Nonlinear Control of an Underactuated Autonomous Surface Vehicle: by Zhenning Yu Thesis Supervisors: Prof. Carlos Silvestre Dr. Qingsong Xu This thesis presents a problem of driving a boat to follow a desired path against disturbance. The solution to this problem consists of a nonlinear adaptive state feedback controller for propeller and steer. For a practical boat, we demonstrate how Lyapunov based techniques and nonlinear hydrodynamic systems yield a control structure that i) guarantees the error between design and actual path converging to Global Asymptotically Stability with current disturbance and ii) ensures the actuation is operating under nonlinear hydrodynamic system and actual environment limitation. The foundation of the boat nonlinear model is also described. Simulation results illustrate the efficacy of the solution proposed.