Abstract: A system for guiding a drill string with an attached umbilical line through a moonpool of a floating structure. The system comprises a support means, and a workhead assembly secured to the outer end of the support means. The workhead assembly is adapted to engage the drill string and umbilical line without damaging the umbilical. The workhead assembly comprises a turntable support, which is secured to the support means, and a turntable. The turntable is positioned about the drill string and umbilical, and rests on the turntable support. Rollers on the turntable allow the drill string and umbilical line to move vertically through the turntable. Roller units on the turntable support allow the turntable and the engaged tool string and umbilical to rotate with respect to the support means.

Abstract: A guidance system for centering and guiding various drill strings or risers within a moonpool of a floating structure, e.g. a caisson vessel. The system comprises one or more guidance vehicles. Each vehicle is movably mounted on a separate track. The tracks, in turn, are spaced about the moonpool wall and extend vertically along the wall of the moonpool from the top of the moonpool to a point near its bottom. Each vehicle has a frame and means to mount the frame on its respective track. Two side arms and a center arm are pivotably mounted on the frame and are movable between a closed position and an open position. Mounted at the outer end of each of the arms is an interchangeable workhead assembly which engages a drill string or riser to center and guide the drill string or riser when the arms are in their closed position. Individual lines controlled by winches above the moonpool are attached to each vehicle for independently raising and lowering that vehicle within the moonpool.