Propulsion of VLCC - MAN Diesel & Turbo

Propulsion of VLCC

Contents
Introduction..................................................................................................5
EEDI.and.Major.Ship.and.Main.Engine.Parameters........................................6
Energy.Efficiency.Design.Index.(EEDI)......................................................6
Major.propeller.and.engine.parameters....................................................7
320,000.dwt.VLCC..................................................................................8
Main.Engine.Operating.Costs.–.16.3.knots....................................................9
Fuel.consumption.and.EEDI.....................................................................9
Operating.costs..................................................................................... 12
Main.Engine.Operating.Costs.–.15.5.knots.................................................. 13
Fuel.consumption.and.EEDI................................................................... 13
Operating.costs..................................................................................... 16
Summary.................................................................................................... 17

Propulsion of VLCC
Introduction
The.size.of.Very.Large.Crude.Carriers,.
VLCCs,. see. Fig.. 1,. is. normally. within.
the. deadweight. range. of. 250,000-
320,000. dwt. and. the. ship’s. overall.
length.is.about.330-335.m.
Recent.development.steps.have.made.
it.possible.to.offer.solutions.which.will.
enable. significantly. lower. transporta-
tion.costs.for.VLCCs.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.
Fig. 1: A VLCC
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.tankers,.the.CO2.emission.from.
new.tankers.in.gram.per.dwt.per.nauti-
cal.mile.must.be.equal.to.or.lower.than.
the.reference.emission.figures.valid.for.
the.specific.tanker.
This. drive. may. often. result. in. opera-
tion. at. lower. than. normal. service. ship.
speeds. compared. to. earlier,. resulting.
in. reduced. propulsion. power. utilisa-
tion..The.design.ship.speed.at.Normal.
Continuous. Rating. (NCR),. including.
15%.sea.margin,.used.to.be.as.high.as.
16.0-16.5.knots..Today,.the.ship.speed.
may.be.expected.to.be.lower,.possibly.
15.5.knots,.or.even.lower..However,.so.
far.only.few,.if.any,.have.specified.lower.
installed.power.for.new.VLCCs.
A.more.technically.advanced.develop-
ment. drive. is. to. optimise. the. aftbody.
and. hull. lines. of. the. ship. –. including.
bulbous. bow,. also. considering. opera-
tion.in.ballast.condition.–.making.it.pos-
sible. to. install. propellers. with. a. larger.
propeller. diameter. and,. thereby,. ob-
Propulsion.of.VLCC
5

taining. higher. propeller. efficiency,. but.
at.a.reduced.optimum.propeller.speed.
As.the.two-stroke.main.engine.is.direct-
ly.coupled.with.the.propeller,.the.intro-
duction.of.the.‘Green’.ultra.long.stroke.
G80ME-C.engine.with.even.lower.than.
usual. shaft. speed. will. meet. this. drive.
and. target. goal.. The. main. dimensions.
for.this.engine.type,.and.for.other.exist-
ing.VLCC.engines,.are.shown.in.Fig..2.
Based. on. a. case. study. of. a. 320,000.
dwt. VLCC,. this. paper. shows. the. in-
fluence. on. fuel. consumption. when.
choosing. the. new. G80ME-C. engine.
compared.with.existing.VLCC.engines..
The. layout. ranges. of. 6. and. 7G80ME-
C9.2. engines. compared. with. existing.
engines.are.shown.in.Fig..3.
13,586
2,656
1,736
5,020
S80ME-C8.2
14,071
2,840
1,890
EEDI and Major Ship and Main Engine
Parameters
Energy Efficiency Design Index (EEDI)
The. Energy. Efficiency. Design. Index.
(EEDI).is.conceived.as.a.future.mandatory.
instrument. to. be. calculated. and.
made. as. available. information. for. new.
ships.. EEDI. represents. the. amount. of.
CO2.in.gram.emitted.when.transporting.
one.deadweight.tonnage.of.cargo.one.
nautical.mile.
For. tankers,. the. EEDI. value. is. essentially.
calculated. on. the. basis. of. maximum.cargo.capacity,.propulsion.power,.ship.speed,.SFOC.and.fuel.type..However,.certain.correction.factors.are.applicable,.
e.g.. for. installed. Waste. Heat.
Recovery. systems.. To. evaluate. the.
achieved. EEDI,. a. reference. value. for.
5,374
S80ME-C9.2
Fig. 2: Main dimensions for a G80ME-C9.2 engine and for other existing VLCC engines
6 Propulsion.of.VLCC
14,879
3,010
1,960
G80ME-C9.2
the.specific.ship.type.and.the.specified.
cargo.capacity.is.used.for.comparison.
The.main.engine’s.75%.SMCR.(Speci-
fied. Maximum. Continuous. Rating). fig-
ure.is.as.standard.applied.in.the.calcu-
lation.of.the.EEDI.figure,.in.which.also.
the.CO2.emission.from.the.auxiliary.en-
gines.of.the.ship.is.included.
According. to. the. rules. finally. decided.
on.15.July.2011,.the.EEDI.of.a.new.ship.
is.reduced.to.a.certain.factor.compared.
to.a.reference.value..Thus,.a.ship.built.
after. 2025. is. required. to. have. a. 30%.
lower.EEDI.than.the.reference.figure.
13,889
5,680 5,000
2,835
1,800
S90ME-C8.2

Propulsion
SMCR power
kW
35,000 4-bladed FP-propellers
constant ship speed coefficient ∝ = 0.28
30,000
25,000
20,000
15,000
10,000
SMCR power and speed are inclusive of:
� 15% sea margin
� 10% engine margin
� 5% light running
T des = 21.0 m
G80ME-C9.2
Bore = 800 mm
Stroke = 3,720 mm
Vpist = 8.43 m/s (8.93 m/s)
S/B = 4.65
MEP = 21 bar
L1 = 4,450 kW/cyl. at 68 r/min
= 4,710 kW/cyl. at 72 r/min)
(L 1
320,000 dwt VLCC
Increased propeller diameter
G80ME-C9.2
M4’
7G80ME-C9.2
6G80ME-C9.2
M4
Possible
Dprop = 11.0 m
(=52.4% T des )
M3
M3’
∝
∝
∝
∝
Possible
Dprop = 10.5 m
(=50.0% T des )
7S80ME-C9.2
6S90ME-C8.2
6S90ME-C7.1
72 r/min
∝
∝
M2’
6S80ME-C9.2
M’ = SMCR (15.5 kn)
M1’ = 27,060 kW x 78.0 r/min 6S80ME-C9.2
M2’ = 26,860 kW x 76.0 r/min 6S90ME-C7.1
M3’ = 26,040 kW x 68.0 r/min 6G80ME-C9.2
M4’ = 25,370 kW x 62.0 r/min 7G80ME-C9.2
M1, M2
M1’
78r/min
76r/min
Existing
Dprop = 10.0 m
(=47.6% T des )
14.0 kn
15.0 kn
15.5 kn
Existing
Dprop = 9.5 m
(=45.2% T des )
16.0 kn
16.5 kn
16.3 kn
M = SMCR (16.3 kn)
M1 = 31,570 kW x 78.0 r/min 7S80ME-C9.2
M2 = 31,570 kW x 78.0 r/min 6S90ME-C8.2
M3 = 30,380 kW x 68.0 r/min 7G80ME-C9.2
M4 = 30,090 kW x 65.7 r/min 7G80ME-C9.2
40 50 60 70 80 90 r/min
Engine/propeller speed at SMCR
Fig. 3: Different main engine and propeller layouts and SMCR possibilities (M1, M2, M3, M4 for 16.3 knots and M1’, M2’, M3’, M4’ for 15.5 knots) for a
320,000 dwt VLCC operating at 16.3 knots and 15.5 knots, respectively.
Major propeller and engine parameters
In.general,.the.larger.the.propeller.diameter,.the.higher.the.propeller.efficiency.and.
the. lower. the. optimum. propeller. speed.
referring.to.an.optimum.ratio.of.the.propeller.pitch.and.propeller.diameter.
When.increasing.the.propeller.pitch.for.
a.given.propeller.diameter.with.optimum.
pitch/diameter. ratio,. the. correspond-
ing. propeller. speed. may. be. reduced.
and. the. efficiency. will. also. be. slightly.
reduced,. of. course. depending. on. the.
degree.of.the.changed.pitch..The.same.
is.valid.for.a.reduced.pitch,.but.here.the.
propeller.speed.may.increase.
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.high-
er. the. engine. efficiency.. This. means,.
for. example,. that. an. ultra. long. stroke.
engine. type,. as. the. G80ME-C9,. may.
have.a.higher.efficiency.compared.with.
a. shorter. stroke. engine. type,. like. a.
K80ME-C9.
Furthermore,. the. application. of. new.
propeller. design. technologies,. NPT.
propellers,. motivates. use. of. main. en-
gines. with. lower. rpm.. Thus,. for. the.
same.propeller.diameter,.these.propel-
ler.types.are.claimed.to.have.an.about.
6%. improved. overall. efficiency. gain. at.
about.10%.lower.propeller.speed.
Hence,.the.advantage.of.the.new.lower.
speed. engines. can. be. utilised. also. in.
case.a.correspondingly.larger.propeller.
cannot.be.accumulated.
Propulsion.of.VLCC
7

320,000 dwt VLCC
For. a. 320,000. dwt. VLCC. tanker,. the.
following.case.study.illustrates.the.potential.for.reducing.fuel.consumption.by.
increasing. the. propeller. diameter. and.
introducing. the. G80ME-C9.2. as. main.
engine.. The. ship. particulars. assumed.
are.as.follows:
Scantling.draught. m. 22.5
Design.draught. m. 21.0
Length.overall. m. 333.0
Length.between.pp. m. 319.0
Breadth. m. 60.0
Sea.margin. %. 15
Engine.margin. %. 10
Design.ship.speed. kn. 16.3.and.15.5
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. different.design.ship.speeds.and.propeller.
diameters,. and. the. corresponding.
SMCR. power. and. speed,. point. M,. for.
propulsion. of. the. VLCC. is. found,. see.
Fig.. 3.. The. propeller. diameter. change.
corresponds.approximately.to.the.constant.ship.speed.factor.α.=.0.28.[PM2.=.
PM1.x.(n2/n1) α ].
Referring. to. the. two. ship. speeds. of.
16.3.knots.and.15.5.knots,.respectively,.four.potential.main.engine.types.and.
pertaining. layout. diagrams. and. SMCR.
points.have.been.drawn-in.in.Fig..3,.and.
the. main. engine. operating. costs. have.
been. calculated. and. described. below.
individually. for. each. ship. speed. case..
The.layout.diagram.of.the.G80ME-C9.2.
below.or.equal.to.68.r/min.is.especially.
suitable.for.VLCCs.whereas.the.speed.
8 Propulsion.of.VLCC
range.from.68.to.72.r/min.is.particularly.
suitable.for.e.g..container.vessels.
It.should.be.noted.that.the.ship.speed.
stated.refers.to.NCR.=.90%.SMCR.including.
15%. sea. margin.. If. based. on.
calm. weather,. i.e.. without. sea. margin,.
the. obtainable. ship. speed. at. NCR. =.
90%. SMCR. will. be. about. 0.7. knots.
higher.
If.based.on.75%.SMCR,.as.applied.for.
calculation.of.the.EEDI,.the.ship.speed.
will.be.about.0.1.knot.lower,.still.based.
on. calm. weather. conditions,. i.e.. with-
out.any.sea.margin.

Main Engine Operating Costs –
16.3 knots
The. calculated. main. engine. examples.
are.as.follows:
16.3.knots
1.. 7S80ME-C9.2..
. M1.=.31,570.kW.x.78.0.r/min
2.. 6S90ME-C8.2.
. M2.=.31,570.kW.x.78.0.r/min.
3.. 7G80ME-C9.2.
. M3.=.30,380.kW.x.68.0.r/min.
4.. 7G80ME-C9.2.
. M4.=.30,090.kW.x.65.7.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. high. ship.
speed. of. 16.3. knots,. as. often. used.
earlier..Furthermore,.the.corresponding.
EEDI.has.been.calculated.on.the.basis.
of.the.75%.SMCR-related.figures.(with-
out.sea.margin).
Fuel consumption and EEDI
Fig.. 4. shows. the. influence. of. the. propeller.diameter.when.going.from.about.
10.0. to. 11.0. m.. Thus,. N4. for. the.
7G80ME-C9.2.with.an.11.0.m.propeller.
diameter. has. a. propulsion. power.
demand. that. is. about. 4.7%. lower.
compared. with. N1. and. N2. valid. for.
the. 7S80ME-C9.2. and. 6S90ME-C8.2,.
both.with.a.propeller.diameter.of.about.
10.0.m.
Propulsion of 320,000 dwt VLCC – 16.3 knots
Expected propulsion power demand at N = NCR = 90% SMCR
Propulsion power
Relative power
demand at N = NCR
reduction
kW
30,000
Inclusive of sea margin = 15%
28,410 kW 28,410 kW
%
12
27,340 kW 27,080 kW 11
25,000
20,000
15,000
10,000
5,000
0
Dprop:
0%
7S80ME-C9.2
N1
10.0 m
0%
6S90ME-C8.2
N2
10.0 m
3.8%
7G80ME-C9.2
N3
10.8 m
Fig. 4: Expected propulsion power demand at NCR for 16.3 knots
4.7%
7G80ME-C9.2
N4
11.0 m
10
9
8
7
6
5
4
3
2
1
0
Propulsion.of.VLCC
9

Propulsion of 320,000 dwt VLCC – 16.3 knots
Expected SFOC
SFOC
g/kWh
174
173
172
171
170
169
168
167
166
165
164
163
162
161
160
25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 % SMCR
Engine shaft power
N = NCR M = SMCR
Fig. 5: Expected SFOC for 16.3 knots
10 Propulsion.of.VLCC
IMO Tier ll
ISO ambient conditions
LCV = 42,700 kJ/kg
Standard high-load
optimised engines
N1
N2
N4
N3
M1 7S80ME-C9.2
M2 6S90ME-C8.2
M4 7G80ME-C9.2 11.0 m
M3 7G80ME-C9.2 10.8 m
Savings
in SFOC
0%
0.6%
1.0%
Dprop
10.0 m
10.0 m
Fig..5.shows.the.influence.on.the.main.
engine.efficiency,.indicated.by.the.Spe-
cific. Fuel. Oil. Consumption,. SFOC,. for.
the. four. cases.. N3. =. 90%. M3. for. the.
7G80ME-C9.2. has. an. SFOC. of. 164.1.
g/kWh,. whereas. the. N4. =. 90%. M4,.
also.for.the.7G80ME-C9.2,.has.a.high-
er. SFOC. of. 164.8. g/kWh. because. of.
the.higher.mean.effective.pressure.
The. 164.8. g/kWh. SFOC. of. the. N4. for.
the.7G80ME-C9.2.is.0.6%.lower.com-
pared. with. N1. for. the. nominally. rated.
7S80ME-C9.2.with.an.SFOC.of.165.8.
g/kWh.. This. is. because. of. the. higher.
stroke/bore.ratio.of.this.G-engine.type.

When.multiplying.the.propulsion.power.
demand. at. N. (Fig.. 4). with. the. SFOC.
(Fig.. 5),. the. daily. fuel. consumption. is.
found. and. is. shown. in. Fig.. 6.. Compared.
with. N1. for. the. 7S80ME-C9.2,.
the.total.reduction.of.fuel.consumption.
of.the.7G80ME-C9.2.at.N4.is.about.5.3.%.
(see. also. the. above-mentioned. 4.7%.
and.0.6%).
The. reference. and. the. actual. EEDI.
figures. have. been. calculated. and. are.
shown. in. Fig.. 7. (EEDIRef. =. 1,218.8. x.
DWT. -0.488 ,. 15. July. 2011).. As. can. be.
seen.for.all.four.cases,.the.actual.EEDI.
figures.are.higher.than.or.equal.to.the.
reference.figure..However,.this.is.to.be.
expected.for.VLCC.operation.on.a.ship.
speed.as.high.as.16.3.knots.
Propulsion of 320,000 dwt VLCC – 16.3 knots
Expected fuel consumption at N = NCR = 90% SMCR
Fuel consumption
IMO Tier ll
of main engine
ISO ambient conditions
t/24h
LCV = 42,700 kJ/kg
Propulsion of 320,000 DWT VLCC – 16.3 knots
Energy Efficiency Design Index (EEDI) 75% SMCR; 16.2 kn without sea margin
Reference and actual EEDI
CO 2 emissions gram per dwt/n mile Actual/Reference EEDI %
3.0
2.5
2.0
1.5
1.0
0.5
120
110
100
90
80
70
60
50
40
30
20
10
0
Dprop:
2.65
2.51 106%
0
7S80ME-C9.2
1
Dprop: 10.0 m
113.1
t/24h
0%
7S80ME-C9.2
N1
10.0 m
113.0
t/24h
6S90ME-C8.2
N2
10.0 m
Fig. 6: Expected fuel consumption at NCR for 16.3 knots
EEDI reference EEDI actual
2.65
2.51 106% 2.51 2.54
101%
6S90ME-C8.2
2
10.0 m
7G80ME-C9.2
3
10.8 m
Fig. 7: Reference and actual Energy Efficiency Design Index (EEDI) for 16.3 knots
0%
107.7
t/24h
4.8%
7G80ME-C9.2
N3
10.8 m
107.1
t/24h
5.3%
7G80ME-C9.2
N4
11.0 m
Relative saving of
fuel consumption
%
2.51
2.50
100%
12
11
10
7G80ME-C9.2
4
11.0 m
9
8
7
6
5
4
3
2
1
0
110
100
90
80
70
60
50
40
30
20
10
0
Propulsion.of.VLCC
11

Propulsion of 320,000 dwt VLCC – 16.3 knots
Total annual main engine operating costs
IMO Tier ll
Annual operating costs
Million USD/Year
ISO ambient conditions
250 days/year
NCR = 90% SMCR
Fuel price: 700 USD/t
Relative saving
in operating costs
%
22 11
20
18
16
14
12
10
8
6
4
2
0%
0
7S80ME-C9.2
N1
Dprop: 10.0 m
0.1%
6S90ME-C8.2
N2
10.0 m
7G80ME-C9.2
N3
10.8 m
Fig. 8: Total annual main engine operating costs for 16.3 knots
Propulsion of 320,000 dwt VLCC – 16.3 knots
Relative saving in main engine operating costs (NPV)
Saving in operating costs
(Net Present Value)
Million USD
25
IMO Tier ll
ISO ambient conditions
20
N = NCR = 90% SMCR
250 days/year
Fuel price: 700 USD/t
Rate of interest and discount: 6% p.a.
15 Rate of inflation: 3% p.a.
10
5
0
4.7%
5.2%
Maintenance
Lub. oil
Fuel oil
7G80ME-C9.2
N4
11.0 m
–5
Lifetime
0 5 10 15 20 25 30 Years
Fig. 9: Relative saving in main engine operating costs (NPV) for 16.3 knots
12 Propulsion.of.VLCC
10
9
8
7
6
5
4
3
2
1
0
N4 11.0 m
7G80ME-C9.2
N3 10.8 m
7G80ME-C9.2
N2 10.0 m
6S90ME-C8.2
N1 10.0 m
7S80ME-C9.2
Operating costs
The. total. main. engine. operating. costs.
per.year,.250.days/year,.and.fuel.price.
of.700.USD/t,.are.shown.in.Fig..8..The.
lube. oil. and. maintenance. costs. are.
shown.too..As.can.be.seen,.the.major.
operating.costs.originate.from.the.fuel.
costs.–.about.96%.
The.relative.savings.in.operating.costs.
in.Net.Present.Value.(NPV),.see.Fig..9,.
with. the. 7S80ME-C9.2. or. 6S90ME-
C8.2. used. as. basis. with. the. propeller.
diameter.of.about.10.0.m,.indicates.an.
NPV. saving. for. the. 7G80ME-C9.2. engines.after.some.years.in.service..After.
25.year.in.operation,.the.saving.is.about.
16.7.million.USD.for.N3.with.7G80ME-
C9.2.with.the.SMCR.speed.of.68.0.r/
min. and. propeller. diameter. of. about.
10.8.m,.and.about.18.4.million.USD.for.
N4. also. with. 7G80ME-C9.2,. but. with.
the.SMCR.speed.of.65.7.r/min.and.a.
propeller.diameter.of.about.11.0.m.

Main Engine Operating Costs –
15.5 knots
The. calculated. main. engine. examples.
are.as.follows:
15.5.knots
1’.. 6S80ME-C9.2.
. . M1’.=.27,060.kW.x.78.0.r/min
2’.. 6S90ME-C7.1.
. . M2’.=.26,860.kW.x.76.0.r/min.
3’.. 6G80ME-C9.2.
. . M3’.=.26,040.kW.x.68.0.r/min.
4’.. 7G80ME-C9.2.
. . M4’.=.25,370.kW.x.62.0.r/min.
The.6S90ME-C7.1.has.been.chosen.as.
case.2’.as.often.used.in.the.past.
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.15.5.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.margin).
Fuel consumption and EEDI
Fig.. 10. shows. the. influence. of. the.
propeller. diameter. when. going. from.
about.9.7.to.11.0.m..Thus,.N4’.for.the.
7G80ME-C9.2.with.an.11.0.m.propeller.
diameter. has. a. propulsion. power.
demand.that.is.about.6.2%.lower.compared.
with. the. N1’. for. the. 6S80ME-
C9.2. with. an. about. 9.7. m. propeller.
diameter.. The. choice. of. the. one. extra.
cylinder. for. the. 7G80ME-C9.2. has.
made. it. possible. to. choose. the. large.
11.0.m..propeller.
Propulsion of 320,000 dwt VLCC – 15.5 knots
Expected propulsion power demand at N’ = NCR = 90% SMCR
Propulsion power
demand at N’ = NCR
kW
30,000
25,000
20,000
15,000
10,000
5,000
0
Dprop:
24,350 kW
0%
6S80ME-C9.2
N1’
9.7 m
Inclusive of sea margin = 15%
24,170 kW
0.7%
6S90ME-C7.1
N2’
9.8 m
23,440 kW
3.8%
6G80ME-C9.2
N3’
10.4 m
Fig. 10: Expected propulsion power demand at NCR for 15.5 knots
22,830 kW
6.2%
7G80ME-C9.2
N4’
11.0 m
Relative power
reduction
%
12
11
10
9
8
7
6
5
4
3
2
1
0
Propulsion.of.VLCC
13

Propulsion of 320,000 dwt VLCC – 15.5 knots
Expected SFOC
SFOC
g/kWh
176
175
174
173
172
171
170
169
168
167
166
165
164
163
162
161
IMO Tier ll
ISO ambient conditions
LCV = 42,700 kJ/kg
Standard high-load
optimised engines
Dprop
9.7 m
9.8 m
M3’ 6G80ME-C9.2 10.4 m
160
2.5%
159
7G80ME-C9.2 11.0 m
25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 % SMCR
Engine shaft power
Fig. 11: Expected SFOC for 15.5 knots
14 Propulsion.of.VLCC
N1’
N3’
N4’
N2’
N1’ = NCR
M1’ 6S80ME-C9.2
M2’ 6S90ME-C7.1
M4’
M1’ = SMCR
Savings
in SFOC
0%
0.3%
1.0%
Fig..11.shows.the.influence.on.the.main.
engine.efficiency,.indicated.by.the.Spe-
cific. Fuel. Oil. Consumption,. SFOC,. for.
the. four. cases.. N4’. =. 90%. M4’. with.
the. 7G80ME-C9.2. has. a. relatively. low.
SFOC. of. 161.6. g/kWh. compared. with.
the.165.8.g/kWh.for.N1’.=.90%.M1’.for.
the.6S80ME-C9.2,.i.e..an.SFOC.reduc-
tion. of. about. 2.5%,. mainly. caused. by.
the.derating.potential.used.for.the.one.
cylinder.bigger.7G80ME-C9.2.engine.

The.daily.fuel.consumption.is.found.by.
multiplying. the. propulsion. power. demand.at.N’.(Fig..10).with.the.SFOC.(Fig..
11),. see. Fig.. 12.. The. total. reduction.
of. fuel. consumption. of. the. 7G80ME-
C9.2.is.about.8.6%.compared.with.the.
6S80ME-C9.2.
The. reference. and. the. actual. EEDI.
figures. have. been. calculated. and. are.
shown. in. Fig.. 13. (EEDI Ref . =. 1,218.8. x.
DWT. -0.488 ,. 15. July. 2011).. As. can. be.
seen.for.all.four.cases,.the.actual.EEDI.
figures.are.now.lower.than.the.reference.
figure.because.of.the.relatively.low.ship.
speed.of.15.5.knots..Particularly,.case.
4’.with.7G80ME-C9.2.has.a.low.EEDI.–.
about.87%.of.the.reference.figure.
Propulsion of 320,000 dwt VLCC – 15.5 knots
Expected fuel consumption at N’ = NCR = 90% SMCR
Fuel consumption
of main engine
t/24h
110
2.5
2.0
1.5
1.0
0.5
100
90
80
70
60
50
40
30
20
96.9
t/24h
10
0%
0
6S80ME-C9.2
N1’
Dprop: 9.7 m
IMO Tier ll
ISO ambient conditions
LCV = 42,700 kJ/kg
95.9
t/24h
1.0%
6S90ME-C7.1
N2’
9.8 m
Fig. 12: Expected fuel consumption at NCR for 15.5 knots
92.3
t/24h
4.8%
6G80ME-C9.2
N3’
10.4 m
Propulsion of 320,000 DWT VLCC – 15.5 knots
Energy Efficiency Design Index (EEDI)
75% SMCR; 15.4 kn without sea margin
88.6
t/24h
8.6%
7G80ME-C9.2
N4’
11.0 m
2.51 2.51 2.51 2.51
2.40
95%
2.37
95%
2.28
91%
2.19
87%
Relative saving of
fuel consumption
%
11
Reference and actual EEDI
CO emissions
2
gram per dwt/n mile Actual/Reference EEDI %
3.0
EEDI reference EEDI actual
0 0
6S80ME-C9.2 6S90ME-C7.1 6G80ME-C9.2 7G80ME-C9.2
1’
2’
3’
4’
Dprop: 9.7 m
9.8 m
10.4 m
11.0 m
Fig. 13: Reference and actual Energy Efficiency Design Index (EEDI) for 15.5 knots
10
9
8
7
6
5
4
3
2
1
0
110
100
90
80
70
60
50
40
30
20
10
Propulsion.of.VLCC
15

Propulsion of 320,000 dwt VLCC – 15.5 knots
Total annual main engine operating costs
Annual operating costs
Million USD/Year
18
16
14
12
10
8
6
4
2
0
Dprop:
0%
6S80ME-C9.2
N1’
9.7 m
IMO Tier ll
ISO ambient conditions
N’ = NCR = 90% SMCR
250 days/year
Fuel price: 700 USD/t
0.9%
6S90ME-C7.1
N2’
9.8 m
4.7%
6G80ME-C9.2
N3’
10.4 m
Fig. 14: Total annual main engine operating costs for 15.5 knots
16 Propulsion.of.VLCC
8.2%
7G80ME-C9.2
N4’
11.0 m
Relative saving
in operating costs
%
Maintenance
Lub. oil
Fuel oil
18
16
14
12
10
8
6
4
2
0
Operating costs
The. total. main. engine. operating. costs.
per.year,.250.days/year,.and.fuel.price.
of. 700. USD/t,. are. shown. in. Fig.. 14..
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%.
The.relative.savings.in.operating.costs.
in.Net.Present.Value,.NPV,.see.Fig..15,.
with.the.6S80ME-C9.2.with.the.propeller.diameter.of.about.9.7.m.used.as.basis,.indicates.an.NPV.saving.after.some.
years. in. service. for. the. G80ME-C9.2.
engines..After.25.years.in.operation,.the.
saving.is.about.14.3.million.USD.for.the.
6G80ME-C9.2. with. the. SMCR. speed.
of. 68.0. r/min. and. propeller. diameter.
of. about. 10.4. m,. and. about. 25.1. million.USD.for.the.derated.7G80ME-C9.2.
with.the.low.SMCR.speed.of.62.0.r/min.
and.a.propeller.diameter.of.about.11.0.m.

Propulsion of 320,000 dwt VLCC – 15.5 knots
Relative saving in main engine operating costs (NPV)
Saving in operating costs
(Net Present Value)
Million USD
35
30
25
20
15
10
5
0
IMO Tier ll
ISO ambient conditions
N’ = NCR = 90% SMCR
250 days/year
Fuel price: 700 USD/t
Rate of interest and discount: 6% p.a.
Rate of inflation: 3% p.a.
–5
0 5 10 15 20 25 30
Fig. 15: Relative saving in main engine operating costs (NPV) for 15.5 knots
N4’ 11.0 m
7G80ME-C9.2
N3’ 10.4 m
6G80ME-C9.2
N2’ 9.8 m
6S90ME-C7.1
N1’ 9.7 m
6S80ME-C7.1
Lifetime
Years
Summary
Traditionally,. super. long. stroke. S-type.
engines,. with. relatively. low. engine.
speeds,. have. been. applied. as. prime.
movers.in.tankers.
Following. the. efficiency. optimisation.
trends. in. the. market,. the. possibility. of.
using. even. larger. propellers. has. been.
thoroughly.evaluated.with.a.view.to.using.engines.with.even.lower.speeds.for.
propulsion.of.particularly.VLCCs.
VLCCs. 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.propeller,.together.with.optimised.
hull.lines.and.bulbous.bow,.considering.
operation.in.ballast.conditions.
The.new.ultra.long.stroke.G80ME-C9.2.
engine. type. meets. this. trend. in. the.
VLCC. market.. This. paper. indicates,.
depending. on. the. propeller. diameter.
used,. an. overall. efficiency. increase. of.
4-9%. when. using. G80ME-C9.2,. compared.
with. existing. main. engines. applied.so.far.
The. Energy. Efficiency. Design. Index.
(EEDI). will. also. be. reduced. when. using.G80ME-C9.2..In.order.to.meet.the.stricter.given.reference.figure.in.the.future,.
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..Among.others,.the.installation.of.
WHR.may.reduce.the.EEDI.value.
Propulsion.of.VLCC
17

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..
5510-0106-01ppr.Aug.2012.Printed.in.Denmark
MAN Diesel & Turbo
Teglholmsgade.41
2450.Copenhagen.SV,.Denmark
Phone. +45.33.85.11.00
Fax. +45.33.85.10.30
info-cph@mandieselturbo.com
www.mandieselturbo.com
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