Modular Hydrokinetic Turbine System

A modular hydrokinetic turbine system for installation in a water stream. The system is assembled from a number of blade modules and a number of support modules, connected in the direction of the water stream. Each blade module has turbine blades, a rotor shaft portion, and two-piece rotor shaft coupling. The support modules rest on the stream bed and support the blade modules. The rotor shaft couplings allow the blade modules to be connected such that the rotor shaft portions provide a rotor shaft, but also allow the blade modules to be separable from the support modules. A generator located at one end of the system is driven by the rotor shaft.