In whitewater rafting, the term "self-bailer" refers to a raft that drains water through the floor. Self-bailing rafts are advantageous because they do not require crew members to spend time and energy bailing water out of the raft in large rapids.
Inflatable, self-bailing rafts are the standard craft used in commercial whitewater rafting. The key to a self-bailing raft is the inflatable floor, which is often laced to the sides of the raft and contains bail holes, which are small holes around the perimeter of the floor that allow the water to drain out. The inflatable floor is essential to this design since it prevents the bottom of the raft from sagging and filling with water. Even with the inflatable floor, self-bailing rafts usually have a small amount of water in the bottom because of the bail holes.
The self-bailing raft is an important innovation in whitewater recreation because of the many advantages it posed over old "bailer" boats. In the old rafts, paddlers would have to stop and bail out their rafts after any major rapid. In the rapids, the old rafts would quickly fill with water and become difficult to steer. The self-bailers solved these issues by draining water almost as quickly as the raft could fill.