Compared with other types of anchors, gravity-installed anchors (GIAs) have several main advantages such as simple structure, convenient installation way and cost reduction. The torpedo anchor is one type of GIAs. The geometric configurations have a direct influence on the hydrodynamic characteristics of the anchor, and thus affect its installation performance in water. The present work aimed to put forward some new aspects for optimizing the existing geometries of torpedo anchors by comprehensively improving the hydrodynamic characteristics of the anchor during installation in water. A computational fluid dynamics (CFD) model was established and numerical simulations were carried out using the software of ANSYS FLUENT. The hydrodynamic characteristics concerned involved the drag coefficient, the terminal velocity and the directional stability. The present study paid more attention to the fin’s design. By changing the fin parameters, including the aspect ratio and the area of the fin, the optimum design method of the fin was proposed, which would make sure of a higher terminal velocity as well as good directional stability. Besides, effects of the mass distribution on the hydrodynamic characteristics were investigated. The present work provides a design reference for torpedo anchors and is also beneficial to the research and development of new types of GIAs.