Analytical and Model Test Study of Platform Jacket Tow in Waves

Abstract

This paper-describes the application of ship motion analysis to predict the motions and accelerations of a platform jacket mounted on a barge for transport to its installation location. Calculations were made for both regular and irregular_ sea conditions for _ various headings of the vessel-pl-atform combination relative to the seaway. Conventional linear frequency response methods via strip theory are used, augmented by inclusion of nonlinear roll damping, for the motion predictions. A time domain simulation for irregular beam seas was also carried out, from which the occurrence of impact loads on the outboard jacket legs is indicated, and a determination is made of the total impact loads and their distribution along the immersed leg. Model test results. for the motions and accelerations are also described, together with a comparison between the test data and theoretical predictions.