Model Test Determination of Sea Loads on Catamaran Cross Structure

摘要

To obtain design loads for the cross structure joining the hulls of a catamaran, a model was instrumented and tested in random waves. Response amplitude operators (RAO's) were obtained from the test data by means of spectral analysis. Then the RAO's were used in conjunction with theoretical Neumann sea spectra to predict loads for sea states higher than those obtained experimentally. Analysis of the results led to the conclusion that (1) as for vertical shear and moment loads on the cross structure, the most severe operating condition was with the ship operating at zero speed in beam seas; (2) the most severe torsional loads occurred with the ship operating at zero speed in quarter-head seas; and (3) since the measured responses agreed well with the predicted loads, support was lent to extrapolation of these loads to higher sea states. (Author)