Recent advances in planing unmanned surface vessels (USV) have renewed interest in motion control, particularly related to transverse instabilities. We propose a novel method to affect maneuver and seakeeping motion by using inertial mass distribution within the vessel hull, in the volume normally occupied by passengers. This requires development of a control oriented model. However, unlike displacement vessels, roll and yaw coupled dynamics in planing vessels must be considered. In this study, we provide a first principles based analysis of these dynamics to establish a reduced order non-linear maneuvering model for prismatic planing hulls in calm water. Using this model, we show that optimized asymmetrical mass distribution yields drag savings of up to 10% with improved stability on a turning maneuver. In addition, we demonstrate the advantages of optimal feedback control using an inertial mass in seakeeping applications over traditional rudder methods. Roll yaw coupled dynamics are not well characterized and existing low cost models are limited in range of applicability. We utilize an interpolation based approach augmented with empirical equations to address a wider range of conditions with reduced computational requirements. By interpolating test data to estimate hydrodynamic forces and empirically modeling roll damping and added mass, we establish a four degree of freedom (4DOF) maneuvering model for prismatic planing hulls in calm water with fixed asymmetrical loading. It is validated against relevant tests and show significant computational resource savings in comparison with potential flow based methods. Simulation of an extreme turning maneuver and an asymmetrical loading case demonstrates its potential for use in initial design, control and evaluation. This model is able to capture the hydrodynamic sensitivities to attitude parameters such as deadrise, heel, and trim angle. These effects are exploited to achieve maneuvering objectives. Demonstrated through numerical model-based simulations, asymmetrical mass distribution on low deadrise hulls affects heel and induce yaw moments that turn the vessel without the use of traditional aft steering mechanisms. On high deadrise hulls, maneuvering by use of a combined rudder and asymmetrical mass results in ~10% drag savings and improved stability in comparison with rudder alone. To consider feedback control of an inertial mass free to move laterally within the hull, additional dynamics are added using a Lagrangian approach to make a 5DOF model. Through numerical simulations, we demonstrate roll control of planing vessels using optimal feedback control. A Linear Quadratic Regulator is implemented to maintain a steady trajectory in the presence of wave disturbances and performance is compared against a rudder roll stabilizer. The results as shown in linear analysis and nonlinear time domain simulation indicate that a mass weighing 10% of vessel weight can achieve a disturbance rejection of greater than 10 dB over rudder stabilization methods and eliminates an undesirable non-minimum phase behavior characteristic of rudder systems. Due to the roll yaw force coupling of planing vessels, such inertial mass methods can be utilized to meet both seakeeping and maneuver objectives and eliminate the need for external fin type control mechanisms such as a rudder.