A marine current turbine rotor comprises a hub and fixed and two or more pitchable blade sections configured to reduce bending moment loads on the pitch bearings and enable the use of non-standard, low-cost structural materials for the hub, blades, and pitch shaft. A submersible pitch drive mechanism or linkage in the hub rotates the pitch shaft to cause the pitchable blade section to move to a specified pitch position. The hub cavity is configured to be “wet” without the expense and maintenance requirement of seals to prevent water intrusion, utilizing water-lubricated pitch bearings.