Offshore platform with outset columns

A semi-submersible drilling rig comprising:

• a hull comprised essentially of
• four buoyant columns arranged in a rectangular planform with each column having an inboard surface, an outboard surface, a pair of opposing side surfaces and a generally rectangular transverse cross section at the nominal waterline whose long axis is aligned with the central vertical axis of the platform;
• at least one buoyant pontoon connected between adjacent columns, the pontoons having a generally rectangular cross section and an outboard, generally vertical surface connected to a side surface of an adjacent column at a location that is inboard of the outboard surface of the column;
• and,
• a deck supported upon the columns above the water.

A tension leg platform comprising:

• at least four buoyant columns arranged in a rectangular planform with each column having an inboard surface, an outboard surface, a pair of opposing side surfaces and a generally rectangular transverse cross section at the nominal waterline whose long axis is disposed at approximately a 45-degree angle to a line between the centers of adjacent columns;
• a generally box-shaped column extension attached to the outboard surface of each column with each extension having an outer panel adjacent to an opposing pair of side panels;
• at least one tendon porch attached to the outer panel of each column extension;
• at least one tendon porch attached to each side panel of each column extension;
• and,
• at least one buoyant pontoon connected between adjacent columns.

A tension leg platform comprising:

• at least four buoyant columns arranged in a substantially square planform with each column having an inboard surface, an outboard surface, a pair of opposing side surfaces and a generally rectangular transverse cross section at the nominal waterline whose long axis is disposed at approximately a 45-degree angle to a line between the centers of adjacent columns;
• a generally box-shaped column extension attached to the outboard surface of each column with each extension having an outer panel adjacent to an opposing pair of side panels;
• at least one tendon porch attached to the outer panel of each column extension;
• at least one tendon porch attached to each side panel of each column extension;
• and,
• at least one buoyant pontoon connected between adjacent columns.

A tension leg platform comprising:

• at least four buoyant columns with each column having an inboard surface, an outboard surface, a pair of opposing side surfaces and a generally rectangular transverse cross section whose long axis is disposed at approximately a 45-degree angle to a line between the centers of adjacent columns;
• a column extension consisting essentially of an open framework of structural members and attached to the outboard surface of each column with each extension having an outboard side and an opposing pair of substantially vertical sides adjacent to the outboard side;
• at least one tendon porch attached to the outboard side of each column extension;
• at least one tendon porch attached to each substantially vertical side adjacent to the outboard side of each column extension;
• and,
• at least one buoyant pontoon connected between adjacent columns.