Plan for Floating Defensive Harbor Battery.
Folded folio sheet, 2 pages of text. 17 x 11 inches, b/w engraved illustrations.
Thomas L. Sturtevant of South Framingham, Massachusetts had this proposal printed for general circulation, probably among government officials to whom he hoped to sell his invention. It consists of a circular armored vessel with multiple gun ports, forming a revolving battery. This vessel floats in a small armored pond to be dug in “shoals or reefs… only too numerous in most harbors.” The idea was that, when an enemy approached, the circular vessel would fire its guns, then sink down into the pond in which it floats, rendering it impervious to enemy fire. He claims to have patented his floating battery on September 27, 1887.