Hyundai Heavy Industries has chalked up another world record in the offshore fabrication field using what it calls the "onshore deck mating" method it pioneered and developed last year. This method cuts time spent in dry dock. HHI has built a 120-meter high drilling rig in July this year using the ODM method.
The ODM construction process is a boon to dry dock use in the shipyard for one big reason-it takes place on the shore, HHI said. The requirement of a dry dock for rig building is thus eliminated. When compared to the sequential block stacking method that uses the dry dock for an extended period to stack unit blocks in sequence from the lower level to the top, the benefits are immediately apparent.
The unassembled drilling rig was in three parts: one top, two bottoms. The upper half was lifted from ground level to 37 meters in the air in part by using a hydraulic lifting system of four steel framed temporary lifting towers and two cylindrical temporary lifting towers. The structural stability and the hydraulic jack system's load status were continuously monitored and controlled by computer. After the upper half of the rig had been lifted, two lower hull structures at the right and left side of the upper structure were skidded beneath it. A hydraulic support system for the jacks was used to prevent the base from sinking and causing structural damage. After the upper and lower sections of the rig were in place, the connection was completed within the 4-mm tolerance for error and sections were welded together. Hyundai has slated January 2001 as the delivery date for the Horizon.