The traditional design method increases the intensity of the drum by increasing the wall thickness,which brings great difficulty to the manufacturing.According to the force characteristics of the ship left drum in practical operation,we put forward a new design method of drum wall thickness.We consider the rope groove as the ring to strengthen the ribs to make the drum wall thickness design more reasonable.The reliability of the drum intensity and deformation under this design method is verified by calculation and finite element analysis,which provides a reference for further improvement of the subsequent design method.