Resistance and trim of heavy displacement standard series ships

(1)

ARCHIEF

A

If

4 0'!NG

ja.

Experimento I Towing Tank

Stevens institute of Technology

Hoboken, New Jersey

I.b. y. Schpbvk&e

Techrche

scd

LAtt

RESISTANCE AND TR]1

OF

HEAVY DPCT STANDARD SERIT

SHIPS

(Stevens Models Nos. S78S83)

for

BUREAU OF SHIPS, NAVY DART(ENT

by

Allan B. Murray

and

Jean A. Barkile

Report No. 279

January, 19LLS

(2)

RESISTANCE AID TRIM

OF

IAVY DISFLCENT STMDARD

_{SERIES SHI}

(Stevens Models NOSG 578-583)

for

BUREAU OF SHIPS, NAVY _DEPARTMENT

Report N0 279

by

Allan B. Murray

and

Jean A. Barklje

January, 1945

Experimental Tcwing Tank

Stevens Institute of Technology

Hoboloen, New Jersey

(3)

C OEflTS

Introduotion .

.

a

i

Models

_.

₂

Particulars

,

Testing . . . . 2

.

3 Results 3 1se of Results 3

Discussion

₄ References . . . 5 Offsets . . I I

.

₆ Curves of Areas . 7

Model Test Data

.

o 9

Curves of Trim . . 15

(4)

This report presents the results of resistance tests of six Standard Series models having higher dIsplacement-length ratios in combination with higher speed-length ratios, than are reported in "The Speed and Power of

Ships", Reference 1. The investigation was suggested by the Office of

Chief of Transportation, Army Service Forces, who found themselves under the

necessity of imking prelirninary estirrtes of effective horsepower for hulls

having displacement-length ratios up to 400, and speed-length ratlos up to

1.5.

The contour charts of residual resistance for the Standard Series, In Refernce 1, reach a _{ximum displacement-length ratio of 250, with a}

speed-length ratio of 1.25. Higher speed-length ratios are reached, but in com-bination with progressively lower displacement-length ratlos. Additional

tests were therefore needed.

It was considered impracticable, under present

conditions,

to test a suf-ficient number of models to permit a complete extension of the contour charts of Reference i to cover a maximum displacement-length ratio of 400, and a

maz-imic speed-length ratio of 1.5. It was decided, therefore, to use the form

of plotting

represented by Figure 30 of Reference 2, and te

limit

the program

to include only enough models to permit ecending these charts within the pc.r-tioular region of interest to the OCT. It was decided, specifically, that the

Only one value of beam-draft ratio was Included, since changes of beam-draft ratio prcduce, in general, only moderate effects on residual resistance, _Of

the two values of' beam-draft used in the origina.1 Standard Series work (2.25

and 3.75), 2.25 is probably nearer to the requirements of the practical designs

contemplated.

The lines for t}e models were developed from the parent lines in Reference 1, Resistances and running trims were measured over the range of speed-length tio from 0.6 to 1.5.

The investigation was started under the sponsorship of the National Defense

Research Comriittee, arid has been completed under the sponsorship of the Bureau of Ships, Navy Department.

R 279

-1-INTRODUCT ION

following

8ix

models would be sufficienti

Beam-Draft Ratio

Displacement-Length

Ratio Prismatic Coefficient

2.25

300

0.50

O CO

2.25

300 o 70

2.25

400 _0.50

2.25

400

o 60 2,25 400 O 70

(5)

IIODELS

The model linès were laid out in accordance with the latest

interpreta-tion of the parent lines for Taylor' s 5tandard Series of Ships. The orf sets

given on page 163 of Reference i were used, but

_{were djutd in order to}

bring the maximum section at the nd-length in accordance with the statement

on page

ici.

Adjustments to the offsets in order to _{vary the prismatic} coef-f icient were made by the method described on page

₅₅

of the reference.

Offsets for the case with prismatic coefficient of 0.60 _{are given in the}

tabulation on

page 6.

Curves of areas f cr the six models _{are given on pages 7} and 6.

PM?TICLP RS

* Wetted Prea calculated without oblic?uity correction.

R 279

-2-Model 1To. ₅₇₆ ₅₇₉ ₅₈₀ ₅₈₁ ₅₈₂

583

Beam Draft Ratio _2.25

Dispi. Length Ratio 300 1400 310 1400 ₃₀₀ ₁₄₀₀

Prismatic Coefficient _0.50 _0.50 _0.60

_o.6o

0.70 0.70 ;:idsection Coefficient

_0.923

Length, In. ₁₄₈ ₁₄₁₄ ₁₄₆ 148 1414 Beam, In. 10.660 _11.1495 _9.9114 1O.1914

9.179 9715

Draft, In. _14.127 _5.109 _14.1406 L.6614 140080 Weight, f.w.,Lbs. _141.80 _14.92 _141.60 142.92 141.80 Wetted !rea, Sq. ft.* _14.16 _14.07 _14.17 14.03 14.17 14.02

(6)

The introduction states that this investigation is to provide "a _method for estin.ting probable requirements of effective horsepower." _{The charts,} pages 17 to 19, giving total resistance per ton versus speed-length ratio _for 400-foot ships, provide the means for ships having displacement-length _ratios

of 300 and 400 and prismatic coefficients of 0.50, 0.60, and 0.70. _These results may be readily converted to effective horsepower _{versus speed.}

A the ship length decreases, the friction resistance coefficient _increases, with the consequent increase in the total resistance _{er ton.} _{If a close}

esti-mate of a shorter ship is required, the increase in resistance _{per ton over the} 400-foot ship can be readily determined from the Froude _constants. _The

follow-ing

are typical figures for displacement-length ratio of 300, prismatic

coef-ficient of 0Q60 and length of 100 feet:

R 279

TESTING

The method usually employed at the Experimental Towing Tank for testing

this type of model was used. This involved towing, from the carriage, a 1/8"

strut 4 inches ahead of the model to induce turbulence. As the strut was not

cor.nected to the model no adjustment for the resistance of the strut was

nec-essa ry.

RESULTS

Tabulations giving measured model resistances and running trims are given

on pages 9 to 14. The curves on page 15 show the change in level at the bow

and stern for the six models. Photographs were taken of each model under way

at

V/vT -

1.0, 12 and 1.5. One of these is given on page 16 The whole set

is available at the Experimental Tow!ng Tank, Stevens Institute of Technology. In order to be directly comparable with Figure 30 on page 94 of Reference 2, the resistances were expanded to a ship length of 400 feet and are presented as

resistance per ton versus speed-length ratio. _{The curves, pages l7to 19, shaw}

these results, one page for each prismatic coefficient. On the3c charts, broken

line curves for three additional displacement-length ratios, 50, 150, and 250, lifted from the above mentioned figure in Reference 2, have been included.

In expanding the test data of the small Stevens models, to full size, care

was exercised to ensure that the results from the tests would be comparable to the curves in Reference 2 obtained from tests of 20 foot models. The Schoenherr

friction formula was used to determine the model friction resistance, This

for-mula conform8 closely with the 20-foot friction plank resistances used with the

20-foot model data (Reference 3).

For full size friction resistance, the same method used for the curves in

Reference 2 was emp1oyd, that is, R. E. Froude's constants for salt water with

the formula Rf - f S V'25.

(7)

Additional

The increase decreases rapidly for lengths over 100 feet.

Interpolation is necessary for intermediate values of displacement-length

ratio and prismatic coefficient.

DISCUSSION

In working up the lines for the models, some minor discrepancies were found in the numerical values given in the Table of Offsets on page 184 of

Reference 1. The necessary information to remove those discrepancies was obtained from the files of the Taylor Model Basin. The table of offsets on

page 6 gives the values actually used for the two models having prismatic

coefficient of 0.60.

All of the resistance charts show little difference between the reais-.

tnces per ton for the two displacement-length ratios. Interpolations for

displacements other than tho8e considered should therefore be quite reliable. The curves show that changes in prismatic coefficient have an important

effect on resistance. Further, the effect is not consistent; it varies in magnitude and direction with speed. Therefore, some judgment is necessary to obtain values for prismatic coefficIents other than those given.

R 279

-4-S pee d- Length

Rat io

Resistance per ton

over 400 Ft. Ship Percent Increase .6

32

10% .8 1.0 .80 8% 1.2 1.10 _5% 1.4 1.50 2%

(8)

.

REFERENCES

Taylor, D. W.: "The Speed and Power of Ships,"

Washington, 1943.

Davidson, K. S. M.:

"Resistance

and

Powering,"

Chapter II of Volume II, Principles of Naval Architecture," New York, 1939.

3,

"Covering Comparisons with

Taylor's Standard

Series," Technical Memorandum No. 33 of the Experimental Towing Tank, Stevens Institute of

Technology. October, 1941,

R 279

(9)

-o-'1'SETS POR STANDARD SERIES WJDEL ?0R PPISMkTIC

- Water Lines (In Fractions of 1/2 Ìaximum Jeamat

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.062.

.063

.103

.110

.116

.121

.126

.127

430 20b

.226

.2DO

.257

.270

.283

.293

.3:4

.3&

.393

.415

.437

.452

.469

.483

.f29

.560

586 .605

.21

G.5 .642

.688

.717

.7.7

.755

.766

.772

.771

.810

aL)4

.849

.359

.865

.869

.864

.895

.911

.921

.927

.930

90 .926

.946

.958

.963

.969

.970

.955

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.960

.976

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.991

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.976

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Spaon

of water lines and heights of buttooks

a1re in fractions of i .draft.

Spíicing of buttooks are in fraotion

of 1/2

xnun beaa at L..L.

Water lino ordinates are iii fractions of 1/2

ma*imum bezn at I.pVI.

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(12)

ODEL TEST DATA

Model No. 578

Length - 4.00 Feet

Displacernent-Leng-th Ratio - 300

Displacement

41.80 Lbs, Fresh Water

Prisiiatic Coefficient

0.50 Test Temperature

730 F. Tank i

Test i, June 30, 1)4

R 279

-9-ooi ioci, iubcd Varnish Fini3h

Model Speed

Model Resistance

Feet/Sec.

Pounds

Trim Change in Inches

Bow

Stern

1.601 .0543

-.10

0

1.356 .0772

-.10

0

2.129 .1030

_-.15

-.02

2.394 .1295

-.20

-.05

2.658 .1682

.1687 -.25 -.05

.1905

2.792 .1934

-.30

-.05

.2085

2.924 .2052

-.35

-.05

3.050 .2243

-.40

-.07

.2338

.188

.2352

-045

-.07 .2578 .D,321

.2588

-.50

-40

-.

.2943

.2948

-.55

-.10

3.586

.3625

-,60

-.15

3.719 .4416 -,55 -.20 3.850 .5708 -.70 -.25 3.984

.7825

-.75

-.30

4.250 _1.269

1,269

75

_-.50

4.14

1.988

1.951 -.65

-.85

4.781 5.050 2.914 4.006 4,003 , -.25 -1.25 -1.35 'urbulence Induced

(13)

MODEL TEST DATA

Model No. 579

Length 3,667 Feet Displ.-Length Ratio - 400

Displacement 42.92 Lbs. Fresh Water Prismatic Coefficient - 0,50

p 279

10

-Test Temperature - 71° F0 Tank i Test t, Aug. 16, 19LL

Zood Nodel, Rubbed Varnish Finish

Model Speed Model Resistance Trim Change in Inches

Feet/Sec. Pounds Bow Stern

1.601 .0610 -.05 +.05 1,866 .0821 -.10 0 2.129 .1079 -.15 0 2,394 .1399 -.20 0 2,526 .1585 -.25 0 2.658 .1810 -.30 -.05 2,792 .2110 -p35 -.05 2.924 .2310 -.40 -.05 3,056 .2524 .,45 -.05 3.138 .2925 -.55 -.10 3,321 _Q3444.3''14 -.55 -010 3.453 .3990 .3943 -.70 -.10 3.586

5253

,75 -.15 3.719 .671C -.80 -.15 3.984 1.2225 1,2243 -.85 -.30 4.250 1.9834 1.9825 -.95 -.50 4.514 3.118 3.115 -.85 -1.00 4.781 4,310 4,280 -.55 -1.45 Turbulcnce induced

(14)

Turbulence Induced

MODEL TEST DATA

Model No. 530

Length 4.00 Feet _{Displacement-Length} _Ratio ₃₀₀

R 279

Displacement - 41.80 Lbs. Fresh Water Prismatic Coeffiolent 0.60 Test Temperature 730 F. Tank 1 Test i\, Jug.

l(, i5Lh

wood ioie1, Rubbed Varnish Finish

Model Speed Model Resistance _{Trim Change in Inches}

Feet/Sec. Pounds _Bow _Stern

.0532 1,601 _.0543 _-.05 ₀

0546

.0773 1.366 .0776 -.10 0 2.129

₁₀₃₂

_-.10 ₀ .1293 2.394 .1282 -.1.5 -.05 .1582 2.658 .1598 -,20 -.05 .1701 2.792 .1704 .25 -.05 2.924 _.1935 _-,25 _-.05 .2 153 3,056 .2153 -.30 -.05 3.188 .2389 _-.30 _-.10 .2789 3.321 .2789 -.35 -.10 .3098 .3144 -.35 -.10

3998

3.719 .4016 -.45 -.15 3.984 _.5471 _-.60 -.15 4.250

8380

_-.60 _.25 4,514 1,2825 1.2871 -.50 -.55 4.781 1.9771 -.35 5.050 2.9571 _+.05 _-1.50

(15)

Lenth

3.667 Feet

Dis placement 42.92 Lbs.

Test Temperature - 720 F.

MODEL TEST DATA Model No, 581 Disp1acement-Lenth Ratio = 400 Prismatic Coefficient - 3,60 -

r1

Test P, Uct. , Fre8h Vater Tan} J.

Fin3h

R 27 12

-iood :ode1, iubbed Verni sh

Model Speed Model Resistance

Feet/Sec0 Poirnds

Trim Changes in Inches

Bow Stern 1.601 i 866 i 997 .0554 .0738 .0882

-.05

-010

-.10

0 3 0

2.129

.1026

_-.12

₀

2.261

₀₁₁₉₃ _a13 _O

2.394

.13 73

_-.17

_-,02

2,526

.1510

_-.20

_-03

2 658

.1693 -.25 ,05

2.924

.2162 _-035

_-.05

3.188

.2629 .2689 45 e10

3.453 3444

_-055 .3435 -.10 3.719 .4480 .4471 -p70 .10 3.984

7335

_{_.}

'7f-.31C

.) 10274 4.250 1.277 _-.30 _-050 1.250 4.514 2.067 2.084

-.65

-.80

4781

3.140 3 158

-.45

-1,20

Turb.ilence Induced

(16)

MODEL TEST DATA

Model NO. 582

Length

4.00 Feet

Displacement-Length Ratio

300 Dieplaoer-zent

41.80 Lbs. Fresh Water

Prinatic Coefficient

0.70 R 279

13 -Test Temperature

73° F.

Tixk i

Test

Wood 1odel, Rubbed Varnish Finish

Model Speed

11ode1 Resistance

Feet/Sec.

Pod

, Oct.

,

1L14

Trim Changes in Inche8

Bow Stern 1.601 .0549 0 0 1.866 .0754 -.05 0 1.997 _.0868 _-.05 ₀ 2,129 .1030 -.08 0 2.394 .1319 -.12 -.05 2.656 .1603 .1704 -.20 -.05

2,o9t

.2235

.2253

-.25

-.10

3.056 .2835

.2816 -.25 .10 3.168 3653

3626

-.30 -.10 3.321 .4653 _-.30 _-Q15 3.453 .5780 -.35 _-.20

35

.6999 .6989 -.40 -

-,20

371q

.7681

.7707 -.45 -.20 3.850 3207 .8226 ,50 -,20

3084

.8571 .8580 -.53 .9226 4,.t6 .9207 ,55 -.25 4,250 1,0053 9989 -.60 -.30 4.514 1317]. -.55 -.50 4.7e]. 1.7935 1,7944 -.45 -.90 - 2.5753 5.Oc0 2.5762 -.10 -1,35 Turbulence Induced

(17)

MODEL TEST DATA

Model No 583

Length 3.667 Feet

Displacement-Length Ratio

400

Displacement 42.92 Lbs. Fresh Water

Prisn.tjc Coefficient - 0.70

R 279

- 14.

Test Temperature a 700 F.

Wood 4ode1, Rubbed Varnish

Model Speed

Ft ./Seo o

Tank i Test A, OCt.

_{17, i9La4}

Finish

Model Resistance Trim Changes in Inches

Pounds Bow Stern

1,601 .0571 .0560 -.10 0 1.733 0668 -.05 0 1.366 .0821 -.10 0 1,997 .0926 -.10 +.05 2.129

1068

o 2.3 94 .1379 -.20 -.05 2,E58 .1760 -.25 -.10 2.792 .2151 -.30 -.05 2,924

2798

27 99 -,30 -.10 3.188 .4798 .4844 -.40 -,10 3.321

5953

.5944 -.40 -.10 3.453 .6662 .6726 -.50 -.15 3 586 .7562 .7544 -.50

-3.719

.8116 .8098 -.55 -.15 3,950 .8626 .8607 -.55 -p10

3984

.9199 .9153

-.70

-.10

4.116

1.0244 -.75 -.10 4.250 1. 1571 1. 1616 -.80 -.20 4.514 1.6699 1.6644 -,70 -.45

478l

2 .3807 2 .3 871 -.50 -.90 Turbulnce Induced

(18)

EXPERIMENTAL TOWiNG TANK

STIT UTE OF TECOLÇ'( -4OCPEN FEW JEFSEY

P 27

(19)

-PHOTOGRAPH OF MODEL NO. 580

DISPLACEMENT-LENGTH RATIO

300 PRISMATIC COEFFICIENT

=

0.60 SPEED-LENGTH RATIO

1.00 R 279

(20)

-16-RESu

LNGT

FR110

FOR

F

EXPERIMENTAL TOWING TANK

STEVENS NSTITUTE OF TECNOLOGY

HOBOKEN, NEW JERSEY

09

LO R L2 i 1.4

90

30

R 25

(21)

-17-EXPERIMENTAL TOWING TANK

STEVENS INSTITUTE OF TECHNOLOGY

(22)

-250

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EXPERIMENTAL TOWING TANK

STEVENS INSTITUTE OF TECHNOLOGY

HOBOKEN. NEW JERSEY

TQTAL RES1STJCE P.TPN

FOR I J

TA LOR'S STANDARD SRIjE$ FOR..

9F 4O

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PRIATIC CO F1ENTO.O

-LN3Ti R1OV

R 279