Offshore Floating Structures

Abstract

An offshore floating structure such as a wind turbine includes a number of improvements. The floating structure can include a chain engaging system configured to prevent any lengthwise movement of a mooring chain. The floating structure can also include a mooring fixture pivotally coupled to the hull to prevent shock loads from being transmitted directly from the mooring line to the hull. The floating structure can also include installation aid structures that provide additional water plane area and/or buoyancy to the structure. The floating structure can also have a hull that is optimized for use as an offshore wind turbine.

1 . A floating structure comprising a chain engaging system configured to hold a mooring chain in a fixed position and prevent any lengthwise movement of the mooring chain relative to the chain engaging system. 
     
     
         2 . The floating structure of  claim 1  wherein the chain engaging system is configured to prevent movement of the mooring chain in a first direction relative to the chain engaging system that decreases tension on the mooring chain and prevent movement of the mooring chain in a second direction relative to the chain engaging system that increases tension on the mooring chain. 
     
     
         3 . The floating structure of  claim 2  wherein the chain engaging system comprises a first chain engaging mechanism configured to prevent movement of the mooring chain in the first direction and a second chain engaging mechanism configured to prevent movement of the mooring chain the second direction. 
     
     
         4 . The floating structure of  claim 1  wherein the chain engaging system holds the mooring chain in the fixed position by biasing adjacent interlocked links in the mooring chain in opposite directions. 
     
     
         5 . The floating structure of  claim 4  wherein the adjacent interlocked links are oriented perpendicular to each other. 
     
     
         6 . The floating structure of  claim 1  wherein the chain engaging system holds the mooring chain in the fixed position by preventing a first link in the mooring chain from moving in a first direction and preventing a second link in the mooring chain that links to the first link from moving in a second direction that is opposite the first direction. 
     
     
         7 . The floating structure of  claim 6  wherein the chain engaging system comprises a first chain engaging mechanism configured to prevent the first link in the mooring chain from moving in the first direction and a second chain engaging mechanism configured to prevent the second link in the mooring chain from moving in the second direction. 
     
     
         8 . The floating structure of  claim 1  wherein the chain engaging system comprises:
 a first engaging member and a second engaging member; 
 wherein the first engaging member rotates between a locked position where the first engaging member prevents the mooring chain from moving in a first direction relative to the chain engaging system and an unlocked position where the first engaging member does not prevent the mooring chain from moving in the first direction; 
 wherein the second engaging member rotates between a locked position where the second engaging member prevents the mooring chain from moving in a second direction relative to the chain engaging system and an unlocked position where the second engaging member does not prevent the mooring chain from moving in the second direction; and 
 wherein moving the mooring chain in the first direction decreases tension on the mooring chain and moving the mooring chain the second direction increases tension on the mooring chain. 
 
     
     
         9 . The floating structure of  claim 1  wherein the chain engaging system comprises a chain engaging mechanism and a chain pulley, wherein the chain pulley is configured to orient adjacent links in the mooring chain perpendicular to each other before the chain engaging mechanism receives the adjacent chain links. 
     
     
         10 . The floating structure of  claim 1  wherein the floating structure includes a wind turbine. 
     
     
         11 . The floating structure of  claim 1  comprising a hull having three support columns oriented vertically and three pontoons oriented horizontally, wherein each of the pontoons is coupled between two of the three support columns to form a triangular shape. 
     
     
         12 . The floating structure of  claim 1  wherein the mooring chain forms at least part of a mooring line. 
     
     
         13 . A floating structure comprising:
 a hull; and   a mooring fixture coupled to the hull;   wherein the mooring fixture pivots relative to the hull.   
     
     
         14 . The floating structure of  claim 13  wherein the mooring fixture is coupled to the hull with a swivel fastener. 
     
     
         15 . The floating structure of  claim 13  wherein the mooring fixture is coupled to the hull with at least two swivel fasteners. 
     
     
         16 . The floating structure of  claim 13  comprising a plurality of mooring fixtures pivotably coupled to the hull, the hull comprising:
 a plurality of support columns oriented vertically; and 
 a plurality of pontoons coupled to the plurality of support columns, each of the plurality of pontoons being oriented horizontally and including opposing ends; 
 wherein at least one of the plurality of mooring fixtures is coupled to each end of the plurality of pontoons. 
 
     
     
         17 . The floating structure of  claim 13  wherein the hull comprises three support columns oriented vertically and three pontoons oriented horizontally, wherein each of the pontoons is coupled between two of the three support columns to form a triangular shape. 
     
     
         18 . The floating structure of  claim 13  wherein the floating structure includes a wind turbine. 
     
     
         19 . An offshore wind turbine comprising:
 a hull comprising;
 a plurality of support columns; 
 a plurality of pontoons coupled to the plurality of support columns; 
 a tower base; and 
 a plurality of trusses extending between the plurality of support columns and the tower base to support the tower base on the plurality of support columns, the plurality of trusses including horizontal trusses that extend horizontally between the plurality of support columns and the tower base, slanted trusses that extend upward from the plurality of support columns to the tower base, and vertical trusses that extend upward adjacent to the tower base; 
   a tower coupled to the tower base; and   a nacelle coupled to the top of the tower.