Abraham Lincoln in 1849 received patent #6469 for “A Device for Buoying Vessels Over Shoals.” After working with boats that were stuck on sand bars, he invented the device that would inflate and move ships to water. However, the device was heavy enough that it caused problems. The model, whittled by Lincoln, is on display at the Smithsonian. Children can see the model and read more at: Lincoln Patent. Lincoln is the only president to hold a patent.