If you’re willing to pay for a custom job, you can likely specify any size of raft frame as long as you can find a manufacturer with the right tooling. Standard raft frames are built for 13- or 14-foot rafts as these are most commonly used on rivers for whitewater and fishing floats. Grand Canyon rafts are typically 16 or 18 feet long to accommodate gear for a two- or three-week trip. Frame are also available for 9- or 10-foot rafts, which can be a good option for river runners looking for an easy overnighter rig.