Abstract: A system and method for accessing contents of a tank through a tank opening disposed on the tank. The system and method may obtain samples, use a sensor to analyze sludge or may clean the tank. The system has a rotatable head connected to a rigid tube having a central axis. The rotatable head is adapted to be inserted through the tank opening. The rotatable head comprises a displacer and a head opening. A flexible tube has an insertable end and an external end. The flexible tube is slideably movable within the rigid tube and has a range of motion relative to the rigid tube so that the insertable end of the flexible tube can be directed by the displacer through the head opening at an angle offset from the central axis of the rigid tube.