Netherlands Ship Model Basin Wageningen, the Netherlands Annual report 1975 Foundation Netherlands Ship Model Basin 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 (France) Dr 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 Dr E. M. Q. Roren Det norske Veritas (Norway) 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 Japan - 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 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 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, Germany, 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 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. 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