Axial flow turbines designed to generate power from underwater currents (tidal and riverine) are similar to the commonly observed wind turbines. With support from U.S. Naval Sea Systems Command, engineers at the Applied Physical Laboratory of the University of Washington (APL-UW) have designed and fabricated a one-meter diameter axial flow turbine for use in APL-UW’s marine energy research program. The system, referred to as the AFT (axial flow turbine), is designed for deployment from R/V Russell Davis Light, where the vessel, under propulsion, is used to simulate naturally occurring currents for power generation. This report summarizes the AFT’s mechanical and electrical design and is intended as a reference to support research efforts performed using the system. Encoders and six-axis load cells installed on the driveshaft and at the root of one of the rotor’s three blades, allow for characterization of the forces and torques generated during operation. The system was designed for reliability and to acquire scientific-quality data to advance studies of axial flow turbines. Thus, system components selected in the design process are not intended to maximize system efficiency and power extraction.