Objectives  Resistance of appendages is one of the important components of ship resistance. The resistance of twin shaft brackets accounts for a high proportion of the resistance of appendages. Through the optimization analysis of the resistance of shaft brackets, the purpose of reducing the ship resistance is to be realized.

  Methods  Firstly, the design parameters of the brackets were selected and the initial scheme of the brackets was determined by the angle of attack corresponding to the streamlines on the hull surface. The velocity vectors of the hull surface, the streamlines of the airfoil profile of the brackets, the pressure distribution on the surface of the brackets and the spatial streamlines at design speed were analyzed by CFD simulation. The streamlines in the plane where the airfoil profile of the brackets was located was taken as a reference, and the multi-scheme design of the brackets was carried out, and the CFD simulation results were compared.

  Results  The results show that it is reasonable to use streamlines in the plane where the airfoil profile of the brackets is located to design the twin shaft brackets. In the scaling model, the total resistance of scheme 1 is reduced by 3.5% compared with the initial scheme, and the pressure distribution on the surface of the brackets is more uniform.

  Conclusions  The design method for determining the angle of attack by streamlines of the airfoil profile of the brackets can provide a reference for the design of ship appendages.