Systematic series model tests on the propulsive performance of high speed cargo ships and the design chart obtained from them

the Propus;v

rir

k

1.

Introduction

It was decided in 1960 that the systematic series

in-vestigations on the propulsive and steering performances

of high speed cargo ships would be carried out on a

nation-wide scale with a three-year program, and these

projects have been carried out as previously arranged by

the Shipbuilding Research Association of Japan and the Ship Research Institute of Ministry of Transportation

under the cooperative activities with the University of Tokyo. the Osaka University. Mitsubishi Heavy

Indus-tries, Ltd., and the several other shiphuilders in Japan. Hence, although it was supposed that the

YAMASHIRO-MARU. well known as the most economical high speed cargo ship in the world, was built by the Mitsubishi

Shipbuilding and Engineering Co.. Ltd., with the results obtained from the above synthetic investigations added

to the builder's own researching results, it was convinced that these synthetic investigations could indicate the

direc-tion to solve the designing problcms aiming to accom-plish the most economical ship form.

Because the theory of wave-making resistance can be more closely approximated to the high speed cargo ships

with fine hull form rather than the low speed tankers

with full hull form, the derivation of ship form from the

theory could also been accomplished with more

reliabili-ties to the high speed fine form inure than to she low

speed full form. Consequently, a number of theoretical

study work has been carried out on the high speed fine ship form and the mans' systematic series model tests

on the high speed fine ship forms have been accornpiched

resulting from the eager desire to study and build the high speed cargo ships especially under the impetus

from the completion of YAMASHIRO-NIARU in Japan. In this article, the study works carried out by the

Ship-building Research Association of Japan with the

priori-ties given to the ship forms having block coefficients C, of 0.625 and the systematic model tests accomplished by

the Ship Research Institute of the Ministry of

Trans-portation to the ship form with block coefficient C of 0.575 will be described in brief and subsequently the

design charts aiming to estimate the propulsive

per-formance obtained from the both investigations described previously will he also illustrated.

fuIr 1966

-th

ì

fl&o-

- I

2.

Outlines of the SR-45

csearch Works

and the Systematic Model rrests

acconi-pushed by the Ship Research Institute

In the research works performed by the No. 45

Com-mittee of the Shipbuilding Research Association of

Japan. the effects of elements of high speed cargo ship

forms on the propulsive and steering performances in stili

and rough waters were investigated, and the standard trials on the suitable actual ships were carried out and then the trial resultants were analyzed. Subsequently. the correlation betseen the models and the actual ships

were investigated and then, finally, the design charts aiming to estimate the propulsive performances of high

speed cargo ships were obtained. In these investigations.

the most emphasized research projects were the

syste-Inalic model tests in still svater involving the following

series.

(I)

CE-Series L/B=7.0. B'd-=2.4. CE=O.55 to 0.65 \Vhere; L : Length of Ship B Breadth of Ship a : Draft of Ship CB: Block Coefficient LIB, B/d-Series

L/B=6.5 to

8.0. B/d2.l

io 2.7, CB= O.62 caSeries

L/B=7.0, B/d=2.4 Cn0.625.

iic +0.70 to +2.50 Where:

lic: Non-dimensional values

indicat-Ing the location of center of

buoy-anc and expressing the distance of

fl4Q

i/

JC'_t.,.

It-by Koichi Yokoo

Dr. Ens.,

Ship Research Institute,

Alinisir of Transportation

5

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L

Ser

Mode Tes'

r ri

Crg3 Shps

f4

C, i

I

center of buoyancy from the mid-ship section in percentage of mid-ship length L. Symbol (+) expresses

the center of buoyancy located abaft the midship section.

Aft-Body Prismatic Curve-Series

L/B=7.0, B/d=2.4. C-0.625

\Vh ere;

Form of aft-bod orisrnatic curve

were changed only. C, c.w Series

L/B7.0, B/d=2.4. C8=0.625,

Ce-0.632 to _{0.652. CM=O.974 t)} 0.990 Where; Cp' Prismatic Coefficient Cy Midship Coefficient

Fore-Body Frame Line-Series

s ,I 3 4 BAAP! h h --, _{INC. SstN} f f L/B=-7.0, B/d=2.4. Cß'=O.625 Where;

Forni of fore-body frame line were

changed only.

(7) Bulb-Series

L/B=7.0, B/d=2.4, CB=0.625 \Vhere;

Size of bulb and forni of water-lines

entering into the bulb were changed.

Of the above series, tests of series (1).

(3), (4) and

(5) were accomplished in the experimental tank of Me-jiro Laboratory of the Ship Research Institute and the series of (2), (6) and (7) were tested in the

experimen-tal _{tank of Nagasaki Shipbuilding Yard of Mitsubishi}

Heavy Industries. Ltd. On the one hand, the University

of Tokyo was in charge of the fore-body prismatic

curve series applied with the analytical research by wave-form analysis, and the systematic model tests of

F- &

Fig.1

_{Body plan, stem and stern contours of}

_{M.S. 1382}

7 1 _8h 95I1

Fig. 2 _{Prismatic curses and water planes of M.S. 1382}

6

these series in ss ave were performed in the Ship

Re-search Institute's facilities with chanoing of Ca, LII? and

B. d. Furthermore, the steering performance lests using

the typical model among L/B, Bid series vere carried

out at the Osaka University and the Ship Research In-stitute, and then. finally, the standard trials were

ac-complished with the YAMATOSIlI-MARU. the YAMA-NASHI-MARU and the RICHMOND-lARU by the Hitachi Shiphuildin & Engineering Co.. Ltd., Yokohama Shipbuilding-Yard and Nagasaki Shipbuilding-Yard of

the Mitsubishi Heavy Industries, Ltd., respectively. In addition to these investigations described above, the systematic series model tests or the LiB. Bld series, with the block coefficient Cn of 0.575. were performed keeping pace with the SR-45 research works as the

unassisted research projects of the Ship Research

In-stitute. Beside, the model with block coefficient C of 0.575 used by the SR-45 research projects was chosen as the parent forni for these experiments.

3.

Systematic Model Tests in Still Water

The parent form chosen for the systematic series

model tests in still water was the M.S. 1382. The body

plan. stem and stern contours are illustrated in Fig. 1,

the prismatic curves and the water plane shapes are

shown in Fig. 2, and the principal particulars with the

dimensions of the corresponding actual ships are explained

in Table I. The shape and the principal particulars of the model propellers used for the self-propulsion tests

are shown in Fig. 3 and Table 2, respectively. The ratio of diameter of model propeller to the full load

draft of the model ship is about 0.717 excepting the specific cases.

Conclusions obtained from the result of the

syste-matic experiments are as follows.

1\lodTl l'o tel!r Nu. (Mejit,)

'I _(Naga'.uki)

Diameter D (inni)

I'iich P (inni)

Pitch Ratio (Cutist.) Boss Rtio

I';xìdccl Arrt Rat io .\1x. J3laílc \Vidtl, Rat k' Blade Thickness Rat o Angle of Rake Direction of Tcrning Number of Blades Type oí IIlacics

I 2a3 316.0 180 .0 0.570 1281 202.0 20 t .0 0.699 256.0 240 .0 0. 938 0.035 ,,0.02C-a 0.0 TO of model propeller 1285 i:ss 1286 rable J

I riticipal l'art iculars of M.S. 1382

Length between Perpendiculars, (m) 150.00 6.000

Length on Load Water Line, Lwi. (ni) 154.175 6.170

Breadth including skin, B (ni) 21.428 0.8572

Rise of Floor (m) 0.225 0.8372

Starting Point of Rise of Floor

from Center Line (m) 0.700 0.0280

Radius of Bilge Circle (ni) 2.273 0.0909

Draft at Full Load Condition, d(nì) 8.930 0.357k

Block Coellicierit, C 0.625

Prismatic Coefficient, Cp 0.642

Midship Coefficient, C3r 0.974

Water Line Coefficient, C10 0.747

Di.sp]acement, F (ni3) 17,933 1.1477

Wetted Surface, S (ni2) 4,363 6.981

B/d 2.400

Lp p/B 7.000

JiLì x ic:i

5.313

Fig. 3 Model propeller

FT/IL LOAD cC2 T /43 NO .'sdR.S; 7TWP tt

/381 -- -

/6.O'C 3e2 /9.0?; /383 /0.0?; 8.0,c /385

/

1339 12S7 (1261) Ship Model fiel 1966 7

(I) The residuary resistance coefficient r11. the thrust

deduction coefficient t', and the wake fraction

Wj' _{are affected largely with L/B rather than Bd.}

However. Bld affects the relative efficiency ti,' in

large more than L/B.

The optimum values of Ca and lea exist in

con-nection with ra. and these optimum values vary

depending on Froude number Fa.

As C becomes smaller and lea shifts further in front, I -wr and 1-t become larger. But, Cn and ¡ca have the relatively small effects on n.

Table 2.

Principal particulars

244.0 210.0 228.0 252.0 256.0 268 .0 1.033 1.067 1.175 0.200 0.650 0.302 0.030 I0'-O' Rigli'. Handed a AU 'Type

-022 0.25

ri-/

/1

'I,, -

_{/ ,, /}

I :t57 (1262) 224.0 200 .0 272.0 296.0 1.214 1 .450

2.6 2.1 -2.6 2.0

'iii'iJkitu

_{dRIDI111III1U}

,ijj

_JPIIIIIIU

r'w

Ill

liii

iiiiilii

!!4iiIIm.

iwiu

i

ilhiuki

III

It _{is more desirable to have fine shoulders of}

pris-matic curves of the fore-body when speed is higher than 0.25 of Fn, but, it is better to swell the should-ers slightly and emaciate the fore-e-id when speed

is lcwer than 0.25 of Fn.

Althouh it is better to have runs ci straightline at

the aft-body prismatic _{curves, it must be avoided}

to square the shoulders and hollow the _curves. In the range of these experiments, the better

re-Suits were obtained when C _{was smaller anZI C,} was larger.

LPP!8

C _{=0.625 Sers}

Curtoura of

SI ç

Full Load Condirioa V/V = It% Trim=0% Lp d/d Fig. 4

Contours of S/çi

for CB = 0.625 C _{=0.625 Sores} Contcurs of

Full 1.oad C.o2itioi

r,s =t00% Trim=0% Lpp

djd 1111Ci3%

v/v'g. L c'wL =0 6.25

The frame lines of fore-body _{were considered} de-sirable to keep the moderate _{U-shape. and neither} the V-shape nor the extreme U-shape resulted in good performa rices.

Although the best performance vere obtained at full load condition when the sectional area of the bulb was I 2 _{of that of midship section, it was} considered _{suitable to keep the bulb}

_{area 6' if}

the light load condition should also be taken

into consideration.

8

Japan Shipbuilding & .Varine Engineering

i I i

ul___

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ik1!kìiUiIiU

6.5 &o.

Fig. 5

Contours of 4 for CB = 0.625 o 75 K 2.6 2.0 2.4 2.3

1.

Design Charts to Estimate the

Propul-sive Performance

The serios used to obtain the design charts aiming to estimate the propulsive performance were L/B. ]3d

series. C13 series and loir series among the systematic

series model tests in still water. The examples of the charts are illustrated in Fie. 4 to Fig. 10. \Vhcre. Fig.

4 shows the variation of non-dimensional values of the wetted

surface S/í° duc to L/B and B/d.

\Vhere, S is the wetted surface and ¡ the displacement. Fig. 5 to Fig. 8 show the variations of residuary resistance

coefficient r,c and self-propulsion factor I t, lWr, and

'JR due to L/13 and B"d at the Froude number Fn=

it

fri/v 1966

2.

Lpp'B

0.25 under the full load condition for C31'.=0.625. In Figs. 9 and lO. the effects of variation of Cii and len upon nr and the self-propulsion factors are illustrated in the ratio to the salues of the parent form for Fn

0.25 at full load condition.

Terms with suffix o are for Parent Form, and those

without suffix for the others.

Relative Wetted Surface Coefficient Residuary Resistance Coefficient =\Vake Fraction

=Thrust Deduction Fraction

Relative Rotative Efficiency

Terms with suffix o are for Parent Form, and those

without suffix for the others.

8.0

C =8.625 Series

Cotocru of

1t

Fut? Load Co'ditin

v/v1. =K5% Tr.c=0% pp dd (25

Fig. 6

Contours of I-t

for Cn 0.625 Ç=625 Series Coreurs et 1Z'Pr

Futi Load Cenditioa VV

Trim =0% L

¿d

IIiUV4a

Ii!RLtuILIrp'

II&%W

1W L

4

1111

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..4W--- I 6.0 70 7.5 7. 0 7. 5 8.0 Lpp;B 2.6 Fig. 7 2.5 Contours of ] -w 2.4 for Cii = 0.625 2.3 2.1 2.0 2.5 2.5 2.4 2.3 2. t 2.0

2.8 2. 7 2.6 2.5 L _2.4 2.3 2.2 2.1 2.0 03 -1 02 t 01 t 00 0 99 O _IC. 09 7.0

Lß

75 I I I t i I I I I I t C 55 0 97 0 il _{2 ei 53} 065 . .. - v'L..

Fig. 9 _{Cross curves of correction}

factors of S/rh

and FnO.2)

7R 1-W, 1-t and t R for Ira (Fui load condition Terms with suffix O _{are tor l)aretlt form, arid} those without suffix for the _others.

= Relative wetted surface coefficient yil=Hesiduarv resistance coefficient 1.W=\%ake fraction

1-t = Thrust deduction fraction = Ielative rotative efficiency

8.0 "L. L-0 99 I Ql 1 00 lo on

I

Ce=0. 625 Series Contours of 'iR.

Full Load Corilition

F2 Trim=O% Lpp d/d_FIl'0 V/jjCDWL =0.25 109/R.700, B/d.. 34Ø t I I t I

/t

Fig. 8

Contours of n for Cia = 0.025 I j I J I t I I I 20 2.4 2 0 8 IS 14 IS IO 05 00

ICB. from Midship (% of Lpp)

Fig. IO _{Cross curves of correction factors of} S/pg,

I -W, l-t and '_{ia for 1c (Full load condition}

and Fn=O.2)

Terms with suffix O _{are for parent form, and} those without suffix for (lie others.

IO

Japan S/nphui1a/in,' & _{.fari,zc En,'inccring}

1

I

-1o1

Lao/B 700. B/d S I T

lu/v 1966 Fig. 12 Contours of rE for C1= 0.575 75 Lpp /13 2.8 2.7 2.6 2.5 . 2.4 OD 2.3 2.2 2.1 2.0 7.5 65 6.5 8.0 80 7.0 70

III-IIJJJJjJpj

iJihIIPII!III

_'-AN

%1k 'iRIuR1LIi

L

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6.5 70 7.5 80 Lpp ¡B 2 8 Ce=rO.5755ri. Lpp /8 2.5 FUL.L Lcd

Ciri

2.4 L r; = 100% Tiim: %L d /ii .=. ico% 7.5 8.0 15 2.5 .Ef!L-Load Ccrdon 2.4 / r 100% Trim = O Lp d/d = i00% 80 2.8 C=0.575Seri. 2.7 2.6 2.3 2.2 Conteurs of rR 2.5 F1LLLoad Con&tic.r 2.4 Trim= fo %Lp, d/d =l0O%

y / Ij

=0.25 2.0 Fig. 13 Contours of 1-t for CB = 0.575 L 1 Fig. 11 L

Contours of S/1

L for CR= 0.575 h r

1j1

1?11Ih

ist:

4.1

4áiIIIH

1111111

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IVI"

fi

11111

EUJIII/

I

i

ARR

ViL-\

J!1II'!iiáì

V _{Lwg t=0.2} 2.8 2.7 2.6 2.5 . 2.4 co 2.3 2.2 2.1 2.0 6.5 70 65 7.0 2.7 CvnI3,.rS of S/?.3 2.6 2.3 2.2 2.1 2.0 2.8 8=0575 Series. Contours of

I-t

2.8 27 2.6 2.5 . 2.4 Fig. 14 Contours of t-w2-for C = 0.375 2.3 2. 2.1 2.0 6.5 6.5 7.0 7.0 28 2.7 2.6 2.5 2.4 Co 2. Lr' /9

The charts obtained from the results of the L/B. B/d

series with CB=0.575 accomplished by the Ship Re-search Institute are illustrated in Fig. 11 to Fig. 15. Where. Fig. 11 shows S/V3, Fig 12 r0, and Fig. 13 to Fig. 15 _{show the self-propulsion factors. These figures}

ale given for the full load condition at Fn=O.25. Each of them illustrated above is only _{one instance} among many after ail, consequently. the details should

he refered to the original reports.

5.

_{Systematic Series Model Tests in Wave}

Principal particulars of the models and the model 12 2. 2. 2.0 7.5 I. b .5 6.5 8.0 80 7.0

io

2.8 C9=0.575Sefies. 2.6 2.5 F1JLL Loud Cor-don. 2.4 2.3 2.2 Lpp ¡TI 75 75 u IA ri t0O1/ Trirn= °Lpí d/d = 00% 2.1 V/ 1Lwig =0.25 2.0 8.0 80 Fig. 15 Contours cf 7/is for C15 _0.575

prcp&lers used for the tests in wave are shown in Table 3 and Table 4. respectively. _{The indexing numbers of}

model propellers used _{for each models are indicated}

in Table 3. therefore, the combinations of models and

model propellers can be found easily.

The prime conclu:dons obtained from the _experiments ore as follows.

In waves whose length is _{longer than the ship's} length, the motions of ships with larger L,'B are

bigger and the resistance increases are less.

In waves whose length _{is longer than the ship's} length, the motons of ships with larger _{B/d ore}

bigger and flic resistance increases are less. Japan S/iipbuildiizy & Mamie Em'iiieeriìzg

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T\IILIk1$

1ohiIurIuiiiin

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ILURRMIR 'SLR

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I ., I .1 -2.8 Ca-0.575 2ors. 2.7 Contours cf 2.6

1. -

T 2.5 ttLLLcad Con:T 1 2.4 A /A r IC Trim = Lp, 2.3 d /d r,tO3 2.2 2.1 7 0.25 2.0 2.7 Contours cl

July ¡966

Table 3.

Principal particulars of models used for the tests in waves

Table 4.

Principal particulars of model propellers used for the tests in waves

(3) Although the pitching motions of ships differ little

depending upon the variations of Cii. the heaving

)O1ions of ships differ considerably, and the

heav-ing is far intensified near the resonance with the

increase of Cii. On the other hand, the resistance

increases arc higge' when C,1 is larger at the ]ower

speed and when Cii is smaller at the higher speed

near the resonance.

Of the experiment results, the thrust increase due to waves are illustrated in Fig. 16 to Fig. I .

6.

Correlation betveen Models and Ships

Fig. 19 and Fig. 20 show the results obtained from the comparison of the model tests with the full scale

measurements. The former shows the scale effect on

wake fraction and the latter the roughness correction JC1. The L!Cp is obtained from the JTTC-1957 Ship

Model Correlation Lines. And. for such high-speed

cargo ships is the YAMAS}-{IRO-MARU and the

RICH-MOND-MARU, it may be considered that JCFO.

F

M,,dei Sui1) N. (Lp,' 45(X) in) 1316

Model Ship No. (Lj.p G. ni) 1382

1517 1351 1371 1575 1353 1358 1576 1189 1577 1490 Length bci'cen ot'. L, i m 4. 50o .1.500 -t .z,i 4.500 4.500 4.300

Length on LIVI.., I-wi in in 4.623 .1.625 .t.1323 4.625 4.625 4.623

Breadth (including skin), B in in 0.6429 0.6429 0.6923 0.5625 0.6429 0.6429

Depth (including skin). D in ni 0.3570 0.3870 0.407(5 0.3533 0.4252 0.3572

Draft (including skin), d in in 0.2379 u.2670 0. 2885 0.23-14 0.3061 0.2381

Freeboard, f in in 0.1191 11.1191 0.1191 0.1191 0.1191 0.1191

Displacement, r in mi o-1812 0.-1160 0.5617 0.3707 0.5527 0.4299

Wetted Stirhict' Are.t, Sl iii iii2 3.027 3.780 -1. ]S7 3.-113 I. 199 3.665

Block Coefticieru, CE 0.625 t).575 0.625 0.625 0.624 0.624

Prismatic Cucflicitni, C 0.6-12 0.602 0.6.12 0.612 0.640 0.640

Midship Area Cocffli-icnt, C1, 0.97.1 t).t36 0.97-1 0.07 t 0.974 0.974

Waierpl;tne Arca Coetlickut, Cr 0.747 0.734 0.743 0.745 0.746 9.716

'-°. (.

IT

yay, 1'i ni

_{1.29 1.89 1.315 1.313 1.315 1.315}

B,'d 2.40 2.10 2.40 2.-10 2.10 2.70

Liii 7.00 7.00 6.50 8.00 7.00 7.00

rj'Lj-i'> tu 5.St.t .1.891 6.16.1 .1.065 3.551 .1.:ttt

Radiii f ( rai ion ti Air, I, iii in (t. 23f.,-» 013Lp» 0.25 L,.» 0.23 L»» 1.25 Lp» (1.25 L»»

Natural Pitching l'crisI ,\Ilo:ii, T,0 in ,»c. 1.22 1.18 1.27 1.15 1.29 1.17

Mall l'ro(aticr N. 1310 lStG 1s16,1S36 1535 1323 1537

Diameter. J) ri ni (L192 0.219 0.192 0.171 0.168

Pitch, II in ni 0.180 0.153 0.209 0.201 0.204

Pitch Ratio, HID 0.937 0.699 1.038 1.175 1.214

Boss Ratio 0.200 0.200 0.200 0.200 0.200

Expanded Area Ratio 6.650 0.650 0.650 0.650 0.650

Max. Blade \Vidth Ratio 0.302 0.302 0.302 0.302 0.302

Blade Thickness Ratio 0.050 0.030 0050 0.051) 0.050

Angle of Rake, in deg. 10-0 10-0 10-0 10-0 10:0

iJirection rit I ortung Rilit

handed

Right

handed Rilithanded

Ri1it handed

Right nanded

Number of Blades 5 5

Blade Section AU AU ALt AU AU

Model Propeller No. (L,» 6.0 in) 1357 1284

-

1256 1359

V -70 o 'o to v o Hw/L00222 ----.--.MIVDISI6 MHO 51? 4 15

/ Ì_"

i2

-$ t O .5 IO 5 2 2.1.

wA'.( LE'5TH/M0QEL LENGtH. .\/I.

Fig. 16 Thrust increase (lue to waves (Effect of C)

11/L - 0.0103 M.NtO,I576 MItO. 577

/J'S \\\\

-r IS -

/

,' 2[ / 'f.. 9 I

i

,,$ [15

/,,/

.5 10 .3 2.0 25 30 WAVE L710 1H / 1.111F LENÇTtI AI L

Fig. 18 Trust increase due to waves (Effect of B/d)

SidCLCd as the considerable reduction of C5 comparing

with the conventional high speed cargo ships and the adopticn of a proper size of bulb. Since the optimum

14 ro 09 08 z O

Fig. 17 Thrust increase due to waves (Effect of L/B)

value of C5 would vary depending upen the speed of

ships, it should be possible to realize the ship form with less C, in order to accomplish the more superior high

speed cargo ship. Furthermore, it should be indispen-sable to accelerate the investigations on the stem bulb

correlating C and the other principal particulars.

- coN°

YAMSNSSHI-MAR1J gr

-.

Io YAMATOSH1- MARU RICHMcuO- MARU o Hw/L 0020! .5 1,0

WAVE LE1.G'H / SHIP t.ENGTH

1.5 20 2.5 3.0 15 YAMA NA 5H- MARU IS 20X109 Reynolds Number Vt. V

Fig. 20 JC

Japan Ship/:eilding & Marine Eni'irzt'erins,'

UNO 574 - MHO 1575 .5/ L 2 0X109 7.

Ciosing Remarks

06

o 04

As described in the introduction of this article, a X

number of research projects on the hih sp-2ed cargo U.

o 02 oe

ship forms have been accomplished and the building of o

Y1MASFllRO-MARU has been considered as one of the most successful results. The greatest factor ac-complishing this economical ship form shcutd be

con--02

Reyrtolds Number R9

VI-Fig. 19 Scale Effect n Wake Fraction (Wv; Wake

Fractio nof Model, Ws; Wake Fraction of Ship)

01

O

i 4

S'vstem Series

Model

in

Japan

1_1

I

T)

I

0

4'

Aoncem iiig

[ne i ropuisive

erormallCe

of Full Ship Forms

'.0

lead from the hull form used in No. 41 Research Pane!,

with nearly saune body plan hut with a small screw

aper-ture for supposed adaption to larger ships.. _{The model}

propeller used in the systematic series model _{tests at the}

Ship Research Institute was MP. No. 457 only and its particulars are shown in Fig. 3. As shown in Table I

the model propellers used in No. 61 Research Panel of

Shiphudding Research Association of Japan were different for each model ship. One example of the results summed

up from these systematic series model tests arc shown

in Fig. 4 and Fig. 5. _{Fig. 4 shows the influences of} length-breadth _{ratio L/B, breadth-draft ratio B/cl arid} block coefficient C _{on residuary resistance coefficient} rp for Freude Number of 0.18, and the followings _are

deduced from this figure:

Remarks These

lesear These

bishi J

_2L_1

are the models tested in the Mejiro Tank of he Shin

Ç3 _Institute.

are the models tested in the Nagasaki Tank of

Mitsu-Icavy Industries, Ltd.

14

Japan Shipbuilding & farjne _Engineering

(/

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A!

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1 DIAMETER 211.0 8055 reAT/O .2/O ,ó24 PITCH RATIO .77û

EXPA/IOEÛ AREA RATIO . 475

MAX. 8140E W/DTHRAT/O . .22q

8LAØE THICKN(S.g PAT/O . oJo

A/t'OLE OF RAKE

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N(I/15ER OK 8L.405S

&/REC TÌOAI a'. 7tOt'N/Nç R/&/FT I4Wa'C

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Table i

_{Model Ships and Propellers Used In the Systematic Series}

Tests of No. 61 Research Panel

M.S. No. * L.; B of the Model B,"d of the Model C of the Model 1725 (1.0 2.76 0.80 1726 6.0 3.06 0.80 1727 1728 1729 5.75 OtO 0.0 2.76 3.06 2.76 0.80 0.80 0.80 1730 0.0 3.06 0.80 1755 6.00 2.46 0.80 1731 .0.I O 2.16 0.80 1753 0.0 2.46 0.80 MS. No. ** 1593 1661 1660 1659 1658 1657 L/13 of the Model 6.0 6.0 5.75 _{0.0 5.5} fl _{d of the Model 2.76 3.06 2.76 3.06 3.76} 3.06

Cro _{of the Model 0.82 0.82 0.82 0.82}

0.82 0.82

Model Prop. No. 1562 1563 1564 1565 1566 1567 1701 1702 1703

Dia (un), D _{0.175 0.158 0.183 0.165 0.191}

(t.172 0.196 0.205 0.214

Pitch (un), H _{0.125 0.142 0.117 0.135 0.109 0.128 0.104 0.095 0.086} Pitch Ratio, H/D _{0.714 0.899 0.639 0.813 0.571 0.744 0.531 0.463 0.402}

Boss Ratio, C 0.180 _{Anglo of Rake}

_10°0'

Exn .Area Ratio 0.67 _{\umI)er of Blades 5}

Mean Width Ratio _{0.256 Blade Section}

MAU

Biade Thickness Ratio 0.050

20 0 2 Q 24 0

PRISMATlC CURVE ¿Jt'/f T _IN 7/Orn.

Fig. 2 Prismatic Curve of M.S. No. 1321 Fig. 3

_{Outline anti Principal Particulars}

of M.P. No. 487 06 04 02 A Io 0$ 06 04 0.2

0.006 0.004 0.002

o

Fig. 1 Effect of LIB, Bld and C1

06 0.5 0,4 0.8 0.7 1.1 10 MARKS; -0.82 Cm = 0.80 & 0.82 55 60 L /

_/8

on r3. of Normal Bow Hull Forms

FULL LOAD CONDITION Fn 0.18

65 7.0 7.5 0.6 0.5 0.4 Lt 0.7 t'o 0.8

that the values obtained by No. 61 Research Pane! are different from those obtained by the other tests. makng

a step at 6.0 of LIB. The comparatively smaller pro-peller aperture and smaller propro-peller diameter, which

re-suhcd from the consideration for their application to larger ships are considered as major reasons for these

differences. The problem f separation was also

con-sidered as having effect on this large difference, but later studies have shown no marked difference in separation at least for the ranoc of these model tests.. This fact seems to he endorsed by the results for

rj

in Fig. 4. This

prob-1cm needs further detailed studies in general. Fig. 5

shows the following results:

(1) \Vake fractions wT and thrust deduction coefficients t increase as LIB decreases.

C S d MARKS 0.80 2.46 2.76 306

--082 2.46 2.76 3.06

-. -

---J J -8cl 306 Sd 276: -- . -1 f ø.'d= 2.46

-__j

--- -

r

¡8 d

TT

- 2.76' . -J

-.

- .... -.. -¿'d - 2.7618 d= 2.46.,

4:

I

--I

May 1966 15 55 60 65 L/8

Fig. 5 Effect of LIB, B,/T and C11 on Self-Propulsion Factors

of Normal

Bow Hull Forms, (B/T=2.76)

Among C11, L/B and B/il, C11 is most influential and

B/il is the least.

r7 has a minimum at L/13 of nearly 7.3 hut its in-crease duc to reduction of L/B is smaller than

ex-pected even for a considerably small L/B.

The influence of B.'d on r7 is not so apparent as

C11 and L/B. but it seems that smaller rn is obtained

with the smaller B,'d for the laroer LIB and with

the larger B/il for the smaller L/B.

Fig. 5 shows the influences of LIB and C,1 on self-propulsion factors. The influence of B/d on self-propul-sion factors being very small in this test range, is shown here only the values for B/il of 2.76. This figure shows

Lpp. 60000m L.W.L. '6 ISOOm F.8 0.485L 0.242 ¡ogt0(Rn.C) «CF

16

Relative rotative efficiency îi has a minimum at

L-B of 7.0 and decreases as LIB increases or

d-creases from this value.

wr and ¡ is larger and 't, smaller for the larger CR

in the range of the larger L/B and w is larger. t

smaller and R remains constant for the larger CR in the ranse of the smaller L/B.

Since increase of r1 and reduction of propulsive

co-efficient i are small for increase of LIB, an economical

ship form is likely to be not with larger Cn but with

larger B.

In the svsteniatic series nìcdel tests of Shipbuilding Research Association of Japan not only the intluence of

hip's principal particulars on the propulsive performance

hut also other miscellaneous items vere studied. The ciher main results are the better performances of the

pnsmatic curve form having fine entrance at bow even

with swefling fore shoulder to some extent, and of

suita-hic U shape of frame lines both at fore and aft bodies, and so forth.

3.

_{Systematic series model tests on hull}

forms with bulbous bow

\'hile the effect of bulbous how is doubtful _{for larger}

L,'B and at smaler Froude Numbers, it becomes quite remarkable for smallerL/B and larger CB even at Froude

Number ;hich are not so large. Not only a number of

r.

---- 2

4 2,

- 9

model tests after Asia-maru have shown the effectiveness of bulbous how. hut also the recent theoretical studies of Prof. Marue mcl Prof. Bessho have shown that hull form with minimum v ave-making resistance has sectional area at the fore perpendicular depending on speed. Therefore,

nearly every full ship constructed recently has bulbous

or cylindrical bow.

The size of bow bulb has to he decided depending upon ship's principal particulars. speed and load condi-tion arid its position as well has a substantial relation with the propulsive performance. The choice of suitable hull form with bulbous how is, therefore. more clitlicult than that of hull form ith normal bow.

The Ship Research Institute has carried out systematic

series tests requested by Saseho Heavy Industries Co.. Ltd. en various LIB and C of models with a bow bulb

of sectional area of 4 of that at midship. The parent

form was MS. No, 1559 and its body plan. stem and

stern contours are shown in Fig. 6. its prismatic curve

in Fig. 7. its particulars in Table 2, and the particulars of the model propeller in Table 3.

The most important results of the tests arc shown in Fig. 8 and Fig. 9, which are showing the influences of C and LiB on rz and self-propulsion factors, at Freude Number of 0.16 in the former figure and of 0.18 in the

latter, both at the full load condition. The general trend

is the same as in case of hull form with normal bow as

clearly seen in comparative representation. _{That is, C}

Fig. 6 Body Plan, Stem and Stern Contours _{of M.S. No. 1559}

"GCE

C. -O9 C..Ca3 C-S9

Fig. 7 Prismatic Curve of M.S. No. 1559

-.

-t

5Wj,

0 OC Fn _0.16 MARKS o

a-

0.60Cs 082 0.80 0.82 t I PRESENT SERIES UT6 SR.41 SERIES R d-276 1/8 70

Fig. S

Effect of L/B and CB on ri and

Self-Propulsion

Factors of

Bulbous Bow Hull

Forms (Fri=0.16)

has a larger influence than L/B, and rn increases arid 1-t

and l-WT decrease as C1 increases or L/B decreases. This

test, carried out only for Bld of 2.76. does not show the

influence of B/d. Since the hull forms with bulbous how

in this series test svere a little different from those with normal how in the series tests above mentioned strict

comparison cannot he made. However, from the fact

IO 09 08 0 07 06 -E. 4 18 6.5 65 o -1: i t i t t _I F,,. 0.18 0,035 55 B d= 2.76 C C TR £5

Fig. 9 Effect of L!B and CB on rn and

Self-Propulsion

Factors of

Bulbous Bow Hull

Forms (Fn=0.1S)

that there is a larger diflerence between the both results than are not attributable to the difference in the hull

forms, it rna' be considered that hull forms with bulbous

how give smaller TR' l-WT, and s,,. and larger 1i than

hull forms with normal bow.

The influences of C,5 and L'B on the propulsive

per-formance are shown in these figures for the hull forni

May 1966 . 17

'rable 2

Principal Particulars of the Model Ships with

I'. Bulb

No. 1559 1561 1563 1558 152t3 155)3 1557 1560 1562 Lpp (ni) 6.9000 6.7000 GJ)00 6.9000 6.S000 7.0000 6.9000 6.7600 6.5000 LDWL (m) 7.0945 6.8896 6.6827 7.C'938 6.9922 7.1973 7.0935 6.8892 6.6832 B (mt 1.0360 1.0512 1.0672 1.0301 1.0610 1.0160 1,0234 1.0384 1.044 .oad Condition d (m) 0.3977 0.103G 0.4097 0.3955 0.40.18 0.3901 0.3922 0.39S6 0.04S ç (ms) 2.2682 2.2715 2.2733 2.2836 2.8775 2.2720 2.2741 2.2723 2.2742 S (ms) 10.875 10.728 10.560 11.241 11.045 10.074 11.(t87 10.748 10.578 CR 0.798 0.799 0.800 0.812 0.809 0.819 0.821 0.8]9 0.820 Ci. 0.803 0.804 0.805 0.817 0.814 0.824 0.826 0.825 0.825 CM 0.994 ICB (Ç of Lpj') -2.12 -2.12 -2.12 -1.90 -2.06 -1.94 -2.31 -1.97 -1.99 Bld 2.605 2.605. 2.605 2.605 2.621 2.605 2.609 2.605 2.605 Lp p/B 6.660 6.37-1 6.091 6.698 6.-109 6.890 6.712 ;..152 6.165 0 10 09 08 07 C, i. 05 04 's 2 76 15 )- Wr 2.76 o

18

\th bulbous how. hut in _{case of hull form with bulbous} ow there still remain the problems of bulb's _{size, shape}

:d position. The results of the _{studies concernin2 these}

problems as vell _{as optimutn longitudinal position of}

-j

i

* Shy

_{the imaginary area of the bulb at the fore end.}

'p, f \

centre of buoyancy which is essential in relation to these are explained below.

The tests were carried out by the Ship Research In-stitute at the request of Kawasaki Dockyard Co., Ltd. The principal particulars of the model ships used in the tests are shown in Table 4, the body plans, stern

and stern contours in Fig. 10 to Fig. 13 and the particulars

of mcdel propellers in Table 5. MS. Nos. 1700, 1701 and 1702 are of hull forms with normal bow for the

study of the influence of longitudinal position of centre

of buoyancy i, and M.S. Nos. l703. 1704 and 1705

are of hull forms with bulbous bow for the same purpose.

The influences of Ira en ni and self-propulsion factors for the hull forms with normal how are shown in Fig.

14 and Fig. 15. and these for the hull forms with bulbous bow in Fig. l6 and Fig. 17. The optimum values of _{'CB in} Tß for the hufl forms with normal b.w can be found only

in case of Froude Number of 0.17 at the full _load con-dition and in the other cases in increases or decreases

/

i

ii

1i JL.

ï

Fig. 10 _{Body Plan, Stem and Stern Contours of 31.S. Nos. 1700f 1701 and 1702}

Japan Shipbuilding & .Vwine Engineering

j

Table 3

Principal Particulars of M.P. No. 1526

Diameter (in) 0.1823

Ross Ratio 0.189

Pitch Ratio (constant) 0.730

Expanded Area Ratio 0.5 75

Blade Thickness Ratio _0.0635

Ancle of Rake

_9'-58'

Number of Blades ₅

BlJe Section _{MAU Type}

Table 4 _{Principal Particulars of the Model Ships}

MS. Yo. _{170 1701 1702 17}

1704 1705 170IA 170-IC 1704B 1706 1TUGA 17o;H

L, _(ni) L fIL _(m) I.) _(rn) 6.000 6.150 0.9231

Full Load Condition

d (ni) 0.3341 Trim O V (ni3) _{1.4804 1.4803 1.4813 1.4817 1.4811 1.4825 1.4823} 1.4832 1.4840 1.4810 1.4827 1.4855 S _{(rn3) 8.127 8.163 8.130} 8.159 8.107 8.164 8.219 8.235 8.250 8.216 8.236 8.269 Ca 0.800 _0.800 0.801 0.801 0.800 0.801 0.801 0.802 0.303 0.800 0.801 0.802 Cr 0.808 0.808 0.S09 0.809 0.808 0.809 0.809 0.810 0.811 0.808 0.809 0.810 C ff 0.900 C8

('- of Lip) -1.49 -2.15 -3.49 -1.54 -2.49 -3.51 -2.58

_{-2.64 -2.67 -2.51 -2.56 -2.66}

Bulb Area A. * ( of Aji) _{4.0 15.0}

Length ( of Lpp) 0.35 1.27 1.85 2.56 0.50 1.27 2.56

Immersion (7- of dpui.i.) _{about 80.0 about 74.0}

Ballast Condition d (in) _{0.1591 0.15S8} 0.1584 'rrinf (Ç of Lrp) 2

r

(ros) _{0.0600 0.6513 0.6490 0.6600 0.6517 1.0476 0.0523 0.6520 0.0531 0.6516 0.6524 3.6536} S

(n)

_{so i} 5.933 5.896 5.913 5.958 5.05 5.1)71 5.979 5.987 5.968 5.978 5.903

as longitudinal centre of buoyancy moves forward. On

the other hand. optimum positionc of centre of buoyancy

arc clearly shown for the hull forms \ ith bulbous Ixi

depending en Froude Numbers at the full load condition. Further comparison between Fig. 14 and Fig. 16 shows that the optimum position of centre of buo rue for ra

moves toward aft with the highLr speed. and that optimum position of centre of buoyancy for the hull forms n ith

bulbous how is more forward than that for the hull forms with normal bow. Concerning the influence of Ir;; on

self-propulsion factors. wal.:c fraction w r increases as irr;

moves aft. but thrust deduction coefficient t and relative rotative efficiency has no constant trend. The varia-tion of r and i';: due to for the hull form with bulbous how is, especially, very small.

May 1966

cv-Fig. 11 Body Plan, Stem and Stern Contours of M.S. Nos. 1703, 1704 and 1705

Fig. 12 Fore Body Plan and Stem Contours of

M.S. Nos. 1704, 1704A, 170413 and 170-iC

The test results on the variation of bulb's longitudinal

position as shown in Fig. 12 for M.S. No. 1704. whose assumed sectional area of the bulb. Aa, at the bulb tip

is 7.5% of midship section area A.5. are shown in Fig. IS and Fig. 19. and those on the variation of bulb's longitudi-nal position as shown in Fig. 13 for M.S. No. 1706 which

lias the bulb of 15% in above mentioned area ratio are

shown in Fig. 20 and Fig. 21. Fig. IS and Fig. 19 show

Fig. 13 Fore Body Plan and Stem Contours of

M.S. Nos. 1706, 1706A and 170GB

that a protrudino how bulb gives a smaller ri: in case of

7.5% bulb with the exc'-tion of the low speed at the

full load condition and bulbs not protruding so much

give a smaller r, in case of I 5 bulb with the exception of the high speed condition. Fig. 19 and Fig. 21 shaw that this difference in longitudinal position of bulb has

very small influence on self-propulsion factors, and there-fore, r may be considered in direct relation with DHP.

19 Table 5 Principal Particulars of MP. No. 1

Diameter (m) 0.1823

Bess Ratio 0.189

Pitch Ratio (constant) 0.730

ENpanded Area Ratio 0.575

Blade Thickness Ratio 0.635

Angle of Ratio 9 r

Number of Blades ç

:0 o oca ç o oosL 04 07 se Q 5 o O z Z 0009-8 F, - 0 21 IF Il -25 MARKS, FOL LOAD BALLAST S .18 '7 IS -25 -35 L, 1- 09 tpp?

Fig. 1-1 Effect of JC Ofl rj

of Normal Bow Hull Forms

C z ¿a: OFL,p) 0 20 F 0 21

/

7

Fig. 15

_{Effect of li on Self'}

L'ropulsion Factors of Normal Bow Hull Forms

O z -35 0 008 '07 06 06 O CO? 009,0-0.005 o c-o-i 0 003 04

0002-L

J

J

9 ,MARKS, FULL LOAD BAUJ-.51

-- 2 5 L,., (- CF Lpp)

Fig. 16 _{Effect of lc,o on r,2 of} Bulbous Bow Hull Forms

\

Po,,lLon ,,I Oplinfl, L'.

Fn O 17 N. . F,,- 0 20 e C z

Fig. 17 Effcct of l,-n on

Self-Propulsion Factors of Bulbous

Bow Hull Forms

Japan Shipbuilc1in' & Marine Engineering

-J 1.0 MARKS

\

_2I FULL LOAD-BALLAST - _0.9 F,, - 0 17

io'

1.0 1L M AR K S, FULL LOAD BALLAST -09 e»--o z O_z -3.5 -IS -2.5 l,,, (? CF Lpp? o coo 0000 0004 Io 09

-IO 00

i

-08 07 08 07 06 05 O May 1966 Y ARK S III LO-O 80LA5T -22 F_c I? I4A7IS ROL bAO 8AL1AST I. 017 lO 2.0 199r or Lop)

-IO 09 'I.0 09 09

I

06 05 O O 1,0 2.0 1/Loor- 0F LAO)

Fig. 20 Effect of Longitudinal

Position of Bulb on rio,

(A11/A,,1=15°.'-) S MAPOS FILI. LOAS P ALL AST Fo 050 MAO KS, FLOt LOAS PALLAST -lo io .17 -lo Ò z S 15 23 30

¿ILpp( -CI9 bAO)

21 005 0007 0054 0.005 o coo o 332 0002-S 02) jv -

I,,

S o_z S 9 S '-0.000 0 007 0.006 0.005 0 004 0.003 0.002 9 I 16 12 20 30 t r coORY)

Fig. IS Effect of Longitudinal

Position of Bulb on 111,

(A8/A31=7.5Y')

Fig. 19 Effect of Longitudinal Fig.21

Effect of Longitudinal Position

Position of Bulb on Self-Propulsion

of Bulb on Self-Propulsion Factors

(AB/A = 7.5c-)

(A11/A' =15)

C z S _9r335

--

. Fr, C 31

O 03 0c.,2

:i

NI 1003 F, -0 7

-

b- _!

L 1° 07 L 80ILsj 1043 -lo A..A1 CFA,i Rl

Fig. 22

Effect of Bulb Size on roo

Fig. 23

Effect of Bulb Size on

Self-Propulsion Factors

2 shows the result of study on the intluence of

'alb iz _{on r e for bulb tip dktances from the fore}

per-pendicular of 1.27 and 2.56v of ships length. It shows

that the lareer and smaller protruding distances of bulb :ove a similar trend and that there is a optimum bulb ze for rif, which increases with speed. i he variation

r ¡ duc to bulb size is iiore remarkable at the ballast ndition than at the full load condition. The number 1 model ships used far each case is oni' three and the precise optimum bulb size cannot he shown. The cross

curve of roo given here is an example of representation. _lt

57910 07 9-21F Xn,,1,1.V, 2 3 4 5 Io ii T _T 7 II I I 0.10 0.12 01' 020 028 000 FR0000 NUI9008 _,

Fig. 2-4 D.H.P. Curves of the 100.5 m Ship Corresponding to M.S. No. 1701

300

can be said, however, that the bulb of 7.5% area ratio was art optimum size for this test range. The influence of bulb size on the self-propulsion factors shown in Fig.

22 is for the bulb with protruding distance of 2.56%

of ships length wr increases with bulb size, but t and do not show such a trend. varying little with bulb

size.

From the above results, the best propulsive

perform-ance for such a full ship form as C is OSO, L/B 6.5

and B/d 2.76 will be obtained in case where its lc is

-2.5%, bulb size 7.5%, and bulb protruding distance

0.5-1.0%. lt _{must he remembered, of course, that these}

figures varies with ship's principal particulars and speed.

For reference the DHI curve of the actual ship corres-ponding to MS. No. 1704 is shown in Fig. 24. Here. the Schoenherr's formula was used in _{calculating the}

frictional resistance, taking .Cf of --0.0003 and the scale

effect of wake fraction w was not taken into account.

-1.

Closing Remarks

Vhat has been explained above is unIv a part of

studies on full ship forms carried out in Japan and other studies have been made not only in the Ship Research

Institute whose activi;ies were explained with emphasis

in this report. hut a number of research studies on full

ship forms have been made in Mitsubishi Heavy

Indus-tries. Ltd., _{University of Tokyo. University of} Yoko-hania and Lrniversitv of Osaka and so forth. _{Since it} is

impossible to report all of these studies, only those

con-sidered as forming main stream of svstaonatic series model

tests have been explained in this report.

'D

Japan Shiphui1din' & !ari Eninecring

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M000I. S'SP NO 704 MOORL ?0G1L.ER NO 026

'20

FU1 LOAD CCO13m016

-- -- SALLA5T C0I2iON _I00

RD ND 39 CO 07 Is 09 s

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O $ 10 A,, A..( 070.0