Most ocean vessels are underactuated but control of their motion in the real ocean environment is essential. Control of Ships and Underwater Vehicles concentrates on the control of underactuated ocean vessels both surface and submarine. Having more degrees of freedom to be controlled than the number of independent control inputs these vessels give rise to numerous challenges within the area of applied nonlinear control which are of growing concern because of their prevalence.Starting with a review of the necessary background on ocean-vessel dynamics and nonlinear control theory, the authors' systematic approach is based on various nontrivial coordinate transformations coupled with advanced nonlinear control design methods building on Lyapunov's direct method, backstepping, and parameter projection techniques. This strategy is then used for the development and analysis of a number of ocean-vessel control systems with the aim of achieving advanced motion control tasks including stabilization, trajectory-tracking, path-tracking and path-following.Control of Ships and Underwater Vehicles offers the reader:'¢ new results in the nonlinear control of underactuated ocean vessels countering environmental disturbances induced by wind, waves and ocean currents;'¢ efficient designs for the practical implementation of controllers on underactuated ocean vessels;'¢ extensive numerical simulations and real-time implementations of the control systems designed on a scale-model ship for each controller developed to illustrate their effectiveness and afford practical guidance; and'¢ general methods and strategies for solving nonlinear control problems of other underactuated systems including underactuated land and aerial vehicles.Written for researchers in and practitioners of control engineering applied to marine technology this monograph provides a variety of solutions to advanced feedback control topics of practical significance in underactuated ocean vessels. Its self-contained, from-the-basics style also makes it a useful resource for graduate students in marine control and readers interested in learning through self-study.