Prior efforts at harbor defense construction had ceased in the 1870s. Since that time the design and construction of heavy ordnance had advanced rapidly, including the development of superior breech-loading and longer-range cannon, making U.S. harbor defenses obsolete. In 1883, the Navy had begun a new construction program with an emphasis on offensive rather than defensive warships, and many foreign powers were building more heavily armored warships with larger guns. These factors combined to create a need for improved coastal defense systems.