Abstract: Aspects of the present disclosure relate generally to apparatus for semi-submersibles, including hulls of semi-submersibles. In one implementation, a hull for a semi-submersible includes a pontoon having one or more sides, and a plurality of columns extending upwards from the pontoon and configured to support a topsides. Each one of the plurality of columns has a cross section that is in a plane perpendicular to an axial centerline of the respective one of the plurality of columns. The cross section includes a first portion being rectangular in shape and a second portion being triangular in shape and having an apex that extends inboard from the first portion.

Abstract: A semi-submersible structure with buoyant vertical columns and a buoyant pontoon. Unlike the typical semi-submersible where the pontoons are attached directly between the columns, the pontoon of the invention encircles the columns and is arranged outside of the columns. The pontoon encircling the columns simplifies construction and attachment of the pontoon and columns and improves the heave characteristics of the structure.