Self-elevating offshore drilling unit legs

An offshore drilling unit of the self-elevating type having a floatable hull and a plurality of legs movable from a raised position, in which said legs are supported by said hull in a body of water, to a lowered position, in which the hull is supported by said legs on the floor of said body of water;

• said legs comprising a plurality of mutually parallel tubular chord members rigidly interconnected by structural bracing members, said tubular chord members comprising elongated tubular body means and elongated plate means, lying in a plane including the longitudinal axis of said tubular body means, rigidly connected to and spanning the interior of said tubular body means, said chord members comprising a pair of rack members, each of which is provided with a set of rack teeth, one rack member being on one side of said tubular body means and the other on the opposite side of said tubular body means and projecting radially away from said tubular body means in a plane substantially corresponding with the plane of said plate means.

An offshore drilling unit of the self-elevating type having a floatable hull;

• a plurality of legs movable from a raised position, in which said legs are supported by said hull in a body of water, to a lowered position, in which said hull is supported by said legs on the floor of said body of water;
• and elevating means carried by said hull and operatively engageable with said legs for moving said legs between said raised and lowered positions;
• said legs comprising a plurality of mutually parallel tubular chord members, rigidly interconnected by structural bracing members, and rack means longitudinally disposed along said chord members and having sets of rack teeth on the faces thereof projecting radially outward from said chord members in a plane containing the longitudinal axis of said tubular chord members, said rack means being engaged by said elevating means for movement of said legs between said raised and lowered positions, said tubular chord members comprising elongated reinforcing plates longitudinally disposed along and spanning the interior thereof in said plane containing said longitudinal axis of said tubular chord members.

An offshore drilling unit of the self-elevating type having a floatable hull;

• a plurality of legs movable from a raised position, in which said legs are supported by said hull in a body of water, to a lowered position, in which said hull is supported by said legs on the floor of said body of water;
• and elevating means carried by said hull and operatively engageable with said legs for moving said legs between said raised and lowered positions;
• said legs comprising a plurality of mutually parallel tubular chord members, rigidly interconnected by structural bracing members, and rack means longitudinally disposed along said chord members and having sets of rack teeth on the faces thereof projecting radially outward from said chord members in a plane containing the longitudinal axis of said tubular chord members, said rack means being engaged by said elevating means for movement of said legs between said raised and lowered positions, said tubular chord members comprising a pair of semi-cylindrical members between the opposing ends of which are welded the backs of said rack means to form a rigid cylindrical construction.