Abstract: A semi-submersible floating platform for use in offshore applications having a semi-submersible hull structure including motion damping support columns, a pontoon structure adjoined to the motion damping support columns at a lower end thereof, and a deck structure supported at an upper end of thereof for supporting equipment mounted thereon above the water surface. Each motion damping support column has an inner water trapping damper chamber of closed base or open base construction that allows natural flooding of said inner water trapping damper chamber during installation and before reaching an operating draft of the platform, and which when flooded provides hydrodynamic mass, damping, and in-water weight to said platform during operation. A plurality of smaller columns are disposed on the perimeter of the upper portion of each support column and surround the upper portion of the inner water trapping damper chamber.

Abstract: A semi-submersible floating platform for use in offshore applications having a semi-submersible hull structure including motion damping support columns, a pontoon structure adjoined to the motion damping support columns at a lower end thereof, and a deck structure supported at an upper end of thereof for supporting equipment mounted thereon above the water surface. Each motion damping support column has an inner water trapping damper chamber of closed base or open base construction that allows natural flooding of said inner water trapping damper chamber during installation and before reaching an operating draft of the platform, and which when flooded provides hydrodynamic mass, damping, and in-water weight to said platform during operation. A plurality of smaller columns are disposed on the perimeter of the upper portion of each support column and surround the upper portion of the inner water trapping damper chamber.

Abstract: A semi-submersible floating platform (10, 10A) for use in offshore applications has a semi-submersible hull structure (11) including support columns (12), a pontoon structure (13) adjoined to the lower ends thereof, and a deck structure (14) supported at an upper end of the columns for supporting the deck and equipment mounted thereon above the water surface. One or more passive damper weight members (15) are suspended below the hull by flexible connection members (16) at variable distances to provide hydrodynamic mass, damping, and in-water weight to the platform during operation, and the flexible connection members are maintained in tension by the damper weight(s) during operation.