An apparatus, system, and method are disclosed for WEC system for a wave energy converter. The system includes a buoyant object, a reaction body and a line coupling the reaction body and the buoyant object. The system further includes a drivetrain coupled to one of the buoyant object or reaction body. The drivetrain includes a sheave coupled to one of the buoyant object or reaction body and an actuator coupled to the sheave. The line is coupled to the sheave, wherein movement of the buoyant object relative to the reaction body applies a force to the sheave. The force on the sheave drives the actuator, wherein the actuator is configured to apply a spring force.