Propulsion of 200,000-210,000 dwt Large Capesize Bulk Carrier

Propulsion of 200,000-210,000 dwtLarge Capesize Bulk Carrier

Content

Introduction .................................................................................................5

EEDI and Major Ship and Main Engine Parameters........................................6

Energy Efficiency Design Index (EEDI) ......................................................6

Major propeller and engine parameters ....................................................7

205,000 dwt large capesize bulk carrier ..................................................9

Main Engine Operating Costs – 14.7 knots ................................................. 10

Fuel consumption and EEDI .................................................................. 10

Operating costs .................................................................................... 12

Main Engine Operating Costs – 14.0 knots ................................................. 14

Fuel consumption and EEDI .................................................................. 14

Operating costs .................................................................................... 17

Summary ................................................................................................... 18

Propulsion of 200,000-210,000 dwt Large Capesize Bulk Carrier

Introduction

The main ship particulars of 205,000-

210,000 dwt large capesize bulk car-

riers are normally approximately as fol-

lows: the overall ship length is 299.9

m, breadth 50 m and scantling draught

17.9-18.4 m, see Fig. 1.

Recent development steps have made

it possible to offer solutions which will

enable significantly lower transporta-

tion costs for large capesize bulk carri-

ers as outlined in the following.

One of the goals in the marine industry

today is to reduce the impact of CO2

emissions from ships and, therefore,

to reduce the fuel consumption for the

propulsion of ships to the widest pos-

sible extent at any load.

This also means that the inherent de-

sign CO2 index of a new ship, the so-

called Energy Efficiency Design Index

(EEDI), will be reduced. Based on an

average reference CO2 emission from

existing bulk carriers, the CO2 emission

from new bulk carriers in gram per dwt

per nautical mile must be equal to or

lower than the reference emission fig-

ures valid for the specific bulk carrier.

This drive may often result in operation

at lower than normal service ship speeds

compared to earlier, resulting in reduced

propulsion power utilisation. The design

ship speed at Normal Continuous Rating

(NCR), including 15% sea margin, used

to be as high as 14.0-15.0 knots and

with an average of about 14.7 knots. To-

day, the required ship speed should be

expected to be lower, however it seems

to be unchanged.

A more technically advanced develop-

ment drive is to optimise the aftbody

and hull lines of the ship – including bul-

bous bow, also considering operation in

ballast condition. This makes it possible

to install propellers with a larger pro-

peller diameter and, thereby, obtaining

higher propeller efficiency, but at a re-

duced optimum propeller speed, i.e. us-

ing less power for the same ship speed.

Fig. 1: Large capesize bulk carrier

5Propulsion of 200,000-210,000 dwt Large Capesize Bulk Carrier

As the two-stroke main engine is directly

coupled with the propeller, the introduc-

tion of the ultra long stroke G70ME-C9.5

engine with even lower than usual shaft

speed will meet this goal. The main di-

mensions for this engine type, and for

the existing large capesize bulk carrier

engine S70ME-C8.5 are shown in Fig. 2.

On the basis of a case study of a

205,000 dwt large capesize bulk carrier

in compliance with IMO Tier II emission

rules, this paper shows the influence on

fuel consumption when choosing the

new G70ME-C9.5 engine compared

with the existing and normally used

S70ME-C8.5 engine. The layout ranges

of 5 and 6G70ME-C9.5 engines com-

pared with 6S70ME-C8.5 are shown

later in Fig. 4.

EEDI and Major Ship and Main Engine Parameters

Energy Efficiency Design Index (EEDI)

The IMO (International Maritime Organi-

sation) based Energy Efficiency Design

Index (EEDI) is a mandatory index re-

quired on all new ships contracted after

1 January 2013. The index is used as

an instrument to fulfil international re-

quirements regarding CO2 emissions

on ships. EEDI represents the amount

of CO2 emitted by a ship in relation to

the transported cargo and is measured

in gram CO2 per dwt per nautical mile.

The EEDI value is calculated on the

basis of maximum cargo capacity (yet

70% for container ships), propulsion

power, ship speed, SFOC (Specific Fuel

Oil Consumption) and fuel type. De-

S70ME-C8.5G70ME-C9.5

1,52

1

2,32

6

12,0

66

1,75

0

2,72

0

4,760 4,390

13,2

45

Fig. 2: Main dimensions for the new G70ME-C9.5 engine and the existing S70ME-C8.5 applied earlier

pending on the date of ship contract,

the EEDI is required to be a certain

percentage lower than an IMO defined

reference value depending on the type

and capacity of the ship.

The main engine’s 75% SMCR (Speci-

fied Maximum Continuous Rating) fig-

ure is as standard applied in the cal-

culation of the EEDI figure, in which

also the CO2 emission from the auxiliary

engines of the ship is included. How-

ever, certain correction figures are ap-

plicable, e.g. for installed waste heat

recovery systems.

According to the rules finally decided

on 15 July 2011, the EEDI of a new

ship is reduced to a certain factor com-

pared to a reference value. Thus, a ship

6 Propulsion of 200,000-210,000 dwt Large Capesize Bulk Carrier

Fig. 3: Influence of propeller diameter and pitch on SMCR for a 205,000 dwt large capesize bulk carrier operating at 14.7 knots

bigger than 20,000 dwt and built after

2025 is required to have a 30% lower

EEDI than the 2013 reference figure,

see also later in Figs. 8 and 14.

Major propeller and engine param-

eters

In general, the highest possible pro-

pulsive efficiency required to provide a

given ship speed is obtained with the

largest possible propeller diameter d,

in combination with the corresponding,

optimum pitch/diameter ratio p/d.

As an example, this is illustrated for a

205,000 dwt large capesize bulk carrier

with a service ship speed of 14.7 knots,

see the black curve in Fig. 3. The need-

ed propulsion SMCR (Specified Maxi-

mum Continuous Rating) power and

speed is shown for a given optimum

propeller diameter d and p/d ratio.

According to the black curve, the ex-

isting propeller diameter of 8.3 m may

have the optimum pitch/diameter ratio

of 0.71, and the lowest possible SMCR

shaft power of about 17,680 kW at

about 88 r/min.

The black curve shows that if a bigger

propeller diameter of 8.8 m is possible,

the necessary SMCR shaft power will be

reduced to about 17,120 kW at about

78 r/min, i.e. the bigger the propeller,

the lower the optimum propeller speed.

If the pitch for this diameter is changed,

the propulsive efficiency will be re-

duced, i.e. the necessary SMCR shaft

power will increase, see the red curve.

The red curve also shows that propul-

sion-wise it will always be an advantage

to choose the largest possible propel-

ler diameter, even though the optimum

pitch/diameter ratio would involve a

too low propeller speed (in relation to

the required main engine speed). Thus,

when using a somewhat lower pitch/

diameter ratio, compared with the op-

timum ratio, the propeller/engine speed

may be increased and will only cause a

minor extra power increase.

14,000

17,000

18,000

15,000

16,000

19,000

60 65 70 75 80 85 90 95 100 105 r/minEngine/propeller speed at SMCR

PropulsionSMCR power

kW

S70ME-C8.5

Power and speed curve for the given propeller diameter d = 8.8 m with different p/d ratios

Power and speed curve for various propeller diameters (d) with optimum p/d ratio

SMCR power and speed are inclusive of:15% sea margin10% engine margin 5% propeller light running

4-bladed FP-propellersd = Propeller diameterp/d = Pitch/diameter ratio Design Ship Speed = 14.7 knDesign Draught = 16.1 m

G70ME-C9.5

G70ME-C9.5S70ME-C8.5

0.95

0.850.73

0.75

9.3 m

8.3 m

8.8 m0.71

p/dd

0.650.60

p/d


0

5,000

10,000

15,000

20,000

25,000

30,000

40 50 60 70 80 90 100 110 120 r/minEngine and propeller speed at SMCR

PropulsionSMCR powerkW

Possible9.3 m × 4

57.8%

Existing8.8 m × 4

54.7%

Existing8.3 m × 4

51.6%

∝

∝∝

∝

∝

Dprop × Nblade:Dprop /Tdes=

14.0 kn14.0 kn, 8.3 m × 4M1’ = 15,190 kW × 84 r/min (6S70ME-C8.5) 14.0 kn, 8.8 m × 4M2’ = 14,720 kW × 75 r/min (5G70ME-C9.5) 14.0 kn, 9.3 m × 4M3’ = 14,260 kW × 67 r/min (5G70ME-C9.5) 14.0 kn, 9.3 m × 4M4’ = 14,260 kW × 67 r/min (6G70ME-C9.5)

14.7 kn14.7 kn, 8.2 m × 4M1 = 17,840 kW × 91 r/min (6S70ME-C8.5) 14.7 kn, 8.7 m × 4M2 = 17,270 kW × 81 r/min (6S70ME-C8.5) 14.7 kn, 8.7 m × 4M3 = 17,270 kW × 81 r/min (6G70ME-C9.5) 14.7 kn, 9.3 m × 4M4 = 16,640 kW × 71 r/min (6G70ME-C9.5)

4 bladed FP-propellersConstant ship speed coefficient ∝ = 0.28

SMCR power and speed are inclusive of:15% sea margin10% engine margin5% light running

Tdes = 16.1 m

16.0 kn

15.0 kn14.7 kn

14.0 kn

13.0 kn

91 r/min83 r/min

6G70ME-C9.5

5G70ME-C9.5

6S70ME-C8.5

M4M4’

M3’M2’ M1’

M2M3

M1

Fig. 4: Different main engine and propeller layouts and SMCR possibilities (M1, M2, M3, M4 for 14.7 knots and M1’, M2’, M3’, M4’ for 14.0 knots) for a

205,000 dwt large capesize bulk carrier operating at 14.7 knots and 14.0 knots, respectively

The efficiency of a two-stroke main en-

gine particularly depends on the ratio of

the maximum (firing) pressure and the

mean effective pressure. The higher the

ratio, the higher the engine efficiency,

i.e. the lower the Specific Fuel Oil Con-

sumption (SFOC).

Furthermore, the higher the stroke/bore

ratio of a two-stroke engine, the higher

the engine efficiency. This means, for

example, that an ultra long stroke en-

gine type, as the G70ME-C9.5, may

have a higher efficiency compared with

a shorter stroke engine type, like a su-

per long stroke S70ME-C8.5.

The application of new propeller design

technologies may also motivate use of

main engines with lower rpm. Thus, for

the same propeller diameter, these pro-

peller types can demonstrate an up to

4% improved overall efficiency gain at the

same or a slightly lower propeller speed.

This is valid for propellers with Kappel

technology available at MAN Diesel &

Turbo, Frederikshavn, Denmark.

Furthermore, due to lower emitted

pressure impulses, the kappel propel-

ler requires less tip clearance that can

be utilised for installing an even larger

propeller diameter, resulting in a further

increase of the propeller efficiency.

Hence, with such a propeller type,

the advantage of the new low speed

G70ME-C9.5 engine can be utilised

also in case a correspondingly larger

propeller cannot be accommodated.


205,000 dwt large capesize bulk

carrier

For a 205,000 dwt large capesize bulk

carrier, the following case study illus-

trates the potential for reducing fuel

consumption by increasing the pro-

peller diameter and introducing the

G70ME-C9.5 as main engine. The ship

particulars assumed are as follows:

Scantling draught m 18.2

Design draught m 16.1

Length overall m 299.9

Length between pp m 291.0

Breadth m 50.0

Sea margin % 15

Engine margin % 10

Design ship speed kn 14.7 and 14.0

Type of propeller FPP

No. of propeller blades 4

Propeller diameter m target

Based on the above-stated average

ship particulars assumed, we have

made a power prediction calculation

(Holtrop & Mennen’s Method) for dif-

ferent design ship speeds and propel-

ler diameters, and the corresponding

SMCR power and speed, point M, for

propulsion of the large capesize bulk

carrier is found, see Fig. 4. The propel-

ler diameter change corresponds ap-

proximately to the constant ship speed

factor α = 0.28 [ref. PM2 = PM1 × (n2/

n1)α.

Referring to the two ship speeds of 14.7

knots and 14.0 knots, respectively, two

potential main engine types, pertaining

layout diagrams and SMCR points have

been drawn-in in Fig. 4, and the main

engine operating costs have been cal-

culated and described.

The S70ME-C8.5 engine type (91 r/

min) has often been used in the past

as prime movers in projects for large

capesize bulk carriers. Therefore, a

comparison between the new G70ME-

C9.5 and the existing S70ME-C8.5 is of

major interest in this paper.

It should be noted that the ship speed

stated refers to NCR = 90% SMCR in-

cluding 15% sea margin. If based on

calm weather, i.e. without sea margin,

the obtainable ship speed at NCR =

90% SMCR will be about 0.6 knots

higher.

If based on 75% SMCR, as applied for

calculation of the EEDI, the ship speed

will be about 0.2 knot lower, still based

on calm weather conditions, i.e. with-

out any sea margin.


1

6,000

8,000

2

3

4

5

6

7

8

9

Relative powerreduction

%Inclusive of sea margin = 15%

Propulsion power demand at N = NCR

kW

0

2,000

4,000

0

16,000

18,000

10,000

12,000

14,000

Dprop:

16,056 kW

6S70ME-C8.5N1

8.2 m × 4

0%

15,543 kW

6S70ME-C8.5N2

8.7 m × 4

3.2%

15,543 kW

6G70ME-C9.5N3

8.7 m × 4

3.2%

14,976 kW

6G70ME-C9.5N4

9.3 m × 4

6.7%

Fig. 5: Expected propulsion power demand at NCR = 90% SMCR for 14.7 knots

Main Engine Operating Costs – 14.7 knots

The calculated main engine examples

are as follows:

14.7 knots

1. 6S70ME-C8.5 (Dprop = 8.2 m)

M1 = 17,840 kW × 91.0 r/min

2. 6S70ME-C8.5 (Dprop = 8.7 m)

M2 = 17,270 kW × 81.0 r/min.

3. 6G70ME-C9.5 (Dprop = 8.7 m)

M3 = 17,270 kW × 81.0 r/min.

4. 6G70ME-C9.5 (Dprop = 9.3 m)

M4 = 16,640 kW × 71.0 r/min.

The main engine fuel consumption and

operating costs at N = NCR = 90%

SMCR have been calculated for the

above four main engine/propeller cases

operating on the average ship speed of

14.7 knots, as often used earlier, but

also today, despite the EEDI demands.

Furthermore, the corresponding EEDI

has been calculated on the basis of the

75% SMCR-related figures (without sea

margin).

Fuel consumption and EEDI

Fig. 5 shows the influence of the pro-

peller diameter with four propeller

blades when going from about 8.2 m to

9.3 m. Thus, N4 for the 6G70ME-C9.5

with a 9.3 m propeller diameter has a

propulsion power demand that is about

6.7% lower compared with N1 valid for

the 6S70ME-C8.5 with a propeller di-

ameter of about 8.2 m.


Fig. 6 shows the influence on the main

engine efficiency, indicated by the

Specific Fuel Oil Consumption, SFOC,

for the four cases. For N3 = 90% M3

with the 6G70ME-C8.5 SFOC is 159.1

g/kWh and for N1 = 90% M1 with

6S70ME-C8.5 SFOC is 164.1 g/kWh.

In N3, the SFOC is about 3.0% lower

compared with N1.

When multiplying the propulsion power

demand at N (Fig. 5) with the SFOC

(Fig. 6), the daily fuel consumption is

found and is shown in Fig. 7. Compared

with N1 for the existing 6S70ME-C8.5,

the total reduction of fuel consump-

tion of the new 6G70ME-C9.5 at N3

is about 6.1% and at N4 about 8.2%

(see also the above-mentioned savings

of 3.2%/6.7% (Fig. 5) and 3.0%/1.6%

(Fig. 6).

Engine shaft power

174

25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100% SMCR156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

SFOCg/kWh

171

172

173 IMO Tier llISO ambient conditionsLCV = 42,700 kJ/kg

Standard high-loadoptimised engines

M = SMCRN = NCR

N1

N3

N2

N

N4

Savings in SFOC

0.0%Basis-1.5%

1.6%

3.0%

DpropM2 6S70ME-C8.5 8.7 m x 4

M1 6S70ME-C8.5 8.2 m x 4

M4 6G70ME-C9.5 9.3 m x 4

M3 6G70ME-C9.5 8.7 m x 4

Fig. 6: Expected SFOC for 14.7 knots


2.592.48

2.42

2.63

6S70ME-C8.5N1

8.2 m × 4

6S70ME-C8.5N2

8.7 m × 4

6G70ME-C9.5N3

8.7 m × 4

6G70ME-C9.5N4

9.3 m × 4Dprop:

0

0.5

1.0

1.5

2.0

2.5

0

10

20

30

40

50

60

70

80

90

100

Reference and actual EEDICO2 emissionsgram per dwt/n mile

Actual/ReferenceEEDI %

3.0

2013Year

Contract datebefore 1 January

2015

2020

2025

92%88%

86%

EEDI actualEEDI reference (2.81/100%)

94%

75% SMCR: 14.5 kn without sea margin

Fig. 8: Reference and actual Energy Efficiency Design Index (EEDI) for 14.7 knots

2

30

40

50

4

6

60

70

8

10

12

14

Relative saving of fuel consumption

%

Fuel consumptionof main engine

t/24h

IMO Tier llISO ambient conditions

LCV = 42,700 kJ/kg

0

10

20

0

Dprop:

63.23t/24h

6S70ME-C8.5N1

8.2 m × 4

0%

62.10t/24h

6S70ME-C8.5N2

8.7 m × 4

1.8%

59.36t/24h

6G70ME-C9.5N3

8.7 m × 4

6.1%

58.06t/24h

6G70ME-C9.5N4

9.3 m × 4

8.2%

Fig. 7: Expected fuel consumption at NCR = 90% SMCR for 14.7 knots

The reference and the actual EEDI

figures have been calculated and

are shown in Fig. 8 (EEDIref = 961.8 x

dwt -0.477, 15 July 2011). As can be seen

for all four cases, the actual EEDI fig-

ures are relatively high with the lowest

EEDI (86%) for case 4 with 6G70ME-

C9.5. Cases 3 and 4 with 6G70ME-

C9.5 are the only ones to meet the

2015 reference EEDI.

Operating costs

The total main engine operating costs

per year, 250 days/year, and fuel price

of 700 USD/t, are shown in Fig. 9. The

lube oil and maintenance costs are

shown too. As can be seen, the major

operating costs originate from the fuel

costs – about 96%.


After some years in service, the rela-

tive savings in operating costs in Net

Present Value (NPV), see Fig. 10, with

the existing 6S70ME-C8.5 used as

basis with the propeller diameter of

about 8.2 m, indicates an NPV saving

for the new 6G70ME-C9.5 engines.

After 25 years in operation, the saving

is about 15.9 million USD for N4 with

6G70ME-C9.5 with the SMCR speed

of 71.0 r/min and propeller diameter of

about 9.3 m.

Fig. 9: Total annual main engine operating costs for 14.7 knots

0

2.0

4.0

6.0

1.0

3.0

5.0

Annual operating costsMillion USD/Year

Relative saving in operating costs

%

Dprop:

7.0

8.0

9.0

10.0

11.0

12.0

0

2

4

6

1

3

5

7

8

9

10

11

12

6S70ME-C8.5N1

8.2 m × 4

6S70ME-C8.5N2

8.7 m × 4

6G70ME-C9.5N3

8.7 m × 4

6G70ME-C9.5N4

9.3 m × 4

0%1.8%

6.0%

8.0%

MaintenanceLubricating oil

Fuel oil


250 days/yearNCR = 90% SMCR

Fuel price: 700 USD/t

YearsLifetime

0

4

2

6

0 5 10 15 20 25 30

8

10

12

14

16

18

Saving in operating costs (Net Present Value)Million USD

IMO Tier llISO ambient conditionsN = NCR = 90% SMCR250 days/yearFuel price: 700 USD/tRate of interest and discount: 6% p.a.Rate of inflation: 3% p.a.

N2: 8.7 m × 46S70ME-C8.5

N3: 8.7 m × 46G70ME-C9.5

N4: 9.3 m × 46G70ME-C9.5

N1: 8.2 m × 4 Basis6S70ME-C8.5

Fig. 10: Relative saving in main engine operating costs (NPV) for 14.7 knots


0

4,000

6,000

2,000

8,000

12,000

14,000

10,000

Relative powerreduction

%

Propulsion power demand at N’ = NCR

kW

0

1

2

3

4

5

6

7

Dprop:

Inclusive of sea margin = 15%

6S70ME-C8.5N1’

8.3 m × 4

13,671 kW

0%

5G70ME-C9.5N2’

8.8 m × 4

13,248 kW

3.1%

5G70ME-C9.5N3’

9.3 m × 4

12,834 kW

6.1%

6G70ME-C9.5N4’

9.3 m × 4

12,834 kW

6.1%

Fig. 11: Expected propulsion power demand at NCR = 90% SMCR for 14.0 knots

Main Engine Operating Costs – 14.0 knots

The calculated main engine examples

are as follows:

14.0 knots

1’. 6S70ME-C8.5 (Dprop = 8.3 m)

M1’ = 15,190 kW × 84.0 r/min

2’. 5G70ME-C9.5 (Dprop = 8.8 m)

M2’ = 14,720 kW × 75.0 r/min.

3’. 5G70ME-C9.5 (Dprop = 9.3 m)

M3’ = 14,260 kW × 67.0 r/min.

4’. 6G70ME-C9.5 (Dprop = 9.3 m)

M4’ = 14,260 kW × 67.0 r/min.

The main engine fuel consumption and

operating costs at N’ = NCR = 90%

SMCR have been calculated for the

above four main engine/propeller cases

operating on the relatively lower ship

speed of 14.0 knots, which is probably

going to be a more normal choice in the

future. Furthermore, the EEDI has been

calculated on the basis of the 75%

SMCR-related figures (without sea mar-

gin). Examples 3’ and 4’ indicate the in-

fluence of one extra engine cylinder.

Fuel consumption and EEDI

Fig. 11 shows the influence of the

propeller diameter with four propeller

blades when going from about 8.3 m to

9.3 m. Thus, N3’ and N4’ for the 5 and

6G70ME-C9.5 with an about 9.3 m pro-

peller diameter has a propulsion power

demand that is about 6.1% lower com-

pared with the N1’ for the 6S70ME-C8.5

with an about 8.3 m propeller diameter.


Engine shaft power

171

172

25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100% SMCR154

155

156

157

158

159

160

161

162

163

164

165

166

167

SFOCg/kWh

168

169

170

IMO Tier llISO ambient conditionsLCV = 42,700 kJ/kg

Standard high-loadoptimised engines

M’ = SMCRN’ = NCR

N1’

N3’

N2’

N4’

M3’ 5G70ME-C9.5 9.3 m ×4

M1’ 6S70ME-C8.5 8.3 m ×4M2’ 5G70ME-C9.5 8.8 m ×4

M4’ 6G70ME-C9.5 9.3 m ×4

Dprop

Savings in SFOC

0.0%Basis

-1.2%

0.2%

1.8%

Fig. 12: Expected SFOC for 14.0 knots

Fig. 12 shows the influence on the main

engine efficiency, indicated by the Spe-

cific Fuel Oil Consumption, SFOC, for

the four cases. N3’ = 90% M3’ with

the 5G70ME-C9.5 has a relatively high

SFOC of 163.9 g/kWh compared with

the 162.0 g/kWh for N1’ = 90% M1’

for the 6S70ME-C8.5, i.e. an SFOC in-

crease of about 1.2%, mainly caused

by the greater speed derating potential

giving higher mep of the 5G70ME-C9.5

engine type, but involving a higher po-

tential propeller efficiency. However,

for N4’ = 90% M4’ (in the same point

as for N3’) for the 6G70ME-C9.5, the

mep derating involves a lower SFOC

of 159.1 g/kWh corresponding to an

SFOC reduction of 1.8%.

The daily fuel consumption is found by

multiplying the propulsion power de-

mand at N’ (Fig. 11) with the SFOC (Fig.

12), see Fig. 13. The total reduction of

fuel consumption of the new 6G70ME-

C9.5, N4’ with propeller diameter 9.3 m,

is about 7.8% compared with the exist-

ing 6S70ME-C8.5 (see also the above-

mentioned savings of 6.1% and 1.8%).


1

2

3

4

5

6

7

8

9

10

Relative saving of fuel consumption

%

Fuel consumptionof main engine

t/24h


LCV = 42,700 kJ/kg

0

10

15

20

25

30

35

40

45

50

60

55

06S70ME-C8.5

N1’8.3 m × 4Dprop:

53.15t/24h

0%

5G70ME-C9.5N2’

8.8 m × 4

51.40t/24h

3.3%

5G70ME-C9.5N3’

9.3 m × 4

50.50t/24h

5.0%

6G70ME-C9.5N4’

9.3 m × 4

49.00t/24h

7.8%

Dprop:

0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0

10

20

30

40

50

60

70

80

90

100

110

120

Reference and actual EEDICO2 emissionsgram per dwt/n mile

Actual/ReferenceEEDI %

2013Year

Contract datebefore 1 January

2015

2020

2025

EEDI actualEEDI reference (2.81/100%)

5G70ME-C9.5N2’

8.8 m × 4

80%2.26

5G70ME-C9.5N3’

9.3 m × 4

79%2.22

6G70ME-C9.5N4’

9.3 m × 4

77%

2.16

6S70ME-C8.5N1’

8.3 m × 4

83%2.34

75% SMCR: 13.8 kn without sea margin

Fig. 14: Reference and actual Energy Efficiency Design Index (EEDI) for 14.0 knots

Fig. 13: Expected fuel consumption at NCR = 90% SMCR for 14.0 knots

The reference and the actual EEDI

figures have been calculated and are

shown in Fig. 14 (EEDIref = 961.8 ×

dwt -0.477, 15 July 2011). As can be seen

for all four cases, the actual EEDI fig-

ures are now somewhat lower than

the reference figure because of the

relatively low ship speed of 14.0 knots.

Particularly, case 4’ with 6G70ME-C9.5

has a low EEDI – about 77% of the

2013 reference figure. All G70ME-C9.5

engine cases will meet the stricter 2020

EEDI reference figure.


0

1

2

3

4

5

6

7

8

9

Annual operating costsMillion USD/Year

Relative saving in operating costs

%

Dprop:

10

0

1

2

3

4

5

6

7

8

9

10

6S70ME-C8.5N1’

8.3 m × 4

0%

5G70ME-C9.5N2’

8.8 m × 4

3.5%

6G70ME-C9.5N4’

9.3 m × 4

7.6%

5G70ME-C9.5N3’

9.3 m × 4

5.2%

MaintenanceLub. oil

Fuel oil


250 days/yearNCR = 90% SMCR

Fuel price: 700 USD/t

Fig. 15: Total annual main engine operating costs for 14.0 knots

Operating costs

The total main engine operating costs

per year, 250 days/year, and fuel price

of 700 USD/t, are shown in Fig. 15.

Lube oil and maintenance costs are

also shown at the top of each column.

As can be seen, the major operating

costs originate from the fuel costs –

about 96%.

After some years in service, the relative

savings in operating costs in Net Present

Value, NPV, see Fig. 16, with the existing

6S70ME-C8.5 with the propeller diam-

eter of about 8.3 m used as basis, indi-

cates an NPV saving after some years in

service for the new 5 and 6G70ME-C9.5

engines. After 25 years in operation, the

saving is about 12.8 million USD for N4’

with the 6G70ME-C9.5 with the SMCR

speed of 67.0 r/min and propeller diam-

eter of about 9.3 m.

LifetimeYears

0

5

3

7

12

14

15

13

11

9

8

6

4

2

1

10

0 5 10 15 20 25 30

Saving in operating costs(Net Present Value)Million USD

IMO Tier llISO ambient conditionsN’ = NCR = 90% SMCR250 days/yearFuel price: 700 USD/tRate of interest and discount: 6% p.a.Rate of inflation: 3% p.a.

N2’: 8.8 m × 45G70ME-C9.5

N3’: 9.3 m × 45G70ME-C9.5

N4’: 9.3 m × 46G70ME-C9.5

N1’: 8.3 m × 46S70ME-C8.5

Fig. 16: Relative saving in main engine operating costs (NPV) for 14.0 knots


Summary

Traditionally, super long stroke S-type

engines, with relatively low engine

speeds, have been applied as prime

movers in bulk carriers.

Following the efficiency optimisation

trends in the market, the possibility of

using even larger propellers has been

thoroughly evaluated with a view to us-

ing engines with even lower speeds for

propulsion of particularly bulk carriers

and tankers.

Large bulk carriers and tankers may be

compatible with propellers with larger

propeller diameters than the current

designs, and thus high efficiencies

following an adaptation of the aft hull

design to accommodate the larger pro-

peller, together with optimised hull lines

and bulbous bow, considering opera-

tion in ballast conditions.

Even in cases where an increased size

of the propeller is limited, the use of

propellers based on the new propeller

technology will be an advantage.

The new and ultra long stroke G70ME-

C9.5 engine type meets this trend in the

large bulk carrier and tanker market. This

paper indicates, depending on the pro-

peller diameter used, an overall efficiency

increase of 3-8% when using G70ME-

C9.5, compared with the existing main

engine type S70ME-C8.5 applied so far.

The Energy Efficiency Design Index

(EEDI) will also be reduced when us-

ing G70ME-C9.5. In order to meet the

stricter given reference figure in the fu-

ture, the design of the ship itself and

the design ship speed applied (reduced

speed) has to be further evaluated by

the shipyards to further reduce the EEDI.


MAN Diesel & TurboTeglholmsgade 412450 Copenhagen SV, DenmarkPhone +45 33 85 11 00Fax +45 33 85 10 [email protected]

MAN Diesel & Turbo – a member of the MAN Group

All data provided in this document is non-binding. This data serves informational purposes only and is especially not guaranteed in any way. Depending on the subsequent specific individual projects, the relevant data may be subject to changes and will be assessed and determined individually for each project. This will depend on the particular characteristics of each individual project, especially specific site and operational conditions. Copyright © MAN Diesel & Turbo. 5510-0146-00ppr Feb 2014 Printed in Denmark

Propulsion of 200,000-210,000 dwt Large Capesize Bulk Carrier

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