This book investigates the adaptation and purpose-built construction of the vessels used by the Federal government to conduct riverine warfare on the waters of the American Mississippi River drainage basin. The book concentrates on the technology, geography, hydrography, and convention which shaped the construction of the vessels comprising the Federal Western Gunboat Flotilla; an organization which after October 1862 became the United States Navy Mississippi Squadron. The ability of an organization to adapt is equipment to conditions encountered during wartime is often a contributing factor in ultimate victory or defeat. During the Civil War, the process adopted by the Navy to adapt and furnish vessels for its riverine force was flawed. This book emphasizes these facts and explores the response of the Navy chain of command to lessons learned in combat about the vulnerabilities of the vessels of the Western Gunboat Flotilla. The study is not intended as a treatise on tactics or the organization of the United States Navy. However, it does address both with regard to their effect on the performance and adaptation of the vessels of the Western Gunboat Flotilla.