Patent ID: 7188574

Claim:
In a circular floating hull formed from a plurality of sections attached together end-to-end, at least one section of the hull comprising: a. a flat circular plate having a central circular cutout; b. a plurality of curved stiffeners attached to said flat circular plate; c. a plurality of radial girders attached to said flat circular plate and said curved stiffeners; d. an inner shell attached to the central circular cutout in said flat circular plate; e. a plurality of longitudinal girders that extend along the length of the outer circumference of said inner shell and are spaced radially around the outer circumference of said inner shell; f. an outer-shell attached to the outer circumference of said flat circular plate; g. a plurality of longitudinal girders attached to the inner circumference of said outer-shell that stop at said flat circular plate and at said radial girders; and h. a secondary panel stiffening arrangement attached to the inner circumference of said outer shell and said longitudinal girders.