International Workshop on Ship Technologies Related to Energy Efficiency Design Index (EEDI)

22, July, 2015

Technologies for estimating andimproving ships’ performance inwind and waves

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1CONTENTS
Introduction
What is fw guidelinesf
Concept & scheme

Technologies
Prediction methodHow to evaluate new technologies

Survey & Certification
Certification of EEDIweather

Summary & Conclusions

2Introduction

Motivation

Awareness of a ship owner
Decrease of ship speed is not the same even if the ships aredesigned under the same specification

 This is related to fuel consumption in the life cycle.
 Ship should be designed for performance in actual seas.
 To evaluate and check the performance in actual seas, 3
it is necessary to make a standard method/index.
Ref) Y.Tanaka1RVKOWOURGGFCPF2GTHQTOCPEG FKHHGTGPEGKPCEVWCNUGCU6'%*01/#4+0'0Q

Introduction

Concept

Evaluation of ship performance
fw is a non-dimensional coefficient indicating thedecrease of speed in representative sea conditions.
The guidelines should promote GHG reductionin actual sea conditions.

 We should evaluate ship performancein wind and waves.
 We should evaluate new technologies
which can make fw increase (improve).
4

Introduction

Scheme of fw and EEDIweather

 To evaluate and check the performance in actual seas,
it is necessary to make a standard method/index.
 fw is a non-dimensional coefficient indicating thedecrease of speed in representative sea conditions
attained EEDIweather
neffnPTI­°§ n½° § neff§ n·§ nME··¨f j ¸¨PME i  C FME i  SFC ME i ¸  PAE  C FAE  SFC AE  ®¨fj
PPTI i f eff i  PAEeff i ¸C FAE  SFC AE ¾  ¨f eff i  Peff i  C FME  SFC ME¸¨¨¸¨¨¸°̄© j °¿ © i i i ¹© j  ¹© i ¹f i  f c  f l  Capacity  f w  Vref¦ ¦¦P

Res.MEPC.212(63);fw and attained EEDIweather, if
calculated, with the representative
sea conditions under which thosevalues are determined, should beindicated in the EEDI Technical File.

¦LQWKHUHSUHVHQWDWLYHVHDFRQGLWLRQV
LQFDOPVHD

fw=Vw / Vref

EEDI power

5Introduction

Vw

VrefVfw guidelines

Discussion on fw guidelines through the informal
corresponding group and MEPC

IMO/MEPC64 (Oct., 2012)
approves fw interim guidelines for trial use,
where the representative sea condition is
BF6 of head winds and waves.
BF6
significant wave height 3mwind speed
12.6m/s

6MEPC.1/Circ.796·¸¸¹

Introduction

fw guidelines
fw can be obtained by

Ship specific Simulation‫ ۼ‬The simulation should be
accurately evaluated newtechnologies, e.g. special bow
shapes/devices.

Standard curves
Alternative method when the fw
simulation can not be performed.

‫ ۼ‬Working the incentive for fw
simulation and from theviewpoint of navigation
safety, the standard curves
should prevent calculating
a greater value than thetruth.

7TechnologiesShip Performance in actual seas
The answer is at the sea!

Ocean waves have irregularity
short crested irregular waves

8Technologies

Irregular waves is expressed bysuperposition of regular waves infrequency and direction

Frequency response of added
resistance in regular waves
ᲢL=225m, head wavesᲣ
ǌ/L=1.1

ǌ/L=0.4

Technologies
Container ship (L=300m)

RAW

Head ྥἼwavesȨgȝa B /LppV NQRW

Wave length = 150m

Accurate estimation
on added resistance in wavesRAWV NQRW



HeadwavesྥἼȨgȝa B /Lpp





9

regular short waves

Spectrum is concentrated
in short waves

Cal. by fw guidelinesࣁ࢖ࣈࣜࢵࢻィ⟬ἲᚑ᮶ࡢィ⟬ἲ
Typical cal. (former)ᐇ㦂್ᶍᆺ⯪㛗P
Exp. (3mmodel)ᐇ㦂್ᶍᆺ⯪㛗P
Exp. (6.3mmodel)









Accuracy improvement
was required!

ȢLppȢLpp

Poor agreement of calculated
and experimental values are
known in short waves.

reflection

㸩 Radiation andDiffraction
Total

Improvement of reflection component

Hybrid method (fw guidelines)

Technologies

Hybrid methodon added resistance in waves‫ ۼ‬Radiation and Diffraction components are calculated by Maruo’stheory‫ ۼ‬Reflection component is calculated as follows.
RAWradded resistance due to wave reflection(semi empirical formula)

Ug] a  BB f D d   DUȘdFn d P




DdDUS  I ke dTerm of draft and frequency
extended by Ursell's formulaS  I ke d  K ke d

CU Fn



Coefficient of advance speed([SȘd kedȘUThe coefficient is obtained by tank tests
in short waves of different speed (hybrid)Șd kdȘd kdȢLpp ȢLȘ GHJ([SȘU Fn

Bf½°
 ­°
® VLQ D  E w VLQ E w dl  VLQ D  E w VLQ E w dl ¾B °̄ I°¿
II³³Bluntness coefficient



derived by Havelock Fn

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Technologies

Hybrid methodon added resistance in waves

Application to the oblique waves
From many results of the tank tests by NMRI, an empirical chart isprepared.
This chart is derived from tests ofconventional ships

Relation between coefficient ofadvance speed (CU) and bluntness
coefficient (Bf).

CUCU ±Bf ȢLpp ‫ ۼ‬Tank tests in oblique waves
are not necessary.
‫ ۼ‬This chart is available for ship
design stage to estimate CU
before the tank test.

Bf([SLQKHDGLQJZDYHV
SUHVHQWPHWKRG)XMLL±7DNDKDVKL Fn )XMLL±7DNDKDVKL Fn ([SLQREOLTXHZDYHV)DOWLQVHQHWDO
1DLWR±8HGD Fn 
1DLWR±8HGD Fn The effect of bow shape, including special bow shape,
can be evaluated by hybrid method.
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12

Technologies

Hybrid methodon added resistance in waves

Resistance test in short head waves
Less ship motion¾ Same setting with resistance test in stillwater is possible.
¾ Setting of radius of inertia is unnecessary.
Test procedures: 3 speed but 1 frequency;
each two points (for reproducibility check)¾ 3 hours to perform

Minimizing the implementation cost

Resistance test in short waves

Towing carriage
RailResistance measurement

13

Validation by round-robin tests

Technologies

Validation by round-robin tests

Resistance test in short head waves
Round-robin tests were conducted (container ship/ bulk carrier / tanker) at 9 institutes in total having
a large towing tank in Japan and EUDU

A(CU=46.6)
B(CU=47.5)

C(CU=41.4)
D(CU=39.1)

E(CU=37.6)
F



G



NMRI(CU=43.5)









FnLinearity of effect of advance
speed (DU) is confirmed.

Speed difference at BF6 is confirmed
within  0.2% (about 0.04knot)

RAO of added resistancein waves (container ship)

14TechnologiesValidation by onboard measurements

VLCC(L=320m)

PCC (L=190m)
BF3 BF4ǻV >NQRW@

BF5

BF6

BF3 BF4

BF7

BF6

BF7㻞㻟㻠

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Ͳ202468㻜BF5㻝㻞㻟㻠㻡

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0HDVXUHG &RUUHFWHG3ѭDQGZHDWKHU0HDVXUHG&DOFXODWHG

Similar results are resulted in container ship (L=280m) and bulk carrier (L=160m)

These results show the calculation method has sufficiently accurate.
The hybrid method is described in the fw guidelines as
an example which is confirmed accuracy.

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Technologies

Application to special bow shape
Result of tank test in short waves

Application to STEP;energy saving devicein actual seas

VFDQWOLQJIXOO OL pp H w >P@D >GHJ@K AW


Tank test in short waves
Without STEPSTEP








F n L ppZLWKRXW67(3ZLWK67(3EvaluationKAW

ZLWKRXW67(3ZLWK67(3&DOZLWKRXW67(3&DOZLWK67(3Fn 

With STEP

18% of added resistance inshort waves can be reduced.



Effect of STEP can be calculatedby the hybrid method!



O/L16

STEP is developed by NMRI and Naikai Zosen Corporationref) M. Kuroda et al.: Development of STEP for the Reduction of Added Resistance in Waves, Proc. of ISOPE2012, Vol.3, 2012.

Technologies

Estimation on wind resistance

Reliable Method Based on the Wind Tunnel Test Data
¾ Empirical formula based onwind tunnel data baseC Dwind  Wind tunnel testALC LOA BLOA

Non-dimensional coefficient of wind resistance.

Validation study by ITTC
Standard error
The most accurate
method is used in fwguidelines.

)XMLZDUD<DPDQRSEESTfw guidelines)XMLZDUD<RQHWDC Dwind,VKHUZRRG
67$

2.01.6
1.2
0.8
0.4
0.0
-0.4 0-0.8-1.2-1.6-2.0

54 ships (compared withwind tunnel data)

CCDwindX

Exp
Cal.

204060䃧 deg

80

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Technologies

Simulation example

Container ship

PCC

Bulk carrier

L

300m

L

190m

L

217m

B

40m

B

32.26mB

32.26m

d14m

d

9m

d14m

75%MCR
V>NQRW@ %) %)

44,650 kW%)

%)

%)

75%MCR
V>NQRW@ %) %)

11,940 kW

75%MCR

6,800 kW%)

V>NQRW@ %) %)

%)

%)

%)





fw =0.94
VLJQLILFDQWZDYHKHLJKW>P@fw =0.87


VLJQLILFDQWZDYHKHLJKW>P@%)

ᾏᢏ◊タィ18
fw =0.87

%)


VLJQLILFDQWZDYHKHLJKW>P@Technologies
Standard fw curves

e.g. Container ship
&RQWDLQHUVKLS

The standard curves are createdby analyzing the operational
data (abstract log data) ofabout 180 existing vessels.


fw 
‫ ۼ‬Working the incentive for fw
simulation and from theviewpoint of navigation
safety, the standard curves
should prevent calculating
a greater value than thetruth.

Capacity

2EVHUYHGIZRIH[LVWLQJVKLSV

fw'UDIWVWDQGDUGIZFXUYH

UHJUHVVLRQ  OQ Capacity  

The curves are passing through the lower limit
value of the data

19

Survey & Certification-KVCPKJQP 5JKRDWKNFKPI%Q.VFCPF0/4+
YQTMGFQPVJGEGTVKHKECVKQPQH''&+YGCVJGT
2TGUUTGNGCUG ,WN[The World’s first certification of EEDIweather is received from class NK.
The Chemical tanker of 19,000 DWT was delivered.
''&+YGCVJGT KUEGTVKHKGFHQT&96%JOKECN VCPMGTCPF
&96%JGOKECNVCPMGT

20
Chemical tanker of 19,000 DWT‘CHEM HOUSTON’ ᲢL=145mᲣ

6CPMVGUVHQTEGTVKHKECVKQPQHHY

Survey & Certification%GTVKHKECVKQPRTQEGUUWhen a calculated fw is used, the attained EEDI using calculated fw is tobe presented as attained EEDIweather.

EEDI weather

EEDI  f w

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 Certification is issued by hull number/model number.
 ''&+ QHVJGRTGNKOKPCT[EGTVKHKGFXCNWG KUWUGF

(KPCNEGTVKHKECVKQP#HVGTRGTHQTOKPIUGCVTKCNU Certification is issued by name of ship.
 ''&+ QHVJGHKPCNEGTVKHKGFXCNWGKUWUGF

21

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Summary & Conclusions
Concept of fw guidelines is to promote GHG reductionin actual sea conditions.
¾ The guidelines for this purpose have been developed andthe certification of EEDIweather has started.
¾ The calculation method in the guidelines is confirmed validity
through tank tests, onboard measurements and ITTC study.
¾ The effect of bow shape, including special bow shape, canbe evaluated by the hybrid method on added resistance inwaves.
¾ The hybrid method can be applied to estimate
performance in actual seas at design stage using theempirical chart (CU-Bf).

22Thank you for your attentions.