Marine hydrokinetic turbines have gained considerable interest in recent decades due to the potential of unrealized renewable energy from ocean currents. These currents are often in deep water where it would be infeasible for an ocean bed tower to reach the fastest currents near the surface. One approach to harvest this source of energy is through the use of tethered, coaxial pairs of turbines for converting mechanical to electrical energy. This type of system is likely to experience freestream flow misalignment from the rotor rotation axis, referred to as skew. Turbine systems attached to tethers require torque cancelation between the two rotors to function in tethered operation. The dissertation presented here discusses empirical data obtained from experiments compared to analytical models to investigate skewed rotors. Specifically, this work studies the capability of modeling a coaxial turbine in skew with a modified blade element momentum theory, and methods to investigate and leverage the unsteady lift loads on a rotor blade element for sinusoidal surge motions at constant incidence and for specialized cases of surge-pitch-plunge motions.