Jackup rig

The buoyant hull enables transportation of the unit and all attached machinery to a desired location.

The legs of such units may be designed to penetrate the sea bed, may be fitted with enlarged sections or footings, or may be attached to a bottom mat.

[1] Generally jackup rigs are not self-propelled and rely on tugs or heavy lift ships for transportation.

[4] Jackup rigs are so named because they are self-elevating with three, four, six and even eight movable legs that can be extended (“jacked”) above or below the hull.

This barge had ten legs which had spud cans to prevent them from digging into the seabed too deep.

[5][6] A jackup rig is a barge fitted with long support legs that can be raised or lowered.

The jackup is maneuvered (self-propelled or by towing) into location with its legs up and the hull floating on the water.

Then "preloading" takes place, where the weight of the barge and additional ballast water are used to drive the legs securely into the sea bottom so they will not penetrate further while operations are carried out.