A self-propelled apparatus for cleaning the submerged bottom surfaces of a pool or tank in a predetermined regular pattern includes a reversible drive means for propelling the apparatus in opposite directions corresponding to the longitudinal axis of the apparatus. A housing is formed by a top wall, depending front and rear walls and depending side walls, where the side walls defining the periphery of the apparatus. At least one projecting pivot member extends from a side wall of the housing, wherein the end of the projecting pivot member serves as a pivot point in contact with a side wall of the pool to change the orientation of the apparatus with respect to the side wall of the pool.