What was the name of Abraham Lincoln's patent for a device to lift boats over shoals?

Abraham Lincoln’s patent for lifting boats over shoals was called “Manner of Buoying Vessels Over Shoals.” The invention received U.S. Patent No. 6,469 on May 22, 1849.

Lincoln designed the device after encountering boats stuck on shallow river obstructions. His plan used expandable, air-filled chambers attached along a vessel’s sides. When inflated, they would increase buoyancy and raise the boat enough to pass over a shoal without unloading its cargo.

The patent is also commonly titled “Buoying Vessels Over Shoals,” the wording used on the patent specification and in many historical references. “Manner of Buoying Vessels Over Shoals” is a defensible full form of the name and clearly identifies the same invention.

Lincoln remains the only U.S. president to hold a patent. His wooden model of the invention is preserved by the Smithsonian, although the device was never put into practical production.