Objectives  This study aims to carry out systematic research on the hydrodynamic performance of a small unmanned catamaran.

  Methods  Based on STAR-CCM+ numerical simulation software, the hydrodynamic performance of a small unmanned catamaran in a hydrostatic state and self-propelled state under different Froude (Fr) numbers is numerically simulated. The unsteady RANSE model is selected and the Dynamic Fluid Body Interaction (DFBI) model and overset grid function are used to simulate the trim and heave of the catamaran. A body-force propeller is used to replace the propeller effect. The empirical formula of the friction resistance coefficient is used to verify the simulation results of the hydrostatic state. The self-propelled experimental results are then compared to the simulation results of the self-propelled state to verify the accuracy of the simulation results.

  Results  When the propeller speed is 3 000 r/min, the difference in total resistance between the self-propelled and hydrostatic states of the small unmanned catamaran is 21.099%. Under different propeller rotation speeds, the relative errors of the thrust between the simulation and experimental results of the self-propelled catamaran is less than 10%.

  Conclusions  The comparison between the simulation results and experimental results verifies the reliability of the simulation. The hydrodynamic performance of the self-propelled ship hull studied by the volume method is quite different from that under hydrostatic conditions. The numerical method can provide valuable references for further predicting the hydrodynamic performance of small unmanned catamarans.