In recent decades, the push for reliable renewable energy sources has led researchers to explore an ever-expanding array of novel devices capable of harvesting such energy. Of the current available renewable energy sources, marine energy is one of the least-utilized categories with wave energy being the least common. However, given their high amount of energy extraction potential, wave energy converter (WEC) devices are gaining interest in the global energy market. One such device is a WEC known as the oscillating wave surge converter (OWSC). OWSCs are paddle-like devices which rotate about a fixed hinge when driven by wave surges (or wave motions). Most research on OWSC devices to date has primarily been based on experimental, scale model testing. Experimental tests on OWSC devices in wave tanks are expensive, time-consuming, and testing facilities are limited. To improve the quality of such tests, computational fluid dynamics (CFD) models may be used to assess and fine-tune a design before running a physical experiment. Modeling an OWSC using available CFD software poses a number of challenges related to model geometry, mesh quality, and solution stability. The high degrees of rotation experienced by these devices make typical mesh-morphing methods untenable. Alternative methods for dealing with the large mesh deformation issues have been devised and implemented; however, many of these alternatives require modifications to the available CFD software. This work presents two CFD models which utilize an overset mesh approach to simulate an OWSC device and require no software modification. The overset mesh approach uses a background and overset (body-fitted) mesh where the overset mesh overlays the static background mesh and moves relative to it. This method avoids mesh deformation altogether and instead relies on interpolation between the two meshes. CFD models were created using the OpenFOAM and STAR-CCM+ software so that the numerical model results could be compared across platforms. These CFD models are also compared to a scale model wave tank test.