Patent ID: 9227703
Filing Date: 2016-01-05
CPC Classification: B63B,B63H

Claim Text:
1. A buoyant structure for at least one of: petroleum drilling, production, storage, and offloading, wherein the buoyant structure comprises: a. a hull defining a vertical axis, whereby the hull has an outer hull side connected to an inner hull side, and the outer hull side is characterized by an outer hull side shape selected from the group: circular, elliptoid, and geodesic in horizontal cross-sections at all elevations; and the hull has an upper hull diameter and the inner hull side characterized by a shape selected from the group: circular, elliptoid, and geodesic; b. a planar keel defining a lower hull diameter; c. a lower cylindrical portion connected to the planar keel, wherein an lower cylindrical portion diameter is identical to the lower hull diameter, and the lower hull diameter is the largest diameter of the hull, and further wherein the lower cylindrical portion diameter is from 105 percent to 130 percent of the upper hull diameter; d. a lower frustoconical portion disposed above the lower cylindrical portion formed with an inwardly sloping wall at a first angle ranging from 50 degrees to 70 degrees with respect to the vertical axis; e. an upper frustoconical portion directly connected to the lower frustoconical portion, the upper frustoconical portion with an outwardly sloping wall sloping at a second angle with respect to the vertical axis from 3 degrees to 45 degrees, and wherein the lower frustoconical portion with the inwardly sloping wall, abuts the outwardly sloping wall forming a hull neck with a hull neck diameter; f. a main deck connected over the upper frustoconical portion; g. a moon pool formed by the inner hull side characterized by a shape selected from the group: circular, elliptoid, and geodesic having a first moon pool diameter proximate the main deck which increases to a second moon pool diameter proximate the planar keel wherein the second moon pool diameter is less than the upper hull diameter; and h. at least one ballast tank in communication with a control center in the hull, the at least one ballast tank is for ballasting and deballasting the hull; and wherein the buoyant structure defines a center of gravity below a center of buoyancy in the moon pool.