Buoying Vessels Over Shoals

Abraham Lincoln, USA, patent 6,469 of 1849. The only patent ever held by a US president.

Overview

As a young man Lincoln saw riverboats run aground on the Mississippi and Sangamon, and in 1849 he patented a system of inflatable bellows attached to a hull to lift a boat over sandbars. His scale model of the device is held by the Smithsonian. The device was never manufactured and probably would not have worked well in practice. Lincoln later praised the patent system for adding the fuel of interest to the fire of genius. He remains the only American president to hold a patent.