Fabrication of the Lena Guyed Tower Jacket

The guyed tower design prompted the development of innovative construction techniques and the application of equipment not commonly utilized in platform fabrication. The jacket's constant cross section allowed the fabricator to divide the structure into rectangular box sections. Each individual box section was built on its side and then rolled to a vertical orientation for mating with the other boxes. Two stationary ringer cranes were used in tandem to install twelve large buoyancy tanks in the central core of the tower. A new fabrication yard skidway system was constructed to accommodate fabrication of the industry's first major side-launched jacket. Critical loadout operations included the complex ballasting and deballasting sequence required as the jacket moved onto the barge. A series of monitoring systems confirmed that loadout progress was within acceptable operational limits.