Using traditional strip method to predict the longitudinal motion of the hybrid monohull, the predicted results are very
different from test results, it can not reflect the effect of the built-up appendage. This paper presents a method to predict the
longitudinal motion of hybrid monohull by using computational fluid dynamics software. In this paper, FLUENT software
is used to calculate the radiation force of three-dimensional hull which slightly heaving and pitching on free surface, and
the lift force of built-up appendage with several attack angles. According to the force calculated by using FLUENT, it
further calculates the viscous hydrodynamic coefficients of the hull and the lift force coefficients of the built-up
appendage. At last, it predicts the longitudinal motion of the hybrid monohull by STF method. The research shows that, the
predicted results of three-dimensional viscous corrected method fit the test results well.