International Shipbuilding Progress - Volume 45, issue 441

Authors: Beukelman, W.

Article Type: Research Article

Abstract: A model of a surface-piercing wing has been towed through the water at three speeds in two opposite directions for different draughts and drift angles. The experiments were carried out in both deep and shallow water. Purpose of the tests was to measure the longitudinal and transverse forces on the wing-model. From the measured forces hydrostatic manoeuvring coefficients were determined as a function of the drift angle. In addition to these static measurements forced horizontal motion tests with a Planar Motion Mechanism (PMM) were carried out to determine the hydrodynamic manoeuvring coefficients. Calculations based on the potential theory and on …the variation of the added mass impulse were carried out to determine the manoeuvring coefficients for small drift angles. Comparison with the measurements showed encouraging results to determine manoeuvring coefficients also for the velocity derivatives. Both experiments and calculations showed a strong increase of the coefficients with draught and reduction of water depth. Show more

DOI: 10.3233/ISP-1998-4544101

Citation: International Shipbuilding Progress, vol. 45, no. 441, pp. 5-26, 1998

Authors: Beukelman, W.

Article Type: Research Article

Abstract: A model of a surface-piercing wing has been towed through the water at three speeds in two opposite directions for different draughts and drift angles. The experiments were carried out in both deep and shallow water. Purpose of the tests was to measure the longitudinal and transverse forces on the wing-model. From the measured forces hydrostatic manoeuvring coefficients were determined as a function of the drift angle. In addition to these static measurements forced horizontal motion tests with a Planar Motion Mechanism (PMM) were carried out to determine the hydrodynamic manoeuvring coefficients. Calculations based on the potential theory and on …the variation of the added mass impulse were carried out to determine the manoeuvring coefficients for small drift angles. Comparison with the measurements showed encouraging results to determine manoeuvring coefficients also for the velocity derivatives. Both experiments and calculations showed a strong increase of the coefficients with draught and reduction of water depth. Show more

DOI: 10.3233/ISP-1998-4544102

Citation: International Shipbuilding Progress, vol. 45, no. 441, pp. 27-50, 1998

Authors: Žerjal, Marko | Bilen, Branislav | Marinković, Marija

Article Type: Research Article

Abstract: The paper treats the problem of crash-stop manoeuver which is of great importance for vessels navigating at restricted and overcrowded inland waterways. A brief review of existing international regulations covering stopping process on inland waterways is given. Three characteristic phases of crash-stop manoeuver for a typical Danube pushboat are described and a simplified calculation procedure is propsed for estimation of stopping distance and stopping time period for a vessel. A propeller's reverse thrust prediction during crash-stop manoeuver was determined according to results of W.B. series 4 quadrant open water testing. Simple emperical formulas for calculation of propeller's reverse thrust are …given either for conventional W.B. series propeller and propeller series KA operating in nozzle type 19A. At the end, some concluding remarks are given on how to influence the stopping abilities of a vessel in design phase. The accuracy of proposed calculation procedure is illustrated through comparison to results of crash-stop trial testing for a pushed concoy and a cargo ship. Show more

DOI: 10.3233/ISP-1998-4544103

Citation: International Shipbuilding Progress, vol. 45, no. 441, pp. 51-70, 1998

Authors: Ramos, J. | Guedes Soares, C.

Article Type: Research Article

Abstract: The present paper describes a method to predict the stresses induced on the ship hull when the forward bottom impacts in water. The relative motion between the ship and waves is determined using a linear strip method. The time history of the relative motion indicates the conditions for the occurrence of slamming. Several empirical methods for the evaluation of the slamming loads based on experimental results are compared. The vibratory response of the ship is calculated by modelling it with finite elements. The response is obtained by modal superposition using the central differences for the time integration. Results are presented …of an example on a container ship. It as shown that very large differences are obtained for the slam induced vertical bending moment amidships depending on the method used to calculate the slamming forces. Show more

DOI: 10.3233/ISP-1998-4544104

Citation: International Shipbuilding Progress, vol. 45, no. 441, pp. 71-87, 1998