Abstract: A device for scrubbing algae and other marine growth from boat hulls comprising a one-piece belt of fibrous fluorocarbon abrasive material and a plurality of floats mounted along the belt undersurface. A number of the floats are of oval cross section and are mounted to pivot at right angles to the belt longitudinal dimension. As the belt is drawn in the direction of its length back and forth beneath a hull, the floats urge the belt into frictional scrubbing contact with the hull surface. The pivotal floats operate synergistically to combine buoyant forces and water drag forces to provide enhanced scrubbing contact with surface irregularities such as stabilization chimes.