An innovative robotic boat has been developed for performing bathymetric mapping of very shallow coastal, estuarine, and inland waters. The boat uses a small waterplane area twin hull design to provide natural platform stability for a multibeam sonar payload, and a navigation system automatically guides the boat in a “lawn-mowing” pattern to map a region of interest. Developed in stages over five years as part of a low-cost student design program, the boat is now operational and is being used to generate science-quality maps for scientific and civil use; it is also being used as a testbed for evaluating the platform for other types of scientific missions and for demonstrating advanced control techniques. This paper reviews the student-based development process, describes the design of the boat, presents results from field operations, and reviews plans for future extensions to the system. © 2012 Wiley Periodicals, Inc.