Jackup

A jackup is a type of mobile offshore drilling unit or work platform characterized by a rigid hull supported by vertically extending legs. The legs rest on the seabed and can be lowered to secure the vessel in place, after which a jacking system raises the hull above the water surface to provide a stable working deck. Jackups are used for oil and gas exploration and development, as well as for construction, maintenance, and seismic work in offshore environments. They are also employed in the installation of offshore wind turbines and related infrastructure.

Typical jackups have a hull that houses living quarters, drilling equipment, and deck space, with legs that may be lattice or tubular in construction. Spud cans at the base of the legs help distribute load on the seabed. The jacking system, usually hydraulic, raises or lowers the hull to transition between transit and operational modes. During transport, the legs are retracted; at the site, they are lowered to contact the seabed, where the hull is then elevated to maximize height and stability.

Operational range varies by design, but jackups are generally suitable for shallow to mid-water depths, offering faster mobilization and lower operating costs for many offshore tasks compared with floating rigs. Their performance depends on seabed conditions, weather, and leg penetration. While versatile, jackups have limitations in deepwater and rough sea states and require careful maintenance and adherence to classification and safety standards from authorities and classification societies.