Importance

Loading Importance Indicators...

Abstract

A mobile sea barge having a unitary lower hull which has sufficient buoyancy to float the entire barge, an upper hull spaced from the lower hull by a single, centrally-positioned, vertical member, and a movable stabilizing hull arranged about the central support member for controlled movement between the upper and lower hulls is provided. Controlled movement of the stabilizing hull permits the operational modes of submerging and emerging of the lower hull into or from a bottom-founded gravity-forced mode from which drilling operations can be carried out. In the bottom-founded mode on the sea floor the barge functions as a gravity platform. Movement of the stabilizing hull is provided by a plurality of jacking legs and jacking units which constitute the control devices. The barge can be quickly switched between the surface-floating and the gravity-forced, bottom-founded modes. Controlled vertical descent to the sea floor is provided by the static stability of the stabilizing hull. The jacking legs, which are preferably four in number, are under compressive force during the submerging and the emerging modes of operation. The vertically movable stabilizing hull may be used to fail ice features by exerting downward pressure on the ice between the upper and lower hulls and by positioning the stabilizing hull adjacent the waterline for engaging ice floes to fail the floes in flexure.

Loading the Abstract Image...

First Claim