Floating offshore structures

1. A floating offshore structure, comprising:

a buoyancy structure arranged such that the buoyancy structure remains below sea level;

a wind turbine comprising a tower;

wherein the buoyancy structure is attached to the tower by a connecting structure capable of holding sea water, the connecting structure comprising one or more openings arranged such that the one or more openings remain below the sea level, wherein the one or more openings allow sea water to flow in and out of the connecting structure so that water level inside the connecting structure corresponds to the sea level;

wherein sea water flows into and out of the connecting structure with variations of the sea level; and

wherein the connecting structure further comprises one or more orifices arranged such that the one or more orifices remain above the sea level, the orifices being configured to enhance the flow of sea water in and out of the connecting structure and permit the flow of air out of the connecting structure, so that no air providing buoyancy remains inside the connecting structure when the sea level rises.

2. The floating offshore structure of claim 1 , further comprising a plurality of radially outwardly extending braces and a mooring line attached to each of the braces at one end and to a seabed at another end.

3. The floating offshore structure of claim 2 , wherein the braces are arranged such that the braces remain above the sea level.

4. The floating offshore structure of claim 2 , wherein the braces are arranged such that the braces remain below the sea level and form part of the buoyancy structure.

5. The floating offshore structure of claim 2 , wherein the braces extend radially outwards from a wind turbine transition piece that is arranged between the connecting structure and the tower.

6. The floating offshore structure of claim 2 , wherein the braces are at least three in number.