Objectives  Designing effective and reliable composite and steel joints is one of the difficulties faced in the application of composite superstructure in ships.

  Methods  Considering the advantages and disadvantages of various joint structures, the π-type composite and steel joints were designed by using the double-bolt and double-shear. With the vertical reaction force and bending moments of the connecting position between the superstructure and the main hull under the action of wave loads extracted as design loads, the strength under two design conditions was checked by the finite element software ANSYS.

  Results  The calculation results show that the stresses checked are less than the ultimate stresses of the material, and a certain safety margin is retained. The designed joints are reasonable and reliable.

  Conclusions  In the strength check under the two design conditions, the safety margin of the shear stress of foam core is the smallest. Therefore, it is noted that failure of shear of core material for the sandwich panels with thicker core material is the main failure mode.