In this presentation, an unstructured, low-Mach, balanced-force, volume of fluid numerical methodology is overviewed whose prime objective is to target the modeling of wave-based renewable energy devices using high-fidelity computational fluid dynamics approaches. A control volume finite element numerical discretization, which includes novel residual-based stabilization for the volume of fluid equation, is established. Although WEC mod/sim requirements lack typical multiphysics complexities, other technical challenges exist, such as ensuring non-diffusive fluid transport in the presence of mesh modification and modeling floating devices that are free to move in a non-prescribed trajectory. The presentation outlines three critical components of a WEC mod/sim tool including 1) stable and accurate unstructured low-Mach fluid mechanics discretizations, 2) low-dissipation volume of fluid transport in the presence of PDE-based sharpening, and 3) mesh motion methodologies that encompass mesh deformation, sliding mesh, and overset approaches. Credibility of this numerical approach is established in the open-source Nalu simulation tool by deploying a code verification and model validation hierarchy across the intersection of the three critical components. A formal buoy validation case, with and without mooring, is presented, in addition to validation benchmark cases that reside in the high-displacement regime. These validation cases showcase an implicit overset unstructured mesh construct that allows a wave energy converter (WEC) geometry to freely move about a background domain, thereby establishing the efficacy of the approach in this challenging multiphase flow application.