Abstract: An offshore exploratory drilling floatable structure ballastable to rest on a sea floor but to extend above water level when so supported and adapted to withstand arctic ice loads, comprising a substantially vertical wall capable of withstanding arctic ice loads; a structural load bearing bottom rigidly connected to a lower portion of the wall; and a floatable vertically displaceable load bearing structural deck inside the wall.

Abstract: A "quick-disconnect" rigid mooring system for attaching a ship to a buoyant tower comprises two rigid yoke structures, one of which is attached to the buoyant tower and the other of which is attached to the ship. Each yoke contains one element of a two-element "quick-disconnect" system, which when locked, achieves a rigid interconnection between the vessel and the buoyant tower. The yoke structures are provided with means which permit the structures to be properly aigned during the connect and disconnect procedures. The locking element of one of the yokes comprises an arm which projects from the end thereof, and a pair of transversely extending pins situated below the outwardly projecting arm. The locking element of the other yoke comprises a pair of spaced, parallel outwardly projecting arms provided with longitudinal slots that accept the outwardly projecting pins on the other yoke and guide the two yokes into aligned proximity, permitting the lock to be effected.