Annual Report 1975 of the Netherlands Ship Model Basin - NSMB - Wageningen

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Netherlands Ship Model Basin

Wageningen, the Netherlands

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Annual report 1975

Foundation

Netherlands Ship Model Basin

Wageningen, the Netherlands

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On March 12,1976, before this Annual Report went to press, M r . John W. Hup-kes, chairman of the Board of Directors, passed away. He was succeeded by M r . P. E. E. Kleyn van WilHgen.

The Netherlands Ship Model Basin is located in Wageningen, Haagsteeg 2, P.O. Box 28,

Telephone: (08370) 19140

Telex: 45148 '• Telegrams: Modeltank

Bankers: Algemene Bank Nederland N.V., Wageningen, Account: 53.93.39.156

The Depressurized Towing Tank is located in Ede, Niels Bohrstraat 10 Telephone: (08380) 19115

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Board of Directors, Management, Advisory

Board, Consultant, Representatives Abroad

Board of directors *

Chairman Vice-Chairman Secretary Members

P. E. E. Kleyn van WiUigen Shipowner

D r H . J. H . Janssen Under-Secretary of State for

Shipping

O. J. van der V o r m Central Association of Dutch

Shipbuilders

J. van der Brugge Ministry of Finance

R. J. H . Fortuyn Royal Netherlands Shipowners

Association

J. Groenendijk Shipowner

Prof, dr W. P. A . van Lammeren Former President

NSMB

C. J. D . Riethof Ministry of Economic Affairs

A . Stikker Shipbuilder

Management

President Vice-Presidents

Prof, dr J. D . van Manen

A . H . Pastoor, Registeraccountant Administration and

Pittance

D r J. P. H o o f t Ship Dynamics - Offshore Technology J. J. Muntjewerf Ship Powering

D r M . W. C. Oosterveld Research and Development

Advisory board

Members A. Laredo Shipbuilder (France) D r L . A . van Gunsteren Shipbuilder J. W. Maingay Ship Propeller Manufacturer J. F. Meijer Royal Netherlands Navy

G. Nilsson Shipbuilder (Sweden) H . M . Oudshoorn Ministry of Transport

and Public Works, Rijkswaterstaat

D r E. M . Q. Roren Det norske Veritas (Norway) L . P. Ruys Shipowner

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Consultant

Prof, dr R. Wereldsma University of Technology,

Delft

Representatives Australia - Antelope Engineering Pty., L t d . , Milson's abroad Point, N.S.W.

U.S.A., Gulf area - M r Blakely Smith, Houston Japan - MacGregor Far East L t d . , Tokyo

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Continuously intellectual enthousiasm, stimulating phenomenon description, criticizing mathematical simulation,

optimizing, talking - listening.

In the loneliness of his scientific level amidst his friends, he passed away, his thoughts are living.

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Memorial: Rein Timman, 1917-1975

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General

The year 1975 saw many initiatives of the shipbuilding and shipping industry to counteract the disastrous collapse of the tanker market. Though the devel-opment of multi-purpose ships, product-carriers, LNG-ships, roll-on roll-off ships is influenced by some lack of confidence of the industry in the economic developments, these moderate activities prevented a decrease of the orders to the N S M B .

This same lack of confidence in world economy caused some stability in the sometimes too rapid growth of offshore and ocean engineering activities.

The maritime aspects of offshore and ocean engineering caused an increase of orders w i t h respect to the development of supply vessels, very large tugs for unconventional tows and the handling of such unconventional tows.

The increasing apphcation of the ship handling simulator for complicated ship manoeuvres around harbour entrances and f o r positioning of offshore structures has to be mentioned, as well as tests combined with extreme sea conditions and the availability of a growing number of software possibilities for the computations of marine projects.

This also holds for the successful penetration of the depressurized towing tank into the investigation of the hydro-acoustic properties of ship propulsion, the effect of cavitation on ship vibrations, the observation techniques of cavi-tating propeller models and the control of the physical properties of tank water.

The D e l f t Hydraulics Laboratory and the Netherlands Ship Model Basin are building up a joint venture in which they will combine their research capa-bilities in the field of offshore constructions to come to a unique scientific in-dustrial service. The name of this joint venture will be Netherlands Ocean En-gineering Laboratories (NOEL). I n this way hydrodynamic, morphologic and soil mechanic problems can be treated in their mutual relations as they occur in ocean engineering.

The close co-operation with the Reactor Centrum Nederland, Petten, with regard to computer operations has been effectuated by the foundation of the partnership R C N - N S M B Computer Centre.

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Some highlights as well as a sad event in the course of the year are mentioned below.

- D r E. Mocklinghof, President of the Federal State of Munster, Germany, visited our laboratories in April.

- I n the May-meeting of the Board of Directors, M r J. Groenendijk entered as a new member, while M r P. de Josselin de Jong and M r O. W. Vos retired.

- M r J. J. Muntjewerf was appointed 'Membre correspondant pour les Pays-Bas' of the Association Technique Maritime et A é r o n a u t i q u e , in August 1975. - I n October prof, dr J. D . van Manen was elected into Fellowship of The

Royal Institute of Navigation, London.

- I n November prof, dr R. Timman, a consultant of the Netherlands Ship Model Basin, passed away.

- I n November M r J. W. Boylston, M r D . J. de K o f f and M r J. J. Muntjewerf were presented with the Certificate of Honorable Mention of the Society of Naval Architects and Marine Engineers, New York, for their paper 'SL-7 Containerships: Design, Construction and Operational Experience'.

- I n the November-meeting of the Board of Directors M r J. van der Brugge entered as a new member.

- D r L. A . van Gunsteren entered as a new member of the Advisory Board. - M r A. Stemerdink, Parliamentary Under-Secretary for Defense (Matériel), and Lieutenant-General J. Hensen, Chairman of the Council of Matériel visited our laboratories in December.

- I n the course of 1975 the 5000th ship model and the 5000th propeUer model were manufactured, which historical events were duly celebrated at the N S M B .

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Cavitating propeller in depressurized towing tank Picture taken by underwater photo camera.

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Also in this year some orders for the offshore industry have been performed. The effect of spoiling and interaction has been investigated for a semi-sub-mersible drilhng platform, fitted with azimuthing right angle drive thrusters. It was shown that the interaction can be significant, dependent upon the thruster configuration and its location. For dynamic positioning it is necessary to include these effects in the dynamic simulation studies.

Spoiling and interaction tests have also been conducted for a ship provided with vertical axis propellers. The effect of interaction and spoiling upon thrust and thrust direction was very interesting.

For a drilling vessel, extensive model tests have been carried out to in-vestigate the forces on the model as a function of current velocity, current direction, pitch setting of propeller and impellers and location of the thruster. Also the mutual interference of the various thrusters has been investigated. In co-operation with shipowners and shipyards, cavitation observations have been performed on a large tanker fitted with a ducted propeller.

A start has been made to investigate the effect of vortex generators upon the vibration behaviour of ships. The investigations will cover propulsion, wake, flow visualization and pressure fluctuations.

Cavitation tunnels

The cavitation tunnel with flow regulator was mainly used for industrial orders. I n this tunnel, cavitation observation tests are made to predict the risk for erosion. The prediction is normally based on the type of cavitation observed. To obtain additional information on the risk of erosion, a research program was initiated in which first an erosion-sensitive paint was developed to be used on propellers and nozzles. The prediction of erosion on nozzles cannot be based on the type of cavitation observed. The paint technique can only give qualita-tive information. To obtain quantitaqualita-tive information a new prediction method is being developed. It basically consists of testing aluminium or copper test pieces inserted in the nozzle.

The large cavitation tunnel was intensively used for testing the cavitation behaviour of propellers behind dummy ship models or in oblique flow. A large number of tests was concerned with ducted controllable pitch propeller systems for tug boats and supply vessels. I n these tests emphasis was laid upon a proper connection of the duct to the ship's hull. Other tests were aimed at getting a better performance for ducted controllable pitch propellers, in particular for the bollard pull condition.

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holo-graphic study of cavitation on axisymmetric bodies was made i n the high speed water tunnel. A new technique has been developed for the purpose of flow visualization. I n principle, the method consists of making holograms when injecting a fluid with an index of refraction slightly different f r o m the surrounding fluid. Two axisymmetric bodies were investigated, one having laminar f l o w separation, the other not having i t . The implications of this feature on incipient and developed cavitation were studied. Further, by in-vestigating the influence of polymer additives on the flow about one of the test models, an explanation was found for the suppression of cavitation by polymer injection.

Depressurized towing tank

It was necessary to work in double shifts because of the load of industrial orders and of the need to take f u l l advantage of the excellent capabilities of the facility to support the scientific research work.

I n addition to the regularly performed tests, such as measurement of re-sistance and propulsion, propeller open-water characteristics, cavitation ob-servations, measurement of dynamic huU pressures and shaft forces etc., the measurement of the steady and dynamic blade spindle torque of controllable pitch propeller models can be carried out. I n particular the effect of cavitation on the steady as well as the dynamic torque can be determined. F r o m the design point of view of controllable pitch propellers this is most important.

The means for the observation of cavitation phenomena on propeUers and appendages, struts etc., have been improved and made more flexible. For instance, underwater photo cameras are available now. Flow phenomena and cavitation can also be observed f r o m a vessel running parallel to the ship model to be tested.

H Pick-up to measure static and

dyna-• mzc Ijlade spindle torque for one blade

HI^HHHB^^^^HilHHIj^^^H

of a controllable pitch propeller.

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N O N - C A V I T A T I N G C O N D I T I O N ( F R O M A T M O S P H E R I C T E S T )

Static and dynamic blade spindle torque of controllable pitch propeller of large container ship for cavitating and non-cavitating condUion at 30 knots ship speed.

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The industrial orders carried out the past year in the depressurized towing tank concerned mainly high powered ships such as liquid natural gas carriers, container ships, ocean going tugs and naval vessels. Besides, right angle drive propellers for dynamically positioned drill ships have been tested. I n projects associated w i t h naval ships and with right angle drive units for drill ships, the radiated propeller noise characteristics were established.

M u c h attention was paid to the fundamental aspects of cavitation. The ef-fect of the air content of the water and the Reynolds number on cavitation inception and the extent of cavitation was studied.

A new laser scattering technique was used to determine the size and the amount of small air bubbles (nuclei) in tank water. A method was adopted (electrolysis) to control the nuclei i n the basin.

Propulsion and ship hydrodynamics

The development of theoretical procedures and computer programs to aid in the interpretation of experimental results, to assess the importance of scale effects, etc., continued. Besides this theoretical work, the involvement in ex-perimental projects i n the depressurized towing tank also continued.

For the analysis of resistance and propulsion tests, a new set of computer programs was implemented. W i t h these programs the test results are cross-faired and extrapolated to f u l l scale by means of scale effect corrections which have been derived f r o m the results of a m o d e l - f u l l scale correlation analysis. This m o d e l - f u l l scale correlation analysis is based on an advanced physical model, together with a statistical data evaluation technique for the interpreta-tion of test results.

A new numerical procedure was developed to calculate the wave-making resistance o f surface ships f r o m parameters describing the waves produced by the ship. Initial results of calculations show promising results.

Research with regard to the wake field of ships was focussed on the dif-ference between nominal and effective wake, i.e. on the change of the wake field due to propeller-hull interaction. To be able to measure the wake in-fluenced by propeller suction in the plane of the propeller, the propeller action was simulated by a diffuser. Preliminary results showed a significant difference between nominal and effective wake.

A computer program has been developed for the determination of the ship frictional resistance with the aid of a semi- three-dimensional boundary layer calculation. The calculation method is based on Head's entrainment method. I n a first test case, fair agreement with experimental results was obtained.

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The theoretical description of the pressure field of a cavitating propeUer, and the associated computer program, was improved. A fair correlation with experimental results was obtained.

The numerical analysis required for the incorporation of propeller blades with rake and for the effect of radial inflow velocities in the mathematical hfting surface model for screw propeUers has been completed. The numerical program has been adapted to this refinement. A start has been made to define a procedure to calculate the non-uniform structure of the wake field which causes a specific unsteady load on the propeller. I n this way i t wiU become pos-sible to determine the structure of the effective wake field when the unsteady load is known, e.g., by measurement. A procedure has also been developed to transform the results of the existing lifting surface program into a format which is suitable as input for the existing program to calculate the stresses i n propeller blades based on finite element theory.

The existing program for the calculation of the performance and cavitation characteristics of screw propellers operating i n non-uniform flow was used in a number of studies to assess the importance of various propeller geometry and inflow parameters to derive advanced criteria for minimizing the occurrence of cavitation. A start was made to incorporate these findings in an advanced numerical program for the design of screw propellers.

Strength and vibrations

Interest i n the use of the finite element technique was growing, especially w i t h regard to the dynamic behaviour of propeller-shaftings. Transverse (whirling) as well as axial vibrations were investigated, accounting for added mass, damping and coupling effect of the water.

Using the unsteady lifting surface theory and the finite element method a detailed stress distribution over the propeller blade has been obtained. Also the dynamic behaviour of the stresses can be studied now, although the added mass and damping effect of the surrounding water have to be investigated in more detaü.

Most of the industrial orders concerned model tests in the depressurized towing tank. The measurement of the pressure fluctuations on the afterbody again accounted for the greater part of these experiments.

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Ocean engineering, ship dynamics

Seakeeping basin

During the year 1975, the tendency towards laborious and complicated ex-perimental projects necessitated a larger number of technicians at the test location.

As a consequence of this, the majority of the work was performed in one shift.

To the seakeeping facility a total of 25 industrial orders were awarded, classified as follows:

- Tests on surface vessels 40 per cent

- Tests on ocean platforms and barges 35 per cent

- Tests on deep water mooring systems and terminals 25 per cent

The demand for experimental research on conventional single-hull vessels decreased as compared with previous years; the traditional seakeeping ex-periments were mainly conducted for ships w i t h lengths ranging between 140 and 200 metres for which the behaviour at sea is important.

A very extensive model test program has been carried out for single point mooring systems projected for the Statfjord field o f f Norway in the northern part of the N o r t h Sea.

Special attention was given to the modelling of the underwater hose systems of these structures and to the electronic modelling of a bow hawser tension limiter, a device designed for reducing the peak forces i n the hawser by which a m o o r e d - o f f tanker is attached to the terminal.

I n these series of tests about 30 measuring channels had to be monitored simultaneously. I n this respect, the expansion of the measuring capacity, ef-fectuated i n 1974 by changing f r o m analog recording instrumentation into digital equipment, proved to be valuable.

Approximately 85 per cent of the total turnover of the year under review was related to orders f r o m the industry. The remaining 15 per cent was spent on account o f N S M B research, comprising a systematic investigation into the roll behaviour of L N G carriers, a systematic investigation into lateral forces and moments on a tanker model as introduced by rudder action (in co-opera-tion with the manoeuvring simulator) and an experimental investigaco-opera-tion into wave d r i f t force phenomena. I n addition to the experimental work, feasibility studies were performed by computer calculations for various configurations of ocean platforms as well as for surface vessels.

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Strip theory was used to predict wetness of declcs for four classes of tankers, ranging between 10,000 and 200,000 D W T , in order to establish to what extent safe operation is influenced by freeboard.

It is intended to modify and improve these prediction techniques so as to include non-linear effects.

Towing tank for unconventional maritime constructions

Most model studies in 1975 were performed to establish the behaviour of several tubular steel jackets during the transportation and installation. To this purpose extensive sea transport tests, launching and upending tests, stability and holding force measurements and critical wave studies - to observe whether the jacket will be overturned by high waves when standing on bottom prior to piling - were carried out. In many cases the upending behaviour of the jackets with some auxiliary buoyancy tanks damaged was examined. For some steel jackets and a hybrid gravity platform the forces and overturning moment were evaluated in waves either in combination with current or not.

To check the computer program which predicts the motions, accelerations and bending moments in the pipeline during laying operations, oscillation tests were conducted with pipelines partly supported by an articulated stinger and a skate, surging, heaving and pitching in calm water and waves. I t is expected that in 1976 model testing on steel jackets will continue.

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Combination of small pick-ups used for measuring longitudinal force and two bending moments in flexible underwater hoses as used on various offshore oil terminals.

Wave and current basin

The activities in the wave and current basin in 1975 were characterized by a large number of smaller projects. A total of 40 model test programs were performed of which only 5 took longer than 2 to 3 weeks to be executed.

Probably as a result of the introduction of new designs of vessels, like L N G carriers and fast container ships with non-familiar manoeuvring and course

keeping characteristics, more attention was paid to the steering of ships than in former years (20 per cent of the total activities).

The knowledge of the behaviour of underwater hose systems and the way in which these systems can be simulated on model scale could be further de-veloped and resulted i n some interesting model test programs on this subject.

I n the course of the year several interesting phenomena were observed on offshore structures which could not be explained w i t h conventional hydro-dynamic theories. Motions of structures in regular waves w i t h frequencies which differ f r o m the frequency of the waves became a subject for further research.

A n important step was put forward in the understanding of the drifting force on moored vessels in irregular waves. I n the near future we may expect to be able to present a sufficiently complete model for the description of these forces which are of major importance for a large number of mooring problems. Finally a study was started in co-operation with the Delft Hydraulics Labo-ratory to investigate problems concerning the generation of waves and current in a new planned deep-water 'Netherlands Ocean Engineering Laboratory'. For that purpose a 1 :10 model of the basin was built.

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LNG carrier moored to a jetty.

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Shallow water basio

The shahow water basin was occupied almost continuously with industrial work.

The extensive model testing of concrete gravity platforms for oil and gas production, reported in the previous annual report, continued. Some programs were carried out with ships moored to jetties or single buoy mooring systems.

The wave loads have been measured for several offshore structures, designed according to new concepts.

Over 40 per cent of the total amount of work was related to manoeuvring of ships, of which a small part consisted of free running model tests. The remainder was made up of static and dynamic force measurements on captive models. From the results of these tests the coefficients of the equations of motion can be determined, which may be used for programming the manoeuvring simula-tor or for computer calculation of standard manoeuvres.

A t the end of the year a large program was started, commissioned by the Ministry of Transport, Hydraulics and Pubhc Works, Rijkswaterstaat (De-partment of Traffic and Waterways) to determine the influence of mud on the bottom of a navigation channel on the manoeuvring of large ships. Since an accurate simulation of small underkeel clearance was essential for these tests, the bottom of the basin was leveled with a precision of + 1 mm before starting the tests.

I n the field of own research, an investigation on the motions of a large tanker in shallow water has been completed with an extensive comparison between results of model tests and of computations w i t h the three-dimensional diffrac-tion theory. The results of this study will be published shortly. Further, a com-puter program to determine the behaviour of a ship, moored to a jetty, became operational. Model tests have been carried out to check the results of this program.

Manoeuvring simulator

The manoeuvring simulator was fully booked with a large number of ma-noeuvring courses and industrial projects. It seems that the usefulness of the simulator for the various problems the maritime industries are confronted with, is becoming generally recognized now. Being aware of the fact that no technological advance may disregard the influences human factors have on the safe and efficient functioning of the systems designed, a consistently grow-ing number of maritime specialists plan real time simulator studies as an in-tegral part of their activities.

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S U R G E E X P E R I M E N T C O M P U T E D M O O R I N G L I N E 3 /

\

J \ — ^ I \ 1 ] M O O R I N G L I N E 4 1 \ ^ — , I - v > 0 . 5 1.0 ÜJ i n r a d . s e c " '

Comparison of measured and computed spectra of the motions and mooring forces of a ship moored to a jetty in shallow water ( Van Oortmerssen's doctor's thesis).

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The manoeuvring courses conducted in 1975 comprised not only a large number of standard five-days courses for mates and masters, but also a number of specially designed courses f o r V L C C pilots, to improve their skill of handling large tankers, also in extreme circumstances.

Among the industrial projects carried out, again the nautical evaluation of new harbour designs played an important role. These studies involve a risk analysis and a calculation of the required width of lane for the different types of ships that are to be expected. For these reasons the simulation of tug-assisted manoeuvres had to be improved to very high standards of realism and flexibility. A project that has to be especially mentioned concerned the positioning of a gravity platform by tugs. This in fact introduced the benefits of real time simulation to the offshore industry and gave new dimensions to the applica-bilities of the manoeuvring simulator. In summary, the project included the mathematical modelling of the behaviour of the platform, the simulation of the tug forces, the imitation of the command cabin on top of the platform, and the creation of the communication channels between the towmaster on the platform and tugmasters. I n this way the positioning operation could be trained and studied on scale 1:1, with the actual towmasters and crews in a realistic scene.

To cope with the rapid developments in the maritime world a great many preparations were made for an extended simulation facility. These included installation of a large new computer system and the construction of a second bridge.

W i t h the extended facility it will be possible in the near future to study not only the behaviour of one element (ship or offshore construction) but also the behaviour of two and more elements in their mutual interactions (collision avoidance, passing and overtaking manoeuvres) together with even more com-plex marine traffic systems (traffic guidance, traffic control).

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Computer centre

General

M u c t i attention lias been paid to the organization of computer activities. Software development will play an increasingly important role in the future. The co-operation with the nuclear research institute R C N at Petten will provide N S M B w i t h more powerful software and hardware tools, and thus will en-hance our ability to develop advanced computer programs.

I n order to improve the internal co-ordination, the three existing computer groups were combined into one computer department.

Hardware

On the systems side, the PDP 11 /45 computer was expanded w i t h powerful peripherals and brought under control of a real-time operating system. This system controls the communication with the C D C 6600 over a 48 kbit link, simultaneously with the processing of a local batch program.

Software development

M u c h effort had to be put in the conversion of production programs to the CDC 6600. Two important basic developments, however, also took place. The software system f o r the analysis of measurement data was connected to a versatile storage and retrieval system, which was implemented on both the CDC 6600 and PDP 11/45 computer systems. The problems of data handling have been greatly reduced, and simple data analysis programs can now easily be implemented on the PDP 11/45. The new program package for ship f o r m definition, including many utilities f o r drawing, printing and interpolation, was completed and connected to the fairing program.

This powerful new system will be connected to other programs using a hull f o r m as input, including the N A L S package. Developments for the N A L S system were continued, directed by orders f r o m the Netherlands Maritime Institute. The software co-operation with R C N already resulted in the acquisi-tion of two software systems: The general purpose plotting package DISSPLA and the data base management system T O T A L .

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Services to the shipbuilding industry

In 1975 three of our customers started to use our N A L S programs by means of terminals connected to the C D C 6600. This reduced our service work but on the other hand the work in the field of the fairing of ship lines increased because of our new fairing program which proved to be very successful. A t the middle of the year the delivery times could be lowered to an average of about three weeks for a body plan and at that time none of the ship forms had to be refused by reason of f o r m complications.

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Personnel

The changes in the staff can be seen f r o m the table below:

1971 1972 1973 1974 1975 Management 6 5 5 5 5 University graduates 33 33 38 45 46 College graduates 35 32 32 37 38 Technicians 216 211 234 273 279 Clerical staff 26 23 25 31 32 Other personnel 21 19 21 21 24 Total 337 323 355 412 424 32

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Prospects

The depressed shipbuilding and shipping market, the hesitating growth in offshore and ocean engineering activities, the tendency of an increasing na-tionalism in the control of research funds are facts that make the realization of some vital points a necessity for a satisfying 1976.

These vital points are:

- A growth in the hydro-acoustic research, due to the possibilities of the depressurized towing tank.

- A n intensification of internationally and nationally co-ordinated maritime research projects.

- A growing governmental and industrial awareness of the significance of the present-day chahenge of the sea and, as a consequence of this awareness, new initiatives.

Realization of these vital points combined with the continuously growing number of rigorous software programs for the computation of maritime problems and the growing number of successful f u l l scale observations w i h undoubtedly have its positive influence on the symbiosis of phenomenology, theory and experiment i n the field of marine technology.

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Some important figures

Turnover o f different 1968 1969 1970 1971 1972 1973 1974 1975 facilities in per cent of

total turnover:

Deep water towing tank 34 30 27 32 30 31 26 24 Depressurized towing tank - - - 13 14

Propulsion

hydrodyna-mics-cavitation 13 6 9 10 8 7 5 5 Total, Ship propulsion 47 36 36 42 38 38 44 43 Wave and current basin 22 32 29 13 21 19 17 15 Seakeeping basin 16 20 17 25 19 18 13 13 Towing tank for

unconventional maritime

constructions _ * _ * _ * _ * _* _ * 5 6 ShaUow water basin 9 6 12 8 7 11 9 11 Manoeuvring simulator - - 1 5 11 9 7 7

Total, Ship

hydrodynamics-Offshore technology 47 58 59 51 58 57 51 52 Computer centre 6 6 5 7 4 5 5 5 Total turnover N S M B ,

per cent 100 100 100 100 100 100 100 100 Orders f r o m foreign

countries in per cent

of total turnover 58 50 53 64 58 58 64 54 N S M B research in per cent

of total turnover 12 16 10 24 19 11 11 21

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1968 1969 1970 1971 1972 1973 1974 1975 Total income (turnover and

other income) in per cent related to 1968

( D f l . 9,191,000.-) = 100 100 110 122 115 131 170 233 269 Index of cost of living

related to 1968 = 100 100 107.5 112.2 120.7 130.2 140.6 154.1 169.8 Personnel 311 311 339 337 323^ 355^ 412^ 424^^ 1 40 of vi'hich are employed in Ede

2 54 of which are employed in Ede ^ 68 of which are employed in Ede * 68 of which are employed in Ede

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Percentage 50 r 45 40 35 30 25 20 15 10

National: 36 per cent International: 64 per cent

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Percentage 50 r 45 '!0 35 30 25 20 15 i r J o --: 0 L \ \

: 1

^0 V ^ \ \ \ \ V \ \ s \ \ S -> \ N ^ \ V \ s s ^ > \ \ X A i O ( ) Ü •V o O

National: 46 per cent International: 54 per cent

CQ p rr-ft Q o

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M A N A G E M E N T Central offices Maintenance Domestics Instrumentation Workshop H U L L A N D P R O P E L L E R Ship powering Ship trials Cavitation Vibrations

Theoretical and applied hydrodynamics Hydroacoustics Propeller design Research co-ordination C O M P U T E R C E N T R E Industrial service Hydrostatics N A L S Hardware control Software control Data reductions S H I P H A N D L I N G Ship manoeuvring characteristics Navigational aids Harbours and waterways Unconventional tows Training

Extreme conditions Marine traffic situations

Organization scheme of NSMB O C E A N E N G I N E E R I N G Transport Launching Mooring Terminals Pipe-laying barges Hydr. aspects of drilling Cargo handling at sea Seakeeping characteristics Hydrodynamic loads in

waves

Feasibility studies Risk analysis

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Publications, lectures, meetings

The followini?

were papers)

§ marked

No. Title

272* De keuze van de voortstuwer

359* Het manoeuvreren met grote schepen

392* Non-conventional propulsion devices 393a Weten.schappelijke

dienst-verlening aan scheepsbouw en scheepvaart

398* Cavitation on hemispherical nosed teflon bodies 419* Dynamic positioning o f

vessels at sea

456 Transverse vibrations o f ship's propulsion systems. Part I . Theoretical analysis 471* SL-7 containerships:

design, construction, and operational experience 479* Further computer-analyzed

data o f the Wageningen B-screw series

480 Method f o r the assessment o f the cavitation performance of marine propellers 481 Ship research activities in the

Netherlands (1969 to 1972) Author J. D . van Manen J. P. H o o f t and G. F. M . Remery .T. D . van Manen J. D . van Manen J. H . J. van der Meulen J. Pinkster S. Hylarides J, W. Boylston, D. J. de K o f f and J. J. Muntjewerf M . W. C. Ooster-veld and P. van Oossanen P. van Oossanen M . W. C. Ooster-veld and P. van Oossanen Published in

Catalogus voor de Scheepvaart, 7de editie 1975, p. 54

Catalogus voor de Scheepvaart, 7de editie 1975, p. 145 Schip en Werf, 1975, p. 57 and 77

Catalogus voor de Scheepvaart, 7de editie 1975, p. 105

Schip en Werf, 1975, p. 99

Int. Centre f o r Mechanical Sciences, Udine, 1971, Courses and Lectures - N o . 105 (1972) ISP, 1975, p. 275 Trans. S N A M E , 1974, p. 427 ISP, 1975, p. 251 ISP, 1975, p. 3 ISP, 1975, p. 35

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No. Title

482 M o d e l and f u l l scale ducted propeller cavitation observations on a 280,000 dwt. tanker 4S3* H a n d l i n g of large ships Author H . Narita, Y . Kunitake, H . Yagi, M . W . C. Oosterveld and M . Hoekstra J. P. H o o f t

484* Some propeller cavitation and excitation considerations f o r large tankers 485* M o t i o n s of stationary structures M . W . C. Ooster-veld, C. Verdonk, J. van der K o o i j and P. van Oossanen J. P. H o o f t

486* Ship relative motions and related phenomena

M . F. van Sluijs

487* The role o f model tests in the design o f single point mooring terminals

488* Optimization o f gravity structures f r o m a hydrodynamic point o f view

489* Some aspects of very large offshore structures J. A . Pinkster and G. F. M . Remery G. van Oortmerssen and L . J. Boreel G. van Oortmerssen

490 Symposium on ' H i g h Powered M . W. C. Oosterveld Propulsion of Large Ships', (Editor) Wageningen, December 10-13,

1974. Part 1 & 2

491* Trade-offs in sub-cavitating P. van Oossanen propeller design

492* Experience after one year o f "W. van den Berg tests i n the N S M B and G. Kuiper depressurised towing tank

493* Prediction of f u l l scale wake M . Hoekstra characteristics based on

model wake survey

Published in

J. S N A Japan, Dec. 1974, p. 61

Proc. West European Conf. on Marine Technology, D e l f t , 1974, p. 37 (1975)

Proc. West European Conf. on Marine Technology, Delft, 1974, p. 72 (1975)

Int. Symp. on the Dynamics of Marine Vehicles and Structures in Waves, London, 1974, p. 68 (1975)

Int. Symp. on the Dynamics of Marine Vehicles and Structures in Waves, London, 1974,p. 198 (1975)

Seventh A n n . Offshore Technology Conf., Houston, Texas, 1975, V o l . I , p. 679 Seventh A n n . Offshore Technology Conf., Houston, Texas, 1975, V o l . I l l , p. 679 N i n t h Symp. on Naval Hydrodynamics, Paris, 1972, V o l . 1, p. 957 (1975) N S M B , Wageningen, 1975 Symp. on ' H i g h Powered Propulsion of Large Ships', Wageningen, 1974, Part 1, Paper 11 (1975)

Symp. on ' H i g h Powered Propulsion o f Large Ships', Wageningen, 1974, Part 1, Paper V I (1975)

Symp. on ' H i g h Powered Propulsion o f Large Ships', Wageningen, 1974, Part 1, Paper X I I (1975) ISP, 1975, p. 204

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No. Title Author

494* Propeller hydrodynamics S. Hylarides and and shaft dynamics W . van Gent

495* A method to calculate the L . Noordzij pressure field induced by a

cavitating propeller

496* Propeller-induced hydrodynamic J. van der K o o i j hull forces on a Great Lakes and A . Jonk bulk carrier. Results of model

tests and f u l l scale measurements 497* A holographic study o f

cavitation inception on a hemispherical nosed body

J. H . J. van dcr IVIeulen and N . B. Oosterveld

498* Dynamic measurement techniques on swimming bodies at the Netherlands Ship Model Basin 499* Wave action on large

off-shore structures

J. D, van Manen and H . Rijken

L . J. Boreel

500* A stochastic model of ship maneuvers

A. J. Hermans

501* Conning a ship with different steering systems

P. J. Paymans and I . Oldenkamp

502* Passing manoeuvre of two large tankers in a channel

504 Unsteady lifting-surface theory for ship screws: derivation and numerical treatment o f integral equation

505* Low-frequency phenomena associated with vessels moored at sea 507* Ausbildung am N . S . M . B . Manoversimulator A. Roos, B. F. Dessing and P. J. Paymans W. van Gent J. A . Pinkster J. P. H o o f t Published in

Symp. on 'High Powered Propulsion o f Large Ships'. Wageningen, 1974, Part I , Paper X I V (1975) Symp. on ' H i g h Powered Propulsion o f Large Ships'. Wageningen, 1974, Part 2, Paper X V I (1975) Symp. on ' H i g h Powered Propulsion o f Large Ships', Wageningen, 1974, Part 2, Paper X I X (1975) Symp. on ' H i g h Powered Propulsion o f Large Ships', Wageningen. 1974, Part 2, Paper X X I I (1975) Proc. Second Int. Symp. on Biomechanics in Swimming, Brussels, 1974, p. 70 (1975)

Proc. C o n f on Off-shore Structures, London, 1974, p. 7 (1975)

Proc. 1975 Summer Computer Simulation Conf., San Fran-cisco, California, 1975, V o l . I , p. 628

Proc. Fourth Ship Control Systems Symp., The Hague, 1975, Vol. 1, p. 5

Proc. Fourth Ship Control Systems Symp., The Hague. 1975, Vol. 3, p. 242 J. of Ship Res., 1975, p. 243

Soc. o f Petroleum Engineers J., 1975, p. 487

Schriftenreihe I H f ü r Seefahrt, 1975, Heft 2, p. 35

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Besides the publications mentioned before,

were given in 1975

the following lectures

Date A p r i l 16 A p r i l 24 A p r i l 30 June 9 July 23 Subject Influence o f cross current in a channel on a man steered ship Author I . Oldenkamp and P. J. Paymans

Research and J. D . van Manen development at N S M B

Recent developments M . W . C. Oosterveld in the N S M B

depressurized towing tank

Ship manoeuvring P. J. Paymans simulator as a

research tool

De belasting op zee-gaande constructies

G. van Oortmerssen

Wake, speed and R. Wereldsma structural dynamics and related to blade S. Hylarides stresses

Audience

National Meeting 1975 'Simula-tion f o r Service o f T r a f f i c ' in Bremen, organized by 'Deutsche Geseilschaft f ü r Ortung und Navigation e.V.'

Meeting i n T o k y o , organized by MacGregor Far East L t d .

National Symposium on Marine Transportation Management in Philadelphia, Pennsylvania, sponsored by U.S. Coast Guard w i t h A r m y Corps of Engineers and M a r i t i m e Administration; organized by University o f Delaware

Middagbijeenkomst over het onderwerp: 'Belasting, responsie en draagkracht van maritieme constructies' at D e l f t , organized by 'Industriële Raad voor de

Oceanologie, Nederlands M a r i -tiem Instituut, Afdeling voor Onderwatertechniek en Sectie voor Scheepstechniek van het K o n i n k l i j k Instituut van Inge-nieurs'

Symposium 'Propellers 75' i n Philadelphia, Pennsylvania, organized by Society of Naval Architects and Marine Engineers in cooperation w i t h Philadelphia Section o f S N A M E

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Date

August 27-28

Subject Author

Four years operation J. P. H o o f t and experience with the P. J. Paymans ship control simulator

Recent results of tests M . W . C. Oosterveld in the N S M B de- and

pressurized towing P. van Oossanen tank

September 25 Inleiding M . W. C. Oosterveld

De r o l van cavitatie P. van Oossanen in het

schroef-ontwerp

Het drukveld van een L . Noordzij caviterende schroef

Audience

First Ship Technology and Research (STAR) Symposium in Washington, D . C , organized by Society o f Naval Architects and Marine Engineers

Bijeenkomst over het onderwerp: 'De hydrodynamica van de scheepsschroef at Ede, organized by 'Afdeling voor Mechanica van van het K o n i n k l i j k Instituut van Ingenieurs'

Volgstroom en W. van Gent schroefdynamica

October 16 De toekomst van de J. D . van Manen Studiedag 'Scheepsbouw in de scheepsbouwindustrie toekomst' at Schiedam, organized nationaal en by 'Commissie Scheepsbouwop-internationaal leidingen van de Stichting

'Vor-ming en Opleiding voor de Metaalindustrie in het R i j n m o n d -gebied'

October 28 The influence o f J. P. H o o f t , Fourth International Symposium human behavior on "V. F. Keith and on Transport o f Hazardous the controllability J. D . Porricelli Cargoes by Sea and Inland Water-of ships ways i n Jacksonville, Florida,

under the auspices o f U.S. De-partment of Transportation, U.S. Coast Guard, with the technical assistance o f National Academy of Sciences, National Research Council Committee on Hazardous Materials

November 13 Hydrodynamische J. P. H o o f t 'Sectie voor Scheepstechniek van aspecten van o f f - het K o n i n k l i j k Instituut van shore constructies van Ingenieurs,

Scheepsbouw-kundig Gezelschap 'William Froude' en Nederlandse "Vereni-ging van Technici op Scheep-vaartgebied' at Delft

(44)

Date November 13 N ovember 19-20 Subject Conning a ship w i t h different steering systems The motions o f a ship i n shallow water Author P. J. Paymans and I . Oldenkamp G. van Oortmerssen

November 21 Schroefblad span- S. Hylarides and ningen bepaald met T. H . Oei N A S T R A N

Audience

Ship C o n t r o l Group o f the Royal Institution o f Naval Architects in L o n d o n

Chesapeake Section of the So-ciety o f Naval Architects and Marine Engineers i n Washington, D . C .

Hydromechanics Colloquium at Bethesda, M a r y l a n d , organized by Ship Performance Department o f David W . Taylor Naval Ship Research and Development Center

PROGEL-Gebruikers-symposium at Enschede

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The following meetings were attended in 1975

January 17 January 23-24 January 30-31 February 18-19 February 26 M a r c l i 3-5 March 11-12 March 13 March 21 A p r i l 2-3 A p r i l 8 A p r i l 15-16 A p r i l 16 A p r i l 29 May 1 May 5-8 May 22 Meeting of S N A M E Panel H - I O (Controllability) i n New Y o r k

N o r t h Sea Towing Tank Conference in Jfamburg I T T C Propeller Committee at Trondheim Meeting of ISO/TC 8/SC 3 in Paris

Bijeenkomst, gewijd aan 'Onderwater-techniek' at Wageningen, organized by ' K r i n g Constructie van de Bond voor Materialenkennis'

I T T C Cavitation Committee in Gothenburg I T T C Performance Committee in Gothenburg Studiedag in Amsterdam, organized by 'Orde van Organisatiekundigen en -Adviseurs'

Meeting o f S N A M E Panel H-10 (Controllability) in Washington, D.C. ISSC Committee II.3 at Wageningen Studiedag over 'Noorse ontwikkelingen bij het gebruik van computers voor scheepvaart management' at Delft, organized by ' K o n i n k l i j k e Nederlandse Redersvereniging'

Leergang Scheepvaartkunde 1975 met als onderwerp 'Maritieme economie en rederij-beheer' in Amsterdam, organized by 'Onderafde-ling der Scheepsbouwkunde van de Technische Hogeschool Delft, K o n i n k l i j k Instituut voor de Marine en Hoger Zeevaartonderwijs'

National Meeting 1975 'Simulation for Service of T r a f f i c ' in Bremen, organized by 'Deutsche Geselischaft f ü r Ortung und Navigation e. V . ' National Symposium on Marine Transportation Management in Philadelphia, Pennsylvania, sponsored by U.S. Coast Guard with A r m y Corps of Engineers and M a r i t i m e Administration; organized by University o f Delaware Seventh Annual Offshore Technology Con-ference in Houston, Texas, sponsored by American Institute o f Mining, Metallurgical, and Petroleum Engineers et al.

Conference on Ship Handling and Manoeuvring Simulation in London, organized by Ship Operation Sub-Committee o f the Ship and Marine Technology Requirements Board in association with General Council o f British Shipping

P. J. Paymans J. D . van Manen M . W . C. Oosterveld J. D . van Manen J. A . Pinkster and M . F. van Sluijs P. van Oossanen J. J. Muntjewerf A . W . Ruys P. J. Paymans M . F. van Sluijs A . Koops, A. W. Ruys and W. Verschuur A. Koops I . Oldenkamp P. J. Paymans J. D . van Manen, M . W. C. Oosterveld, G. van Oortmerssen, J. A . Pinkster and M . F. van Sluijs K . Meurs

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June 4-5 June 9 June 13 July 21-23 July 22-23 August 26-29 August 28 September 2-11 September 10-11 September 24-26 October 15 October 16 October 20-22

Meeting o f Ship Control Group of the Royal Institution o f Naval Architects in Liverpool Middagbijeenkomst over het onderwerp:

'Belasting, responsie en draagkracht van maritieme constructies' at D e l f t , organized by 'Industriële Raad voor de Oceanologie, Nederlands M a r i t i e m Instituut, Afdeling voor Onderwatertechniek en Sectie voor Scheepstechniek van het K o n i n k l i j k Instituut van Ingenieurs'

Meeting o f S N A M E Panel H-10 (Controllability) in New Y o r k

Summer Computer Simulation Conference in San Francisco, Califomia, sponsored by American Institute f o r Chemical Engineers, American Meteorological Society, Instrument Society o f America, Society f o r Computer Simulation and I B M Users Group

Symposium 'Propellers 75' in Philadelphia, Pennsylvania, organized by Society o f Naval Architects and Marine Engineers in cooperation w i t h Philadelphia Section of S N A M E

First Ship Technology and Research (STAR) Symposium in Washington, D . C , organized by Society o f Naval Architects and Marine Engineers

Meeting o f S N A M E Panel H-10 (Controllability) in Washington, D . C . 14th International Towing Tank Conference in Ottawa

Meeting o f ISO/TC108/SC2/'WG2 at H o o f d d o r p Meeting o f I S O / T C 8/SC 15 (Computer Applications in Shipbuilding) at Wallsend Annual General Meeting of the Royal Institute o f Navigation i n London

The Royal Institute of Navigation presentation: 'Comparison o f Facilities on Computer Based Radar' i n London, under the sponsorship of Shell International Marine Limited

First International Conference on Numerical Ship Hydrodynamics at Gaithersburg, Maryland, sponsored and organized by David W . Taylor Naval Ship Research and Development Center with the cooperation of Office o f Naval Research and Naval Sea System^ Command

G. M a k M . "W. C. Oosterveld, T. H . Oei and G. van Oortmerssen P. J. Paymans A . J. Hermans S. Hylarides J. D . van Manen, M . "W. C. Oosterveld, P. van Oossanen and P. J. Paymans P. J. Paymans

J. D . van Manen, J. J. Muntjewerf, M . W . C. Oosterveld, P. van Oossanen and M . F. van Sluijs S. Hylarides A . Koops K . Meurs K . Meurs G. Kuiper and L . Noordzij 46

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October 24 October 27-31 November 4-5 November 11-13 November 13-15 November 17 November 21 November 21 December 16

Symposium 'Technology of Buoy M o o r i n g Systems' in London, organized by Society for Underwater Technology in association with Department of Agriculture and Fisheries for Scotland and Institute of Oceanographic Sciences Fourth Ship Control Systems Symposium in The Hague, organized by Royal Netherlands Naval College

I T T C Performance Committee at Ede 5, Internationale Tagung zu Problemen der S c h i f f s f ü h r u n g at W a r n e m ü n d e , organized by 'Bezirksvorstand Rostock der Kammer der Technik und Ingenieurhochschule f ü r Seefahrt W a r n e m ü n d e / W u s t r o w Sektion S c h i f f s f ü h r u n g ' Eighty-third Annual Meeting o f the Society of Naval Architects and Marine Engineers in New Y o r k

Symposium 'Stochastische trillingsverschijnselen' at D e l f t , organized by 'Sectie voor

Milieu-techniek, Afdeling voor 'Werktuig- en Scheepsbouw en Afdeling voor Onderwatertechniek van het K o n i n k l i j k Instituut van Ingenieurs'

PROGEL-Gebruikerssymposium at Enschede

Meeting o f S N A M E Panel H-10 (Controllability) in New Y o r k

Jaarvergadering met als thema 'Offshore techniek en wetenschapsbeleid' van de Stichting

Materiaalonderzoek in de Zee at Delft

R. Kokkeel J. D . van Manen, M , W. C. Oosterveld, H . J, C r u i j f f , I . Oldenkamp, P. van Oossanen, P. J. Paymans and F. G. J. Witt J. J. Muntjewerf K . Meurs J. J. Muntjewerf

H . van de Beek and J. van der K o o i j S. Hylarides and T. H . Oei P. J. Paymans J. D . van Manen, J. P. H o o f t , M . W. C. Oosterveld and G. F. M . Remery

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Annual Report 1975 of the Netherlands Ship Model Basin - NSMB - Wageningen

Netherlands Ship Model Basin

Wageningen, the Netherlands

Annual report 1975

Foundation

Netherlands Ship Model Basin

Wageningen, the Netherlands

Contents

Board of Directors, Management, Advisory

Board, Consultant, Representatives Abroad

General

HI^HHHB^^^^HilHHIj^^^H

Ocean engineering, ship dynamics

\

Computer centre

Personnel

Prospects

Some important figures

: 1

Publications, lectures, meetings

The followini?

were papers)

§ marked

Besides the publications mentioned before,

were given in 1975

the following lectures

The following meetings were attended in 1975