MODEL STUDIES OF THE DYNAMICS OF AN LSM MOORED IN WAVES

R. L. Wiegel, K. E. Beebe, R. A. Dilley

Abstract


Presented in this report are the results of model tests performed to determine the motions of a moored LSM (Landing Ship Medium) and the associated mooring cable forces when subjected to the action of uniform periodic water waves. Details are given of the design and construction of the 1:60 scale model LSM and the dynamic balancing of the model. Principles of the designs of the model mooring cables and of the meter for measuring the cable forces are also presented. The use of the laboratory equipment, such as the wave-towing tank, the model basin, the photography equipment, and the force and wave height meters are described, and the testing procedure is outlined. The data are presented in terms of the prototype in graphical form. Resonance conditions in the surging and heaving motions and the associated high cable forces, are shown to exist for some initial cable tensions within the range of wave periods normal encountered in many ocean areas. The effect of a roll damping device is shown.

Keywords


ship model studies; mooring analysis; roll damping

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