Real time estimation of ship motions in short crested seas

The presented research is part of the development of an onboard wave and motion estimation system that aims to predict wave elevation and vessel motions some 60–120 s ahead, using wave elevation measurements by means of X-band radar. In order to validate the prediction model, scale experiments have been carried out in short crested waves for 3 different sea states with varying directional spreading, during which wave elevation and vessel motions were measured. To compare predicted and measured wave elevation, three wave probes were used at different distances from a large set of wave probes that was used as input to the model. At one of the prediction locations, also tests were performed to measure vessel motions. This setup allowed validation of a method that was used for initializing the linear wave prediction and ship motion prediction model. Various observations and conclusions are presented concerning optimal combinations of prediction model parameters, probe set-up and sea state.