A gravity-based structure (1) for supporting offshore installations comprising a foundation (4). The foundation (4) has a basal portion (11). The basal portion (11) has a plurality of openings (10) for drainage of water. There is at least one first layer (7) of filter material, with a gradation suitable for draining water entrapped beneath the basal portion (11) to the openings (10). The layer (7) is installed on the seabed (8) beneath the foundation (4). The foundation has a downwardly extending skirt (5) that is adapted to penetrate into the seabed beneath the filter material layer (7).

A gravity-based structure (1) for supporting offshore installations comprising a foundation (4). The foundation (4) has a basal portion (11). The basal portion (11) has a plurality of openings (10) for drainage of water. There is at least one first layer (7) of filter material, with a gradation suitable for draining water entrapped beneath the basal portion (11) to the openings (10). The layer (7) is installed on the seabed (8) beneath the foundation (4). The foundation has a downwardly extending skirt (5) that is adapted to penetrate into the seabed beneath the filter material layer (7).

A pile holding system is to be mounted on a deck of a vessel, e.g. for installation of a pile adapted to support an offshore wind turbine. The pile holding system is configured to support the pile in an upright position at a pile installation location next to the vessel. A vessel is provided with such a pile holder system. A method for installation of a pile and a pile holder are also disclosed.

A pile holding system is to be mounted on a deck of a vessel, e.g. for installation of a pile adapted to support an offshore wind turbine. The pile holding system is configured to support the pile in an upright position at a pile installation location next to the vessel. A vessel is provided with such a pile holder system. A method for installation of a pile and a pile holder are also disclosed.

A device and a method for securing a connection to be formed between a leg of a marine structure and a pile of a fundament fastened in a seabed. The connection has the leg partly inserted into an opening of the pile. The device is configured to be firmly connected to the leg. The device comprises a sleeve element configured, together with the leg of the marine structure, to be brought to vicinity of an upper portion of the pile. The device further has a clamping arrangement attached to the sleeve element comprising at least one clamping device configured to form an attachment between the sleeve element and the upper portion of the pile.

A device and a method for securing a connection to be formed between a leg of a marine structure and a pile of a fundament fastened in a seabed. The connection has the leg partly inserted into an opening of the pile. The device is configured to be firmly connected to the leg. The device comprises a sleeve element configured, together with the leg of the marine structure, to be brought to vicinity of an upper portion of the pile. The device further has a clamping arrangement attached to the sleeve element comprising at least one clamping device configured to form an attachment between the sleeve element and the upper portion of the pile.

A device is for securing a connection to be formed between a leg of a marine structure and a pile of a fundament fastened in a seabed. The connection has the leg partly inserted into an opening of the pile. The device is configured to be firmly connected to the leg. The device comprises a sleeve element configured, together with the leg of the marine structure, to be brought to vicinity of an upper portion of the pile. The device further has a clamping arrangement attached to the sleeve element comprising at least one clamping device configured to form an attachment between the sleeve element and the upper portion of the pile.

A device is for securing a connection to be formed between a leg of a marine structure and a pile of a fundament fastened in a seabed. The connection has the leg partly inserted into an opening of the pile. The device is configured to be firmly connected to the leg. The device comprises a sleeve element configured, together with the leg of the marine structure, to be brought to vicinity of an upper portion of the pile. The device further has a clamping arrangement attached to the sleeve element comprising at least one clamping device configured to form an attachment between the sleeve element and the upper portion of the pile.

Offshore structure comprising a pile of a foundation and at least one offshore element, mounted on the pile, forming a slip joint, wherein between an inner surface of the offshore element and an outer surface of the pile: a coating, especially an anti-fouling coating is provided, increasing friction between the said two surfaces and/or preventing corrosion of one or both of said surfaces and/or at least two spaced apart areas are provided with a substance, forming a seal between the said outer surface and the said inner surface, near an upper end of the pile and the off shore element and between a lower end of the off shore element and the pile.

Offshore structure comprising a pile of a foundation and at least one offshore element, mounted on the pile, forming a slip joint, wherein between an inner surface of the offshore element and an outer surface of the pile: a coating, especially an anti-fouling coating is provided, increasing friction between the said two surfaces and/or preventing corrosion of one or both of said surfaces and/or at least two spaced apart areas are provided with a substance, forming a seal between the said outer surface and the said inner surface, near an upper end of the pile and the off shore element and between a lower end of the off shore element and the pile.