing sulphate dangerous for the injection system. If welded reservoirs are used, make sure they do not release welding dust or sludge.
■ It shall be fitted with a breather to prevent pressurisation and depression. Foresee also a breather
valve to stop the fuel leak in the event of capsizing, preventing at the same time dust and water from getting inside.
■ It shall ensure a fuel reser ve in any condition. For this purpose, the instrument panel shall be fitted
with a fuel level gauge or an alarm for the fuel low level.Verify that the engine delivers the maxi­mum power even when only the reserve quantity is present.
For any solution, it is requested to respect the depression limit values of the suction pipe when the fil­ter is clogged and the counter-pressure values of the fuel return pipe to the reservoir. Further specifications are given in the installation diagrams relevant to each engine.
NOTE
On the boats fitted with many reservoirs, to prevent excessive suction depression it is suggested to use a small reservoir, called service reser voir, placed next to the engines and to which the main reservoirs will be connected to ensure the required autonomy.
With service reservoirs, you are suggested to connect the fuel return pipe from the engine to the main reser­voir to prevent the service reser voir overheating and derating. It is also advisable to check that the transfer from the main reservoir to the service reser voir is ensured at each fuel level and for each sailing trim.
Figure 5 illustrates what mentioned above.
1. Waterproof filling plug - 2. Mesh filter - 3.To the decanting prefilter - 4. Cleaning mobile panel -
5. 5% volume of sedimentation tank - 6. Water breaker baffles - 7. Distance from the
bottom from 20 to 30 mm - 8. Draining plug - 9. Fuel pipe - 10. 1.5% volume for fuel expansion -
11. Swan neck breather - 12. Cock - 13. Fuel return - 14. Injector draining (when used).
MARCH 2004 FUEL SUPPLY
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Figure 5
1
2
3
12
13
14
5
7 6
8
10
11
9
4
12
MARCH 2004FUEL SUPPLY
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NOTE
In particular, the fuel reser voir, the pipes and the relevant pipe unions shall observe the specifications and rules of the country where the boat is to be used, especially in relation to fire safety rules.

6.4 ENGINE-RESERVOIR PIPES

The engine and the reservoir are mutually connected by fuel supply and return pipes. The two pipes can have different diameter, i.e. the supply pipe diameter is higher because of the high­er fuel capacity, at least double. However, they must have the same diameter for those engines where the injector draining is combined with the injection pump return. The pipe size depends on the installation structure and on the pipe unions set on the engines; to iden­tify their diameters and length, refer to the relevant installation diagrams provided with each engine. The pipe unions can be of eyelet type with rubber holder or with threaded end. Prescriptions:
■ For fuel circuits it is possible to use pipes “without welding”, preferably made of ferrous alloy or stainless steel. Synthetic resin, nylon and similar pipes are not accepted by the Classification Bodies as they are not suitable in the event of fire.
■ The pipes must be suitable in temperature and pressure conditions typical of the engine application.
■ The pipe diameter shall not be lower than the diameter of the pipe unions on the engine and grow
as the engine - reservoir distance increases.
■ The engine-pipe union connections shall be designed for all types of engine suspensions, rigid or flexible. They shall be realised by inserting a flexible element between the engine and the pipe. If present, the rubber holder eyelet shall consist of a rubber sleeve reinforced with textile inserts, suit­able for diesel fuel and resisting the fire according to the rules in force in each single country and with the right length, to be tightened on pipes and unions by means of screw clamps. If there is a threaded pipe union, a low pressure hose shall be inserted in between, suitable for diesel oil and resisting fire, fitted with threaded pipe unions at the two ends.
■ The pipes fitted with rubber sleeves shall be bordered to ensure perfect tightness of the screw clamps (see figure 6).
■ Take great care when joining the pipes and regularly check their tightness.
■ The pipe anchoring on the boat structure shall be carried out safely and by means of brackets suit-
ably spaced to prevent the vibration and bending resonance due to the pipe weight; it is suggested to use brackets with flexible coating.
■ The pipe routing shall foresee the minimum number of curves which, if present, shall be wide enough to prevent the formation of intermediate pockets. Foresee also the suitable guards in the areas exposed to bumps or heat.
■ Always make sure that there is no possibility of air inlet/suction.
CAUTION
Clean accurately the pipes and the reservoirs before using them through washing and blowing to remove the impurities and remains inside them.When you finish using these pipes and reservoirs, put them away protected by the suitable protecting caps.
1. Rubber holder pipe union with bordered end - 2.Threaded pipe union.

6.5 FUEL FILTERING

IVECO engines are fitted with replaceable single or double-filters with paper filtering element which meet the requirements of the injection system in terms of filtering level.They are inserted in the feed pump supply circuit, before the high-pressure injection pump. Other data and information about the maintenance intervals are included in the use and maintenance handbooks of each engine. The range of more powerful engines can be fitted, when required by the Classification Bodies, with double-cartridge filters suitable for the replacement when the engine is running; make reference to the use and maintenance handbook for the correct use of the shunting cock (see figure 7). IVECO supplies a decanting pre-filter with the engine which, if installed at the shipyard along the pipe supplying the fuel to the engine, protects the feed pump against the wear caused by the impurities and the water present in the fuel.
Prescriptions:
■ The pre-filter shall be installed on the feeding pipe next to the reservoir, in a point relatively low of
the circuit and in a position easily accessible for maintenance, water and deposit bleeding, and prim­ing. The position close to the reservoir ensures that the pipe is free of water and deposits which might damage it.
■ Do not use additional filters, mesh or paper filters, along the feeding pipes between the decanting
pre-filter and the pump.The filters fitted on the engine fulfil their functions correctly and being on the engine, i.e. in a “hot” place, the risk of clogging due to ice or paraffin oils is limited.
■ In the choice of the engine installation in the engine room, foresee an easy access to the filters to
make sure they can be replaced easily and ensure the correct system bleeding.
In those countries where dust and water can be present in the fuel, such as Africa, the Middle and Far East, Eastern Europe, South America, it is suggested to insert another decanting pre-filter.
MARCH 2004 FUEL SUPPLY
6.72
Figure 6
1 2
MARCH 2004FUEL SUPPLY
6.73
FUEL FILTERS
1. Individual cartridge fuel filter - 2. Dual car tridge fuel filter with possibility of substitution with running engine - 3. Exclusion lever.
NOTE
The design and realisation of the whole fuel system (reservoirs included) are part of the expertise and respon­sibility of the shipyard.
Figure 7
1 2
3
MARCH 2004 FUEL SUPPLY
6.74
SECTION 7
MARCH 2004LUBRICATION
7.75

LUBRICATION

Page
7.1 LUBRICANT CHARACTERISTICS 77
7.2 OIL FILTERS 77
7.3 OIL QUANTITY AND LEVEL DIPSTICK 78
7.4 LOW PRESSURE SIGNALLING 78
7.5 PERIODIC CHANGE 78
7.6 ENGINE VENT 79
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7.1 LUBRICANT CHARACTERISTICS

The type, grade, working temperature and required quantity of oil for the different engines are specified in the technical information table of each engine and in the corresponding manuals of use and maintenance. As regards the oil change intervals mentioned in the different publications, it should be remembered that the use of oils that do not comply with the characteristics of the European standard ACEA E3 -E5 or higher grade oils, reduce change intervals to the half.

7.2 OIL FILTERS

IVECO engines take full flow; easy-change filters, or filter cartridges that filter the total flow of oil in the engine. The filtering material of the cartridge is a special kind of paper, which has a filtering level suitable to the engine type of use. The number of filters varies ranging from one to more than one, depending on their size and on the flow of lubricant oil in the engine. Complying with the Classifying Organisms parameters, the most powerful engines are fitted with a filter support, which includes at least two filters and allows their replacement even while the engine is run­ning. During the oil change, the filters are removed from the lubrication circuit alternatively to secure a continuous filtration through the filter that is kept in the system (fig. 1).
For information about different oil change procedures, refer to the manual of use and maintenance.
1. Oil filters assembly- 2. Oil filter cartridges - A. Functioning filter - B. Filter removal.
Figure 1
1
XX
2
A A
B B
Sez. X-X
7.3 OIL QUANTITY AND LEVEL DIPSTICK
The oil quantities suggested in the repair and use and maintenance manuals refer to the engine that is set up in horizontal position or slightly tilted. The use of engines that are set up with inclination angles that are not considered in the installation instructions, require accurate testing of the exact quantity of oil needed. The quantity of oil in the engine oil sump is checked with the level dipstick. Due to the importance of the presence and level of oil in the oil sump, a frequent and careful control is required. The engines that are set up with an inclination angle different to the ones specified in the manuals require specific oil level dipsticks. It is possible to choose the side to place the dipstick in some versions.
CAUTION
■ When choosing how to install an engine, make sure that the dipstick can be easily reached to check the level of oil daily.
■ An excessive level of oil may cause the formation of foam, a temperature increase and extra oil consumption.
■ An extremely low level of oil may lead to a partial or a total oil pressure drop and, consequently, to the engine wear and tear or jamming.

7.4 LOW PRESSURE SIGNALLING

Engine lubrication is so important to require the setting up of an oil low-pressure sensor located on the engine block and connected to the main lubrication conduit, that activates a visual and/or an acoustic signal. The signal must be activated with a suitable delay to avoid alarms during transient periods; an electronic timer may be used, for example.
NOTE
Proper signalling which prompts intervention avoids serious damage to the engine.

7.5 PERIODIC CHANGE

The main cause of lubricant oil degradation is the engine running condition; other contributing factors are the following:
■ The overheated functioning during long periods reduces the oil resistance to oxidation and increas­es the quantity of insoluble pollutants that constitute a residual oil, which causes the filter wear and tear and obstruction.
■ The fuel pollution caused by the fuel dissolved by the lubricant reduces its viscosity and changes its characteristic.This is generally attributed to poor maintenance of the injection device.
■ Water pollution causes an extreme reduction of the oil lubricant proper ty due to the fact that both substances are impossible to be mixed.
■ In countries in which diesel oil contains ≥ 0.5% of sulphur, oil change intervals should be reduced to the half, with respect to the instructions described for each engine.
To substitute the oil easily, IVECO engines are fitted with a special pump, shown in fig. 2, which is con­nected to the bottom of the oil sump through a pipe that leads to the oil drain plug.
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MARCH 2004LUBRICATION
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When setting up the engine, it is essential to take into account that there must be enough room in the engine compartment to have access to the pump and replace the lubricant.
NOTE
During the oil change procedure, take the necessary proper counter measures to avoid spilling oil in the bilge.
A., B. Manual pump activation to drain the oil.

7.6 ENGINE VENT

Inside the engine, part of the combustion gas leaks out of the cylinders and flows into the lubrication circuits due to the high pressure; at the same time, the oil produces vapour due to the high tempera­ture. This gas mixture, generally called blow-by, is exhausted out of the engine because of the engine overpressure. In the IVECO marine engines, the blow-by gases are concentrated in calibrated channels before they reach the air filter, to be suctioned again and taken into combustion. Every model has a device that reg­ulates the flow of re-suctioned blow-by, separates the liquid components through appropriate filters and leads them to the oil sump. Filters must be periodically changed; thus, easy access to this device should be guaranteed.
Figure 2
A
B
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SECTION 8
MARCH 2004COOLING
8.81

COOLING

Page
8.1 INSTALLATION 83
8.2 PRIMARY CIRCUIT 84
Filling 84
Coolant tank 84
Heater 84
8.3 SECONDARY CIRCUIT 84
Water seacock fitting 85
Water filter 85
Pipes and connexions 86
Water pump 87
Heat exchangers 87
8.4 KEEL COOLING 87
8.5
GALVANIC CORROSION PROTECTION
89
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MARCH 2004COOLING
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The aim of the cooling system is to keep the engine at a constant temperature to ensure proper func­tioning and guarantee the expected nominal performance.
Marine engines are generally provided with a cooling system made up of two circuits:
■ A closed and pressurised primary circuit through which coolant circulates (water 50% and Paraflu
11 or its equivalent, complying with SAE J 1034).
■ An open secondary circuit through which water is taken into and out of the hull.
The heat removed by the coolant in the primary circuit is then passed to the secondar y circuit water in the heat exchanger. The cooling systems also include lubricant oil; intercooler and transmission oil heat exchangers, if needed.
1. Water temperature sensor. - 2. Water temperature sensor (EDC). - 3.Water/water heat exchanger.
- 4. Refrigerated exhaust manifold. - 5. Water drain plug. - 6. Seawater/waste gas mixer. -
7.Turbo-compressor. - 8. Oil inverter heat exchanger. - 9. Seawater filter. - 10. Seawater pump. -
11. Air/water heat exchanger. - 12. Engine base. - 13. Primary circuit water pump. - 14. Primary circuit thermostatic valve. - 15. Pressurised expansion tank. - 16. Water high temperature transmitter.
A. Sea discharge - B.To inverter - C. Seawater suction -
D. /E. Air passage from turbocharger to engine.
CAUTION
To avoid overheating and damage to engine elements, the engine must not run without coolant or water in the secondary circuit.
In some cases, the cooling system is only one single circuit.The heat exchange is done through the keel or the hull wall, the “keel-cooling” system.

8.1 INSTALLATION

E D 9 C
B
Figure 1
13
12
11
14
8
7
A
6543
15
1 216
10
0,5 bar

8.2 PRIMARY CIRCUIT

This circuit cools down the engine, the lubricant oil, and often the exhaust manifold, as well. The pri­mary circuit is enclosed and pressurised, and except for the keel-cooling system, it does not require installation procedures. However, installers must pay special attention to the following:
Filling
The engine installation must guarantee easy filling and coolant level control.The filling volume ranges from 8 to 10 litres per minute, and the procedure should be carried out by the dockyard personnel. Make sure there are no air bubbles in the circuit, which might cause localised overheating and cavita­tions. During filling, air could escape from the cooling system to the charging and expansion tank installed on the engine. It is necessary to consult each engine use and maintenance manual to verify whether to open the corresponding degassing plugs. To ensure the total escape of the air and the complete filling of the circuit, the engine must be tilted backward when installed.
Coolant tank
The engine has an expansion and charging tank to receive the coolant when its volume increases due to heating, and to release it when the engine cools down.The tank filler has a cap to guarantee circuit pressurisation calibrated at 0.5 - 1 bar. Pressurisation increases the liquid boiling point, so cavitations in the circulation pump are avoided.To increase expansion volumes, an extra tank could be set up in some cases. It should be connected to the main tank by a pipe fastened to the overfilled hose-end valve.This tank cap must have a vacuum valve for liquid reflux during engine cooling.This non-pressurised second tank, generally made of transparent material, is suitable to be installed to control the level easily, even though it must also be periodically controlled in the main tank.
Heater
It is possible to set up a heater to obtain hot water, taking advantage of the coolant residual heat. Make sure that:
■ the serpentine highest point is not higher than the filling tank point
■ in the connexion pipe there is a degassing plug near the serpentine upper section
■ liquid drainage and filling points are the ones suggested in the installation layout.

8.3 SECONDARY CIRCUIT

It cools down the engine coolant, the turbocharger air and transmission oil, if applicable.The water taken through a seacock valve at the bottom of the hull is circulated by a positive-displacement pump placed in the engine for this purpose. Small quantities of water may be allowed to drip behind the inter­changers to refrigerate the packing gland.
The following items are part of the dockyard personnel’s responsibilities:
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Water seacock fitting
It draws sea water overboard for the secondary cooling circuit. It must be properly fitted to filter out debris before it gets into the suction pipe and to resist seawater aggressions. Its position in the hull must be carefully chosen to guarantee correct water suction in any navigation condition. In the case of swift hulls, shallow areas shall be avoided. Use special seacocks, if necessary. In the case of metallic hulls, the seacock fittings must be made of the same material to avoid galvanic corrosion. Otherwise, the seacock valve must be electrically insulated. An appropriate sluice valve should be placed between the seacock fitting and the pump to close the seacock valve in case of emergency and extended moorings. Sluice valve installation must guarantee a quick closure, and remote controls may be adopted, if necessary.
Water filter
It filters the debris that the seacock fails to filter, and which could damage pump impeller or obstruct the heat exchangers. Once properly sized, it must be placed in the secondary circuit suction pipes. In order to protect the circuit efficiently, this filter should be oversized so that it does not get obstruct­ed too fast or cause excessive pressure drops. The most important feature to take into account when making a choice is the filter total bored area. Its size area should be at least five or six times greater than the size of the pump suction pipe section.
Figure 2
Figure 3
Pipes and connexions
The secondary circuit water pipes should not cause excessive pressure drop, which may be incompat­ible with proper pump functioning and regular engine refrigeration. Suction vacuum at the engine maximum power rate, including the suction lift and all the connected ele­ments lift should not be over 0.2 bar. As regards dimensional details mentioned in each engine technical chart, indications about pipe inter­nal diameters for installing the engine at a short distance from the water intake or outlet fittings will be given:
■ The suction pipe diameter must be larger or equal to the pump inlet pipe diameter.
■ The main circuit outlet diameter must be larger or equal to the discharge outlet diameter (in the
case of unmixed discharge).
Such diameter shall be increased according to the pipes lengths.
The pipes installed by the dockyard should be made of annealed copper of suitable thickness.They must be properly flanged, when necessary, with a wide bending radius to avoid suction reduction.
Two pipes shall be connected as follows:
■ Pipes ends must have a flange.
■ The connexion must be done with fabric-reinforced flexible rubber couplings.They must have the
appropriate length and characteristics to be used with seawater. (Fig. 4)
■ The coupling must be fastened to the pipe with adjustable clamps with stainless steel screw.
1. Screw clamp - 2. Motor side - 3. Flanged pipe ends details. - 4. Sea water intake.
NOTE
Careful engine circuit connexion, proper flexibility and pipe tightness are extremely important. Constant con­trol and necessary adjustments must be carried out in both circuits maintenance phases, taking special care of the suction section. Airflow into the circuit due to coupling closing failure or fissures caused by wear and tear is generally detected by water leaks and, unless they are immediately detected they can impair refrig­eration causing overheating, which may damage the engine.
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Figure 4
3
4 2
1
MARCH 2004COOLING
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Water pump
As a rule, the water pump is mounted in and activated by the engine.The rubber or neoprene impeller is subjected to wear and tear and it needs to be periodically changed, as indicated in the use and main­tenance manuals. Easy access to the pump must be guaranteed to carry out maintenance procedures.
Heat exchangers
They are part of the equipment, and enough room for their installation must be considered when set­ting up the engine. Easy access to heat exchangers is important, since they need periodic control and cleaning procedures.
NOTE The dockyard personnel are responsible for the layout and installation of the cooling system before and after
installing the engine.

8.4 KEEL COOLING

Keel cooling system is commonly used in vessels generally used in sandy, muddy or shallow waters to avoid continuous filter obstructions. The heat exchanger, through which the coolant runs, is placed under the keel or is incorporated to the keel itself. It is an exposed underwater exchange unit (fig. 6). The coolant protecting function is extended to all the installation sections.
The dockyard personnel are responsible for sizing the keel cooling system according to the thermal bal­ance information supplied by each engine data sheet.
Keel cooling can only be used in engines equipped with circuits for such purpose. In some cases, secondary circuit keel cooling is possible, in which case it becomes a closed circuit. This system can only be adopted in the case of engines that have been programmed for this purpose, due to the fact that the engine cooling system installation is normally sized for water getting into the sec­ondary circuit with a temperature below 32 ºC. Then, the keel cooling system would be closed. It is practically impossible to use, except for the case of navigation in very cold water ; to avoid the risk of engine and turbocharger air overheating it is necessary to plan a power-down.
An example of circuit for a supercharged engine:
1. Water charge tank - 2. Inverter water/oil exchanger - 3. Water/air exchanger - 4. Keel cooling - 5. Water intake - 6.Water outlet - 7. Freshwater pump - 8. Refrigerated turbine - 9. Refrigerated
exhaust manifold - 10. Water/oil engine exchanger - 11. Head water intake manifold - 12. Cylinder
water intake manifold - 13. Head water outlet manifold -14.Thermostatic valve - 15. By pass
The coolant exits the engine (6) through the thermostatic valve (14); after running through the keel exchanger (4) it gets back refrigerated to be suctioned (5) by the engine water pump (7) which circu­lates it again. The charging tank (1), always at a higher position than the engine highest point, works as the circuit expansion and compensation tank in the keel cooling system.The tank fitted in the engine may not com­ply with installation requirements. A larger volume tank may be necessary when great water volumes circulate. Generally, the volume in the tank is equal to or near the 15% of the total engine system capac­ity plus the external circuit capacity.The quantity of cold water in the tank must range from 1/3 to 1/2 of the total volume. The tank must be connected near the water pump intake, the engine connexion near the keel exchang­er. Connexions must always be flexible and tightness must be guaranteed.
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Figure 5
1
23144 6 15
7
5
10 9
8
11
13
12
MARCH 2004COOLING
8.89
Figure 6 shows the implementation layout of a heat exchanger placed under the keel with distant water inlet and outlet.
8.5 GALVANIC CORROSION PROTECTION
Seawater stimulates the circulation of eddy currents due to its high electrical conductivity. It behaves as an electrolyte when metallic elements are immersed. Each metal has a particular electrochemical poten­tial that generates a difference in potential originating the electric current influx.The subsequent effect will be the corrosion of the more active metal or system anode. Therefore, the materials used for sea navigation, and particularly in the seawater circuits should be sim­ilar and therefore close on the electrochemical scale to avoid differences in potentials that will originate strong eddy currents. (See Section 13 - Galvanic corrosion protection). Important corrosive effects can also be checked by electric leakage between the engine and the sea­water circuit. These effects can be minimised by the use of engine electrical equipment with isolated poles and a safe and complete ground connexion. It is advisable to refer to the electrical equipment section for more details. All IVECO engines are supplied with protection zinc anodes all along the secondary cooling circuit.The dockyard personnel must pay attention to the instructions about protection against eddy currents cor­rosion by using the suitable protective anodes in the complementary installation components and relat­ed parts.
Instructions:
■ When ending an installation, instrumental controls should be carried out: the equipment compo-
nents electric potential and eddy currents must be measured.
■ Efficient protection duration is only guaranteed by periodic control and change of zinc anodes when
there is intense corrosion.
■ In the vessel first year of use, zinc anodes consumption should be checked every three months.
■ When the anodes original size is reduced by 50% they should be changed.
Figure 6
PLUG WITH ANODE PROTECTION EFFECT
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Figure 7
SECTION 9
MARCH 2004DISCHARGE
9.91

DISCHARGE

Page
9.1 OVERVIEW 93
9.2 DRY DISCHARGE 93
9.3 MIXED DISCHARGE 94
Engine with exhaustion gas outlet flange above the water line 94
Engine with exhaustion gas outlet flange below the water line 94
9.4 SILENCERS 96
9.5 COUNTERPRESSURE 96
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MARCH 2004DISCHARGE
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9.1 OVERVIEW

The discharge system of marine engine exhaust gases can be divided in two categories:
■ Dr y discharge
■ Mixed discharge
The choice of the type of discharge is the staff ’s decision and it depends on the vessel structure and on the desired comfort. Dry discharge is generally chosen by high power engines in professional ves­sels, while mixed discharge is chosen for pleasure vessels that need more comfort in terms of noise and fumes in passenger areas.

9.2 DRY DISCHARGE

Exhaust gases are expelled through pipes; for safety reasons and to avoid heat radiation these pipes should be fitted with an appropriate thermal insulation made of non-flammable, fuel-proof and lubri­cant oil-resistant.
An alternative system to protect discharge conduits consists of lining the pipes to make water run through the interstice.This solution requires the regulation of the flow of refrigeration water to avoid exhaust gases excessive cooling, since this would form acid condensations and fumes during exhaus­tion. The three-way valve regulation allows the engine circuit water drainage without causing throttling in the water circuit. If secondary circuit water is used, this should be drained at the circuit outlet, paying special attention to avoid spillage that would reduce the pump water flow. Coolant from the engine primary circuit must not be used.
In the case of engines mounted on rigid supports, the pipes must be fitted with a joint to compensate thermal dilatation. The expansion joints, generally shaped as stainless steel bellows, must axially com­pensate dilatations and must not vibrate (Fig. 1).
Insulating exhaust pipes with thermal lining, not only aims to avoid the vibration caused by the engine and the thrust of the exhaust gases, but also thermal dilatations due to high temperature.Therefore, it is important to provide flexible insulation to reduce vibration without hindering dilatation movements.
Figure 1
Engines mounted on flexible supports take special flexible pipes to allow movement between the engines and exhaust installation. In both cases, follow the recommendations below:
■ The exhaust pipes placed after the flexible elements must be fastened with braces to the vessel
structure not to lay their weight onto the engine and to avoid shaking and vibrations that may cause breakings with time.
■ In the case of upward motion discharge, taken into account drainage and condensed material col-
lection fitting, installed near the engine and at the bottom of the pipe to make sure that water or rain do not enter the engine.
■ Avoid the mixture of gases coming from other engines in one exhaustion pipe system. Provide a
separate discharge outlets for each engine and avoid multiple engine exhaust gases into a single exhaust system.
■ Pipes that go through bulkheads must be insulated to avoid noise or heat transmission.
■ It is advisable to construct exhaust pipes with anticorrosion material such as stainless steel, scour-
ing weldings properly.
■ Guaranty accurate tightness of gas pipes to avoid hazardous gas leaking into the vessel com-
partments.

9.3 MIXED DISCHARGE

Gases are mixed with the water of the secondary cooling circuit when they exit the engine.This sys­tem is only adopted for engines supplied with water/water heat exchanger. Generally, it cannot be used in keel cooling systems. The two main systems depend on the engine position in the hull in relation to the waterline, and they are the following:
■ Engine with exhaustion gas outlet above the water line
■ Engine with exhaustion gas outlet below the water line
Engine with exhaustion gas outlet flange above the water line
When planning, take into account that the mixer bottom edge is at a minimum elevation of 300 mm over the waterline. The pipes placed after the mixer must be resistant to exhaust gases and certified by vessel certifying Entities. IVECO mixer configuration may not be suitable for all kinds of vessels. The dockyard personnel have to devise an exhaust system in such a way to avoid the return of water to the exhaust manifold or to the engine turbine under any working conditions.They should also install an appropriate mixer to properly exhaust gases, paying special attention not to overload the manifold or the turbine. Perfect gas and water tightness must be guaranteed.
Engine with exhaustion gas outlet flange below the water line
For this type of installation the system may require:
a) The construction of a special raiser to meet the conditions stated in the previous item.
b) The use of an exhaust system compatible with the room available on the engine (fig. 2).
The inverted U-tube and the air vent made at the dockyard hinder water transfer from the cooling cir­cuit to the engine when the vessel is stopped.
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MARCH 2004DISCHARGE
9.95
The overboard discharge pipe is also an inverted U-shaped tube that hinders direct outside water flow­ing; its height depends on the kind of vessel. The silencer capacity must be superior to the water volume discharged when stopping the engine. Materials used must be resistant to exhaust gases and seawater aggression. It is advisable to use stain­less steel and to avoid using copper and bronze. The dockyard shall be responsible for preventing corrosion phenomena, mainly when the discharge pipe is below the water line.The staff must also check that the system works correctly. Besides, the dockyard personnel should pay special attention to avoid uncovered sections on those spe­cial raisers and insulated pipes and to ensure that they are water-cooled to avoid heat radiation that may cause burning or fire danger.
1.Vent pipe - 2. Waterline - 3. Secondary cooling circuit discharge - 4. Engine - 5. Secondary cooling
circuit pump - 6. Silencer - 7. Gas and seawater flow- 8. Engine discharge - 9. Mixing area -
A. Elevation depending on the type of installation.
It is important to choose the right gases exhaust position to avoid their flowing into vessel passenger or crew areas. In the case of large superstructures, usually there is an aft turbulence zone that favours residual gases. Therefore, the layout of pipe ends must be carefully planned to avoid such zone. The dockyard personnel must make sure that the pipes are correctly fastened to the hull and that use­less water accumulation is not formed.
NOTE
Dry discharge systems, as well as mixers, are subjected to corrosion and wear and tear caused by the con­stitutive material and the circulating fluids.
They must be periodically controlled and the worn out parts must be changed, if necessar y, to guarantee com­fort and safety.
Figure 2
A
1
Ø from 5 to 6 mm
300 mm MIN
2
4
5
6
9
87
3

9.4 SILENCERS

It is possible to fit the engine with commercially available or special models. In either case, the instal­lation and manufacturing features must meet the requirements to avoid the return of water to the engine under any navigation conditions.The total counterpressure, including pipes pressure, must be within permitted limits.

9.5 COUNTERPRESSURE

In the case of any of the discharge systems previously described, it is necessary to check that the dis­charge counterpressure value is within the limits mentioned in the engines specific technical chart.
Overlooking limits causes:
■ Reduced performance
■ Fuel consumption increase
■ Fumes
■ Engine overheating
The dockyard personnel must assess installation on the basis of their knowledge and expertise and on the equipment assembly layout on the vessel. IVECO provides estimates for exhaust gases volume and temperature for their own engines, in case they are needed. The diagram in fig. 3 merely illustrates a procedure to measure the diameter of an exhaust pipe system for gas not mixed with water. To size the pipes for gas mixed with water increase the diameter by 10% taking as a reference value the dry discharge pipe diameter. In engines equipped with IVECO standard mixers, the pipe diameter shall never be smaller than the mixer outlet diameter. In each case, it is advisable to check the counterpressure originated by the dis­charge pipe and the silencer, if present. The measuring must be taken near the exhaust manifold outlet clamp or the turbine in a straight sec­tion, if possible. This should be done during navigation, with the engine at maximum speed; IVECO engines are fitted with a screwed intake to insert the pressure gauge.
MARCH 2004 DISCHARGE
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MARCH 2004DISCHARGE
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Figure 3
Counterpressure inside pipe
in mm H2O (silencer excluded)
Pipe diameter in mm
Insulated
Not insulated
Elbows number at 90° - R=2.5 D
Elbows number at 90° - R=2.5 D
Exhaust gas flow rate m
3
/ h
MARCH 2004 DISCHARGE
9.98
SECTION 10
MARCH 2004AUXILIARY SERVICES
10.99

AUXILIARY SERVICES

Page
10.1 OVERVIEW 101
10.2
POWER TAKE-OFF ON THE FLY WHEEL
101
On the engine shafts 101
Lateral with belt transmission 102
10.3 FRONT PULLEY POWER TAKE-OFF 102
On the engine shafts 102
Lateral with belt transmission 103
10.4 BUILT-IN POWER TAKE-OFF ON TIMING OR FLYWHEEL HOUSING 103
MARCH 2004 AUXILIARY SERVICES
10.100
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