A SYSTEM FOR A JACK-UP RIG UNIT FOR OFFSHORE USE AND A METHOD OF SECURING THE SUPPORT LEGS OF SUCH A UNIT

摘要

A jack-up rig unit for offshore use and a method of making such a unit with its support legs rigid. The unit comprises at least one leg (2) with a set of rack teeth (6) fixedly connected thereto and disposed at least generally in a vertical direction along at least a substantial portion of the leg (2) length; a floatable hull (1) supportable above the water line on said leg(s) (2); rack chock means (7) carried by said hull (1) for each of said leg(s) (2) for rigidly locking the leg(s) (2) to said hull (1) for rigidification of the hull (1) and leg(s) (2) together without introducing any substantial bending moments in the leg(s) (2), said rack chock means (7) including as a part thereof laterally movable teeth engaging means for rigidly interdigitating with in-locking, mating engagement the rack teeth (6) of its respective leg (2) in its rigidification disposition but laterally movable with respect to said rack teeth (6) out of any engagement with said rack teeth (6) when it is desired to jack said leg(s) (2) up and down. The method of rigidifying the above unit with its support legs includes providing separate rack chock means on each leg, said means being separate from the jacking drive (4), vertically positioning the leg(s) (2) with respect to the hull (1) by use of the jacking means (4) and then moving the rack chock means into locking, making engagement with its respective rack teeth (6).