Abstract
The current practical long-term prediction method for ship responses estimates higher values than real values, because it does not consider ship operation conditions and does not assume non-linearity between significant wave height and standard deviation of the ship response. We propose a long-term prediction method with operation criteria for ship responses that considers these influences. We define a critical standard deviation of the ship response and propose the utilization of onboard monitor data of ships. The validity of the proposal method is confirmed by comparative results of the long-term predictions and the onboard monitor data from an actual ship.