The steering of a ship during the stopping manoeuvre

REPORT No. 114 S

September 1969

(S 2/101)

NEDERLANDS SCHEEPSSTUDIECENTRUM TNO

NETHERLANDS SHIP RESEARCH CENTRE TNO

SHIPBUILDING DEPARTMENT

LEEGHWATERSTRAAT 5, DELFT

*

THE STEERING OF A SHIP DURING THE

STOPPING MANOEUVRE

(HET STUREN VAN EEN SCHIP GEDURENDE HET STOPPEN)

by

IR. J. P. HOOFT

Head of the Wave and Current Basin of the Netherlands Ship Model Basin

Het afnemen van de bestuurbaarheid van schepen gedurende bet stOppen is in het algemeen gesproken een bdkend feit.

Heden ten dage worden de voorñaamste factoren die de be-stuurbaarheid beinvloeden, ñameijk de dynamische

koersstabili-teit en de manoeuvreerbaarheid, moeilijke punten in verband

met de snel groeiende afmetingen van de schepen en wel vooral van die van bet tankertype.

Het dod van het onderoek is orn in kwalitatieve zin het belang van de verschillende parameters te bepalen voor bet ingewikkelde

vraagstuk der bestuurbaarheid tijdens de stopmanoeuvre.

Uit-gaande van de bewegingsvergelijkingen van Euler voor het hori-zontale vlák, herschrëven en gelineariseerd, kan een betrekking

worden geformuleerd op een zodanige wijze, dat hierin de

hydrodynamische c ëfficienten welke door modeiproeven worden bepaald, kunnen worden gesubstitueerd.

Door rniddel van de ,,planar motion" beweging kunnen de

hydrodynamische coëfficiënten zoals demping en toegevoegde massa voor respectieveijk dè zuivere verzet- en gierbewegingen worden bepaald voor diverse snetheden en schroeftoerentallen, door het meten van de in- en üit-fase componenten van de

op-tredende krachten. Bovendien zijn de laterale krachten en bet

draaimoment gemeten op basis van roerhoek in athankelijkheid

van het toerental. V

Het blijkt dat de bestuurbaarhëid kan worden gehandhaafd

zelfs voor het dynamisch onstabiele schip mits de roerwerking voldoende is. Deze làatste factor blijkt sterk af te hangen van bet schroeftoerental en in mindere mate van de snetheid.

Tenslotte wordt een diagram ontwikkeld, waaruit men kan

afleiden in hoeverre bestuurbaarheid onder gegeveñ omstandig-beden kan worden vervacht, -bijvoorbeeld athankelijk van een combinatie van snelheid en toerental.

RET NEDERLANDS SCHEEPSSTUDIECENTRtJM TNO

The diminishing of the controllability of ships during the stopping manoeuvre is a well-known fact in general. Nowadays the gov-erning factors that influence the controllability, i.e. the dynamic stability and the manoetwrability, become weak points because

the rapidly growing size of the ships, especially those of the

tanker type.

The purpose of this investigation is to determine in qualitative

sence the importance of the various variables in the complex

problem of the controllability during stopping. Startiñg from the Euler's equations of motion for the horizontal plane, rewritten

and linearized, a form can be derived in such a way that the hydrodynamic coefficients can be used, determined by model tests.

By means of the planar motion mechanism the hydrodynarnic coefficients (i.e. damping and added mass coefficients) for the pure sway and pure yaw motiOn can be determined for several speeds and RPM by measuring the in- and out-phase components

of the forces exercised. Moreover lateral force and turning

moment were measured on a base of rudder angle depending on RPM.

It appears that the controllability can be maintained even in the case that the ship is dynamically unstable to a certain amount,

provided that the rudder effectiveness is sufficient. The latter

factor appears to be strongly influenced by the number of revolu-tions of the propeller and to a smaller extent by the speed of the ship.

Finally a diagram has been developed from which can be derived to what extent controllability can be expected under

certain given circümstances, for example for a combination of speed and RPM.

THE NETHERLANDS SHIP RESEARCH CENTRE TNO

CONTENTS

page Summary 7

i

Introduction. 7 2 Method of approach 7 3 Test procedure 7

4 Equations of planar motion 8

5 Hydrodynamic coefficients 9

5.1 Pure sway 9

5.2 Pure yaw 10

6 Rudder effectiveness 10

7 Discussion of test results 10

7.1 General remarks 10 7.2 Dynamic stability . 10 7.3 Rudder effectiveness 11 8 Conclusions 12 References 12 Appendix 13

g

k

kL, m

r

t

u u0 V, W X, y, z Yo

Yi,i

Cy(6)

Fn

G

H

'xx, 'yy' 1zz

K1' and K2'

L

N

N0

N

N5)

N0 Nr

N

SL

T

U

Y Yo Yß Y(0) Yo Yr Yr Yv Yù ß Q ( ;ti O)

Acceleration due to gravity

Longitudinal radius of gyiation of ship mass

Longitudinal radius of gyration of ship mass in non-dimensional form

Mass of ship

Angular velocity of yaw

Time

Speed, or small change of speed of (centre of gravity of) ship

along the x-axis

Constant speed of ship along the xaxis

Speed of ship along the axes Y and Z respectively

Orthogonal coordinates of a right-handed system of body axes,

moving with the ship

Amplitude of j12

Distance of fore and aft fastening point

Constant of the derivative of N(0)

Constant of the derivative of Y(o)

Froude number

Centre of gravity

Draught

Mass moment of inertia about the axes x, y and z respectively

Non-dimensional manoeuvrabiity indibes

Length of ship (La,,)

Yawing moment about the z-axis

Amplitude of oscillating yawing moment

Stiffness derivative (N = - UNV)

Moment due to rudder deflection, on rudder and hull

Derivative of N(o)

Moment-angular velocity (rotary) derivative

Moment-angular acceleration derivative

Moment-velocity derivative

Moment-acceleration derivative

Lateral area of reference (here equal to LH)

Period of time

Velocity of origin of body axes relative to the fluid; speed of ship

Hydrodynamieforce on body along the yaxis

Amplitude of oscillating hydrodynamic force

Stiffness derivative (Yß - UYV)

Force due to rudder deflection, on rudder and hull

Derivative of Y(ò)

Force-angular velocity (rotary) derivative

Force-angular acceleration derivative

Force-velocity derivative

Force acceleration derivative

Angle of drift or side slip (/3

- v/U)

Rudder angle (deflection)

Relative distance of rudder (rudder axis) aft of G of ship

Density of the water

Phase shift of transfer function

Angle of yaw, or heading error

Angular frequency of ship yawing oscillations

LIST OF SYMBOLS

Non-dimensional form

as used

kL,

= k/L

m' = ifl/QLSL

r' =rL/U

t'

=tU/L

u/U

u0/ U

v/U, w/U

C1(5) = CN(Ó)/QU2SLL

C(6) = CY(Ö)/QU2SL

U/jgL

H/B, H/L

lt

_{- m nL}

t12 Y'

=

= YJ4QU2SL

Y _YßI3QU2SL

Y0) =

Y0' = Yo/+QU2SL

y;

= IÇ/4Q USL

YI.'

= 1Ç/QSL

Y,,'

= Y,,/QUSL

Y,,'

= Y/SL

k = Lo/2U, co' =

N'

= N/QU2SLL

N0' = No/QU2SLL

N'

N,/QU2SL

N0) = N(o)/4QU2SLL

N0'

= NO/QU2SLL

Nr'

= N,/-QUSLL2

N' = N,/QSLL3

N' = NV/+Q USLL

N' = No/4QSLL2

THE STEERING OF A SHIP DURING THE STOPPING MANOEUVRE

by

Ir. J. P. HOOFT

Summary

The paper presents the results of modelexperiments on a "Series-60" model with a blockcoefficient of 0.80 regarding the governing factors in respect of the controllability during the stopping manoeuvre. A quasi-stationary solution of the equations of motion in the

hoiizontal plane is given which restriction is allowed if it can be assumed that the effect of deceleration on the hydrodynamic

coefficients is slight e.g. in the case of large ships. In the conclusion appears that the aspect of manoeuvrability is the governing factor for the controllability during the stopping manoeuvre.

i

Introduction

The controllability of a ship is a function of two items:

dynamic stability and manoeuvrability.

A ship is said to be dynamically stable if, after a

slight disturbance, it returns to its initial motion

with-out the use of the rudder.

A ship that has good manoeuvrability, responds

quickly to a change of helm. The manoeuvrability is

dependent upon the rudder effectiveness.

The controllability of a ship is markedly impaired

while stopping; both the dynamic stability and the

manoeÚvrability is altered:

The velocity of flow over the ship decreases due to

the reduction of the ship speed.

The velocity of flow over the rudder decreases.

Moreover the flow around the ship and the rudder

will be disturbed due to the deceleration of the ship.

The factors mèntioned under a. and b. were

investi-gated through model tests at the Netherlands Ship

Model Basin. This report presents the method of

ap-proach and the results of these tests.

2 Method of approach

The following method has been used to solve the

problem:

I. Determine the hydrodynamic coefficients such as

added mass and damping for which:

Euler's equations of planar motion are

rewrit-ten in terms of forces, mòments and motions

of a ship.

The equations are linearized to accept model

data.

The hydrodynamic coefficients of planar

mo-tion are determined by substituting model test

data into the above equations.

-

II. Determine the dynamic stability expressed in the

)

p valúe by substituting the hydrodynamic

coef-ficients into the linearized equations.

III. Determine the manoeuvrability by substituting the

hydrodynamic coefficients and the rudder

coef-ficients into the linearized equations. The rudder

effectiveness was determined by measuring the

force and moment acting on the model as a

func-tion of the rudder angle, model velocity and

propeller RPM.

3

Test procedure

A "Series 60" model having a block coefficient of 0.80

was selected. It was built of wood. The principal

dimen-sions of the model and the propeller characteristics are

given in table I. Figure 1 shows a body plan of the

model.

Table 1. Principal ditheñsioñs of ship model and propeller

7

Ship model:

Length between perpendiculars LPD 3.048 m

Length on waterline L,0 3.104 m

Breadth B 0.435 m

Draught T 0.174 m

Displacement volume V 0.1849 m3

Dimensionless mass of the model 0.229

Location of centre of buoyancy forward of zLDD 0.Ò76 m Radius of gyration (non-dimensional) 0.240

Radius of gyration as a percentage of

the model length 24%

Rudder area 0.077 m2

Rudder area in % of lateral area 1.45 Propeller model:

Diameter D 121.94 mm

Pitch at 0.7R P0.7 117.67 mm

Pitch ratio PQ.,/D 0.965

Boss diameter d 20.36 mm

Blade area ratio A0/A 0.55

Number of blades z 4

Shallow water basin:

Depth 1 m

Width 15,75 m

8

Propeller: torque, thrust, RPM

Rudder

deflection

Model:

resistance, heading, side forces

Carriage:

velocity

All tests were run in smooth water.

ELECTRIC MOTOR

Fig. 2. Testset-up p1aiar motion mechanism

4

Equations of planar motion

Euler's equations of motion in a hon ontal plane can

be adapted to include hydrodynamic forces acting upon

a moving ship.

A brief derivation follows (see also [1]). The reference

Fig. 1. Lines of the ship model

The tests were conducted in the Shallow Water

axes are moving with the ship; see figure 3 and the list

Laboratory, the dimensions of which are also given in

of symbols for notations used.

table I. The model was rigidly connected to a planar

motion mechanism fixed to the carriage as shown in

figure 2 The carriage and the model were accelerated

to a predetermined speed and the model was forced to

move in either pure yaw or pure sway. The propeller

was set at a patticùlar RPM. In general the following

data were noted:

(CENTRE OF GRAVITY)G

5

10-14

X0(FIXED DATUM DIRECTION)

dt

'V

Euler's equations are

m(ù-rv) = X

m(a+ru) = Y

(1)

4t=N

X, Y and N can be written in terms of the motions and

accelerations u, y, r, ú, L', t and rudder deflection (5.

Y= Y(u,ù...,v,L'...,r,t

,5,...)

(2)

N=N(u,û...,v,L'...,r,t

,(5,...)

Equations (2) can be linearized siñce only small changes

of the motions are studied

PERIOD (T)

It should be noted here that now only a quasi-stationary

solution can be obtained. The coefficients to be

deter-mined for equations (3) will only be valid for a short

period during the actual stopping procedure.

For this reason the effect of deceleration on the

hydrodynamic coefficients could not be observed.

Equations (3) can be simplified by deleting the higher

order terms. When the remaining terms are substituted

back into Euler's equations (1) one obtains the sim

plified planar motion equations for a ship

(m-X)ù-mr-Xv-X,r = Xö+S-W

(m-Y)L'-Yv-(Y-mu)r

Yô

(hzz)tNr1u = Nö

Fig. 4. Pure swaying

Equations (4) are now in such a form that the coefficients

can be found by means of the model test data. Since

the planar motion mechanism yields sinusoidal

mo-tions, the ship's motion and forces denoted by S(s) and

F(s) respectively, cafr-t'xpressed as

S(s) = S0 sin oit

F(f) = F0sin(wt+a)

= (F0cos or) sin oit + (F0 sin n)cos oit

From (5) the components of the force which are in and

out of phase with the model motion are

F0cos or

in phase

F0 sin or

out of phase

The amplitude and period of the model motion are

known. The amplitude of the above force components

are found by FOurier analysis:

2k

F0cos or = '- $ Fsin oitdcot

ir0

2k

F0sm or =

_-

_ir0

J FCOS wtdwt

5

Hydrodynamic coefficients

5.1 Pure sway

Pure sway was obtained by oscillating the model

ath-wardships such that her centreline temained parallel

to the average course; see figure 4. For these tests the

rudder was set fore and aft.. The total force Y acting

on the model equalled the sum of the forces measured

in each arm of the planar motion mechanism. The

hydrodynamic moment acting on the hull was obtained

by considering the distance between these arms.

RATH OF THE MODEL C y0 SIN .t ) SPEED AHEAD 9

ax

ax.

ox

ax.

X=u+u+...v+v+...etc.

Ou Où oz aL'

Y=

N = IS/u + N

+

(3) TRANSVERSE AMPLITUDE (Y0)

lo

After the components of he motion in phase and out

of phase have been determined, equations (4) can be

rewritten (see [2]).

Y0cos1 = yoo.)2(mYo)

Y0sin1

Y.yow

N0sinc2

Ny0a

In eqúations (7) cx

and a2 are the phase differences

between the swaying motion and the applied force and

moment respectively.

The amplitude of the motion is simply y0. The

hydrodynamic coefficients are determined by solving

equations (7) and given in á hon-dimensional form in

diagram no. i (see appendix).

5.2 Pure yaw

Pure yaw was obtained by oscillating the model

ath-wardships such that her centreline was always tangçnt

to the path of the centre of gravity; see figure 5. The

rudder was held fore and aft.

Afterthe in phase and oUt of phase components are

detennined, equations (4) were rewritten (see [2])

Y0sinx1 = (rnUYr)i/ow

N0cös 2 =

(8)

N0 sin a2

- 0WNr

In equation (8)

and a2 are. the respective force and

moment phase differences relative to the yawing

mo-tion.

is the amplitude of the yaw angle in radians.

The solution of equations (8) yields the

hydro-dynamic coefficients fot pure yaw. These results are

plotted m a non-dimensional form in diagram no 2

(see appendix).

PERIOD (T)

TRANSVERSE AMPLITUDE yo,

Fig. 5. Pure yawing

6 Rudder effectiveness

The model wàs rigidly fi)ed to the carriage with its

centreliné parallel to the direction of motion. The

rud-der was set to a particular angle of deflection. The

carriage and model were accelerated to a predetermined

velocity which was then held constant for the duration

of the run. The side force and moment acting on the

model were measured and aSe plotted

non-dimensional-ly in diagram no. 3 and 4 respectivenon-dimensional-ly (see appendix).

7

Discussion of test results

7.1

General remarks

In this research programme the influence of the

de-celeration was not considered. Both the dynamic

stability and the rudder effectiveness were determined

for a range of constant speeds of the model.

This quasi-stationary method cañ be used for large

tankers only because then the deceleration will be

smaÏl. At each moment of the stopping procedure the

dynamic stability and the rudder effectiveness will be

only a function Of the ship speed and the number of

revolutions of the propel1er.

72 Dynamic siability

The ship's motion caused by some disturbance can be

written as a function of time by

drift velocity y

y0 e'

rate of turning r = r0 e"

}

(9)

in which y0 and r0 are the ship velocities due to the

disturbance.

Substitution of equations (9) into equations (4) gives

two solutions fot p. One solution, Po' is always a large

negative value. The

other

solution, p, determines the

dynamic stability. If Pi > O then the ship motions

PATH OF THE MODEL

-increaseand the ship is said to be dynamically unstable.

The dynamic stability indices Pi are given in a

non-dimensional form in diagram no. 5 (see appendix). This

non-dimensional stability index Pi' has the following

meaning:

a.

Dynamically stable (Pi' < O):

When the ship has travelled a distance equal to her own

length the initial disturbance is decreased by an amount

(le'"') x 100%. So when Ip'I is large then the

distur-bance soon has damped out:

n:

DISTANCE TRAVELLED

SHIP LENGTH

b. Dynamically unstable (p ' > 0):

When the ship has travelled a distance equal to her

own length the initial disturbance is increased to

e" x 100%

n :

DISTANCETRAVELLED

SHIP LENGTH

2

2

It can be seen from diagram no. 5 that the ship will be

dynamically unstable during most of the stopping

procedure. However, the instability is so small that the

ship can be controlled if the rudder effectiveness is

sufficient.

In other words diagram no. 5 points out that the

rudder effectiveness is the critical factor in course

keeping for ships of this form.

7.3 Rudder effectiveness

Looking at the ship and rudders as a "unit" (i.e. wing),

the rudder may contrOl the moment and side force,

acting on the "unit" causing yaw and sway; see diagram

no. 3 and 4. Two important items are deduced from

diagram no. 3 and 4.

First the rates of rudder effectiveness are

deter-mined i.e. LY(Ò)/&5 and AN(6)/M.

From this one can see how the side force and turning

moment acting on the "unit" vary as a function of

rudder angle. Neither the non-dimensional moment

nor the non-dimensional side force caused by the

nid-der on the "unit" is strongly influenced by the ship's

velocity.

Consequently the ship will make the same manoeuvre

independent of her speed. The number of revolutions

of the propeller, however, has a very pronounced

influence. The rudder effectiveness steadily decreases

as the RPM decrease.

Secondly the rudder position was determined at

which there is no resultant turning, moment on the

"unit". This position is referred to as tudder "zero m".

There is alsç such a position for the side force, as can

be seen from diagram no. 3. At almost all ship speeds

with propellers turning ahead rudder "zero m" occurs

at about 2° to port. This is probably due to the

propeller rotation. At 20 to port, the ship will not yaw,

but only sway, since rudder "zero rn" and rudder

"zero f" do not coincide. This sway, however, will

cause additional turning moments, and therefore the

ship must be continuousÏy steered.

From the diagrams no. 3 and 4 it can be deduced that

at a decreasing RPM the ship will firt lose control due

to excessive yaw.

Consequently diagram no. 6 was constructed by

cross plotting data from diagram no. 4, to study the

turning moment more thoroughly.

It is assumed that therudder can be rotated 35° either

side of the centreline position. If thé "zero in" setting

is greater than 35°, the ship is considered to be out of

control. The RPM at which this happens can be read

from diagram no. 6:

RPM IL

n=

I-60 \jg

1.80 3.05

astern

3.70

An example will further clarify the use of diagram

no. 6. It might be required that the rudder "zero

m"

setting has to be smaller than 350 for instance when

also effects of wind and or bank suction have to be

counteracted.

Because of these effects a 250 rudder angle may be

required for a point of view of safety consequently the

11

u' =

0.110 0.165 0.219

12

ship can be controlled if the number of revolutions

does not become less than following:

The author would like to point out that no attempt

was made to extrapolate these data to full scale. This

investigation was primarily a feasability study of a

proposed method for the determination of stopping

manoeuvrability properties.

The absolute numbers were not of primary impor--

-tance.

8 Conclusions

1.

Manoeuvrability is the governing factor of poor

controllability while stopping. The rudder

effective-ness decreases with decreasing RPM and has

vir-tually no effect after the propeller rotation has been

reversed.

2. The dynamic stability also decreases during

stop-ping, not due to ship speed, but due to lower

propeller RPM and thiust. This, however, was a

secondary effect compared to the lack of

manoeu-vrability.

References

DAVIDSON, K. S. M. and L. I. Sciin'i', Turning and

course-keeping qualities Transactions Soc Nay Arch Mar Eng

1946.

HORN, F. and E. A. W.ur4siu, Untersuchungen über

dreh-manöver und Kuzsstabilität von Schiffen. Schiffstechnik -5 and 6,- Heft 29 and 30; 1958-1959.

JAEGER, H. E. and M. Joulwft.IN, Le freinage de grands na-vires; Corrélation entre navire et modèle. A.T.M.A. SessiOn 1966.

S.N.A.M.E., Gide to the selection of backing power.

New York 1957, Technical and Research Bulletin no.- 3-5. u'

n'

at 6 "zero m"

loo

0.110

zero

0.165 1.10

astern

0.50

- c.

>-

I-z

W

o

IL W

O

o

0.25

o

z

Q-4

D

O

I-z

W

YO

E>?

Wz

00

Wo

mw

<a:

9

Da:

DO

411

-0.25

0

Appendix

0.3

-

_z

I-z

w

o

u-w

o

o

0.25

o

z

Q-4

D

O 13

RPM

I

\JL

TO THE

ASTERN

n' CORRESPONDING

n":ZERO

MODEL SPEED

- -

n':4.27

\\

T

L)':

0.701

(j:Q.701

-5- ---$ I

/

L)=0.701

s s V

k

--0.2

0.1

u-vit

14

₀

-L.

_z

I

z

w

C.) Li.. LA..

w

o

C.)

-

0.05

ç-D

z

Q-4

O

-

0.10 o

4

w

z

o

z

w

0.01

0 ....i

LiU)

Ou)

I-4

z

WO

3w

O

LL0

Ii.

w

OU.

₀₀

-0.0

- L.

>-

I--z

w

Ç)

U-w

o

o

:0.25

'D

z

n-4

O

O

d

Is..RPM

I

CORRESPONDING

n';ZERO

ASTERN

TO THE

____

MODEL SPEED

N'

n':4.27

Ca) :0.350

/"/

(4:0.701

N

W':O.350

r.

(4:0.701

-

-_-(J=0.350

N

I

- -:

Ci.) :0.701

O 0.2 0.3 U

vit

0.030

0.025

0.020

0.015

0.010

0.00

6)

0

-0.00

-0.01

-0.01

-0.02

RUDDER ANGLE IN DEGREES

Diagram 3. Coefficient of the lateral force due to the rudder angle.

15

-2

b-0.110

0.219.

A

r

n1:M

gL

V'

I

À

o

n'CORRESFN TO MODEL DING ;PEED

/

/

Q

o

U) - PORT

STARBOARD

ic

in

0 5 10 15

20

16 0.010 0.0075 0.0050 0.0025

*6)

o

-0.0025

-0.0050

-0.0075

-0.0100

-0.0125 -0.0150 15 10 5 0 5

RUDDER ANGLE IN DEGREES

10

Diagram 4. Coefficient of the turning moment due to the rudder angle.

15 20

vc-.

u_a219

-i

___-\flI4.2

-o

o

TO fl'CORRESPONDINC MODEL SPEED

U

427

o STARBOARD PORT

0.50

.0.25

w

D

z

o

-0.25

-0.50

17

MODEL SPEED

I

1._RPM fi::

I

n CORRESPONDING

n:ZERO

rÇ:4.2IASTERN

60

g

TO THE

______

-UNSTABE

/

/

/

I-/

/4

-

-y,

-

-/

i-/

STABLE

I

o

oi

0.3

U

vt

18

₁₀

o

10

20

3°

40

Diagram 6. Rudder angle at which the turning moment acting on the ship becomes zero.

i

In

._RPM. liT

-5

_i0

-

---60JT

AHEAD

UI-ASTERN

jO

-'.165

0.110

//"

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5. M Determination of the dynamic properties and propeller excited

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i 964.

58 S Numerical calculation of vertical hûli vibrations of ships by

discretizing the vibration system, J. de Vries, 1964.

59 M Controllable pitch propellers, their suitability and economy for large sea-going ships piopelled by conventional, directly coi.ipled engines. C. Kapsenberg, 1964.

60 S Natural frequencies of free vertiìal ship vibrations. C. B.

Vreug-denhil, 1964.

61 S The distribution of the hydrodynamic forces on a heaving and

pitching shipmodel in still water. J. Gerritsma and W.

Beukel-man, 1964.

62 C The mode of action of anti-fouling paints : Interaction between anti-fouling paints and sea water. A. M. van Londen, 1964.

63 M Corrosion fri exhaust driven turbochargers on marine diesel

engines using heavy fuels. R. W. Stuart Michell and V. A. Ogale, 1965..

64 C Barnacle fouling on aged anti-fouling paints ; a survey of perti-nent literature aiIdsome recent observations. P. de WoLf, 1964. 65 S The lateral damping and added mass of a horizontally oscillating

shipmodel. G. van Leeuwen, 1964.

66 S Investigations into the strength of ships' derricks. Part. I. F. X. P. Soejadi, 1965.

67 S Heat-transfer in cargotanks of a 50,000 DWTtanker. D. J. van

der Heeden and L. L. Mulder, 1965.

68 M Guide to the applicatiòn of Method for calculation of cylinder liner temperatures in diesel engines. H. W. van Tijen, 1965.

69 M Stress measurements on a propeller model for a 42,000 DWT

tanker. R. Wereldsma, 1965.

70 M Experiments on vibrating propeller models. R. Wereldsma, 1965.

71 S Research on bulbous bow ships. Part II. A. Still water

perfor-mance of a 24,000 DWT bulkcarrier with a large bulbous bow. W. P. A. van Lammeren and J. J. Muntjewerf, 1965.

72 S Research on bulbous bow ships. Part. .11. B. Behaviour of a

24,000 DWT bulkcarrier with a large bulbous bow in a seaway. W. P. A. van Lammeren and F. V. A. Pangalila, 1965. 73 S Stress and strain distribution in a vertically corrugated bulkhead.

H. E. Jaeger and P. A. van Katwijk, 1965.

74 5 Research on bulbous bow ships. Part. I. A. Still water investiga-tions into bulbous bow forms for a fast cargo liner, W. P. A. van Larnmeren and R. Wahab, 1965.

75 S Hull vibrations of the cargo-passenger motor ship "Oranje

Nassau", W. van Horssen, 1965.

76 5 Research on bulbous bow ships. Part I. B. The behaviour of a fast cargo liner with a conventional and with a bulbous bow in a sea-way. R. Wahab, 1965.

77 M Comparative shipboard measurements of surface temperatures

and surface corrosion in air cooled and water coOled turbine outlet casings of exhaust driven marine diesel engine

turbo-chargers. R. W. Stuart Mitchell and V. A. Ogale, 1965. 78 M Stern tube vibratiön measurements of a cargo ship with special

afterbody. R. Wereldsma, 1965.

79 C The pre-treatment of ship plates: A comparative investigation

on some pre-treatment methods in use in the shipbüilding ifldus-try. A. M. van Londen, 1965.

80 C The pre-treatment of ship plates: A practical investigation into

the influence of different working procedures in over-coating

zinc rich epoxy-resin based pre-construction primers. A. M. van Londen and W. Mulder, 1965.

81 S The performance of U-tanks as a passive anti-rolling device. C. Stigter, 1966.

82 S Low-cycle fatigue of steel structures. J. J. W. Nibbering and

J. van Lint, 1966.

83 S Roll damping by free surface tanks. J. J. van den Bosch and J. H.

Vugts, 1966.

84 5 Behaviour of a ship ma seaway, J. Gerritsma, 1966.

ss s Brittle fracture of full scale structures damaged by fatigue. J. J.

W. Nibbering, J. van Lint and R. T. van Leeuwen. 1966. 86 M Theoretical evaluation of heattransfer in dry cargo ship's tanks

using thermal oil as a heat transfer medium. D. J. van der

Heeden. 1966.

87 S Model experiments on sound transmission from engineroom to accommodation in motorships. J. H. Janssen. 1966.

88 5 Pitch and heave with fixed and controlled bow fins. J. H. Vugts 1966.

89 S Estimation of the natural frequencies of a ship's double bottom by means of a sandwich theory. S. Hylarides, 1967.

90 S Computation of pitch and heave motions for arbitrary ship forms. w. E. Smith, 1967.

91 M Corrosion in exhaust driven turbochargers on marine diesel en-gifles using heavy fùeis. R. W. Stuart Mitchell, A. J. M. S. van

Montfoort and V. A. Ogale, 1967.

92 M Residual fuel treatment on board ship. Part II. Comparative

cylinder wear measurements on a laboratory diesel engihe using filtered or centrifuged residual fuel. A. de Mooy, M. Verwoest and G. G. van der Meulen, 1967.

93 C Cost relations of the treatments of ship hulls and the fuel

con-sumption of ships. H. J. Lageveen-van Kuijk, 1967.

94 C Optimum conditions for blast cleaning ofsteel plate. J. Remrnelts,

.1967.

95 M Residual fuel treatment on board ship. Part. I. The effect of

cen-trifuging, filtering and homogenizing on the unsolubles in

residtial fùel. M. Verwoest and F. J. Côlon, 1967.

96 S Analysis of the modified strip theory for the calculation of ship motions and wave bending moments. J. Gerritsma and W.

Beu-kelman, 1967.

97 S On the efficacy of two different roll-damping tanks. J. Bootsma and J. J. van den Bosch, 1967.

98 S Equation of motion coefficients for a pitching and heaving des-träyer model. W. E. Smith, 1967.

99 S The manoeuvrability of ships on a straight course. J. P. Hooft,

1967.

100 S Amidships forces and moments on a CB = 0.80 "Series 60"

model in waves from various directions. R. Wahab, I 967. 101 C Optimum conditions for blast cleaning ofsteel plate. Conclusion.

J. Remmelts, 1967.

102 M The axial stiffness of marine diesel engine crankshafts. Part I., Comparison between the results of full scale measurements and

those of calculations according to published formulae. N. J. Visser, 1967.

103 M The axial stiffñess of marine diesel engine crankshafts. Part II.

-Theory and results of scale model measurements and comparison with published formulae. C. A. M. van der Linden, 1967.

104 M Marine diesel engine exhaust noise. Part I. A mathematical moci.J.

J. H. Janssen, 1967.

105 M Marine diesel engine exhaust noise. Part H. Scale models of

exhaust systems. J. Buiten and J. H. Janssen, 1968.

106 M Marine diesel engine exhaust noise. Part. III. Exhaust sound

er ter à for bridge wings. J. H. Janssen en J. Buiten. 1967.

107 5 Ship vibration analysis by finite element technique. Part. 1. General review and application to timple structures, statically

loaded. S. Hylarides, 1967.

108 M Marine refrigeration engineering. Part I. Testing of a

decentral-ised refrigerating installation. J.. A. Knobbout and R. W. J. Kouffeld, 1967.

109 S A comparative study on four different passive roll damping

tanks. Part I. J. H. Vugts, 1968.

1IOS Strain, stress and flexure of two corrugated and one plane

bulk-head subjected to a lateral, distributed load. H. E. Jaeger and

P. A. van Katwijk, 1968.

111 M Experimental evaluation of heat transfer in a dry-cargo ships' tank, using thermal oil as a heat transfer medium. D. J. van der

Heeden, 1968.

ll2S The hydrodynamic coefficients for swaying, heaving and roiling cylinders in a free surface. J. H. Vugts, 1968.

113 M Marine refrigeration engineering Part H. Some results of testing a decentraliséd marine réfrigerating unit with R 502. J. A. Knob-bout and C. B. Colenbrander, 1968.

114 S The steering of a ship during the stopping manoeuvre. J. P.

Hooft, 1969.

115 5 Cylindér motions in beam waves. J. H. Vugts, 1968.

116 M Torsional-axial vibrations of a ship's propulsiOn system. Part I. Comparative investigation of calculated and measured

torsibnàl-axial vibrations in the shafting of a dry cargo motorship.

C. A. M. vañ der Linden, H. H. 't Hart and E. R. Dolfin, 1968.

117 S A comparative study on fouÈ different passive roll damping tanks Part II. J. H. Vugts, 1969.

118 M Stem gear arrangement and electric power generation in ships propelled by controllable pitch propellers. C. Kapsenberg, 1968. 119 M Marine diesel engine exhaust noise. Part IV. Transfer damping

data of 40 modelvariants of a compound resonatorsilener. J. Buiten, M. J. A. M. de Regt and W. P. H. Hanen, 1968; 120 C Durability tests with prefabrication primers in use of steel plates.

A. M. van Londen and W. Mulder, 1969.

121 S Proposal for the testiñg of weld metal from the viewpoint of brittle fracture initiation. W. P. van den Blink and J. J. W.

Nibbering, 1968.

122 M The corrosion behaviour of cunifer 10 alloys in seawaterpiping-systems on board ship. Part I. W. J. J. Goetzee and F. J. Kievits, 1968.

123 M Marine refrigeration engineeriiig. Part HI. Proposal for a

specifi-cation of a marine refrigerating unit and test procedures. i. A.

Knobbout and R. W. J. Kouffeld, 1968.

125 S A proposal on noise criteria for sea-going ships. J. Buiten, 1969. 126 S A proposal for standardized measurements and annoyance rating of simultaneous noise and vibration in ships. J. H. Janssen, 1969. 127 S The braking of large vessels U. H. E. Jaeger in collaboration with

M. Jourdain, 1969.

128 M Guide for the calculation of heating capacity and heating coils for double bottom fuel Oil tanks in dry cargo ships. D. J. van der Heeden. 1969.

129 M Residual fuel treatment on board ship. Part Ill. A. de Mooy,

P. J. Brandenburg and G. G. van der Meulen, 1969.

130 M Marine diesel engine exhaust noise. Part V. Investigation of a double resonatorsilencer. J. Buiten, 1969.

131 S Model and full scale motions of a twin-hull vesseL

M. F. van Sluijs, 1969.

CommunicatiOns

11 C Investigatioñs into the use of some shipbottom paints, based on scarcely saponifiàble vehicles (Dutch). A. M. van Londen and P. de Wolf, 1964.

12 C The pre-treatment of ship plates: The treatment of welded joints

prior to painting (Dutch). A. M. van Landen and W. Mulder, 1965.

13 C Corrosion, ship bottom paints (Dutch). H. C. Ekama, 1966.

14 S Human reaction to shipboard vibratiOn, a study of existing

literature (Dutch). W.. ten Cate, 1966.

15 M Refrigerated containerized transport (Dutch). J. A. Knobboüt, 1967

16 S Measures to prevent sound and vibration annoyan aboard a seagoing passenger and carferry, fitted out with diese1engins (DUtch). J. Balten, J. H. Janss6n,HF. Steenhoek and L. A. S.

Hageman, 1968.

17 S Guide for the specification, testing and inspectiOn of glass reinforced polyester Structures in shipbuildiìig (Dutch). G.

Hamm, 1968.

18 S An experimental simulator for the manoeuvring of surface ships. J. B. van den Brug and W. A. Wagenaar, 1969.

19 S The computer programmes system arid the NALS language fOr numerical control for shipbuilding. H. le Grand, 1969.