Tuesday kicks off the 8th annual Missouri River 340, a 340 mile canoe and kayak race down the Missouri River starting at Kaw Point in Kansas City.

It’s no float trip, its a grueling marathon style race that must be completed in 88 hours. Organizer Scott Mansker says you must reach checkpoint on time as well.

The race kicks off early, around 7am as long as the weather allows. After the start, racers have to be in Lexington by 5:00pm. That’s a pace of roughly five miles an hour and the river flows around three miles per hour.

And, it’s grueling, an ultra marathon, the largest non-stop paddle race in the world.

“If you just floating you will not make the first checkpoint in Lexington,” Mansker said. It’s a pretty aggressive pace during the day, we dial the pace back a little bit in the night, but the top competitors are going to finish this race in 38 hours across the state of Missouri, they’re not going to get out of the boat, they are going to paddle night and day.”

The race started in 2006, with 11 boats. It’s grown to more than 300 boats a year. It grew largely from online promotion and word of mouth. Now, this years race is sponsored by Missouri American Water.

And to finish the race, now that, Mansker says, is a big accomplishment.

“Just finishing this is a big, big deal,” Mansker said.