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Title Resistance Test of Geosim Models of Semi-Planing Type Passenger Ship
Author(s) Harano, Susumu
Editor(s)
CitationBulletin of University of Osaka Prefecture. Series A, Engineering and nat
ural sciences. 1993, 42(1), p.69-86
Issue Date 1993-12-01
URL http://hdl.handle.net/10466/8578
Rights
Bulletin of University of Osaka PrefectureVol. 42, No.1, 1993, pp.69-86.
Resistance Test of Geosim Models of
Semi-Planing Type Passenger Ship
69
Susumu HIRANo
(Received July 14. 1993)
1. Introduction
Recent trend of modal shift from road transportation to sea transportation leads to
a necessity of offering higher-speed and reliable shipping system. For this purpose it
is necessary to design high speed ships by taking hydrodynarnic aspects into account.
Theoretical prediction of hydrodynamic performance of high speed planing hulls is
therefore needed in this view point.
Since there have been few experimental works on hydrodynamically fundamentalfeature of planing hqll forms, the author has begun to rpake m,ea$ur,ements of hydro-
dynamic properties using several simplified ship models, Iike wedge shaped planing
hull and rectangular cylinder models, in which the shapes are composed by flat plate
componential planes. For these several years measurements have been carried out intowing tank on the items of three-component forces, huil .pressure distribution, wave
patterns, spray phenom.e,no. n and its momentum loss,.etc,')'g)'3)･f)'5) These measurements
enable us to make separation of resistanee components of planing hull forms. The
author's group has also made theoretical coMputation of the wave phenomena by us-
ing linear water wave theory.6) Basic hydrodynamic features of this kind of simplifi-
ed hull forms has thus become clear one by one.
The present work, on the other hand, concerns with an, existing hull form, in which
resistance tests are carried out using geosim (geometrically similar) models of an ex-
isting semi-planing type high-speed passenger ship. Two geosim models are used with
lengths between perpendiculars, O.75m and O.40m, and usual procedures in resistance
test is used except for the towing direction set along the thrust axis.
The test results are analysed to obtain the relationship among the model speed, atti-
tude, and resistance. These are compared and discussed with Savitsky's practical for-
mulaT) for planing hull forms. Comparisons are also made with the existing results
obtained in other experimental facilities for the same but large geosim models.8)
It is found through these discussions that the author's results using comparatively
* Department of Marine System Engineering, College of Engineering
70 Susumu HIRANO
small models are also reliable when size effects are taken into accounts.
The original actual ship
normal speed 28 knots, the
stern. Table 1 shows its
the scale ratios 1130.9 and
and O.4m respectively.
2. Ship Models
is a semi-planing type passenger ship of length 24.6m and
form of which is V-shape hull with chine and has transom
principal dimensions. The corresponding two models are of
1158.0, have the length between perpendiculars Lpp, O,75m
Table 1 Principal dimension
Length between perpendiculars (m)Length at designed over-all (m)Length at designed load water line (m)Max. breadth (m)Depth (m)Designed draft (m)Water line, bow & buttock line apart (m)
Maximum section (from ST No.5) (m)Sqare station apart (rn)
Initial trim (m)
23,2
26.4
23.2
5.20
2.40
O.87
O.20
1.00
2.32
O.50
GrossMainPowerSpeed
tonnage (t)
englne & revolution(knot)
69.0
Diesel 2 set
1,OOOps × 2170rpmll064rpm28.0 (full load cond.90%MCR)
Figure 1 illustrates their appearance and Fig.2 shows their body plans. Offsets of
the O.75m model are tabulated in Tables 2-1 and 2-2. Since the models are small and
are planned to make test in trial condition, the material is chosen to be FRP and the
model is manufactured as light in weight as possible, reducing their weight in various
view points. An upper deck is attached for preventing water immersion at high speed
testing. But turbulence stimulator is not attached.
In the
along the
models is
tests.
3. Expermental Apparatus and Procedures
resistance tests, the models are set free from surging motion and towed
prescribed thrust axis to measure the towing force. The attitude of the
also obtained by measuring the fore and aft drafts during the resistance
Resε8繊Cε7es孟（ゾGeOS‘肌Mo4eJs（ゾSe履一P♂磁η9乃ρe Pαsse陀ger SんどP 71
Fig．1Mode．1s
一．O 曳
へ
B．L．
Fig．2 Body plan
Passenger 'BoatModel .Ship Particulars
Length between PerpendicularsLength at Designed Over AllLength at Designed Load Water LineBreadthDepthDraft (Design)Water Line, Bow & Buttock Line ApartMaximum Section (From ST no. 5)Square Station ApartInitial Trim
.75 m-Model HALF-BREADTHStation (m) -O. O1939 O. OOOOOord. No. (Lppllo) -o. 2seso o. oooooWL. No. Height (m)BaseO. 20
O. 40
O. 60
O. 80
1. 00
1. 20
1. 60
2. 00
2. 40
ChineChineDeck
.75
o. oooooO. O0647O. O1294O. O1939-
O. 02586O. 03233O. Osa79O. 05173O. Oec65O. 07759(In)(Out)
Side
o. ooooo
o. oooooO. 03559
O. 06328O. 07635
O. 07733O. 07828O. os025
O. oa214
O. os406O. 07258
O. 07577O. os406
m-Model HALF-BREADTHStation (m) O. 48750Ord. No. (LppllO) 6. soooOWL. Nb. Height (m)BaseO. 20
O. 40
O. 60
O. 80
1. 00
1. 20
1. 60
2. 00
2. 40
ChineChineDeck
o. oooooO. O0647'O. O1294
O. O1939O. 02586O. e3233O. Osa79O. 05173O. 06465O. 07759
(In) (Out)Side
O. O0647O. 02618
O. 04213O. 05os3
O. 07028O. 07815O. 07898
O. osos6
O. os237O. oa406
O. 07436O. 07759
O. oa406
o. oooooo. oooooO. Osa88O. 06180O. 07639O. 07734
O. 07830O. 08029O. 08216O. 08406O. 07262
O. 07ss8O. 08406
O. 52scO7. 00000
O. O0765O. 02469O. 03917O. 05273O. 06593O. 07761O. 07851
O. 08036O. 08220O. Ogn06O. 07399O. 07725O. 08406
O. 03750O. 5ooOO
o. oooooo. oooooO. 03489O. 06009O. 07652O. 07746O. 07841O. oa033O. 08220O. oa406O. 07290O. 07613O. 08406
O. sc250'
7. 50000
O. O0782O. 02216O. 035osO. pa7ssO. 05929O. 07097O. 07626O. 07896O. os160O. os387O. 07172O. 075osO. oa406
Actuar
23. 2ooO26. 4ooO
23. 2ooO5. 2ooO
2. 4ooO
O. 8700O. 2ooO
1. 0ooO2. 3200
O. 5ooO
O. 07soO1. 00000
O- OOOOOO. OO165
O. 03639
O. 06021O. 07671O. 07763
O. 07854O. 08038
O. 08222O. 08406O. 07311O. 07633
O. Ogn06
O. 6ooOO
s. oeooo
O. O0709O. O18ssO. 02957O. 04016
O. 05064O.- os094
O. 07136O. 07ss4
O. 07ce9O. 08340
O. 06722
O. 07046O. Ogn06
.75-model.
O. 7500 O.,8534 O. 7500 O. 1os1 O. 0776 O. 0281 O. O065 O. 0323 O. 0750 O. O162
O. 112501. 50000
o. oooooO. oo632
O. 037ss
O. osO15O. 07682
O. 07772O. 07864O. os044
O. os226
O. os406O. 07326O. 07648
O. os4os
O. 637508. 50000
O. O0557O. O1393
O. 02269O. 03141O. 04022
O. 04911O. Oss03
O. 06954
O. 07596O. oa1ggO. 06047
O. 06353O. 084os
O. 150002. 00000
o. oooooO. OI022O. 03878O. 06eo8O. 07691･
O. 07781
O. 07869'O. 08048
O. 06228O. oa406O. 07339O. 07661O. 08406
O. 675009. 00000
O. oo317O. oo8scO. O1451O. 02106O. 02811O. 03551･
O. 04328'
O. 05899O. 06853O. 07719O. 05138O. 05398O. os121
O. 225oo3. ooOoo
o. oooooO. O1618O. oo065O. 059caO. 07714O. 078ooO. 078es
O. os059O. os233O. os4ooO. 07367O. 07689O. 08406
O. 693759. 25000
O. OO163O. O0525o. oooceO. O1539O. 02143O. 028osO. 03518O. 051ggO. 06279O. 07303
O. oo5ggO. 04824O. 07845
O. 30ooO4. 00ooO
o. oooooO. 02072O. 04221O. 05ce3O. 07734O. 07819O. 07oo1
O. os070O. os239O. oa406O. 07395O. 07718O. ce406
O. 712509. 50ooO
o. oooooO. OO191
O. O0518O. O0938O. O1438O..02016O. 02es1
O. 04gg3
O.05541O. os722O. 03966O. 04172O. 07449
Table 2-1 Offset of O.75 m model (half breadth)
O. 375oo5. 0oooo
o. oooooO. 02428
o.o43scO. 05970O. 07755O. 07836
O. 07918O. 08079O. 08243
o. ognos
O. 07423O. 07746
o. ognos
O. 731259. 750oo
o. ooooo
o. ooooo
o. ooeooO. O03os
O. Q0703O.'Ol196Oi .O1759
O. 03Q68･
Q. ,04650
O. 05976'
O. 03266O. 03443O. 069oa
O.･ 40733
5. 43100
O. OO032.
0. 02559Q. 04406O. 05964O. 07759O. 07839O, 07920O. osos1
O. oa244
O. os406O. 07436O. 07759O. os406
O.,7500010. 00ooO
o. oooooo. oooooo. ooooo･o..ooooo
o. oooooO. oo332O. oo806
O. Olso3.
0. 03591O. 05oo2
O. 02488O. 02629O. os203
Or 4sooo6. 000oo
O. O0411
O. 026ngO. 04378O. Oss93O. 07303O. 078ggO. 079ooO. 08074O. 08241
O. OMos･O. 07436O. 07759
O. OMos
O. 79202.10. 56000
o. oooooo. oooooo. ooooo.o. ooooo
o. oooooo. ooooo'o. ooooo
o. oooooO. O0641O. 02241
O. O0521
O. O0536O. 03923
rs
98Bpt
:Hpa>Zo
.75 mLpp Model Ship Passenger Boat
Offset Table Hight (above base line)
Station (rn)
Ord. No. (Lpp/10)
BL No.
C. L.
O. 20
O. 40
O. 80
1. 20
1. 60
2. 00
ChinDeck
Breadth (m)o. ooooo
O. Oos47
O. O12pa
O. 02586
O. Oss79
O. 05173
O. 06465
LineSide
-O. O1939 O. OOOOO-O. 25850 O. OooOO
O. oo711
O. O0791
O. oogg5
O. Oll03
O.O1359
O. O1650
O. O1976
O. 02190
O. 07759
Offset Table Hight (above base line)
Station (m)Ord. No. (LppllO)
BL. No.
C. L.
O. 20
O. 40
O. 80
1. 20
1. 60
2. 00
ChinDeck
Breadth (m) o. ooooo
O. O0647
O. O1294
O. 02ss6
O. Osa79
O. 05173
O. Ooo65
LineSide
O. O0726
O. Ooa03
O. O0894
O. Oll14
O. OlsaO
O. Olas4
O. 02019
O. 02239
O. 07759
O. ng750 O. 525006. 50ooO 7. 00000
-O. oo152
o. ooooo
O. oo1gg
O. oo632
O. Ol148
O. O1714
O.02316 O. 02786
O. 07oo7
O. 03750
o. sooeo
O. O0701
O. oo780
O. Oos76
O. Oll03
O. O1384
O. O1710
O. 020os
O. 02306
O. 07759
O. 56250
7. 5oooo
-O. O0223 -O. oo294-O.OO039 -O.oo056
O. OO178
O. Oos94
O. O1273
O. O1888
O. 02522
O. 02991
O. osO18
O. O0216
O. Oos25
O. O14es
O. 021os
O. 02882
O. 03272
O. 07841
O. 07500
1. 00000
O. O0630
O. O0714
O. Oos16
O. OI058
O. O1356
O. O1699
O. 02078
O. 02334
O. 07759
O. 6ooOO
8. 00000
-O. O0366
-O. Ooo34
O. O0323
O. Olco9
O. Oles3
O. 02653
O. 03467
O. 03632
O. 08014
O. 112sc
1. 500oo
O. O0559
O. oo649
O. O07ss
O. OIO13
O. O1326
O. O16gg
O. 02087
O. 023as
O. on759
O. 63750
8. 5oooo
O. 15ooO
2. 00000
O. OOng8
O. OOss3
O. oo598
O. OO%8O. O1296
O. O1676
O. 02096
O. 02391
O. 07759
O. 67500
9. ooOOO
-O. Ooo35 -O. O0506O. oo069
O. co570
O. O1526
O. 02479
O. 03422
O. on2ss
o. caosc
O. os207
O. O0431
O. Ol131
O. 02sa3
O. 03508
O. 04521
O. 05927
O. 04526
O. os413
Table 2-2 Offset of O.75m model
O. 225oo
3. 0oooo
O. oo345
O. O0452
O. oo579
O. Ooa76
O. O12sa
O. O1656
O. 02115
O. 02447
O. 07759
O. 69375
9. 250oo
-O. oo3M O. Oos21
O. O16M O. Oso23
O. oo193
O. 05171
O. 066gg
O. 04785
O. 08524
(height
o. soooo
4. ooOOO
O. oo203
O. oo321
O. eo461
O. oo786
O. Ol179
O. Olos3
O. 02134
O. 02505
O. 07759
O. 71250
9. 50ooO
O. oo1ee
O. O1500
O. 02406
O. Osa06
O. 04ce6
O. os077
O.07464
O. 05059
O. oaos4
above baseline)
O. 37500
5. 00000
O. Ooo62
O. OO189
O. O0341
O. O06ss
O. Oll19
O. O1611
O. 02153
O. 02561
O. 07759
O. 73125
9. 75000
O. O13MO. 02499
O. 03349
O. 04723
O. 05749
O. 06953
O. 08267
O. Oss46
O. os747
O. 40733
5. 43100
o. ooooo
O. OO133
O. O0291
O. O0656
O. OI095
O. O1601
O. 02160
O. 02ss6
O. 07759
O. 75000
10. 00000
O. 02813
O. 03666
O. oa449
O. 05646
O. 06711
O. 07875
o. ooooo
O. 05an6
O. 08858
O. 4scOO
6. 0ooOO
-O. OO081
O. OOOMO. O0225
O. Oos24
O. OI095
O. O1622
O. 02196
O. 02649
O. 07759
O. 79202
10. 560oo
O. 06094
O. OM65O. 06992
O. 08033
O. Oco69
o. ooooo
o. ooooo
O. 06377
O. 091 14
tuzaor･p"
"R-･ll
8"g[gt
8.s
gilgiig)
gY･te
RR.di-･s
gos
tsD8ReqR
ge6'
at
74 Susumu HIRANO
The experimental system is composed by the following four sub-systems, i.e., tow-
angle control device, resistance measurement system, draft measurement system) and
model-hull guide system, which are illustrated in Fig,3. The guide system fixes the
model allowing only the surging motion, and the model is towed by a thin wire,
which is connected with the towing lever located at the center of buoyancy, and is led
to a load cell in the other end through a pulley which is hunged at an end of a step-
ping-motor driven crank lever. The towing arm is connected with a potentiometer
which output voltage proportional to the inclination angle of the towing wire. The
tow-angle control device moves the crank lever to the right position so as the angle
of the towing wire to become the prescribed value, by using servo-amplifier system.
A load cell installed in the resistance rneasurment system measure the towing force a-
long the towing direction. Two guide poles put at both perpendiculars of the model
are used to measure draft values by use of two sets of VTR camera
, towin:angleadjuster
apparatussettingrail,
loadcell
,,
`
,
,
guidepole
guideStePPingnotor
,
tewingwireguidepole
FPdraftgUidegauge :
v-APdraftgailgecrankbulkheadlever
e
(petentioleter) .pulley
leverV.L.
to"ingT CB
7501400'F'
AP F'p unit in MM Fig. 3 Experirnental system
As for the experimental prcedure, the towing angle is always controlled during the
running time, and the towing force is measured when the running speed becomes
steady. The measured analogue data are converted to digital values with sampling
time 5 sec, sampling interval O.05 sec, and sarnple number 100. The drafts at FP and
AP are recorded into VTR and analysed afterwards to get their values.
Tests both in full and trial load conditions are carried ou-t for the O.75m model,
although for the O.40m model test is made only in full load condition becaxLse of the
Resistance Tbst of Geosii7z Mbdels of Serni-Planing T>tpe Passenger Ship 75
constraints of its weight. Towing speeds are set totally 21 values with O.2m/sec in-
terval from O.5mlsec to 2.5mlsec. These test conditions are'shown in Table 3.
4. Test Results and Diseussions
The measured towed resistance is converted to the residual resistance after subticac-
tion of the flat plate friction resistance, for which the wetted area surface at still
water level is taken.'The total resistance coefficient curves are plotted in Fig.4 for
full load condition and in Fig.5 for trial condition with ordinates of Reynolds num-
ber. The residual resistance coefficients are plotted in Fig.6 and the trim and sinkage
are shown in Figs.7 and 8 respectively.
4. 1 Resistance, trim and sinkage
The results of full load condition are shown in Fig.9 both for O.75m and O.40m
models. In case of the O.75m model, the residual resistance coefficient increases as
Froude number up to Fn=O.48, attains the last hump value Cr==O.O0698 at Fn =O.49,
and then decreases rapidly with Froude number. The value of trim keeps constant for
Froude number up to Fn==O.375, then shows rapid increase, and satulates to have a
value of about 3 percent Lpp aft in the region of Fn larger than O.625. The sinkage
behaves in the same way that it decreases gradually with Fn up to Fn=O.475, and
then it increases to the value higher than the still water level when Fn is beyond O.65.
The value of Cr for the O.40m model reaches its last hump O.O078 at Fn=O.5, and
then it rapidly decreases. The Cr curve shows a discontinuous change at Fn=O.35
which' is called discontinuous point hereafter. Trim keeps its value with Fn less than
O.35, and increases its value until it reaches a saturated value of 4 percent trim in the
region Fn=O.65 or More. The sinkage also behaves in the similar manner to the case
of full load condition. It decreases graduaJly in the region of Fn less than O.45 and
increases higher than still water level when Fn=O.6 or more.
A common feature between the two models can be reeognized that the last hump in
the residual resistance curve occurs when the trim changes rapidly and the sinkage
becomes maximum. If we judge the occurrence of planing condition from the state of
sinkage turning to a positive value, the planing state is. attained at Fn==O.65. The
residual resistance coefficient of both models are nearly the same in the planing condi-
Next we compare the results of these two'models. The residual resistance curves
are parallel to each other in the region of Fn grgater than O.6, and the value of the ' 'smaller model shows. higher. value especially when they take the values of Cr=O.O0698
ttand O.O078 for the O.75m and O.40m models respectively at the last hump Fn =O.5. In
the low speed region the Cr value of the smaller model becomes smaller because of
Lpp (m)Scale
Bmax (m)D (m)Full Cond
draft (m) AP MS FPTrim (m)B (at MaxSect (m))
d( Do (m))Dispt naked (m3)App (Shaft Bkt (m3)
(Rudder (m3)
Dispt All App (M3)
Wet Surf AreaApp (Shaft Bkt (Rudder
(m2)
(m2))
(M2))
Wet S A (App) (M2)
Cb Cp Cmax Cw lcb(%Lpp) aft LIB BId
Shaft CL Hight above BL at APRakeDist between Shaft CL-Hull CLRake
O. 7500030. 93330
O. 16811
O. 07759
O. 02713
O. 02809 O. 02903
-O. OO189
O. 15578
O. 02816
O. OO154
o. ooooo
o. ooooo
O. OO154
O. 11412
O. OO172
O. OO169
O. 11753
O. 46810
O. 81270
O. 57600
O. 87820
5. 90780
4. 81500
5. 53100
O. 4000058. 00000
O. 08966
O. 04138
O. Ol447
O. O1498
O. OIM8-O. OOIOI
O. Ogg08
O. O1502
O. OO023
o. ooooo
o. ooooo
O. OO023
O. 03246
O. OO049
O. OO048
O. 03en3
O. 46810
O. 81270
O. 57600
O. 87820
5. 90780
4. 81500
5. 53100
Lpp (m)Scale
Bmax (m)D (m)Trial Cond
draft (m) AP MS FPTrim (m)B (at MaxSect (m))
d( Do (m))Dispt naked (m3)App (Shaft Bkt (m') (Rudder (m3)
Dispt All App (M3)
Wet Surf Area (m2)App (Shaft Bkt (m2))
(Rudder (mt))
Wet S A (App) (m2)
-O. Ol121
7. 896M O. 03071
o. ooooo
-O. O0598
7. 896M O. e1638
o. ooooo
Table3 Test
Cb Cp Cmax cw lcb(%Lpp) aft L/B B/d
Shaft CL Hight above BL at AP
Dist between Shaft CL-Hull CLRake
condition
O. 75000
30. 93330
O. 16811
O. 07759
O. 02gg5
O. 02501
O. 02168
O. O0668
O. 14su4
O. 02473
O. OO130
o. ooooo
o. ooooo
O. OO130
O. 10579
O. OO172
O. OO169
O. Ie921
O. 48960
O. 86850
O. 56370
O. 89670
9. 88690
5. 22900
5. 80000
O. 40000
58. 00000
O. 08966
O. 04138
e. O1512
O. O13sc
O. Ol156
O. O0356
O. 07650 '
O. O1319
o. eoo2o
o. ooooo
o. ooooo
O. OO020
O. 03009
O. OOoo9
O. OO048
O. 03106
O. 48960
O. 86850
O. 56370
O. 89670
9. 88690
5. 22900
5. 80000
-O. Ol121
7. 89654
O. 03071
o. ooooo
-O. O0598
7. 89654
O. O1638
o. ooooo
al
III)
$Bpt
=Hto>Zo
Resistance Test of Geosim Models of Semi-Planing T)Lpe Passenger Ship
Fig.
Fig.
e
o-
×
-o
12
8
4
Fullloadcend.uithappendages
+ree+
-l
9
'e"
(e.,,
+ +"ee
+?eJ.s
+ fo
t?Sch
oenh er
7Cl957
t'lioe
Meanline
1os
4 Total resistance coeft.
in full load cond.
or
o'-t
×
-O
!2
8
4
10S R(Ct=Rtl(O.5pSoU2))
n
mRn curves
Trialcond.withappendages
<
a q feoa
NN
ao.)S."e
(s(
t7Sch
oenh ett
?c19S2
'
lilte
taeanI･Jne
1os5 Total resistance in trial cond.
coeft.
106(Ct==Rtl(O.5ps,u2)) -Rn
Rn curve
77
78 Susumu HIRANO
m
o.--l
×
kU
8
6
4
2
withappendages
+
<a O
Lpp=O.75m'FulleTrialC
Lpp=O.40mFull+<e
< eb
qe
Ca ete
< o+ ` e++
a
++
o.
Fig. 6
2 O.4 O.6 O.8 1.0 1.2 FnResidual resistance coeft. (Cr=Rrl(O.5pSoU2))"Fn curvesfor two models.
6
a.a
:4N=.H
e-2kts
o
-2
withappendages
+ +
+ e
Qq a
e<
(e
Lpp=O.75mFulleTrial(
Lpp=O.40mFull+
O.2 O.4 O.6 O.8 1.0 FnFig. 7 Trim (% of Lpp) for two models.
1.2
Resistarrce Ttrst of Geosim M7t}dels of Semi-Planing T)lpe Passenger Ship 79
aa'-'t
"-l
o
N=.d
otnrd
M=.Hca
2
o
-2
withappendages
Lpp=O.75nFulleTrial(
Lpp=O.40mFull+
+ +8re g
O-,GJ
O.2 e.4 O.6 O.8 LO 1.2
FnFig. 8 Sinkage (% of Lpp) for two models.
Fig. 9
8
"
o-
X4ko
o
k'
"4x
H 2::
:o
: F= 1 x NO ･=-
g -i
: O O.4 ine-
Residual resistance coeft.
in full load cond. for two
A tppze.T5eFull-".--Lppie.IOtEull.
.
'
t-s.XsK
N.-
.ny- -
.e"}e"ge
.
.
f..
.
9 .
P
O.8 L2 Fn(Cr==Rrl(O.5pSoU2)),
models.trirn and sinkage
80 Susumu HIRANO
the laminar effect. The trim change of the smaller model appears in the lower speed
than in case of the larger model, and in the higher speed range the O.40m model has
larger trim values of about 4 percent Lpp compared to 3 percent Lpp value of the
O.75m model. The O.40m model also a slightly larger value of sinkage.
4. 2 Resistance and attitude
There is a discontinuity point in the resistance curve at a Froude number slightly
lower than the hump point, especially for O.75 model. In the existing data of the
eooperating experiment, there is also such a discontinuity point, in which 21 cases in
total 31 tests for full load cOndition and 10 cases in 26 tests for trial condition can
be recognized to have the discontinuity in the resistance curves. Fig. 10 shows the
Froude number at which this discontinuity occurs, i.e., Fn=O.35 and Fn =O.3 for full
and trial Ioad conditions respectively.
>e.-=c.-
e=oout
.-
v"-,
e=ta
O.4
O.3
O.2
O.1
aecoe a
eoee
OFull'loadcond.
Srrialcond.
withappendage
O1234 Lpp in m
Fig. 10 Froude number of discontinuity.
Looking at the discontinuity point Fn=O.375 in the resistance curve and at the same
time, at the change of the draft change at FP and AP as shown in Fig. 11, we can ob-
serve that this discontinuity point corresponds to the timing of the rapid change of
the trim curve. The draft at AP station begins to sink at Fn=O.375, the draft at FP
station rises at Fn==O.45, the draft at AP becomes constant at Fn==O.6, and then FP
point follows to be steadyat Fn=O.7. The speed Fn=O.375 thus corresponds to asitu-
ation that the AP draft is starting sinkage whereas the FP draft keeps still. There-
fore we can conclude that this Fn point of discontinuity of resistance curve means the
point at which the trim and the draft start changing rapidly, especially the sinkage at
AP starts. ･
Resistance Test of Geosim ILfodels of Serni-Planing T)Lpe Passenger ShCp 81
Full load cond. with appendage,
e8 o "
× 4 " U
o
o
a e -1 .E
:1 :
n o
O O.4 O.8 1.2 Fn ' Fig' 11 E}tetrdpuaalngevipslance coeft･ (Cr=Rrl(O･5pSou2)) and draft
'4. 3 Comparison with existing data for several geosim models
Discussion is made here comparing resistance curves in full load condition for 6 geo-
sim models including existing data measured in other towing tank facilities. Fig. 12
shows such a comparison. A common feature of having peek value of about Cr=O.O07
at Fn==O.5, excluding the one of the smaJlest O.40m model, can be recognized, and the
smaller models have the larger Cr values at Fn under the last hurnp point O,50. In
the lowest speed region at Fn less than O.35 the smallest modeis, i.e., O.40m and O.75
m, shows an laminar effect in Cr curve.
Figure 13 represents the trim and the sinkage for these 6 models. The sinkage
seems to be the same in all models and shows a planing state at Fn =O.65 or more.
The trim curves show some differences among models, i. e., the smaller model has the
larger trim, e. g., 4.0 percent Lpp for O.4m model against 2.5 percent for over 2m
models. The Fn points of beginning the trim change and the points of approaching to
a steady state seem to be the same for all the models. These results suggests us that
the smaller models can be used for resistance tests if we are careful about the Iamina-
rization in low speed range and slightly 1arger trim value for smaller models.
Lpp:O.75m
,
b･
%e
. % AP
. e.'
'ae
82 Susumu HIRANO
10
8
m
os-
×4"O
2
Full
sle 1 tOeeGS ieuvil-t
;
load cond.
-++ 'vs; S?;g
!iu
1l o
+
e
"ith
+e
appendage
pt
In:b or
i nj1- e" }
ptete+gi
eeAoo+
++g e ,'
Lpp =
1
o
o
4e3
2
.5
.75
.4
+l E+
VH+1 -Ee
o O. 3
Fig. 12 Residual resistance models in full load
Oi 8
coeft.
cond.
o･g 1.2Fn(Cr==Rrl(O.5pSoU2)) for 6 geoslm
1, S
A a"ti'`
o
.N
2
1
o
3
2
1
o
Fullloadcond.Nithappendage
sinkage."E" ･pmo A A
. o O
g7 oo
'N"V AAA baVA aa a6A'KS
h OLpp=4e
M21+i.5VO.76Oo.4
Fig. 13 Trim and Sinkage
o.
for 6 geosim
8
models in full
1.
Ioad
2
cond.
4. 4 Comparison with Savitsky's formula-
Savitsky's formula7) for the total resistance of simple planing hull forms is well
known for predicting the resistance performance. Comparisons with the formula is
here made for three models of lengths O.40m, O.75m, and 4.0m.- Since so called Savit-
sky's short form is aimed to predict resistance in planing state, comparison is made
in the Fn range over the last hump. Savitsky's formula was derived from experimen-
tal data on cylinder-type planing forms of constant beam and rise-of-floor angle. The
Resistance Tlest of Geosim Mbdels of Serni-Planiug Tbepe Passenger Ship 83
present model form has almost constant value of rise-of-floor angle, 9.0 degree from
the midship section to the transom end.
' Figure 14 shows an example of the comparison of measured resistance with the pre-
diction by Savitsky's formula using the above angle 9.0 deg. The agreement seems
poor since the present model is a semi-planing hull form and the fore bottom is al-
ways located under the water. If the riseof-floor angle is taken at the station of
spray splashing, i. e., at the square statlon No.8 for this model, the bottom angle is
30.0 degree. Putting this value into Savitsky's formula, we obtain an agreement as
shown in Fig. 15. This suggests us that the rise-of-floor angle in Savitsky's formula
should be taken at the stations near the stagnation line or the spray root line in case
of practical planing hull forms.
5. Conclusions
Resistance tests of high-speed planing-hull passenger ship models are carried out and
comparisons with existing data are made. It can be concluded as follows.
1) A discontinuous behavior appears in the residual resistance curve at Froude num-
ber when the fore-part rising trim begins, and the last hump takes place before the
steady state of the trim attains. At the last hump the sinkage also becomes mini-
Full load cond. with appendage' o r5 ･ y. , +"l e . +0 + ÷t -eo ") + ti tZ"ti,,,,.licr%!,x,"'x {xO%fx!;.
="--..t.T.
+ Savitsky' short form (dead rise 9.0 deg) e Etperiment
o
1Os
Fig. 14 Comparison
Rn
with Savitsky' short form (dead rise 9 deg)
en Susumu HIRANO
mo-
×
-o
15
10
5
o
1
'
t
"
-
F-u1 1' '
o+'- + e..'e . te. .. :t cre!"HSs
ite' '
-t ' 'il:k
load
o ) cr e e o
1:N+ Savitsky'
(dead rise
e Experinent
cond
Z-.
%s v..
short
3e.o
ferm
deg)
. with
..
.
a'ppeRdage
. ++
++. re
+++%
"' X'"e
t`tKeK,
-S"N
Os
Fig. 15
106
Comparison with Savitsky'
R
short
n
form
1o7
(dead rise 30 deg)
mum. The presentcomes steady.
ship form get the planing state at Fn>O.65, when the trim be-
2)The
the
The smaller the model size, the greater both the residual resistance and
greater residual resistance seems to be caused by greater viscous effects,
reason for the greater trim for the smal1 model is still unclear.
the trim.
although
3) Comparisons with
length O.75m without
high-speed planing ship
speed range.
other existing data, it is
turbulence stimulator can
forms, if we are careful
found that even
be used for the
of the Iaminar
the small
reslstance
effects in
model
tests
the
of
ef
low
4)floor
For applying the Savitsky's short
value near the spray root line.
form program, it is better to use the rise-of-
The author is quite grateful
Prefecture for their assistanee
Univ. of Osaka Prefecture for
to
of
his
Mr. Inoue and other students of
towing tank experirnents, and
contmuous encouragements and
University
to Prof.
advices.
of Osaka
Himeno of
Resistance Test of Geosirn Models of Serni-Planing T){pe Passenger Ship 8s
'
Nomenclature
Lpp :length between perpendiculars
U :towing speedg :acceleration of gravity
So ･ wetted surface area in still water
Fn :Froude number=U/,I(gLpp)Rn :Reynolds number=ULpplvRt ･total resistance t-Rr ･residual resistance
Ct : total resistance coefficient=Rtl(O.5pSoU2)
Cr : residual resistance coefficient=Rrl(O.5pSaU2)
p :density of waterp : kinetic viscosity=n/p
n :coefficient of viscosity
References
1 ) S. Hirano, S. Yoshikawa, Y. Himeno: Pressure Measurement on the bottorn of a Wedge
Form Planing Plate, J. of the Kansai Society of Naval Arch., Japan, No. 208, p. 45
(1988)
2 ) S. Hirano, S. Uchida, Y. Himeno: Pressure Measurement on the bottom of Prismatic
Planing Hulls, J. of the Kansai Society of Naval Arch., Japan, No.213, p. 7 (1990)
3 ) S. Hirano, S. Inatsu, Y. Himeno: Observation of the Spray of Prismatic Planing-Hull
Models, J. of the Kansai Society of Naval Arch., Japan, No, 214, p. 65 (1990)
4 ) S. Hirano, Y. Himeno, T. Nakagawa, K. Kitagawa: Separation of Resistance Compo-
nents of Prismatic Planing Hull Forms, J. of the Kansai Society of Naval Arch.,
Japan No.215, p. 45 (1991)
5) S. Hirano, Y. Himeno, T.Nakagawa, K. Kitagawa: An Observation of wave-Pattern of
a Wedge-Form Planing Plate, J. of the Kansai Society of Na'val Arch., Japan, No. 218,
p.93 (1992)
6 ) Y. Himeno, S. Hirano, K. Kitagawa: Wave Characteristics of Water-Surface Planing
Hull Form, Submitted to J..of the Kansai Society of Naval Arch., Japan, No.219
(1993)
7) D. Savitsky: Hydrodynamic Design of PIaning Hulls, Marine Tech., Vol.1, No. 1, p. 71
(1964)
8) H. Tanaka, M. Nakato, K. Nakatake, T. Ueda, S. Araki: Cooperative Resistance Tests
with Geosirn Semi-Displacement Craft, The Society of Naval Arch. of Japan, Vol. 169,
p.55 (1991)
86 Susumu HIRANO
Summary
This paper concerns with an existing hull form, in which resistance tests are carried
out using geosim models of an semi-planing type passenger ship. Two geosim models
are used with lengths between perpendiculars, O.75m and O.40m.
The test results are analysed to obtain the relationship among the model speed, atti-
tude and resistance.
These are compared and discussed with Savitsky's short form program, also with
the existing results obtained in other facilities for large geosim models.
It is found through these discussions that the results using comparatively small mo-
dels without turbulence stimulator are reliable.
