Netherlands Model Basin Wageningen, the

Annual report 1975

Foundation Netherlands Wageningen, the Netherlands On March 12,1976, before this Annual Report went to press, Mr. John W. Hup­ kes, chairman of the Board of Directors, passed away. He was succeeded by Mr. 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 Contents

Memorial John W. Hupkes 5 Board of Directors, Management, Advisory Board, Consultant, Representatives abroad 6 Memorial Kein Timman 9 General 10

Industrial service and research to create new possibilities for 12 industrial service Powering, ship propulsion 12 Deep water towing tanlc 12 Cavitation tunnels 15 Depressurized towing tank 16 Propulsion and ship hydrodynamics 18 Strength and vibrations 20

Ocean engineering, ship dynamics 22 Seakeeping basin 22 Towing tank for unconventional maritime constructions 23 Wave and current basin 24 Shallow water basin 27 Manoeuvring simulator 27

Computer centre 30

Personnel 32 Prospects 33

Some important figures 34 Specification of orders and NSMB research in 1974 36 Specification of orders and NSMB research in 1975 37 Organization scheme of the NSMB 38 Publications, lectures, meetings 39 Up to the last moment, full of spirit and charm, with a style of living - of thinking - and doing, he stimulated his colleagues, and friends. This picture of him is stroiig, and will stay long alive. Memorial; John W. Hupkes, 1908-1976 1951-1966 Member of the board of directors, 1966-1976 Chairman of the board of directors of the Netherlands Ship Model Basin

5 Board of Directors, Management, Advisory Board, Consultant, Representatives Abroad

Board of directors * Chairman P. E. E. Kleyn van WiUigen Shipowner Vice-Chairman Dr H. J. H. Janssen Under-Secretary of State for Shipping Secretary O. J. van der Vorm Central Association of Dutch Shipbuilders Members 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 Prof, dr J. D. van Manen Vice-Presidents A. H. Pastoor, Registeraccountant Administration and Pittance Dr J. P. Hooft Ship Dynamics - Offshore Technology J. J. Muntjewerf Ship Powering Dr M. W. C. Oosterveld Research and Development

Advisory board Members A. Laredo Shipbuilder () Dr L. A. van Gunsteren Shipbuilder J. W. Maingay Ship Propeller Manufacturer J. F. Meijer Royal Netherlands Navy G. Nilsson Shipbuilder () H. M. Oudshoorn Ministry of Transport and Public Works, Rijkswaterstaat Dr E. M. Q. Roren Det norske Veritas () L. P. Ruys Shipowner

6 Consultant Prof, dr R. Wereldsma University of Technology, Delft

Representatives Australia - Antelope Engineering Pty., Ltd., Milson's abroad Point, N.S.W. U.S.A., Gulf area - Mr Blakely Smith, Houston - MacGregor Far East Ltd., Tokyo

* Effective per May, 1976.

7 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. Memorial: Rein Timman, 1917-1975 1955-1975 Consultant of the Netherlands Ship Model Basin

9 General

The year 1975 saw many initiatives of the and shipping industry to counteract the disastrous collapse of the tanker market. Though the devel­ opment of multi-purpose , 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 NSMB. 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 with 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 for 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 Delft 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). In 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 RCN-NSMB Computer Centre.

10 Some highlights as well as a sad event in the course of the year are mentioned below. - Dr E. Mocklinghof, President of the Federal State of Munster, , visited our laboratories in April. - In the May-meeting of the Board of Directors, Mr J. Groenendijk entered as a new member, while Mr P. de Josselin de Jong and Mr O. W. Vos retired. - Mr J. J. Muntjewerf was appointed 'Membre correspondant pour les Pays- Bas' of the Association Technique Maritime et Aéronautique, in August 1975. - In October prof, dr J. D. van Manen was elected into Fellowship of The Royal Institute of Navigation, London. - In November prof, dr R. Timman, a consultant of the Netherlands Ship Model Basin, passed away. - In November Mr J. W. Boylston, Mr D. J. de Koff and Mr 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'. - In the November-meeting of the Board of Directors Mr J. van der Brugge entered as a new member. - Dr L. A. van Gunsteren entered as a new member of the Advisory Board. - Mr A. Stemerdink, Parliamentary Under-Secretary for Defense (Matériel), and Lieutenant-General J. Hensen, Chairman of the Council of Matériel visited our laboratories in December. - In the course of 1975 the 5000th ship model and the 5000th propeUer model were manufactured, which historical events were duly celebrated at the NSMB.

11 Cavitating propeller in depressurized towing tank Picture taken by underwater photo camera. 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 , 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. In 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 quantitative 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. In 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. In co-operation with the Institute of Applied Physics TNO-TH, a holo-

15 graphic study of cavitation on axisymmetric bodies was made in the high speed water tunnel. A new technique has been developed for the purpose of flow visualization. In principle, the method consists of making holograms when injecting a fluid with an index of refraction slightly different from the surrounding fluid. Two axisymmetric bodies were investigated, one having laminar flow separation, the other not having it. 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 full advantage of the excellent capabilities of the facility to support the scientific research work. In 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. In particular the effect of cavitation on the steady as well as the dynamic torque can be determined. From 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 from 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.

16 NON - CAVITATING CONDITION (FROM ATMOSPHERIC TEST)

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.

17 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. In projects associated with naval ships and with right angle drive units for drill ships, the radiated propeller noise characteristics were established. Much 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 in 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 in the depressurized towing tank also continued. For the analysis of resistance and propulsion tests, a new set of computer programs was implemented. With these programs the test results are cross- faired and extrapolated to full scale by means of scale effect corrections which have been derived from the results of a model-full scale correlation analysis. This model-full 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 of surface ships from 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. In a first test case, fair agreement with experimental results was obtained.

18 19 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. In this way it 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 in propeller blades based on finite element theory. The existing program for the calculation of the performance and cavitation characteristics of screw propellers operating in 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 in the use of the finite element technique was growing, especially with 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.

20 21 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 with 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 off Norway in the northern part of the North 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 in the hawser by which a moored-off tanker is attached to the terminal. In these series of tests about 30 measuring channels had to be monitored simultaneously. In this respect, the expansion of the measuring capacity, ef­ fectuated in 1974 by changing from 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 from the industry. The remaining 15 per cent was spent on account of NSMB research, comprising a systematic investigation into the roll behaviour of LNG 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 investigation into wave drift force phenomena. In addition to the experimental work, feasibility studies were performed by computer calculations for various configurations of ocean platforms as well as for surface vessels.

22 Strip theory was used to predict wetness of declcs for four classes of tankers, ranging between 10,000 and 200,000 DWT, 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. It is expected that in 1976 model testing on steel jackets will continue.

Oscillating skate with pipe line.

23 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 LNG 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 in some interesting model test programs on this subject. In the course of the year several interesting phenomena were observed on offshore structures which could not be explained with conventional hydro- dynamic theories. Motions of structures in regular waves with frequencies which differ from the frequency of the waves became a subject for further research. An important step was put forward in the understanding of the drifting force on moored vessels in irregular waves. In 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.

24 Catenary anchor leg mooring buoy LNG carrier moored to a jetty.

26 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. At 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. In 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 with 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.

27 SURGE

EXPERIMENT

COMPUTED

MOORING LINE 3

/ \ J \ —^

MOORING LINE 4 I \ 1 ]

1 \^—, I v> - 0.5 1.0 ÜJ in rad.sec"'

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). 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 for VLCC 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. In 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. With 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).

29 Computer centre

General

Mucti 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 RCN at Petten will provide NSMB with more powerful software and hardware tools, and thus will en­ hance our ability to develop advanced computer programs. In 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 with powerful peripherals and brought under control of a real-time operating system. This system controls the communication with the CDC 6600 over a 48 kbit link, simultaneously with the processing of a local batch program.

Software development

Much 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 for 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 form definition, including many utilities for 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 form as input, including the NALS package. Developments for the NALS system were continued, directed by orders from the Netherlands Maritime Institute. The software co-operation with RCN already resulted in the acquisi­ tion of two software systems: The general purpose plotting package DISSPLA and the data base management system TOTAL.

30 Services to the shipbuilding industry

In 1975 three of our customers started to use our NALS programs by means of terminals connected to the CDC 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. At 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 form complications.

31 Personnel

The changes in the staff can be seen from 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 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. - An 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 full scale observations wih undoubtedly have its positive influence on the symbiosis of phenomenology, theory and experiment in the field of marine technology.

33 Some important figures

Turnover of 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 NSMB, per cent 100 100 100 100 100 100 100 100

Orders from foreign countries in per cent of total turnover 58 50 53 64 58 58 64 54

NSMB research in per cent of total turnover 12 16 10 24 19 11 11 21

34 1968 1969 1970 1971 1972 1973 1974 1975

Total income (turnover and other income) in per cent related to 1968 (Dfl. 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 * In the years 1968 through 1973 included in turnover of seakeeping basin.

35 Percentage 50 r

45

40 National: 36 per cent

International: 64 per cent 35

30

25

20

15

10

Specification of orders and NSMB research in 1974. Percentage 50 r

45

'!0 i National: 46 per cent r J i International: 54 per cent O 35 ()

30

25 Ü •V ^0 CQ

20 o

O 15

o p --: V ^ \ \ \ \ V \ Q \ s rr- \ \ o

S -> \N ft ^ \ V \

\ \ s s 0 L :1 ^> \ \ XA Specification of orders and NSMB research in 1975. MANAGEMENT

Central offices Maintenance Domestics Research Instrumentation co-ordination Workshop

HULL AND PROPELLER COMPUTER CENTRE SHIP HANDLING OCEAN ENGINEERING Ship powering Industrial service Ship manoeuvring Transport Ship trials Hydrostatics characteristics Launching Cavitation NALS Navigational aids Mooring Vibrations Hardware control Harbours and waterways Terminals Theoretical and applied Software control Unconventional tows Pipe-laying barges hydrodynamics Data reductions Training Hydr. aspects of drilling Hydroacoustics Extreme conditions Cargo handling at sea Propeller design Marine traffic situations Seakeeping characteristics Hydrodynamic loads in waves Feasibility studies Risk analysis Organization scheme of NSMB Publications, lectures, meetings

The followini? § marked were papers)

No. Title Author Published in

272* De keuze van de voortstuwer J. D. van Manen Catalogus voor de Scheepvaart, 7de editie 1975, p. 54 359* Het manoeuvreren met grote J. P. Hooft and Catalogus voor de Scheepvaart, schepen G. F. M. Remery 7de editie 1975, p. 145 392* Non-conventional .T. D. van Manen Schip en Werf, 1975, propulsion devices p. 57 and 77 393a Weten.schappelijke dienst­ J. D. van Manen Catalogus voor de Scheepvaart, verlening aan scheepsbouw 7de editie 1975, p. 105 en scheepvaart 398* Cavitation on hemispherical J. H. J. van der Schip en Werf, 1975, p. 99 nosed teflon bodies Meulen 419* Dynamic positioning of J. Pinkster Int. Centre for Mechanical vessels at sea Sciences, Udine, 1971, Courses and Lectures -No. 105 (1972) 456 Transverse vibrations of ship's S. Hylarides ISP, 1975, p. 275 propulsion systems. Part I. Theoretical analysis 471* SL-7 containerships: J, W. Boylston, Trans. SNAME, 1974, p. 427 design, construction, and D. J. de Koff and operational experience J. J. Muntjewerf 479* Further computer-analyzed M. W. C. Ooster­ ISP, 1975, p. 251 data of the Wageningen veld and B-screw series P. van Oossanen 480 Method for the assessment of P. van Oossanen ISP, 1975, p. 3 the cavitation performance of marine propellers 481 Ship research activities in the M. W. C. Ooster­ ISP, 1975, p. 35 Netherlands (1969 to 1972) veld and P. van Oossanen

39 No. Title Author Published in

482 Model and full scale ducted H. Narita, J. SNA Japan, propeller cavitation Y. Kunitake, Dec. 1974, p. 61 observations on a H. Yagi, M. W. C. 280,000 dwt. tanker Oosterveld and M. Hoekstra 4S3* Handling of large ships J. P. Hooft Proc. West European Conf. on Marine Technology, Delft, 1974, p. 37 (1975) 484* Some propeller cavitation and M. W. C. Ooster­ Proc. West European Conf. on excitation considerations for veld, C. Verdonk, Marine Technology, Delft, large tankers J. van der Kooij and 1974, p. 72 (1975) P. van Oossanen 485* Motions of stationary J. P. Hooft Int. Symp. on the Dynamics of structures Marine Vehicles and Structures in Waves, London, 1974, p. 68 (1975) 486* Ship relative motions and M. F. van Sluijs Int. Symp. on the Dynamics related phenomena of Marine Vehicles and Structures in Waves, London, 1974,p. 198 (1975) 487* The role of model tests in the J. A. Pinkster and Seventh Ann. Offshore design of single point mooring G. F. M. Remery Technology Conf., Houston, terminals Texas, 1975, Vol. I, p. 679 488* Optimization of gravity G. van Oortmerssen Seventh Ann. Offshore structures from a hydrodynamic and L. J. Boreel Technology Conf., Houston, point of view Texas, 1975, Vol. Ill, p. 679 489* Some aspects of very large G. van Oortmerssen Ninth Symp. on Naval offshore structures Hydrodynamics, Paris, 1972, Vol. 1, p. 957 (1975) 490 Symposium on 'High Powered M. W. C. Oosterveld NSMB, Wageningen, 1975 Propulsion of Large Ships', (Editor) Wageningen, December 10-13, 1974. Part 1 & 2 491* Trade-offs in sub-cavitating P. van Oossanen Symp. on 'High Powered propeller design Propulsion of Large Ships', Wageningen, 1974, Part 1, Paper 11 (1975) 492* Experience after one year of "W. van den Berg Symp. on 'High Powered tests in the NSMB and G. Kuiper Propulsion of Large Ships', depressurised towing tank Wageningen, 1974, Part 1, Paper VI (1975) 493* Prediction of full scale wake M. Hoekstra Symp. on 'High Powered characteristics based on Propulsion of Large Ships', model wake survey Wageningen, 1974, Part 1, Paper XII (1975) ISP, 1975, p. 204 No. Title Author Published in

494* Propeller hydrodynamics S. Hylarides and Symp. on 'High Powered and shaft dynamics W. van Gent Propulsion of Large Ships'. Wageningen, 1974, Part I, Paper XIV (1975) 495* A method to calculate the L. Noordzij Symp. on 'High Powered pressure field induced by a Propulsion of Large Ships'. cavitating propeller Wageningen, 1974, Part 2, Paper XVI (1975) 496* Propeller-induced hydrodynamic J. van der Kooij Symp. on 'High Powered hull forces on a Great Lakes and A. Jonk Propulsion of Large Ships', bulk carrier. Results of model Wageningen, 1974, Part 2, tests and full scale measurements Paper XIX (1975) 497* A holographic study of J. H. J. van dcr Symp. on 'High Powered cavitation inception on a IVIeulen and Propulsion of Large Ships', hemispherical nosed body N. B. Oosterveld Wageningen. 1974, Part 2, Paper XXII (1975) 498* Dynamic measurement J. D, van Manen Proc. Second Int. Symp. on techniques on swimming and H. Rijken Biomechanics in Swimming, bodies at the Netherlands Brussels, 1974, p. 70 (1975) Ship Model Basin 499* Wave action on large L. J. Boreel Proc. Conf on Off-shore off-shore structures Structures, London, 1974, p. 7 (1975) 500* A stochastic model of ship A. J. Hermans Proc. 1975 Summer Computer maneuvers Simulation Conf., San Fran­ cisco, California, 1975, Vol. I, p. 628 501* Conning a ship with different P. J. Paymans and Proc. Fourth Ship Control steering systems I. Oldenkamp Systems Symp., The Hague, 1975, Vol. 1, p. 5 502* Passing manoeuvre of two A. Roos, Proc. Fourth Ship Control large tankers in a channel B. F. Dessing and Systems Symp., The Hague. P. J. Paymans 1975, Vol. 3, p. 242 504 Unsteady lifting-surface theory W. van Gent J. of Ship Res., 1975, p. 243 for ship screws: derivation and numerical treatment of integral equation 505* Low-frequency phenomena J. A. Pinkster Soc. of Petroleum Engineers J., associated with vessels moored at 1975, p. 487 sea 507* Ausbildung am N.S.M.B. J. P. Hooft Schriftenreihe IH für Seefahrt, Manoversimulator 1975, Heft 2, p. 35

41 Besides the publications mentioned before, the following lectures were given in 1975

Date Subject Author Audience

April 16 Influence of cross I. Oldenkamp and National Meeting 1975 'Simula­ current in a channel P. J. Paymans tion for Service of Traffic' in on a man steered Bremen, organized by 'Deutsche ship Geseilschaft für Ortung und Navigation e.V.' April 24 Research and J. D. van Manen Meeting in Tokyo, organized by development at NSMB MacGregor Far East Ltd. Recent developments M. W. C. Oosterveld in the NSMB depressurized towing tank April 30 Ship manoeuvring P. J. Paymans National Symposium on Marine simulator as a Transportation Management in research tool Philadelphia, Pennsylvania, sponsored by U.S. Coast Guard with Army Corps of Engineers and Maritime Administration; organized by University of Delaware June 9 De belasting op zee­ G. van Oortmerssen Middagbijeenkomst over het gaande constructies onderwerp: 'Belasting, responsie en draagkracht van maritieme constructies' at Delft, organized by 'Industriële Raad voor de Oceanologie, Nederlands Mari­ tiem Instituut, Afdeling voor Onderwatertechniek en Sectie voor Scheepstechniek van het Koninklijk Instituut van Inge­ nieurs' July 23 Wake, speed and R. Wereldsma Symposium 'Propellers 75' in structural dynamics and Philadelphia, Pennsylvania, related to blade S. Hylarides organized by Society of Naval stresses Architects and Marine Engineers in cooperation with Philadelphia Section of SNAME

42 Date Subject Author Audience

August Four years operation J. P. Hooft and First Ship Technology and 27-28 experience with the P. J. Paymans Research (STAR) Symposium in ship control simulator Washington, D.C, organized by Society of Naval Architects and Recent results of tests M. W. C. Oosterveld Marine Engineers in the NSMB de- and pressurized towing P. van Oossanen tank September 25 Inleiding M. W. C. Oosterveld Bijeenkomst over het onderwerp: 'De hydrodynamica van de De rol van cavitatie P. van Oossanen scheepsschroef at Ede, organized in het schroef- by 'Afdeling voor Mechanica van ontwerp van het Koninklijk Instituut van Ingenieurs' Het drukveld van een L. Noordzij caviterende schroef

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 Rijnmond­ gebied' October 28 The influence of J. P. Hooft, Fourth International Symposium human behavior on "V. F. Keith and on Transport of Hazardous the controllability J. D. Porricelli Cargoes by Sea and Inland Water- of ships ways in Jacksonville, Florida, under the auspices of U.S. De­ partment of Transportation, U.S. Coast Guard, with the technical assistance of National Academy of Sciences, National Research Council Committee on Hazardous Materials November 13 Hydrodynamische J. P. Hooft 'Sectie voor Scheepstechniek van aspecten van off- het Koninklijk Instituut van shore constructies van Ingenieurs, Scheepsbouw­ kundig Gezelschap '' en Nederlandse "Vereni­ ging van Technici op Scheep­ vaartgebied' at Delft

43 Date Subject Author Audience

November 13 Conning a ship with P. J. Paymans Ship Control Group of the Royal different steering and Institution of Naval Architects systems I. Oldenkamp in London N ovember The motions of a G. van Oortmerssen Chesapeake Section of the So­ 19-20 ship in shallow ciety of Naval Architects and water Marine Engineers in Washington, D.C. Hydromechanics Colloquium at Bethesda, Maryland, organized by Ship Performance Department of David W. Taylor Naval Ship Research and Development Center November 21 Schroefblad span- S. Hylarides and PROGEL-Gebruikers-symposium ningen bepaald met T. H. Oei at Enschede NASTRAN

44 The following meetings were attended in 1975

January 17 Meeting of SNAME Panel H-IO P. J. Paymans (Controllability) in New York January 23-24 North Sea Towing Tank Conference in Jfamburg J. D. van Manen January 30-31 ITTC Propeller Committee at M. W. C. Oosterveld February 18-19 Meeting of ISO/TC 8/SC 3 in Paris J. D. van Manen February 26 Bijeenkomst, gewijd aan 'Onderwater-techniek' J. A. Pinkster and at Wageningen, organized by 'Kring Constructie M. F. van Sluijs van de Bond voor Materialenkennis' Marcli 3-5 ITTC Cavitation Committee in Gothenburg P. van Oossanen March 11-12 ITTC Performance Committee in Gothenburg J. J. Muntjewerf March 13 Studiedag in Amsterdam, organized by 'Orde van A.W. Ruys Organisatiekundigen en -Adviseurs' March 21 Meeting of SNAME Panel H-10 P. J. Paymans (Controllability) in Washington, D.C. April 2-3 ISSC Committee II.3 at Wageningen M. F. van Sluijs April 8 Studiedag over 'Noorse ontwikkelingen bij het A. Koops, gebruik van computers voor scheepvaart A. W. Ruys and management' at Delft, organized by 'Koninklijke W. Verschuur Nederlandse Redersvereniging' April 15-16 Leergang Scheepvaartkunde 1975 met als A. Koops onderwerp 'Maritieme economie en rederij- beheer' in Amsterdam, organized by 'Onderafde­ ling der Scheepsbouwkunde van de Technische Hogeschool Delft, Koninklijk Instituut voor de Marine en Hoger Zeevaartonderwijs' April 16 National Meeting 1975 'Simulation for Service I. Oldenkamp of Traffic' in Bremen, organized by 'Deutsche Geselischaft für Ortung und Navigation e. V.' April 29 National Symposium on Marine Transportation P. J. Paymans May 1 Management in Philadelphia, Pennsylvania, sponsored by U.S. Coast Guard with Army Corps of Engineers and Maritime Administration; organized by University of Delaware May 5-8 Seventh Annual Offshore Technology Con­ J. D. van Manen, ference in Houston, Texas, sponsored by M. W. C. Oosterveld, American Institute of Mining, Metallurgical, G. van Oortmerssen, and Petroleum Engineers et al. J. A. Pinkster and M. F. van Sluijs May 22 Conference on Ship Handling and Manoeuvring K. Meurs Simulation in London, organized by Ship Operation Sub-Committee of the Ship and Marine Technology Requirements Board in association with General Council of British Shipping

45 June 4-5 Meeting of Ship Control Group of the Royal G. Mak Institution of Naval Architects in Liverpool June 9 Middagbijeenkomst over het onderwerp: M. "W. C. Oosterveld, 'Belasting, responsie en draagkracht van maritieme T. H. Oei and constructies' at Delft, organized by 'Industriële G. van Oortmerssen Raad voor de Oceanologie, Nederlands Maritiem Instituut, Afdeling voor Onderwatertechniek en Sectie voor Scheepstechniek van het Koninklijk Instituut van Ingenieurs' June 13 Meeting of SNAME Panel H-10 P. J. Paymans (Controllability) in New York July 21-23 Summer Computer Simulation Conference in A. J. Hermans San Francisco, Califomia, sponsored by American Institute for Chemical Engineers, American Meteorological Society, Instrument Society of America, Society for Computer Simulation and IBM Users Group July 22-23 Symposium 'Propellers 75' in Philadelphia, S. Hylarides Pennsylvania, organized by Society of Naval Architects and Marine Engineers in cooperation with Philadelphia Section of SNAME August 26-29 First Ship Technology and Research (STAR) J. D. van Manen, Symposium in Washington, D.C, organized by M. "W. C. Oosterveld, Society of Naval Architects and Marine P. van Oossanen and Engineers P. J. Paymans August 28 Meeting of SNAME Panel H-10 P. J. Paymans (Controllability) in Washington, D.C. September 2-11 14th International Towing Tank Conference in J. D. van Manen, Ottawa J. J. Muntjewerf, M. W. C. Oosterveld, P. van Oossanen and M. F. van Sluijs September 10-11 Meeting of ISO/TC108/SC2/'WG2 at Hoofddorp S. Hylarides September 24-26 Meeting of ISO/TC 8/SC 15 (Computer A. Koops Applications in Shipbuilding) at Wallsend October 15 Annual General Meeting of the Royal Institute of K. Meurs Navigation in London October 16 The Royal Institute of Navigation presentation: K. Meurs 'Comparison of Facilities on Computer Based Radar' in London, under the sponsorship of Shell International Marine Limited October 20-22 First International Conference on Numerical Ship G. Kuiper and Hydrodynamics at Gaithersburg, Maryland, L. Noordzij sponsored and organized by David W. Taylor Naval Ship Research and Development Center with the cooperation of Office of Naval Research and Naval Sea System^ Command

46 October 24 Symposium 'Technology of Buoy Mooring R. Kokkeel Systems' in London, organized by Society for Underwater Technology in association with Department of Agriculture and Fisheries for Scotland and Institute of Oceanographic Sciences October 27-31 Fourth Ship Control Systems Symposium in J. D. van Manen, The Hague, organized by Royal Netherlands M, W. C. Oosterveld, Naval College H. J, Cruijff, I. Oldenkamp, P. van Oossanen, P. J. Paymans and F. G. J. Witt November 4-5 ITTC Performance Committee at Ede J. J. Muntjewerf November 11-13 5, Internationale Tagung zu Problemen der K. Meurs Schiffsführung at Warnemünde, organized by 'Bezirksvorstand Rostock der Kammer der Technik und Ingenieurhochschule für Seefahrt Warnemünde/Wustrow Sektion Schiffsführung' November 13-15 Eighty-third Annual Meeting of the Society of J. J. Muntjewerf Naval Architects and Marine Engineers in New York November 17 Symposium 'Stochastische trillingsverschijnselen' H. van de Beek and at Delft, organized by 'Sectie voor Milieu­ J. van der Kooij techniek, Afdeling voor 'Werktuig- en Scheepsbouw en Afdeling voor Onderwatertechniek van het Koninklijk Instituut van Ingenieurs' November 21 PROGEL-Gebruikerssymposium at Enschede S. Hylarides and T. H. Oei November 21 Meeting of SNAME Panel H-10 P. J. Paymans (Controllability) in New York December 16 Jaarvergadering met als thema 'Offshore techniek J. D. van Manen, en wetenschapsbeleid' van de Stichting J. P. Hooft, Materiaalonderzoek in de Zee at Delft M. W. C. Oosterveld and G. F. M. Remery

47