Calculations and experiments with regard to the stopping of a ship with diesel propulsion and fitted with a controllable pitch propeller

REPORT No. 168S

November 1974

(SH 319)

NEDERLANDS SCHEEPSSTUDIECENTRUM TNO

NETHERLANDS SHIP RESEARCH CENTRE TNO

SHIPBUILDING DEPARTMENT

LEEGHWATERS1RAAT 5, DELFT

*

CALCULATIONS AND EXPERIMENTS WITH REGARD

TO THE STOPPING OF A SHIP WITH DIESEL PROPULSION

AND FITTED WITH A CONTROLLABLE PITCH PROPELLER

(BEREKENINGEN EN EXPERIMENTEN BETREFFENDE STOPKARAKTERISTIEKEN

VAN EEN SCHIP MET DIESELMOTOR VOORTSTUWING EN

UITGERUST MET EEN VERSTELBARE SCHROEF)

by

IR. C. B. VAN DE VOORDE

Institute TNO for Mechanical Constructions)

rLFO

Verwacht mag worden, dat in de naaste toekomst hoge eisen

gesteld zullen worden aan de manoeuvreereigenschappen van

schepen.

De scheepvaart op drukbevaren routes, zoals o.a. het Engels Kanaal, zal in toenemende mate verbetering in het gedrag vergen. Dit vooral door de veruiteenlopende manoeuvreer-eigenschappen van de vele verkeersdeelnemers, en het groeiend

aantal in de vaart komende schepen voor het vervoer van

ge-vaarlijke stoffen waaronder chemicaliëntankers, gastankers, e.d.

Het is daarom dat in de voorgaande jaren aan het onderwerp ,,manoeuvreereigenschappen van schepen" veel aandacht is besteed in researchiaboratoria in binnen- en buitenland.

Een bijzonder facet van de manoeuvreereigenschappen is het

,,stop" gedrag. Hierbij was bekend dat ondermeer een schip

met dieselmotorvoortstuwing en een verstelbare schroef beter

te stoppen is. In welke mate en op welke wijze de stopeigen-schappen van een dergelijk schip echter beter en eventueel te

optimaliseren zijn, was in de meeste gevallen niet bekend. Naast de hydrodynamische aspekten van schip en schroef, spelen ook andere faktoren een belangrijke rol.

De versteiregeling van de schroef en de regeling van de hoofd-dieselmotor dienen op elkaar en op de eerder genoemde hydro-dynamische aspekten te worden afgesternd. Hiermede zijn ver-schijnselen zoals "propeller racing", overbelasting en dergelijke

te vermijden. Dit pleit voor een programmering van de

nood-stopmanoeuvre. Zeker in het licht van de complexe dynamische

eigenschappen van het schip en het

motor-asleiding-schroef-systeem en mede omdat niet te verwachten is dat de aktie van de mens in dergelíjke situaties optimaal zal zijn.

In 1969 stelde de "Verenigde Nederlandsche Scheepvaart Maatschappij" haar m.s. "Koudekerk" beschikbaar voor

uit-gebreide stopproeven. Daarmede zjn de stopeigenschappen van dit schip met dieselmotorvoortstuwing en uitgerust met een ver-stelbare schroef kwantitatief vastgelegd. Daaraan voorafgaand zijn modelexperimentele proeven verricht bij het ederlandsch

Scheepsbouwkundig Proefstation met het doel een goed inzicht te verkrijgen in de mogelijkheden voor een optimalisatie van de stopmanoeuvre. Dit experimentele onderzoek leverde veel infor-matie op betreffende de te verwachten verschijnselen, doch een werkelijkheidsgetrouwe simulatie werd niet

bereikt daar de

dynamische eigenschappen van bet diesel-motor-as leiding-ver-stelbare schroefsysteem onvoldoende bekend waren.

Toen eind 1972 de toepassing van siniulatietechnieken bu het Instituut TNO voor Werktuigkundige Constructies mogelijk

werd, is bet onderzoek aldaar voortgezet gebruik makend van alle inmiddels verkregen resultaten, teneinde een betrouwbare

prognose- en optimalisatiemethode voor stopeigenschappen

mogelijk te maken.

Het rapport no. 168 S "Calculations and experiments with

regard to the stopping of a ship with diesel propulsion and fitted with a controllable pitch propeller" geeft de totaalresultaten van

bet onderzoek. Hiermede is een goed inzicht verkregen in de

It may be expected that high demands shall be made upon

manoeuvrability of ships in the nearby future.

The shipping in crowded areas, such as the English Channel

will require increasingly improvements in the manoeuvring

behaviour. This especially because of the many differing manoeu-vring characteristics of the many marine traffic participants and

of the growing number of ships for the transportation of

haz-ardous cargoes, such as product carriers, gas tankers, etc.

It is therefore that during the past years much attention lias

been paid to the subject "manoeuvrability of ships" in research laboratories in this country and abroad.

A specific aspect of manoeuvrability is the stopping behaviour. lt is known that for example a ship with dieselengine propulsion and fitted with a controllable pitch propeller has better stopping abilities. To which extent and in which way the stopping charac-teristics of such a ship are better and may be optiniised, was in most cases unknown.

Apart from the hydrodynamical aspects of ship and propeller

also other factors play an important role. The control

mech-anism of the propeller and the control of the main diesel engine should be tuned to each other and to the hydrodynamical aspects earlier mentioned. Herewith phenomena such as propeller racing, overloading, etc. can be avoided. This advocates a programming

of the crash stopping manoeuvre. Especially because of the complex dynamical characteristics of the ship and the

diesel-engine - shaft - propeller system and also because it can not be expected that human actions in such situations would be optimal.

In 1969 the "Verenigde Nederlandsche Scheepvaart

Maat-schappij" made lier ms "Koudekerk" available for carrying Out an extensive programme of stopping tests. Herewith the stopping characteristics of this ship with diesel engine propulsion and fitted

with a controllable pitch propeller were quantitatively ascertained.

Previously model experiments were carried out at the Nether-lands Ship Model Basin, in order to obtain a good insight into

the possibilities for optimisation of the stopping manoeuvre.

These experimental investigations, gave much information about the phenomena that could be expected, however, a real simula-tion was not achieved because the dynamical characteristics of

the diesel engine - shaft - propeller system were not known sufficiently.

When at the end of 1972 practical applications of simulation techniques were possible at the Institute TNO for Mechanical Constructions the subject investigations were continued at that

institute using all the information already gained, in order to

obtain a reliable method for predicting and optimizing the stop-ping manoeuvre.

The NSS/TNO report no. 168 S "Calculations and experiments with regard to the stopping of a ship with diesel propulsion and fitted with a controllable pitch propeller" gives the overall results

of the subject investigations. This report gives a good insight

into the parametric sensitivity with regard to the stopping

characteristics.

parameter gevoeligheid met betrekking tot de stopkarakteris-tieken.

Simulatietechnieken kunnen ook voor de naaste toekomst met vrucht worden toegepast voor hijvoorbeeld een evaluatie

van het stopgedrag van schepen uitgerust met een elektronisch

geregeld voortstuwingsmachine-asleiding-schroefsysteem. Met

simulatietechnieken is ook een prognose op te stellen, betreffende

de invloed op het stopged rag van het moment en de wijze waarop

handelingen op de brug en in de machinekamer worden uitge-voerd. Deze resultaten kunnen mede dienen als invoer voor een anti-aanvaringssysteem.

Ook training op dergelijke noodsituaties met verschillende

soorten hulp apparatuur behoort tot de mogelijkheden.

Dezer-zijds mag met grote erkentelijkheid de royale medewerking

van de "Verenigde Nederlandsche Scheepvaart Maatschappij",

thans opgenomen in de Nederlandse Scheepvaart Unie en de toenmalige gezagvoerder en bemanning van bet ms.

"Koude-kerk" worden vermeld.

HET NEDERLANDS SCHEEPSSTUDIECENTRUM TNO

ir

In the nearby future good use can be made of applied

simula-tion techniques. For example they can be used for an evaluasimula-tion of the stopping behaviour of ships fitted with an electronic con-trolled engine - shaft - propeller system. Simulation techniques

may also be utilized to predict the effect on the overall ship

behaviour of how and the instant on which procedures are exe-cuted on the bridge and in the engine room. These results may

serve as input for a collision avoidance system. Also training

for emergency situations such as crash stops with different types of instruments is possible.

The generous cooperation with the "Verenigde Nederlandsche Scheepvaart Maatschappij" today incorporated into the "Neder-landse Scheepvaart Unie" and with the captain and the crew of

the ms. "Koudekerk" at that time is greatfully acknowledged.

CONTENTS

page

List of symbols

6

Summary

7 i

Introduction

7 2

Derivation of equations

8

3

Solution of the longitudinal equation of motion (X-equation)

9

3.1

Introductory remarks

9

3.2

Solution of the X-equation using as input the thrust, obtained from

tests on a model

12

3.3

Solution of the X-equation using as input the thrust, obtained from

full scale tests

12

4 Discussion 16

5 References 16

Appendix 1 17

Stopping tests in a towing tank on a model of M.S. "Koudekerk",

equipped with a controllable pitch propeller

Appendix 2

18

Full scale stopping tests on M.S. "Koudekerk", equipped with a

controllable pitch propeller

LIST OF SYMBOLS

A2

factor equal to ship's resistance R divided by speed

{kgm1]

squared

CT

propeller thrust coefficient T/-(1 - w)2u2 (ir/4)D2

-CQ

_{propeller torque coefficient Q/4(l w)2u2(ir/4)D3}

-D

propeller diameter

[ml

I,

polar mass inertia-moment of the rotating parts of the

_[kgm2]

propulsion machinery, related to number of revolutions

of propeller

AI

apparent polar mass inertia moment

_[kgm2]

m

ship's mass

[kg]

Am

apparent ship's mass

[kg]

n

number of revolutions per second

[sec 1]

dn/dt

rate of change of n

[sec 2]

Q

shaft friction loss, which arises from friction in the bearings

[Nm]

and stern tube glands

Qm

driving shaft torque at propulsion machinery

[Nm]

Q'.,

shaft torque at propeller

[Nm]

R

ship's resistance

[N]

s

distance travelled

[ml

t

time

_[sec]

t

thrust deduction factor: lt = (X+ R)/T

-T

propeller thrust

[N]

u

ship's speed

_[msec1]

du/dt

rate of change of speed

[m sec2)

w

wake factor; advance speed of propeller = (1 w)u

-X

tow rope force; X= (m+Am) du/dt

_[Ni

çOo.

pitch at O.7D

i

Introduction

Some years ago the Netherlands Ship Research Centre

TNO initiated a programme ultimately aimed at

achieving a method for predicting the stopping

per-formance of a ship equipped with a controllable-pitch

propeller and at performing simulation studies for

establishing the optimum stopping procedure.

This publication concerns the

first stage of the

programme, dealing with:

the derivation of the equations;

calculations of the head reach and the stopping

time (actually the speed and path history during a

deceleration

manoeuvre

until

stop)

for

m.s.

"Koudekerk" equipped with a C.P.-propeller.

The calculations are carried out by solving the

longitu-dinal equation of motion, though using as input the

measured values of the propeller thrust, obtained

either from stopping tests on a model of m.s.

"Koude-kerk" or from those on the actual ship.

The purpose of these calculations is first to find the

values of the remaining unknown quantities in the

X-equation, like added mass and especially the thrust

deduction factor, following the technique of matching

the calculated results with the experimental ones.

Secondly to establish the sensitivity of the calculated

results for an error in the estimation of these quantities;

hence to establish the accuracy which these quantities

have to be estimated with, in those cases where no

experimental results are available.

lt has been planned to deal with the second stage

of the programme after a satisfactory conclusion of

the first stage.

This second stage will concern the calculation of the

CALCULATIONS AND EXPERIMENTS WITH REGARD TO THE

STOPPING OF A SHIP WITH DIESEL PROPULSION AND FITTED

WITH A CONTROLLABLE PITCH PROPELLER

by

Ir. C. B. VAN DE VOORDE

Summary

Predictions have been made of the head reach and the stopping time for a high speed cargo ship equipped with a controllable-pitch

propeller.

These predictions are based indeed on theoretical considerations, though for solving the longitudinal equation of motion, measured values of the propeller thrust, obtained from either model or full scale stopping tests, have been used as input.

It is indicated that the assumption of the thrust deduction factor being constant throughout the manoeuvre may lead to large errors in the predictions. Most probably this applies also to the wake factor.

It is stated that for obtaining satisfactory predictions a reasonable knowledge of the magnitude of these factors for all the various conditions occurring during the stopping manoeuvre, will be indispensable.

Descriptions of the model and the full scale experiments are given in appendices. Special attention is being paid to the new technique, which was introduced for performing the model tests. This technique makes use of a device, which automatically takes care of the appropriate skin friction correction force, thus enabling a stopping test in a towing tank to be carried out in a direct way.

history of speed and distance travelled during any

ar-bitrary deceleration manoeuvre, using for input any

feasible

machinery manoeuvre,

for instance with

regard to pitch and fuel settings. Hence the propeller

thrust will then also have to be calculated.

Subsequently the programme is to be concluded by

simulation studies in order to find the optimum

stop-ping procedure i.e. the optimum machinery manoeuvre.

Because in the first stage, like been said, the thrust

values obtained from either model or full scale tests

have been applied as input for the calculations, short

descriptions of these tests are given.

In appendix i a description of the tests on a model

of ms. "Koudekerk", conducted

in aug./sept. 1968

in a towing tank of the Netherlands Ship Model Basin.

The main object of these tests was the development

of a new technique for conducting a stopping test in a

towing tank, making use of a special device, which

automatically takes care of the appropriate skin

fric-tion correcfric-tion force.

Appendix 2 deals with the full scale stopping

ma-noeuvres, which were executed in november 1968.

Although it was planned to have carried out

cor-relation tests in the towing tank after the full scale

trials have been completed, those model tests

un-fortunately have never been conducted. The existing

difference in the machinery manoeuvres makes a

cor-relation between the available results of the model and

full scale experiments impossible.

* These tests were conducted by the author at the time hewas

Head of the Shallow Water Basin of the NSMB.

In 1970 he joined The Institute TNO for Mechanical

Con-structions.

2 Derivation of equations

and

The motion of translation of a ship on a straight course

in unrestricted water, is described by the longitudinal

equation of motion (or X-equation),

du

= A2u2-l-(1t)T

(1)

or

neglecting rudder forces in case of rudder actions

applied to keep the ship on a straight course, wind

forces on the superstructure and coupling effects of

heave, roll and pitch motions.

The second equation of importance describes the

motion of rotation of the single propeller shaft.

d(I+M)n

-- .,

Q

Ql

2ir

dt

27r(I

₊

2

d(Í+ii)dço

dq

dt

= Q,,QpQf

(2)

The mathematical model is completed by two other

first order differential equations, describing the pitch

servo mechanism and the fuel rate servo-mechanism.

Before discussing the variables involved in the

math-ematical model, some remarks will be made abaut

the thrust deduction factor and the wake factor.

Both factors are in the first place dependent of

course on the geometry of the pertaining ship,

espe-cially of its after body, on the propeller arrangement,

loading condition etc.

For a given ship it seems reasonable to assume that

the thrust deduction factor t and the effective wake

factor

i' will be only functions of the speed and the

propeller thrust, hence independent at what

coni-bination of speed, RPM and pitch

this

thrust

is achieved.

Furthermore by some reasoning it can be made

plausible, that if Reynolds and Froude effects may be

neglected, both t and w are a mere function of the

thrust divided by speed squared, hence a mere

func-tion of the dimensionless propeller thrust coefficient

CT, defined by T/-Q(7r/4)D2 (I 1i')2u2. The author is

not familiar with

literature,

mentioning that

the

existence of such a relationship for a C.P.-propeller

has been checked in a single case, let alone literature,

reporting investigations into the validity of such a

relationship for a class of ships.

Looking again at eq. 1 and 2, and writing

T = CT QD2(l w)2u2

(3)

in which CT and CQ are functions of the pitch and the

flow parameter (1 w)u/nD *), and assuming t and w

are both a function of CT, it can be seen that

du

=f1(,n,p)

Furthermore it can be seen that

du

dt

= f,(u, n, ço and fuel rate)

knowing the driving shaft torque Qm is a function of

fuel rate and RPM, and taking the shaft friction loss

Q1 as

Ql = Ql

in which Q1

amounts to a certain percentage of the

maximum propeller torque.

If the pitch and the fuel rate are taken as independent

variables, the machinery manoeuvre during the

stop-ping is characterized by a specified sequence of pitch

and fuel rate orders. Hence with the aid of the two

servo control equations the pitch and the fuel rate are

at any time during the manoeuvre known quantities,

leaving u and n as dependent variables, to be solved

from equations 5 and 6.

From these equations

du

=f(u,n)

can be derived. Solution of this equation yields

ti =f4(n)

(9)

Substituting eq. 9 into eq. 5, solving dt and integrating

over the required speed range, yields the manoeuvring

(stopping) time

U,,nd

d

=

UgIn

f5(u)

The distance travelled (head reach) may be found by

udi =

du

Ubgin Ut,cginf5(U)

* Based on the work of Ström-Tejsen and Porter. ref. [11, a

computer programme has been made, which enables to calcul-ate CT and C0 as a function of pitch and (1 - w)u/nD for any propeller with given geometry.

(7)

(8)

(10)

3

Solution of the longitudinal equation of motion

3.1 Introductory remarks

In the previous section it is shown how in principle the

equations can be solved and the stopping time and the

head reach can be calculated for a specified machinery

manoeuvre.

For the determination of the various functions

Table I. Results of stopping tests on a model

mentioned, various quantities have to be estimated.

Quantities like

m, A 2' AI are fairly well to be

esti-mated, however so little is known about the magnitudes

of

t

and w tinder the various conditions arising during

a stopping manoeuvre, that this most probably will be

the bottleneck in making reliable predictions. That is,

if no extensive tank tests, so-called overload tests, on

a model of the pertaining ship have been conducted.

9

test no. 869) test no. 8693

time in sec. pitch in degrees RPM thrust in MN speed m/sec. calculated I time in sec. pitch in degrees RPM thrust in MN speed in m!sec. calculated

I -r

o 23 09.7 0.7768 10.03 0.824 0 23 109.7 0.7768 10.03 0.824 2.6 20.2 109.7 0.2317 10.03 2.336 2.1 21.1 109.7 0.3862 10.03 1.037 7.8 14.7 109.7 -0.2317 9.94 -0.416 7.3 15.6 109.7 -0.1545 9.81 -0.325 13.0 I 1.0 109.7 -0.7337 9.71 0.422 12.5 1 1.0 109.7 -0.5793 9.70 - 0.047 15.1 9.6 109.7 -0.8496 9.60 0.307 17.7 5.9 109.7 -0.9655 9.49 0.201 18.2 8.9 109.7 -0.6565 9.49 0.217 22.9 0.0 109.7 -1.1585 9.27 0.356 23.4 8.9 109.7

-05793

9.26 0.124 28.1

- 5.5

109.7 -1.5447 8.94 0.512 28.6 8.9 109.7 --0.7724 915 0.! 16 32.2 -- 9.2 109.7 -1.6992 8.61 0.772 33.8 4.1 109.7 -1.1585 8.92 0.429 33.3 9.2 109.7 -1.4289 8.50 0.929 37.4 0.4 109.7 -1.2744 8.70 0.613 39.5 9.2 109.7 -1.3130 8.07 0.512 39.0

- 0.9

96.5 - 1.2358 8.58 0.534 43.6

- 9.2

73.7 - 1.0427 7.85 0.778 41.6

- 3.2

73.7 - 1.2358 8.47 0.292 48.8 12.8 73.7 -1.3902 7.41 0.651 44.2

- 5.5

73.7 -. 1.2744 8.36 0.292 52.5 7.4 73.7 --1.3516 7.19 0.646 49.4

-11.0

73.7 --1.4675 8.13 0.395 54.0

-17.4

73.7 -1.4675 7.09 0.560 54.6

-16.5

73.7 1.6220 7.79 0.874 59.2

-17.4

73.7 -0.9268 6.87 0.594 55.6 --17.4 73.7 12358 7.68 1.105 65.5

-17.4

73.7 -0.7724 6.54 0.092 59.8

-17.4

73.7 --1.2358 7.45 0.572 68.6

-17.4

109.7 -0.8496 6.54 .322 63.4 ---17.4 109.7 -1.5061 7.23 1.184 69.6

-17.4

109.7 -0.81 lO 6.43 1.728 64.9

-17.4

109.7 -- 1.5061 7.00 I . 155 74.8 - 17.4 09.7 --0.81 10 6.21 0.856 70.1

-17.4

100.7 1.1199 6.89 0.440 80.0

-17.4

09.7 -0.7724 5.89 0.693 75.3

-17.4

109.7 1.004! 6.55 0.701 85.2

-17.4

109.7 -0.7724 5.78 0.702 80.5

-17.4

109.7 -10041 6.32 0.530 90.4

-17.4

109.7 -0.7337 5.45 1.012 85.7

-17.4

109.7 0.9268 6.10 0.591 95.6

-17.4

109.7 -0.6951 5.23 0.567 93.9

-17.4

109.7 0.9268 5.87 0.606 100.8

-17.4

109.7 -0.7337 5.12 0.545 96.1

-17.4

109.7 0.8496 5.65 0.678 106.0

-17.4

109.7 -0.6565 4.90 0.902 01.3

-17.4

109.7 0.8110 5.42 0.727 111.2

-17.4

109.7 -0.6565 4.69 0.644 06.5

-17.4

109.7 -0.8496 5.19 0.709 116.4

-17.4

109.7 -0.6565 4.58 0.653 11.7

-17.4

109.7 -0.8496 4.97 0.723 121.6

-17.4

109.7 -0.6565 4.36 0.943 16.9

-17.4

109.7 --0.8110 4.74 0.772 126.8

-17.4

109.7 -0.6179 4.14 0.120 22.1

-17.4

109.7 -0.8496 4.52 0.567 128.3

-17.4

109.7 -0.6179 4.14 0.10! 26.3

-17.4

109.7 -0.8496 4.40 1.747 132.0

-17.4

73.7 -0.5020 4.03 0.725 27.3

-17.4

99.1 ---0.7724 4.29 1.600 137.2

-17.4

73.7 -0.5407 3.92 0.848 29,9

-17.4

73.7 -0.695! 4.29 0.395 142.4

-17.4

73.7 -0.5407 3.70 1.198 32.5

-17.4

73.7 -0.7337 4.18 0.72! 147.6

-17.4

73.7 -0.5793 3.49 0.821 37.7

-17.4

73.7 -0.7724 4.06 0.611 152.8 -17.4 73.7 -0.5407 3,38 0.553 42.9

-17.4

73.7 -0.7724 3.84 0.865 158.0

-17.4

73.7 -0.5407 3.27 0.894 48.1

-17.4

73.7 -0.7337 3.61 0.923 163.2

-17.4

73.7 -0.5020 3.05 0.978 53.3

-17.4

73.7 -0.7337 3.39 0.680 168.4

-17.4

73.7 -0.4634 2.94 1.067 58.5

-17.4

73.7 -0.7337 3.27 0.430 173.5

-17.4

73.7 --0.4248 2.72 0.755 63.7

-17.4

73.7 -0.6951 3.16 0.460 178.7

-17.4

73.7 -0.4248 2.72 0.330 68.9 -17.4 73.7 -0.7337 3.05 0.696 183.9

-17.4

73.7 -0.4248 2.61 1.187 74.! -17.4 73.7 -0.6951 2.82 0.745 189.1

-17.4

73.7 -0.4634 2.39 1.490 79.3

-17.4

73.7 -0.6179 2.71 0.54! 194.3

-17.4

73.7 --0.5020 2.18 1.027 84.5

-17.4

73.7 -0.5793 2.59 0.582 199.5

-17.4

73.7 - 0.4634 2.07 1.118 89.7

-17.4

73.7 -0.6565 2.48 0.803 204.7

-17.4

73.7 -0.5020 1.85 1.400 94.8

-17.4

73.7 -0.6565 2.26 0.812 209.9

-17.4

73.7 -0.5020 1.63 1.049 200.0

-17.4

73.7 -0.6565 2.14 0.816 215.1

-17.4

73.7 -0.5020 1.52 1.053 205.2

-17.4

73.7 -0.6951 1.92 0.778 220.3

-17.4

73.7 --0.4634 1.30 1.537 210.4

-17.4

73.7 -0.6565 1.80 0.827 225.5

-17.4

73.7 -0.4634 1.09 1.543 215.6

-17.4

73.7 -0.6565 1.58 0.833 230.7

-17.4

73.7 -0.4634 0.87 1.548 220.8

-17.4

73.7 -0.6565 1.46 0.836 235.9

-17.4

73.7 -0.4634 0.65 1.162 226.0

-17.4

73.7 -0.6565 1.24 0.841 241.!

-17.4

73.7 - 0.4634 0.54 1.164 231.2

-17.4

73.7 -0.6565 1.13 0.843 246.3

-17.4

73.7 -0.4634 0.32 1.166 236.4

-17.4

73.7 -0.6565 0.90 1.13! 251.5

-17.4

73.7 -0.4634 0.21 1.167 241.6

-17.4

73.7 -0.6565 0.67 1.134 256.7

-17.4

73.7 -0.4634 0.00 1.995 246.8

-17.4

73.7 -0.6565 0.45 0.852 252.0

-17.4

73.7 -0.6565 0.33 0.568 257.2

-17.4

73.7 -0.6565 0.22 0.853 262.4

-17.4

73.7 -0.6565 0.00 -1.043

lo

r

a

-18 13 12 11 10 9 8 7 6 5 4 3

0

s ¡n rn '<1/100 U in rn/sec. N pitch N N N N

r

measured on a model;test

no.8690.

calculated with measured

-

thrust values used as

-input andl-t=0.824

distance travelled S

-

--/

E

It

--S-ships speed U

----S,

so

ióo

150

200 time in sec. 250

u

M

('J

Fig. I. Comparison between calculated and measured histories of speed and distance travelled for model with given stopping

procedure. rpm 110-

100-90

80-70 60- 50-

40-30

20 10

0

24 thrust in MN xlO

rpm

22 20 1a 16- 14-i 2-10' 8 6 4 2 o 50 100 150 _{200 time in sec} 25C

-4

-6

-8--12 , ..-...-.----.-.---.-.

/N._._._._._._._.

L_.

rpm

110 22

lOO- 20

90

18

80

16

70

14

60

12

so

io

40

8 30 6 20 4 10 2

0

O

24 thrust in MN xlO

-2

-4

-6

- 8

r

_L) -o. -16 -18 13 12 11 U in rn/sec. 10 9 8 7 6 5 4 3 2

o

s ¡n m xl/100

\

N. N 100

measured on a model; test no 8693

N

N

-S.

calculated with measured thrust

values used as input and

1-t = 0.8 24 r pm

test no 8693

150

200timcinsec.

250

thrust

pitch

distance travel!ed S

-

E -.5.--u 91

ss speed U

Fig. 2. Comparison between calculated and measured histories of speed and distance travelled for model with given stopping

procedure.

11

iòo

12

Because these tests were not conducted indeed,

it

has been tried to find a function for the thrust

deduc-tion factor after having solved this factor from eq. 1,

using the available results of stopping tests on a model.

during which tests the propeller thrust and the speed

were measured as a function of time.

This will be discussed in paragraph 3.2.

3.2

Solution of

the X-equation, using

as input

the

thrust,

obtained

from tests

on a model

The X-equation is

(ni+Am)

=

A2u2+(l t)T

(1)

During the tests the full scale volume displacement

amounted to 16,212 m3 (mean draft 8.05 m): hence

in =

16, 212 x l0

kg.

The apparent mass

Am

is taken as 6 per cent of

ni

hence

m+Am =

17,185 x l0 kg.

From results of resistance tests in a towing tank and

of calculations of the resistance for the lower speed

range the following expressions forA2 has been derived.

A, = 5356.0 kg m' for the speed range

0< u

16 knots

and

A2 = 5356.0+31201.3

-

0.82051 kgm1

Luo

_J

for the speed range u> 16 knots, with u0

19.5 knots.

The values of the thrust and speed, derived from the

recordings, made during the stopping tests on the

model, are given in Table I with reference to time.

With these data and those given above for

Am

and A2,

the quantity I t has been solved from eq.

I.

These results are presented in Table I as well.

The values for the thrust deduction factor appear to

be very inconsistent.

In attempts to find a function for I - t, the data were

plotted versus

T

or versus the parameter

u/nD

for constant pitch angles.

These attempts failed because the data scattered too

much.

This is not surprising in view of the inaccuracies

in-volved both in the thrust and speed data as well as in

the process of differentiation.

In many publications concerning the calculation of

stopping manoeuvres the thrust deduction factor is

taken as a constant, most probably because of the fact

that nothing better is known.

If I - t is assumed to be a constant equal to 0.824 and

if again the measured thrust values are used as input,

u =f(t) can be solved from eq.

1

and the distance

travelled s = [(r) be calculated. Fig. I and 2 show the

comparison between these calculated results and the

measured histories of speed and distance travelled.

Actually the distance travelled was not recorded

during the test runs.

By "measured distance travelled"

is

meant the

distance travelled resulting from an integration of the

measured speed.

As can be noticed the assumption of the thrust

deduction factor being constant throughout the whole

stopping manoeuvre can lead to large errors in the

predictions.

3.3 Solution

of the X-equation, using

as input the

thrust,

obtained from

full

scale

tests

The same equation holds

(rn+Ain) =

du

A,u2+(lt)T

dt

(1)

During the full scale tests the weight displacement

amounted to 16,875 metric tons (mean draft 8.14 m)

hencem = 16,875 x iO kg.

The apparent mass

Am

_{is taken as 6 per cent of ni}

hence

m+Am =

17,888 x iO kg.

For A2 the same expressions as mentioned in

para-graph 3.2 have been used, though the draft of the ship

during the full scale tests was slightly more than the

full scale value corresponding to the draft of the model.

The values of the thrust, derived from the recordings,

made during crash stops with the actual ship, are given

in Table 2 with refereace to time.

With the assumption of I t being constant, equal

to 0.824 throughout the whole manoeuvre. u=f(t)

can be solved from eq. I. Subsequently the distance

travelled has been calculated from s =fudt.

Fig. 3 and 4 show for two crash stops the

compari-son between this calculated result and the measured

history of distance travelled, which latter data are

given in Table 2.

These figures also show u ==f(t) as calculated.

For both crash stops the predicted head reach falls

short with respect to the measured value (about 7 per

cent). For crash stop no. 2 the predicted stopping time

is only a little too low, and for crash stop no. 3 about

6 per cent too high. Looking at the history of the

distance travelled it can be seen that for crash stop no. 2

in the beginning of the stopping manoeuvre a too small

Table 2. Experimental results of full scale stopping tests

crash stop no. 2 crash stop no. 3

13 time in sec, pitch in degrees RPM thrust in MN distance travelled in m 0 23 114 0.7916 0 5 22 90 0.2969

-6.5

-

-

-

74.4 10 19.5 78 -0.2177

-15 11.5 97 --0.7323

-16.5

-

-

-

146.3 20 7.0 94 -0.8510

-25 7.0 79 -0.8312

-26.5

-

-

-

253.1 30 7.0 80 -0.7916

-35 7.0 100 -0.7718

-36.5

-

-

-

349.0 40 7.0 97 - 0.7125

-45 7.0 94 -0.6927

-46.5

-

-

-

432.0 50 7.0 91 -0.6828

-55 7.0 89 -0.6531

-56.5

-

-

-

504.1 60 7.0 86.5 -0.6135

-65 7.0 85 - 0.5937 -66.5

-

-

-

587.1 70 7.0 82.5 0.5739

-75 7.0 81 -0.5541

-76.5

-

-

-

670.3 80 7.0 78 -0.554!

-85 7.0 76.5 -0.5343

-86.5

-

-

-

742.5 90 7.0 73 -0.5146

-95 7.0 72 0.4948

-96.5

-

-

-

802.! lOO 7.0 70 0.4552

-105 7.0 67 0.4354

-106.5

-

-

898.5 110 0.5 63 - 0.6135

-115 4.5 44 -0.6432

-116.5

-

-

-

934.6 120

- 4.5

53.5 -- 0.5838

-125

- 4.5

53.5 -0.5541

-126.5

-

-

-

1018.1 130

- 4.5

53.5 0.5442

-135

- 4.5

53.5 0.5343

-136.5

-

-

-

1066.5 140

- 4.5

53.5 - 0.5146

-145 -10.0 50 -0.554!

-146.5

-

-

-

1114.8 150

-17

51.5 0.7125

-155 --17 62.0 -0.8609

-156.5

-

-

-

_1138.9 160

-17

73.5 0.8015

-165

-17

77.5 0.7125

-166.5

-

-

-

1163.1 170

-17

80 - 0.7224

-175

-17

81.5 - 0.7125

-176.5

-

-

-

1187.2 180

-17

82.5 0,7125

-185 17 83 --0.7125

-186.5

-

-

- 1211.4 190 17 83.5 0.7125

-195 - 7 84 0.7125

-196.5

-

-

-

1235.6 200 17 90.5 -0.7125

-205 17 93 -0.7125

-206.5

-

-

-

1250.4 210 - 17 94.5 -0.7125

-215 --17 94.5 -0.7125

-216.5 -

-

-

1274.5 220 7 94.5 -0.7125

-225 --17 93.5 -0.7125

-226.5

-

-

-

1282.0 230 17 92.5 -0.7125

-235

-17

91 -0.6927

-236.5

-

-

-

1290.0 240

-17

80 -0.6927

-245

-17

86 -0.6927

-246

-

-

-

1300.0 time in sec, pitch in degrees RPM thrust in MN distance travelled in ni 0 23 114 0.7916 0 5 19.5 100 0.4552 31.8 10 24.5 87 0.0990

-15 23.5 77 -0.2969 115.7 20 20.0 79 -0.5937 -25 13.5 95 -0.9697 213.3 30 8.0 78 1.1083

-35 7.0 97 -1.0687 287.7 40 7.0 93 -1.0291

-45 7.0 91 -0.9895 356.5 50 7.0 87 -0.9500

-55 7.0 85 -0.9203 422.0 60 7.0 83 -0.8807

-65 7.0 81 -0.8312 487.5 70 7.0 78 -0.8015

-75 7.0 76 -0.7718 553.0 80 7.0 73 -0.7520

-85 7.0 71 -0.7224 618.0 90 7.0 67 -0.7026

-95 7.0 65 -0.6828 667.7 100 7.0 63 -0.6531

-105 7.0 61 -0.6333 716.5 110 7.0 60 -0.6135

-115 7.0 58 -0.5739 770.7 120 7.0 56.5 -0.5541

-125 7.0 55 -0.5343 821.7 130 7.0 53 -0.5146

-135 7.0 52 -0.4849 871.4 140 7.0 50 -0.5541

-145 LO 51 -0.6927 912.6 ISO

- 3.5

52 -0.6036

-55

- 3.5

52 -0.5343 962.2 60

- 3.5

52 -0.4948

-165

- 3.5

52 -0.4750 1010.9 170

- 3.5

52 -0.4750

-175

- 3.5

52 -0.4750 1045.3 180

- 3.5

52 -0.4750

-185 - 3.5 52 -0.5146 1079.6 190 -10.0 52 -0.6036

-195 ---13.5 52 -0.6828 1110.8 200 -15.5 64 -0.7125

-205 -16.0 68 -0.7125 1144.7 210 -16.0 71 -0.7026

-215 -16.0 72 -0.6828 1178.6 220 -16.0 73 -0.6630

-225 -16.0 74 -0.6531 1199.2 230 --16.0 74 -0.6432

-235 -16.0 74 -0.6333 1215.6 240 -16.0 74 -0.6333

-245 -16.0 74 -0.6333 1236.1 250 -16.0 74 -0.6333

-255 -16.0 75 -0.6333 1258.3 260 -16.5 75 -0.6333

-265 -16.5 76 --0.6333 1259.2 270 -16.5 77 -0.6333

-275 -16.5 77 -0.6333 1259.7 278 -16.5 78 -0.6333 1260.0

14

rpm 24

110 22

loo 20

90 18

80 16

70 14

60 12

50 10

3. 6

20 4

10 2

00

-2

-4

-6

-8

41 8

L1O O) C

s-16

n. -18

i

sin m x1/1OO -12 1 l lU in rn/sec.

thrust in MN 'xlO

lol---..'

ç:;]

-I

-/

4!

50

100 150

200 time in sec. 250

full scale measurement; crash

stop no. 2.

calculated for

m=0.06m

calculated

for

m=0.10 m

calculations were carried out

using the measured thrustvalues

as input and applying

1-t=0.82_---pitch

thrust

t=278s. S=1260.O

distance travelled S

-ships speed )

50

110 150

_{200 time in sec. 250}

E

n

h. V) o N V)

Fig. 3. Comparison between calculated and measured histories of speed and distance travelled for ship with given stopping procedure.

rpm 24

110 22

100 20

90 18

80

16

70 14

60 12

50 lo

40 8

30- 6

20 4 10- 2

o- o

-2

-4

-6

-

8--lo.

L 7- 6-4 3- 2-

1-o

thrust ¡n MN xlO

sin m

xl/lOO

-50

loo

\ 150 200 time ¡n sec.

250

Ta-.-

fpr-tCh

\

./

full scale measurement; crash

stop no

3.

calculated for

m=0.06m.

calculated for

rn=0.l0 m.

calculations were carried out

using measured thrust values

as input

and applying

U n rn/sec

1-t=O.824

- -S---S____._ S- SSS5 -'S '--S- -SS55

-thrust

pitch

distance tmvelled S

t-246 S-1300m s -c----.. _{ships speed U}

----.

-S- -E o CLI LI,

200 time in sec. 250

Fig. 4. Comparison between calculated and measured histories of speed and distance travelled for ship with given stopping proced ure. 15 13 12 11

lo

9 8 So 100 150

16

deceleration is predicted, and for crash stop no. 3 just

the opposite.

In order to investigate the sensitivity of the calculated

results for a change in the estimated magnitude of the

apparent mass, the calculations were repeated, with

¿tni equal to IO per cent

of m

instead

of

to 6 per cent.

The results are also shown in Fig. 3 and 4.

As can be noticed, the effect of the change is small,

and as a matter of fact only noticeable towards the

end of the manoeuvres, for crash stop no. 2 giving an

improvement with respect to the head reach and the

stopping time, for crash stop no. 3 also with respect

to the head reach, but being adverse with respect to the

stopping time.

4 Discussion

The reason for using in the first instance measured

thrust values for the calculation of the stopping time

an the head reach is of course that otherwise the thrust

should have had to be calculated as well, which would

have introduced the uncertainty with respect to the

wake factor.

Although the thrust measurements are not very

accurate (the tests on the model were in the first place

aimed at the development

of

a special technique for

carrying out stopping tests in a towing tank), the

con-clusion may be drawn from the foregoing paragraphs

that the assumption of the thrust deduction factor being

constant throughout the manoeuvre may lead to large

errors in the predictions.

Hence it can be stated, that for obtaining

satis-factory predictions a reasonable knowledge of the

magnitude of this factor for all the various conditions

occurring during the stopping manoeuvre is necessary.

Most probably this will also apply to the wake factor.

If the thrust deduction factor is solved from the

longitudinal equation

of

motion, using the measured

values of the thrust and speed as known quantities

(so for the case of complete agreement between

mea-surements and calculations with respect to the histories

of speed and distance travelled), these t-values appear

to be very inconsistent. It has appeared to be impassible

to derive a function oft related to propeller parameters,

due to too much scattering of the data.

A variation in the estimation of the apparent mass

from 1.06 m to 1.10 m appears to have little effect.

Remark:

Inaccuracies in the expression for the ship's resistance

in the lower speed range appear to be less important,

because for instance at 12 knots the resistance amounts

only to about 25 per cent of the braking propeller force.

5 References

I. STRÖM-TEJSEN.J. and R. R. PORTER, Prediction of controllable

pitch propeller performance in off-design conditions. Third Ship Control Systems Symposium-Bath; paper VII B-l. VAN DE VOORDE, C. B., Stopping abilities of a high speed

cargo ship equipped with a controllable pitch propeller

NSMB - report no. 68-057 BT.

'T HART, H. H., Speed trials and stopping manoeuvres on

m.s. Koudekerk". Institute TNO for Mechanical

Con-structions; Report 4709/3; febr. 1969 (in dutch).

- Decca Navigator Speed Trials ms. "Koudekerk", report of

22nd nov. 1968. Internationale Navigatie apparaten n.y.

APPENDIX i

Stopping tests in a towing tank on a model of

m.s. "Koudekerk", equipped with a controllable

pitch propeller

In 1968 the Netherlands Ship Research Centre

- TNO

ordered the Netherlands Ship Model Basin to carry

out exploratory stopping tests on a model of ms.

"Koudekerk".

A summary of the work, reported in ref. [2:1, is given

here.

I. Particulars

of

ship and propeller

length between perpendiculars

Lpp = 152.4

m

breadth moulded

B

= 21.03 m

draft moulded on FP

T

=

7.82 m

draft moulded on AP

TA 8.28 ni

mean draft

8.05 IT)

displacement volume

V

_{= 16,212m3}

propeller type

C.P.

propeller diameter

D

=

6.1 m

pitch ratio at 0.7 radius

P07/D = 0.932

blade area ratio

AE/AO = 0.483

number of blades

z

=4

The propeller was designed to absorb 12,740 DHP

metric at 114 RPM and a speed of 19.5 knots.

rollers

2 Method

of

testing

The application of Froude's scaling law requires a

correction on the skin friction force, due to differences

in Reynolds number for model and ship. Hence a

stopping test on a model would yield incorrect data

for the ship, if the test in the towing tank is carried out

without any provision for making up for this

speed-dependent skin friction correction force.

Such a provision lias been found in the application

of a so-called skin friction correction force device,

which is a winged body consisting of some perforated

plastic tubes with open end faces. In operation, it will

be completely submerged and towed through the

water by the towing carriage, while small adjustable

fins and stabilizers will prevent the device from

de-viating from a straight horizontal course.

The configuration of this resistance creating body

has been made such, that its resistance at any speed is

equal to the calculated skin friction correction force.

The resistance may be considered as being only friction

resistance. Inertia forces may be neglected, because

the mass and the displacement (added mass) are very

small. The test set-up is depicted in fIg. 5.

The ship model under the towing carriage is free to

move in the course direction, after the carriage has

brought the model to its initial speed and the now

self-propelled model has been released.

Guiding rods and rollers prevent the model from

pivot -

jcint_-2

position manually

adj usted

Fig. 5. Sketch of test set-up for conducting stopping tests in a towing tank. Guiding rod connected to carriage.

Skin friction correction force device.

Pulley.

Bar connected to carriage by means of a pivot-joint for correcting differences between speed of carriage and of model.

18

going athwart. The resistance of the device is

trans-mitted as a pulling force to the ship model by means of

a wire around a pulley. This pulley is connected to one

end of a long bar, which at the other end is attached to

the carriage by means of a pivot-joint.

During a stopping test the towing carriage follows

the model as accurate as possible. Inevitable small

speed deviations are corrected for by continuous

manual adjustments of the bar, maintaining the relative

position of the pulley with respect to the ship model;

thus ensuring at any time equal speeds of ship model

and device.

As can be seen in Fig. 5 the position of the device

has been chosen ahead of the model; far ahead so that

the ship model will hardly be affected by the wake of

the device. The device aft of the ship model would

have been too much affected by the propeller slip

stream.

The stopping manoeuvre is initiated by a change of

pitch. Both pitch and RPM are remotely controlled

from the carriage. Rate of change of pitch amounts to

1.0375 degrees per second.

During the manoeuvre the RPM was varied by

manual contrcl in such a way that neither wind milling

of the propeller occurred nor the maximum allowable

torque was hardly exceeded.

The data recorded during a run were: distance

trav-elled, speed, RPM, thrust, torque, pitch angle and the

resistance of the skin friction correction force device.

3

Tests carried out

0f the tests carried out two runs have been selected as

examples to serve the purpose set out in paragraph 3.2.

From the recordings made during these two runs

the following data have been taken; time, pitch, RPM,

thrust and speed. They are presented in Table I.

The

initial speed amounts to 19.5 knots at RPM =

109.7

and at 23° pitch setting.

APPENDIX 2

Full scale stopping tests on m.s. "Koudekerk",

equipped with a controllable pitch propeller

I

Particulars of ship and propeller

length between perpendiculars

Lpp

= 152.4

m

breadth moulded

B

= 21.03 m

draft on FP

TF

=

8.204m

draft on AP

TA

=

8.077m

mean draft

814 m

displacement weight

A

= 16,875

metric tons

propeller type

c.P.

diameter

D

=

6.1

pitch ratio at 0.7 radius

P07/D =

0.933

blade area ratio

AE!AO = 0.467

number of blades

z

=

4

The propeller was designed for an engine power of

14,200 (metric) HP at 117.5 RPM (no gear reduction).

2

Method of testing

During a crash stop the following quantities were

recorded:

RPM, thrust, torque, pitch and position of fuel

handle. The speed was not recorded.

For details on the technique applied reference is

made to ref. [3]. The tests were conducted in the

Gall-opper area.

The distance travelled was derived from Decca plots

(ref. [4]).

The head reach is taken as the sum of the distances

between the positions measured at two consecutive

points of time, hence it is not taken as the distance

be-tween the positions at the beginning and at the end of

a run.

3 Tests carried out

Of the crash stops carried out two runs have been

selected as examples to serve the purpose set out in

paragraph 3.3.

From the available information the following data

have been taken: time, pitch, RPM, thrust and

dis-tance travelled. They are presented in Table

2.

The initial speed amounts to 19.6 knots at RPM-I 14

and at 23 pitch setting. During both runs there was

no current.

During crash stop no. 2 the prevailing wind was,

wind force 5, head on. During crash stop no. 3 the

wind conditions were; wind force 5, on starboard beam

under 60° from the bow.

For keeping course rudder action was applied

PUBLICATIONS OF THE NETHERLANDS SHIP RESEARCH CENTRE TNO

LIST OF EARLIER PUBLICATIONS AVAILABLE ON REQUEST PRICE PER COPY DFL. lo.- (POSTAGE NOT INCLUDED)

M = engineering department S = shipbui1dng department C = corrosion and antifouling department

Reports

i 14 S The steering of a ship during the stopping manoeuvre. J. P.

Hooft, 1969.

115 S Cylinder motions in beam waves. J. H. Vugts. 1968.

116 M Torsional-axial vibrations of a ship's propulsion system. Part I. Comparative investigation ofcalculated and measured torsional-axial vibrations

in the shafting of a dry cargo motorship.

C. A. M. van der Linden, H. H. 't Hart and E. R. Dolfìn, 1968.

J 17 S A comparative study on four different passive roll damping

tanks. Part II. J. H. Vugts, 1969.

I I 8 M Stern gear arrangement and electric power generation in ships propelled by controllable pitch propellers. C. Kapsenberg, I 968. I 19 M Marine diesel engine exhaust noise. Part IV. Transferdamping

data of 40 modelvariants of a compound resonator silencer.

J. Buiten, M. J. A. M. de Regt and W. P. Hanen, 1968. 120 C Durability tests with prefabrication primers in use for steel plates.

A. M. van Londen and W. Mulder. 1970.

121 S Proposal for the testing of weld metal from the viewpoint of

brittle fracture initiation. W. P. van den Blink and J. J. W.

Nib-bering, 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 engineering. Part III. Proposal for a specifi-cation of a marine refrigerating unit and test procedures. J. A. Knobbout and R. W. J. Kouffeld, 1968.

124 S The design of U-tanks for roll damping of ships. J. D. van den Bunt, 1969.

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 II. 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 oíl tanks in dry cargo ships. D. J. van der

Heeden. 1969.

129 M Residual fuel treatment on board ship. Part EJE. 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.

132 M Torsional-axial vibrations of a ship's propulsion system. Part II. W. van Gent and S. Hylarides, 1969.

133 S A model study on the noise reduction effect of damping layers aboard ships. F. H. van ToI. 1970.

134 M The corrosion behaviour of cunifer-lO alloys in

seawaterpiping-systems on board ship. Part Il. P. J. Berg and R. G. de Lange.

1969.

135 S Boundary layer control on a ship's rudder. J. H. G. Verhagen.

1970.

136 S Observations on waves and ships behaviour made ori board

of Dutch ships. M. F. van Sluijs and J. J. Stijnman, 1971. 137 M Torsional-axial vibrations of a ship's propulsion system. Part 11E.

C. A. M. an der Linden, 1969.

138 5 The manoeuvrability of ships at low speed. J. P. Hooft and

M. W. C. Oosterveld, 1970.

139 5 Prevention of noise and vibration annoyance aboard a sea-going

passenger and carferry equipped with diesel engines. Part I.

Line of thoughts and predictions. J. Buiten, J. H. Janssen.

Fi. F. Steenhoek and L. A. S. Hageman, 1971.

140 S Prevention of noise and vibration annoyance aboard a sea-going

passenger and carferry equipped with diesel engines. Part II. Measures applied and comparison of computed values with

measurements. J. Buiten, 1971.

141 S Resistance and propulsion of a high-speed single-screw cargo liner design. J. J. Muntjewerf. 1970.

142 S Optimal meteorological ship routeing. C. de Wit, 1970.

143 S Hull vibrations of the cargo-liner "Koudekerk". H. H. 't Hart,

1970.

144 S Critical consideration of present hull vibration analysis. S.

Hyla-rides. 1970.

145 S Computation of the hydrodynamic coefficients of oscillating

cylinders. B. de Jong, 1973.

146 M Marine refrigeration engineering. Part IV. A Comparative study on single and two stage compression. A. H. van der Tak, 1970. 147 M Fire detection in machinery spaces. P. J. Brandenburg. 1971.

148 S A reduced method for the calculation of the shear stiffness of a ship hull. W. van Horssen, 1971.

149 M Maritime transportation of containerized cargo. Part II. Experi-mental investigation concerning the carriage of green coffee from Colombia to Europe in sealed containers. J. A. Knobbout, 1971. 150 5 The hydsodynamic forces and ship motions in oblique waves.

J. H. Vugts, 1971.

1 51 M Maritime transportation of containerized cargo. Part I. Theoretical and experimental evaluation of the condensation risk

when transporting containers loaded with tins in cardboard

boxes. J. A. Knobbout, 1971.

I 52 S Acoustical investigations of asphaltic floating floors applied on a steel deck. J. Buiten, 1971.

I 53 S Ship vibration analysis by finite element technique. Part II. Vibra-tion analysis. S. Hylarides, 1971.

154 S Canceled.

155 M Marine diesel engine exhaust noise. Part VI. Model experiments on the influence of the shape of funnel and superstructure on the radiated exhaust sound. J. Buiten and M. J. A. M. de Regt, 1971. 156 S The behaviour of a five-column floating drilling unit in waves.

J. P. Hooft, 1971.

I 57 S Computer programs for the design and analysis of general cargo ships. J. Holtrop, 1971.

158 5 Prediction of ship manoeuvrability. G. van Leeuwen and

J. M. J. Journée, 1972.

159 S DASH computer program for Dynamic Analysis of Ship Hulls. S. Hylarides, 1971.

160 M Marine refrigeration engineering. Part VII. Predicting the con-trol properties of water valves in marine refrigerating installations A. H. van der Tak, 1971.

161 S Full-scale measurements of stresses

in the bulkcarrier m.v.

'Ossendrecht'. ist Progress Report: General introduction and

information. Verification of the gaussian law for stress-response to waves. F. X. P. Soejadi, 1971.

162 S Motions and mooring forces of twin-hulled ship configurations. M. F. van Sluijs, 1971.

163 S Performance and propeller load fluctuations of a ship in waves. M. F. van Sluijs, 1972.

164S The efficiency of rope sheaves. F. L. Noordegraaf and C. Spaans, 1972.

165 S Stress-analysis of a plane bulkhead subjected to a lateral load.

P. Meijers, 1972.

166 M Contrarotating propeller propulsion, Part I, Stern gear, line

shaft system and engine room arrangement for driving contra-rotating propellers. A. de Vos, 1972.

167 M Contrarotating propeller propulsion. Part H. Theory of the dynamic behaviour of a line shaft system for driving

contra-rotating propellers. A. W. van Beek, 1972.

168 S Calculations and experiments with regard to the stopping of a

ship with diesel propulsion and fitted with a controllable pitch propeller. C. B. van de Voorde. 1974.

169 S Analysis of the resistance increase in waves of a fast cargo ship. J. Gerritsma and W. Beukelman, 1972.

170 S Simulation of the steering- and manoeuvririg characteristics of

a second generation container ship. G. M. A. Brummer, C. B.

van de Voorde, W. R. van Wijk and C. C. Glansdorp, 1972.

172 M Reliability analysis of piston rings of slow speed two-stroke

marine diesel engines from field data. P. J. Brandenburg, 1972. 173 S Wave load measurements on a model of a large container ship.

Tan Seng Gie, t972.

174 M Guide for the calculation of heating capacity and heating coils for deep tanks. D. J. van der Heeden and A. D. Koppenol, 1972. 175 S Some aspects of ship motions in irregular beam and following

waves. 13. de Jong. 1973.

177 M Maritime transportation of containerized cargo. Part HI. Fire

tests in closed containers. H. J. Souer, 1973. 178 S Fracture mechanics and fracture control for ships.

J. J. W. Nibbering, 1973.

179 S Effect offorward draught variation on performance offull ships. M. F. van Sluijs and C. Flokstra, 1973.

I 80 S Roll damping by free surface tanks with partially raised bottom. J. J. van den Bosch and A. P. de Zwaan, 1974.

182 S Finite element analysis of a third generation containership.

A. W. van Beck, 1973.

183 M Marine diesel engine exhaust noise. Part VII. Calculation of the

acoustical performance of diesel engine exhaust systems. J. Buiten,

E. Gerretsen and J. C. Vellekoop, 1974.

184 S Numerical and experimental vibration analysis of a deckhouse. P. Meijers, W. ten Cate, L. J. Webers and J. H. Vink, 1973. 185 S Full scale measurements and predicted seakeeping performance

of the containership "Atlantic Crown". W. Beukelman and

M. Buitenhek, 1973.

186 5 Waves induced motions and drift forces on a floating structure. R. Wahab, 1973.

187 M Economical and technical aspects of shipboard reliquefaction of cargo "Boil-off" for LNG carriers. J. A. Knobbout, 1974. 188 S The behaviour of a ship in head waves at restricted water depths.

J. P. Hooft, 1974

189 M Marine diesel engine exhaust noise. Part VIII. A revised mathe-maticaJ model for calculating the acoustical source strength of the combination diesel engine - exhaust turbine. P. J. Branden-burg, 1974.

190 M Condition monitoring, trend analysis and maintenance prediction for ship's machinery (literature survey). W. de Jong, 1974.

191 5 Further analysis of wave-induced vibratory ship hull bending

moments. F. F. van Gunsteren, 1974.

192 S Hull resonance no explanation of excessive vibrations. S.

Hyla-rides, 1974.

193 S Wave induced motions and loads on ships in oblique waves.

R. Wahab and J. H. Vink, 1974.

194 M On the potentialities of polyphenylene oxide (PPO) as a wet-insulation material for cargo tanks of LNG-carriers. G. Opschoor,

1974.

195 S Numerical hull vibration analysis of a Far East container ship.

P. Meijers, 1974.

196 S Comparative tests of four fast motor boat models - in calm

water and in irregular head waves and an attempt to obtain full-scale confirmation. J. J. van den Bosch, 1974.

197 M Transverse vibrations of ship's propulsion systems. Part I. Theoretical analysis. S. Hylarides. 1974.

198 M Maritime transportation of containerized cargo. Part IV.

Evalu-ation of the quality loss of tropical products due to moisture

during seatransport. P. J. Verhoef, 1974.

199 S Acoustical effects of mechanical short-circuits between a floating floor and a steel deck. J. Buiten and J. W. Verheij, 1974. 200 M Corrosivity monitoring of crankcase lubricating oils for marine

diesel engines. L. M. Rientsma and H. Zeilmaker, 1974. 201 S Progress and developments of ocean weather routcing. C. de Wit,

1974.

202 M Maritime transportation of containerized cargo. Part V. Fire

tests in a closed aluminium container. H. J. Souer, 1974.

203 M Transverse vibrations of ship's propulsion systems. Part Il.

Experimental analysis. L. J. Wevers, 1974.

206 S Synthesis of cooperative fatigue investigations with notched plates and welded ship structures of St 42 and St 52. J. J. V. Nibbering, H. G. Schotte and J. van Lint, 1974.

Communications (Mededelingen)

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

19 S The computer programmes system and the N.ALS language for numerical control for shipbuilding. H. le Grand, 1969.

20 S A case study on networkplanning in shipbuilding (Dutch). J. S. Folkers, H. J. de Ruiter, A. W. Ruys, 1970.

21 S The effect of a contracted time-scale on the learning ability for manoeuvring oflarge ships (Dutch). C. L. Truijens, W. A. Wage-naar, W. R. van Wijk, 1970.

22 M An improved stern gear arrangement. C. Kapsenberg, 1970. 23 M Marine refrigeration engineering. Part V (Dutch). A. H. van der

Tak, ¡970.

24 M Marine refrigeration engineering. Part VI (Dutch). P. J. G. Goris and A. H. van der Tak, 1970.

25 S A second case study on the application of networks for pro-ductionpianning in shipbuilding (Dutch). H. J. de Ruiter, H.

Aartscn, W. G. Stapper and W. F. V. Vrisou van Eck, 1971.

26 S On optimum propellers with a duct of finite length. Part I!.

C. A. Slijper and J. A. Sparenberg, 1971.

27 S Finite element and experimental stress analysis of models of shipdecks, provided with large openings (Dutch). A. W. van

Beck and J. Stapel, 1972.

28 S Auxiliary equipment as a compensation for the effect of course instability on the performance of helmsmen. W. A. Wagenaar,

P. J. Paymans, G. M. A. Brummer, W. R. van Wijk and C. C.

Gtansdorp, 1972.

29 5 The equilibrium drift and rudder angles of a hopper dredger

with a single suction pipe. C. B. van de Voorde, 1972.

30 S A third case study on the application of networks for production-planning in shipbuilding (Dutch). H. J. de Ruiter and C. F.

Heu-nen, 1973.

31 S Some experiments on one-side welding with various backing

materials. Part 1. Manual metal arc welding with coated

electro-des and semi-automatic gas shielded arc welding (Dutch). .1. M. Vink, 1973.

32 S The application of computers aboard ships. Review of the state of the art and possible future developments (Dutch). G. J. Hoge-wind and R. Wahab, 1973.

33 S FRODO, a computerprogram for resource allocation in network-planning (Dutch). H. E. I. Bodewes, 1973.

34 5 Bridge design on dutch merchant vessels; an ergonomic study. Part

I: A summary of ergonomic points of view (Dutch).

A. Lazet, H. SchufTel, J. Moraal, H. J. Leebeek and H. van Dam, 1973.

35 S Bridge design on dutch merchant vessels; an ergonomic study.

Part Il: First results of a questionnaire completed by captains, navigating officers and pilots. J. Moraal, H. Schuffel and A. Lazet,

1973.

36 S Bridge design on dutch merchant vessels; an ergonomic study.

Part III: Observations and preliminary recommendations. A. Lazet, H. Schuffel, J. Moraal, H. J. Leebeek and H. van Dam,

1973.

37 S Application of finite element method for the detailed analysis of hatch corner stresses (Dutch), J. H. Vink, 1973.

38 S A computerprogram for displacement and stress analysis with membrane elements on constructions consisting of plates and trusses. User's manual (Dutch). G. Homniel and J. H. Vink, 1974.

39 S Some experiments on one-side welding with various backing

materials. Part IL. Mcchanised gas-shielded arc welding in the flat and horizontal position (Dutch). J. M. Vink, 1974.