[PATENT MODEL]. Patent model for Certain Improvements in the Manner of Building Iron Vessels? by Richard Powell [Washington, D.C., January 21, 1874]. Wooden and metal model of a cross-section of part of a hull (135 x 122 x 18 mm). With original tags attached with (later?) string, and small COA laid-in. Some general aging to model. ?The objects of my invention, are, first, an improved plan of constructing the hulls of iron vessels, so as to have a fair and smooth outside surface; second, to secure wood backing or filling, for the reception of wood planking to be covered with copper sheathing, so that none of the fastenings will pass through or penetrate the outer iron plating or skin of the vessel, particularly in the portion to be immersed; third, to lessen the rolling motion of iron vessels, with advantage to their speed, steering etc.? Specifications and Drawings of Patents Issued from the United States Patent Office, 1875, p. 606.