Manoeuvring experiments with Delft model No. 41

ARC 1

lab.

c

ScheepsbouwkwlJe

Technische Hogeschoo

NATIONAL PHYSICAL

LABORATORY

SHIP DIVISION

MANOEUVRING EXPERIMENTS WITH

DELFT MODEL NO.41

by

G.J. Goodrichand W.H. Sims

A Station of the

Ministry of Technology

SHIP T.M.138

June 1966

Manoeuvrin Experiments with

De1ft Model No.L1

by

G.J. oodridh and. W.H. Sims

I Introduction

The purpose of these experiments was to determine the turning circle,

rate of turn and. speed in the turn of this model for a range of rudder angles. The glass fibre model had been extensively tested a the ShipbuildingLaboratory of the Technical University of DelftW, using

forced oscillation techniques. The model, together with its propelJer was transported from Delft to Ship Division and for these experiments the loading of the model was the same as for the De]±t experiments.

2. eriment techniq

The details of the model are given in Table I. Radi control

equipment was fitted in the model giving control of the rudder and

propeller. Jri ultrasonic transmitter was also fitted and the transmitter

crystal projected through the bottom of the model at the longitudinal

centre of gravity. Signals from the transmitter were picked up by

receivers at the four corners of the tank and. from these results the track of the centre of gravity of model was determined.. The transmissions occurred. at fixed. intervals of time and hence the rate of turn of the model and the speed in the turn could. be deduced from these results.

The speed. of the model was varied. for each speed through a nunber of stepped resistances fitted. in the armature circuit of the propulsion motor. Each setting remained constant during the experiments covering a

range of helm angles for each speed; no control was fitted. to giv

constant propeller r.p.m

The experiments were carried out at three forward. speeds of I .85, and 3.20 ft per sec. These speeds are for zero helm. Turns were

made to port and starboard with angles of helm of

5.8°, ii.6°, 17.)-i-°,

Particulars of Model

- The model used was one of the Todd Series Sixty with a block

5. Reference (i ) 2 -Table I Details, of Model No. of Blades H/D :. .. .

i:.io

Service Speed

0.928

Revolutions (Service Speed) 10.LiAi.P.S.

Li., perimeht results

/

The results are given in Figs.1-L. Fig.1 shows the rate Of turn in degrees per secpnd for the range of rudder angles for the three spèds

tested. The results have been inte'polated for the speed F = 0.2 and the burve is. shown. This spe,ed. was used for the Deift experiments.

Fig.2 gives the, results of the tnrning circle measurements. They are plotted as model length/turing cirOle diameter L/'D for a range of

rudder angles.

Pig.,3 shows the speed in the, turn V1 against rUdder angle for the three speeds tested.

Fig. is a replot .of Fig.1 with the results non-dimensionalised,

using the

second., L is model length and V1 the speed in the turn.'

Ceneral remarks

This report gives results which will be comparable with computer calculations vhich can be carried out using the results obtained from

the Deift experiments.

Leeuwen, C. van The lateral damping and. added mass of an

oscillatory ship model. Deift Technical University Publication

Noo23, 196k.

Length Between Perpendiculaxs 2.258 m

Length on Waterline

_2.296

Breadth

_0.323

Draught

_0.129

Volume of Displacement

_{0.0657 rn3}

L.C.B. fOrd Lpp/2 0.011.rn

Lateral plazie area (L.T.)

_0.291

Rudder .A±ea' .. 0. OOiLi-3 m2

Radius of Gation

_0.25

DELFT MODEL N° 41

'7

0

A

24Sf.i.

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NTEAPOLATED RESULT FOR FM - 02

a

3

RATE

HEUII ANGLE DEGREES

FIG. j.

O4 %

PE.!T.MQDEL

4

_PLOTTING

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£ 245 Lp. V. SPEED WrTH ZERO HE.M

+ 3'aOtp.J

Do STEADY TURNING CMCI-E DIA

A 1 D S

40

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SPEED ON TURN (v1)

DELFT

MODEL

N°

8S!.p.si

245 f.p.s4V SPEED WITH ZERO HELM

0

3.20f.P4j.

-

WI/v

PLOTTING

FIG. 4.

PROJECT N° 24/3

0

40