Designing a Remotely Operated Vehicle (ROV) is a complicated task in which the design team deals with a considerable amount of uncertainty before the device is able to be tested at full scale. A way to cope with such uncertainty is to use simulation software to evaluate design concepts along the different levels of abstraction of the process. In this work, the use of aNySIM, the Maritime Research Institute Netherlands (MARIN) multibody time-domain simulation tool, as a part of the design process of an ROV is addressed. The simulation software is able to solve the equations of motion of the vehicle based on rigid body dynamics, including features such as hydrodynamics, hydrostatics, thrusters, thrust allocation, and PID control. Different simulation scenarios are proposed to evaluate different concept solutions to the design, including thruster parameters and distribution. The results are further used to select the concept solutions to be implemented in the final design.