Did you know that Abraham Lincoln is the only American president ever to hold a patent? Unfortunately, his invention wasn't any good. But it was hilarious.
Lincoln worked on river boats when he was young. River levels rise and drop due to varying factors, including drought conditions, season, and the way rivers build up and discharge debris in different places over time. Boats have different weights, depending on their cargo. A boat may easily clear the bottom of a river at one time, and run aground at another. When Lincoln was a teen, one of his boats hit bottom and tipped, taking on water. Lincoln had to offload cargo and drill a hole in the boat to let the water out before the boat rose high enough to continue. When he was a congressman, he saw the same thing. This time, the captain grabbed some barrels and some sticks and wedged them under the boat until it floated up.
Lincoln was mechanically-minded, and wherever he went he liked to inspect gadgets to see how they worked. When he saw the procedure to float the ship, he thought he might have a gadget idea of his own. Between congressional terms, he started working on an invention which combined a firm frame with a lot of rubberized sacks that could be filled with air. His plan was that captains could inflate or deflate these sacks so they didn't have offload cargo or water from the boats to get them on their way. On March 10, 1849, he became the first, and so far only, president of the United States to file a patent.
Apparently he had high hopes for this device, and talked to friends about how it would revolutionize the boating world. The friends stayed politely quiet and let history prove him wrong. Still, we applaud his spirit of invention. Makes you wonder what other presidents might have invented if they had filed patents.