Mobile, offshore, self-elevating (jack-up) unit leg/hull rigidification system

The method of securing the support leg(s) of an offshore jack-up rig unit having a hull, legs with rack teeth and a jacking drive associated therewith, comprising the following steps:

• (a) providing on said hull a separate rack chock means for each of said legs operationally separate and apart from said jacking drive, which rack chock means have teeth engaging portions which are at least laterally movable with respect to its respective rack teeth and are capable of interdigitating with in locking mating engagement its respective rack teeth;
• (b) vertically positioning the leg(s) of the rig with respect to the rig hull to the height desired by means of said jacking drive;
• and
• (c) after the foregoing steps, laterally moving the teeth engaging portions of each of said rack chock means into locking, mating engagement with its respective rack teeth, and locking all of said rack chock means to said leg(s), to thereby rigidify the rig without relying solely on said jacking drive or any pinion drive or on any associated guidance system for said jacking drive.

The method of securing the support leg(s) of a mobile, offshore, self-elevating type jack-up unit when the leg(s) is in a desired vertical position with respect to the hull structure of the unit, which leg(s) each having at least one set of rack teeth on at least two opposed leg chords, comprising the following steps:

• (a) providing rack chock means movable both longitudinally and laterally with respect to the rack of the leg(s), which rack chock means has at least one rigid structural element sized and configured to engage at least the upper and lower surfaces of two teeth on said rack;
• (b) moving said structural element longitudinally with respect to said rack until said structural element is positioned across from two teeth on the said rack and moving said structural element laterally into face-to-face, in-line engagement with the upper and lower surfaces of said two teeth;
• and
• (c) rigidly locking said structural element to said rack and and to said hull structure;
• and
• (d) repeating steps "a" through "c" for the rack(s) on at least two opposed cords for each leg of the unit to rigidify the leg(s) to the hull structure.