Mobile offshore drilling or installation unit with retractable legs that are lowered to the seabed, lifting the hull clear of the water surface for operations.
Quick facts
Regulation
SOLAS Chapter XI
In practice
Drilling jack-ups are employed for exploration, appraisal, and development wells on the continental shelf. A separate and growing market uses purpose-designed wind-farm installation jack-ups (WIJUs) to install turbine foundations, transition pieces, and nacelles in shallower waters; these carry large rotating cranes rather than drilling derricks. Leading contractors include Valaris, Noble, Borr Drilling (drilling), and Cadeler, Eneti (wind installation).
Regulatory detail & full definition
A jack-up rig (or self-elevating unit) is a mobile offshore unit comprising a buoyant triangular or rectangular hull (mat or independent-leg) fitted with three or four lattice or cylindrical legs. In transit, the legs are raised and the hull floats; on location, the legs are hydraulically or electrically jacked down to the seabed, and the hull is elevated above wave action to provide a stable working platform. Operational water depths are typically up to 120–150 m for drilling jack-ups, though enhanced designs reach 170 m.
Drilling jack-ups are employed for exploration, appraisal, and development wells on the continental shelf. A separate and growing market uses purpose-designed wind-farm installation jack-ups (WIJUs) to install turbine foundations, transition pieces, and nacelles in shallower waters; these carry large rotating cranes rather than drilling derricks. Leading contractors include Valaris, Noble, Borr Drilling (drilling), and Cadeler, Eneti (wind installation).
Jack-up rigs are classified under the IMO MODU Code (Code for the Construction and Equipment of Mobile Offshore Drilling Units), made mandatory under SOLAS Chapter XI-2 for security, with structural design governed by classification society rules (ABS, DNV, Lloyd's Register). Flag State requirements under SOLAS Chapter II-1 (stability and buoyancy when afloat) and MARPOL apply during tow transits. ISM Code compliance (SOLAS Chapter IX) is mandatory for the owning company.