# US 11,993,351 B2 · Single-column semi-submersible platform

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- Number: US 11,993,351 B2
- Document ID: US11993351B2
- Status: Granted
- Kind: B2
- Application number: 17/601,916
- Filed: 2020-04-07
- Published: 2022-05-12
- Granted: 2024-05-28
- Earliest claimed: 2019-04-08
- Assignees: Stationmar AS
- Applicants: Stationmar AS
- Inventors: Per Andreas Vatne
- Web page: https://patentgrep.com/patent/US11993351B2

## CPC

- B63B 39/02: to decrease vessel movements by displacement of masses
- B63B 21/26: securing to bed
- B63B 21/30: rigid when in use {(B63B21/28 takes precedence)}
- B63B 35/44: Floating buildings, stores, drilling platforms, or workshops, e.g. carrying water-oil separating devices {(construction methods for floating offshore platforms B63B75/00)}
- B63B 7/04: sectionalised (sectionalised water sports boards B63B32/53; sectionalised canoes, kayaks or the like B63B34/23)
- B63B 2035/442: {Spar-type semi-submersible structures, i.e. shaped as single slender, e.g. substantially cylindrical or trussed vertical bodies}
- B63B 2035/446: {for converting wind energy into electric energy}
- F03D 13/25: specially adapted for offshore installation
- F05B 2240/93: on a structure floating on a liquid surface
- F05B 2240/97: on a submerged structure
- B63B: SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING (arrangements of vessel ventilation, heating, cooling, or air-conditioning B63J2/00; floating substructures as supports of dredgers or soil-shifting machines E02F9/06)
- F03D: WIND MOTORS
- F05B: INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G

## Abstract

A single-column semi-submersible platform for fixed anchoring in deep water. The semi-submersible platform comprises a lower solid ballast module, a middle seawater ballast module and a top buoyancy module. The three modules are arranged telescopically in an axial direction and can be controlled relative to each other in the axial direction such that the semi-submersible platform may float vertically and steadily in a body of water. Draught for the seawater ballast module and buoyancy module is provided by seawater ballasting. The axial position of the solid ballast module relative to the seawater ballast module is controlled by seawater being pumped in and out of a closed annulus formed between the solid ballast module and the seawater ballast module.

## Claims

### Claim 1

A single-column semi-submersible platform for fixed anchoring in deep water, the semi-submersible platform comprising:
a lower solid ballast module;
a middle seawater ballast module; and
a top buoyancy module,
wherein the lower solid ballast module, the middle seawater ballast module, and the top buoyancy module are arranged telescopically in an axial direction and can be controlled relative to each other in the axial direction such that the semi-submersible platform floats vertically and steadily in a body of water, and
wherein a closed annulus is formed between at least a portion of the middle seawater ballast module and at least a portion of the lower solid ballast module, and a conduit is provided for pumping pressurized seawater into the annulus and for draining the annulus.

### Claim 2 (depends on 1)

The semi-submersible platform of claim 1, wherein the lower solid ballast module comprises an upper cylindrical portion that has a diameter that is greater than a lower cylindrical portion.

### Claim 3 (depends on 1)

The semi-submersible platform of claim 1, wherein the middle seawater ballast module is a hollow cylinder with inner cylindrical portions of various diameters.

### Claim 4 (depends on 1)

The semi-submersible platform of claim 1, wherein the top buoyancy module comprises a lower cylindrical portion and an upper cylindrical portion.

### Claim 5 (depends on 1)

The semi-submersible platform of claim 1, wherein the middle seawater ballast module is hollow for accommodating the lower solid ballast module and the top buoyancy module.

### Claim 6 (depends on 1)

The semi-submersible platform of claim 1, wherein the lower solid ballast module, the middle seawater ballast module and the top buoyancy module each comprises a through-going axial cavity.

### Claim 7 (depends on 1)

The semi-submersible platform of claim 1, wherein the top buoyancy module comprises an integrated heave-neutralizing system with a confined air pressure volume, which balances a level in a rise canister under a lowest water level of a sea for waves and tide for a current location.

### Claim 8 (depends on 7)

The semi-submersible platform of claim 7, wherein the integrated heave-neutralizing system allows rigid anchoring without vertical heave movements and thereby allows a secondary rigid anchoring with flat angle at a lower level on the semi-submersible platform, so that the vertical banking angle is reduced, and the semi-submersible platform is exposed to minimum environmental impact.

### Claim 9 (depends on 1)

The semi-submersible platform of claim 1, wherein the top buoyancy module comprises a foundation for connection to a tower for wind generators.

### Claim 10 (depends on 1)

The semi-submersible platform of claim 1, wherein the semi-submersible platform is anchored to a seabed by means of anchoring lines.

### Claim 11 (depends on 3)

The semi-submersible platform of claim 3, wherein the annulus is formed between the lower solid ballast module lower cylindrical portion and an inner wall of the middle seawater ballast module.

### Claim 12

A method of controlling a semi-submersible platform comprising a lower solid ballast module, a middle seawater ballast module, a top buoyancy module; wherein the lower solid ballast module, the middle seawater ballast module, and the top buoyancy module are arranged telescopically in an axial direction, the semi-submersible platform comprising a closed annulus formed between at least a portion of the lower solid ballast module and at least a portion of the middle seawater ballast module, the method comprising:
pumping pressurized seawater into the annulus; and
draining the annulus, whereby an axial position of the lower solid ballast module relative to the middle seawater ballast module is controlled.

### Claim 13 (depends on 12)

The method of claim 12, wherein the lower solid ballast module comprises an upper cylindrical portion that has a diameter that is greater than a lower cylindrical portion.

### Claim 14 (depends on 12)

The method of claim 12, wherein the middle seawater ballast module is a hollow cylinder with inner cylindrical portions of various diameters, and wherein the middle seawater ballast module is hollow for accommodating the lower solid ballast module and the top buoyancy module.

### Claim 15 (depends on 12)

The method of claim 12, wherein the top buoyancy module comprises a lower cylindrical portion and an upper cylindrical portion.

### Claim 16 (depends on 12)

The method of claim 12, wherein the lower solid ballast module, the middle seawater ballast module and the top buoyancy module each comprises a through-going axial cavity.

### Claim 17 (depends on 12)

The method of claim 12, wherein the top buoyancy module comprises an integrated heave-neutralizing system with a confined air pressure volume, which balances a level in a rise canister under a lowest water level of a sea for waves and tide for a current location, wherein the integrated heave-neutralizing system allows rigid anchoring without vertical heave movements and thereby allows a secondary rigid anchoring with flat angle at a lower level on the semi-submersive platform, so that the vertical banking angle is reduced, and the semi-submersible platform is exposed to minimum environmental impact.

### Claim 18 (depends on 12)

The method of claim 12, wherein the top buoyancy module comprises a foundation for connection to a tower for wind generators.

### Claim 19 (depends on 12)

The method of claim 12, wherein the semi-submersible platform is anchored to a seabed by means of anchoring lines.

### Claim 20 (depends on 14)

The method of claim 14, wherein the annulus is formed between the lower solid ballast module lower cylindrical portion and an inner wall of the middle seawater ballast module.