Stevens's Ironclad Floating Battery Small 320×119 Medium 640×239 Large 1024×382 Download Tiff Original 2400×895 | (1.1 MB) Description Robert Livingston Stevens applied the wave line, concave waterlines on a steamboat hull, in 1808. Keywords concave waterlines, floating battery, ironclad, Robert Livingston Stevens, steamboat Galleries Steam-Powered Source: Benson John Lossing, ed. Harper's Encyclopedia of United States History (vol. 8) (New York, NY: Harper and Brothers, 1912)