Surfing is a water sport where riders stand on a surfboard to ride waves towards the shore. There are two basic types of surfboards - shortboards less than 2.1 meters and longboards greater than 2.75 meters. The basic surfing maneuvers include taking off on the wave, bottom turning to escape the breaking wave, cutting back with a 180 degree turn to reapproach the wave, reentry by turning 180 degrees back into the wave, and tubing by sliding within the barrel of the breaking wave. More advanced maneuvers include floats, airs by launching into the air, 360 degree rotations, and snaps which are abrupt cutbacks.