Abstract: A semi automatic coke drum deheader device for use on a coke drum wherein the coke drum includes an upper opening, a flange surrounding the upper opening and a first vessel cover releasably attached to the flange. The deheader device comprises a frame attached to the coke drum, a bridge for supporting the first vessel cover and a second vessel cover, a central shaft having a distal end connected to the bridge and a thrust collar surrounding the shaft below the distal end. A lift assembly is attached to the frame for engaging the thrust collar to selectively raise and lower the bridge relative to the flange, and a rotational assembly is operatively connected to the central shaft for rotating the bridge to selectively align the first vessel cover or the second vessel cover above the flange during the delayed coking process.