There may not be a fountain of youth, but Smooth Rapids Outfitters has discovered a river of success.Since getting its start over four years ago in April 2012, Smooth Rapids has quadrupled its number of kayaks to rent, bought a campground, and just recently opened a general store, complete with deck overlooking the Barren Fork River. “Our 10-year plan has become a four-year plan,” said Jimmy Barker, one of four Smooth Rapids co-owners. “We’ve come a long way from when we started in my garage.”The business got its start with 20 kayaks and has grown that number to 63 -- with 20 more on the way.