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Marine
Service Manual
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Iveco Marine Service Manual

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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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
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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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