Patent ID: 7815398

Claim:
A method comprising: moving an elevating support vessel within proximity of an offshore structure; mapping at least a portion of a sea floor near the offshore structure; using the mapped portion of the sea floor and attitude measuring devices to determine a jack-up location, wherein the attitude measuring devices are in communication with a computer; moving the elevating support vessel to the determined jack-up location; using the attitude measuring devices to determine subsequent positions of the elevating support vessel; using the computer to measure the subsequent positions of the elevating support vessel relative to the jack-up location; using the computer to determine an amount of force and a vector direction that the must be exerted on the elevating support vessel to move the elevating support vessel back to the jack-up location; transmitting an electrical signal to the at least three azimuthing thrusters to move the elevating support vessel in the determined force and vector direction; using a crane disposed on a crane support apparatus to lower a first cable from the elevating support vessel to the sea floor, wherein a first end of the first cable is affixed to first end of the elevating support vessel's transom and the second end of the first cable is affixed to an anchor, and the crane support apparatus comprises: at least two vertical members with each vertical member having a first and second end, the first end of the first vertical member is affixed to a first track, the first end of the second vertical member is affixed to a second track, the first and second tracks are affixed to a deck of the elevating support vessel, the second end of the first vertical member is affixed to a first side of a platform, the second end of the second vertical member is affixed to a second side of the platform; and a column having a proximate and distal end, the proximate end is affixed to the platform, and the crane is rotatably affixed to the distal end of the column, the platform has a lower side disposed at least about 2 meters above the deck, the crane support apparatus is movable along the track; using the crane to lower a second cable from the elevating support vessel to the sea floor, wherein a first end of the second cable is affixed to second end of the elevating support vessel's transom and the second end of the second cable is affixed to an anchor, wherein the Elevating Support Vessel remains within at least a 3 meter radius from the jack-up location; and jacking-up the elevating support vessel.