Abstract: Petroleum coking drums and other vessels may be inspected to determine if dimensional changes or bulges have occurred in the surface of the vessel by an inspection device including a reflected laser light measuring survey apparatus and a video camera mounted on a frame which may be disposed in selected vertical positions along a central axis of the vessel and rotatably positioned by a rotary positioner interposed between a support stem for the device and the frame. Plural distance measurements and video scans are transmitted to a remote control console for recording and plotting of the contours of bulges or other dimensional anomalies surveyed by the survey apparatus. Components of the device are sealed or gas pressurized to minimize the chance of explosion in hazardous environments such as the interior of a petroleum coking drum. The system is adapted to be supported on the distal end of a coking drum drillstem and centralized by a removable clamp unit mounted on the drum manway flange.