Abstract: A vehicle includes a submersible housing and a propulsion mechanism, which is coupled to drive the housing over an interior surface of a container in which the housing is submerged. A hollow tube is fixed to the housing and is configured to be filled with a fluid having a first specific gravity. One or more objects, which have a second specific gravity that is less than the first specific gravity, are contained within and capable of moving inside the hollow tube so as to stabilize the housing in response to changes of an angle of the interior surface over which the vehicle travels.

Abstract: A vehicle includes a submersible housing and a propulsion mechanism, which is coupled to drive the housing over an interior surface of a container in which the housing is submerged. A hollow tube is fixed to the housing and is configured to be filled with a fluid having a first specific gravity. One or more objects, which have a second specific gravity that is less than the first specific gravity, are contained within and capable of moving inside the hollow tube so as to stabilize the housing in response to changes of an angle of the interior surface over which the vehicle travels.

Abstract: Cleaning apparatus includes a housing, which includes a lower side comprising an opening, and an upper side including an egress port and a lid, which opens to provide access to an interior of the housing. An impeller is disposed within the housing so as to draw water into the housing through the opening and to expel the water through the egress port. A filter assembly is contained within the housing and is of a size and shape suitable for removal from the housing via the lid. The filter assembly includes separable upper and lower segments having a wall that includes a filter material. The lower segment has an ingress port that communicates with the ingress port so that the water drawn in through the opening enters the filter assembly through the ingress port and exits the filter assembly through the filter material.