Innovative Methodology for Assembling Jack up Leg of 205m on ground of Ultra

Generally, in jack up rig design for harsh environment, its leg height is a major factor for achieving a sufficient serviceability & operability in terms of the worst environment and the workable depth. Due to difficulties in constructing such a high-slender leg, inaccessibility of yard fabrication equipment, etc. the construction of Jack up rig fur harsh deep sea has not been common. Method using heavy crawler crane, fabrication tower or extension by the floating crane vessel is still conventional construction but, considering high cost fur mobilizing heavy lift vessel (HLV) or additional marine work for implementing preload / full height test at sea, the ground-base construction is much advantageous. Air skidding method (ASM hereafter) is ground-based construction methodology, newly developed due to such requests. ASM could also be extended to similar engineering fields. This paper presents the operating sequence, design parameters and procedure which were verified through successful operation at the end of May 2002.