Abstract: This invention provides improvements to apparatus for automatically cleaning surfaces submerged in a liquid. Thus, there is provided an apparatus having a pivotally displaceable float by means of which the apparatus is caused to turn around when migrating up an upright surface so as not to break the surface of the liquid. The pivotal axis of the float is further tiltable, a tilting float being provided to tilt the privotal axis to assist in displacing the float. The apparatus further has a sealing flange which has perimetral concertina-like folds so as to be resiliently extensible. Still further, the apparatus has a cleaning head, the region thereof that engages the surface to be cleaned having zones with differing frictional characteristics to cater for various surfaces. In a preferred embodiment this is effected by providing sockets in the cleaning head in which studs having the required frictional characteristics are secured.