Okay kiddo, so Lewis and Clark were two guys who went on a really long camping trip a really long time ago. But instead of a tent, they had something called a keelboat.
A keelboat is like a big boat with a flat bottom that you can put lots of stuff on. It's a bit like a moving truck on the water. The keelboat that Lewis and Clark used was about 55 feet long, which is longer than a school bus!
Their keelboat had a cabin on it where they slept and ate their food. It also had sails that helped it move, but sometimes they had to use oars to row it. The boat was really important because it helped them travel up and down the rivers to explore places that they wouldn't be able to get to on land.
They even had cannons on their keelboat to keep bad guys away! That's why it was important to have a strong, sturdy boat to keep them safe. And that's the story of Lewis and Clark's keelboat.