Description of Townsend's Patent Metallic [sic] Trestletree, for Vessels' Use

Philadelphia, Pennsylvania, 1870. Minor toning, letter folds. Very good.. Printed promotion for a new patented "Metallic Trestletree" made of steel for the use in vessels, replacing old wooden versions of the same shipbuilding part. "It has a beveled orifice, fitting upon a beveled shoulder, forming a band to ships mastheads, which adds great strength, and preserves them from decay at a place where they generally break". Offers further specifications, and signed by the four owners of the patent, all Philadelphia-based : a rigger, a spar marker, a ship chandler, and a molder. Single printed leaf (9.75" by 8").