plate-forme de forage autoélévatrice

CONT: La technique désormais classique pour les profondeurs d'eau relativement faibles repose sur l'utilisation de «jack-up», plates-formes autoélévatrices qui restent solidaires du fond pendant les travaux de forage. Celles-ci sont mises en position à la hauteur souhaitée, compte tenu de la houle, au-dessus des flots en prenant appui sur des piles mobiles par un système de vérins et de crémaillères.
OBS: Pluriel : des plateformes, des plates-formes.

CONT: [A] mobile jack-up platform ... consists basically of a dumb barge which can raise itself out of the water on legs to well above storm wave height, and upon which is mounted a drilling rig. Some of the hulls are roughly triangular in plan and have three legs, but most are matchbox and have four or six legs ... The jack-up barge is towed to location, the legs are dropped or jacked down to the sea bed, and then the hull is raised out of the water some 50 to 60 ft.
CONT: A jack-up rig is towed or propelled to the location with the legs up, and machinery is engaged to move the legs to the seafloor while the deck and hull ... remain above the water. Once the legs are firmly positioned on bottom, the deck height may be further adjusted and leveled.