Method and device for installation of an elongated offshore structure

Abstract

A method and device for installation of an offshore elongated offshore structure are disclosed. The device includes a vessel an outer frame pivotable in relation to the vessel between a substantially horizontal position for transporting the elongated offshore structure to the installation site and a substantially vertical position for installation of the elongated offshore structure at the installation site. A connection device is provided for connection of the elongated offshore structure to the outer frame via a longitudinal actuation device. The connection device includes a first supporting element for providing the elongated offshore structure in a free hanging configuration when the outer frame is in the substantially vertical position. The longitudinal actuation device is provided for lowering the elongated offshore structure towards the seabed when the elongated offshore structure is in the free hanging configuration.

1 . A device for installation of an elongated offshore structure, wherein the device comprises:
 a vessel;   an outer frame pivotable in relation to the vessel between a substantially horizontal position for transporting the elongated offshore structure to the installation site and a substantially vertical position for installation of the elongated offshore structure at the installation site;   a connection device for connection of the elongated offshore structure to the outer frame via a longitudinal actuation device;   wherein the connection device comprises a first supporting element for providing the elongated offshore structure in a free hanging configuration when the outer frame is in the substantially vertical position, and   wherein the longitudinal actuation device is provided for lowering the elongated offshore structure towards the seabed when the elongated offshore structure is in the free hanging configuration.   
     
     
         2 . The device according to  claim 1 , wherein the elongated offshore structure is a wind turbine device comprising a tower device with a nacelle and at least one rotor blade provided in a first end thereof and a foundation provided in a second end thereof. 
     
     
         3 . The device according to  claim 1 , wherein the connection device comprises a cross bar slidingly arranged in relation to the outer frame by means of the longitudinal actuation device. 
     
     
         4 . The device according to  claim 3 , wherein the first supporting element is connected to the cross bar. 
     
     
         5 . The device according to  claim 3 , wherein the connection device comprises a second supporting element for releasable connection of the elongated offshore structure in relation to the outer frame. 
     
     
         6 . The device according to  claim 1 , wherein an inner frame is provided inside the outer frame, wherein the inner frame comprising a first supporting device for supporting the elongated offshore structure in the substantially horizontal position during transportation to the installation site. 
     
     
         7 . The device according to  claim 6 , wherein the inner frame comprises a cross bar supporting device for supporting the cross bar in relation to the inner frame. 
     
     
         8 . The device according to  claim 7 , wherein the cross bar supporting device is configured to release the support of the cross bar in the substantially vertical position. 
     
     
         9 . The device according to  claim 6 , wherein the inner frame is displaceable in a longitudinal direction with respect to the outer frame. 
     
     
         10 . The device according to  claim 1 , wherein the longitudinal actuation device is pivotably mounted to the outer frame. 
     
     
         11 . The device according to  claim 1 , wherein control devices are provided to control the orientation of the elongated offshore structure in the free hanging configuration. 
     
     
         12 . The device according to  claim 5 , wherein a locking device is provided for locking the inner frame to the outer frame. 
     
     
         13 . A method for installation of an offshore elongated offshore structure, wherein the method comprises:
 connecting the elongated offshore structure to an outer frame via a longitudinal actuation device, wherein the outer frame is pivotable in relation to a vessel;   transporting the elongated offshore structure to the installation site in a substantially horizontal position;   pivoting the outer frame to a substantially vertical position at the installation site;   providing the elongated offshore structure in a free hanging configuration via the longitudinal actuation device when the outer frame is in the substantially vertical position;   lowering the elongated offshore structure towards the seabed by means of the longitudinal actuation device when the elongated offshore structure is in the free hanging configuration.   
     
     
         14 . The method according to  claim 13 , wherein the elongated offshore structure is a wind turbine device comprising a tower device with a nacelle and at least one rotor blade provided in a first end thereof and a foundation provided in a second end thereof. 
     
     
         15 . The method according to  claim 13 , further comprising the step of providing the connection device with a cross bar slidingly arranged in relation to the outer frame by means of the longitudinal actuation device. 
     
     
         16 . The method according to  claim 13 , further comprising the step of connecting the first supporting element to the cross bar. 
     
     
         17 . The method according to  claim 13 , further comprising the step of providing the connection device with a second supporting element for releasably connecting the elongated offshore structure in relation to the outer frame. 
     
     
         18 . The method according to  claim 13 , further comprising the step of providing an inner frame inside the outer frame, wherein the inner frame comprising a first supporting device for supporting the elongated offshore structure in the substantially horizontal position during transportation to the installation site. 
     
     
         19 . The method according to  claim 18 , further comprising the step of providing the inner frame with a cross bar supporting device for supporting the cross bar in relation to the inner frame. 
     
     
         20 . The method according to  claim 19 , further comprising the step of configuring the cross bar supporting device to release the support of the cross bar in the substantially vertical position. 
     
     
         21 . The method according to  claim 13 , further comprising the step of displacing the inner frame in a longitudinal direction with respect to the outer frame. 
     
     
         22 . The method according to  claim 13 , further comprising the step of controlling the orientation of the elongated offshore structure in the free hanging configuration. 
     
     
         23 . The method according to  claim 18 , further comprising the step of locking the inner frame to the outer frame.