Method and apparatus for submersion and installation of fundament structures on the sea bottom
AssigneeNorwegian Contractors
InventorsKarel Karal, Jan Skjong
Life of this patent
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Abstract
A method and apparatus for installation of heavy, ballastable, gravity fundament structures on the sea bottom at large depths. In accordance with the invention, there is utilized air, water, and a liquid lighter than water in various proportions and combinations to provide the structure with the required buoyancy and submerged weight during the sequential phases of the transport and descent operations in order to finally position the structure in a selected location on the sea bottom. Various modes can be used to accomplish the descent and the structure may in a final stage be penetrated down into the sea bottom to a sufficient degree.
Claims19
A method of installing fundament structures on the sea bottom, comprising:
- providing a fundament structure having at least one confined cell therein open to the ambient sea at a lower end thereof;
- bringing the fundament structure to an upright floating position and towing the fundament structure to an installation side by its own buoyance by filling the at least one confined cell with a quantity of air sufficient to tow the fundament structure with a freeboard;
- and
- ballasting the fundament structure at the installation side in order to submerge and lower the fundament structure down to a selected location on the sea bottom, said step of ballasting the fundament structure including
- providing an auxiliary vessel,
- connecting at least one flexible tube between the at least one confined cell of the fundament structure and the auxiliary vessel,
- replacing the air in the at least one confined cell of the fundament structure with a sufficient quantity of a liquid lighter than water in order to bring the fundament structure into a substantially neutral buoyancy condition, and
- subjecting the fundament structure to a downwardly directed force such that the fundament structure is lowered to the selected location on the sea bottom.
A method of penetrating a structure into the sea bed having at least one confined cell therein in communication with the ambient sea and being positioned on the sea bottom, said method comprising the steps of:
- filling the at least one confined cell in the structure partly with water and partly with a liquid lighter than water before lowering the structure from a position on the surface of the sea to a position on the sea bottom, the structure being provided with at least one tube extending between that at least one cell and an auxiliary vessel on the surface of the sea;
- and
- after the structure has been positioned on the sea bottom, opening the at least one tube such that the at least one cell is communicated with a receptor on the auxiliary vessel such that the liquid lighter than water floats from the at least one cell up to the receptor, thereby generating a lower pressure condition in the at least one cell and causing the structure to penetrate down into the sea bed.
Dependencies are inferred from the claim text.