Offshore structure having at least one fairlead

Abstract

Disclosed is a structure such as a floating structure, including at least one fairlead for guiding an anchoring element thereof at an anchoring point, the fairlead including a guide to guide the anchoring element in translation between the structure and the anchoring point, a unit for moving the anchoring element in translation in the guide in order to place the anchoring element under tension, and a lock to prevent the anchoring element from moving in translation in the guide, for mooring the structure to the anchoring point. The unit for moving the anchoring element in translation in the guide is integrated into a distinct part separate from the rest of the structure of the fairlead, and this part and the rest of the structure of the fairlead include the retractable coupling unit thereof.

1 . An offshore structure ( 1 ) including at least one fairlead ( 5 ) for guiding an anchoring element ( 3 ) thereof at an anchoring point ( 4 ), said fairlead ( 5 ) comprising guide means ( 11 ) that are able to guide the anchoring element ( 3 ) in translation between the structure ( 1 ) and the anchoring point ( 4 ), means ( 26 ) for moving the anchoring element ( 3 ) in translation in the guide means in order to place said anchoring element ( 3 ) under tension, and locking means ( 40 ) able to prevent the anchoring element ( 3 ) from moving in translation in the guide means ( 11 ), for mooring the structure to the anchoring point, wherein the means for moving the anchoring element ( 3 ) in translation in the guide means ( 11 ) are integrated into a distinct part ( 13 ,  14 ) separate from the rest of the structure ( 12 ) of the fairlead, and wherein this part and the rest of the structure of the fairlead comprise retractable coupling means ( 15 ,  16 ,  17 ,  18 ,  19 ,  20 ) thereof. 
     
     
         2 . The offshore structure according to  claim 1 , wherein the distinct part ( 13 ) in which the movement means of the anchoring element are incorporated includes a support frame ( 14 ) for said movement means, suitable for being engaged on the rest ( 12 ) of the guide fairlead, and including means for centering ( 15 ,  16 ) this part ( 13 ) and locking ( 17 ,  18 ,  19 ,  20 ) it in position on the rest of the fairlead, the locking means being movable by the first actuators ( 22 ), between an active coupling position of the frame ( 14 ) on the rest of the guide fairlead ( 12 ), and a retracted position releasing this part to allow it to be detached from the rest of the fairlead. 
     
     
         3 . The offshore structure according to  claim 2 , wherein the centering means comprise centering lugs ( 15 ) able to cooperate with centering elements ( 16 ) complementary to the rest of the fairlead ( 12 ) allowing the alignment and the centering of the locking means, and the locking means comprise locking pins ( 21 ) movable by the first actuators ( 22 ), between an active locking position, protruding in corresponding locking holes ( 23 ) of the rest of the fairlead, and a released retracted position. 
     
     
         4 . The offshore structure according to  claim 1 , wherein the means for movement in translation of the anchoring element comprise a carriage ( 26 ) for movement and tensioning of the anchoring element ( 3 ), movable in a to-and-fro movement, on guideways ( 27 ,  28 ) of the distinct part, by at least one second actuator ( 29 ,  30 ). 
     
     
         5 . The offshore structure according to  claim 4 , wherein the carriage ( 26 ) for movement and tensioning of the anchoring element ( 3 ) includes means ( 31 ,  32 ) for grasping the anchoring element ( 3 ) movable by at least one third actuator ( 33 ,  34 ), between an active position for grasping of the anchoring element ( 3 ) in order to allow the movement of said anchoring element by the tensioning carriage ( 26 ) when the latter moves in a direction under the action of said at least one second actuator ( 29 ,  30 ), and a retracted position for freeing the latter, allowing the carriage ( 26 ) to return in the other direction under the action of said at least one second actuator ( 29 ,  30 ) or the release of the distinct part from the rest of the fairlead. 
     
     
         6 . The offshore structure according to  claim 5 , wherein the locking means ( 40 ) able to lock the translation of the anchoring element ( 3 ) in the guide means comprise stop means ( 41 ,  42 ) for the latter, movable under the control of at least one fourth actuator ( 43 ), between an active stop position to lock the anchoring element and a retracted position to release said element. 
     
     
         7 . The offshore structure according to  claim 6 , further comprising control means ( 50 ,  51 ) of the actuators to:
 control the first actuators ( 17  to  20 ) of the locking means in the locking position of the distinct part on the rest of the guide fairlead,   control the or each third actuator ( 33 ,  34 ) of the grasping means in the active grasping position of the anchoring element,   control the or each fourth actuator ( 42 ) of the locking means of the anchoring element in the released retracted position of the anchoring element,   control the or each second actuator ( 29 ,  30 ) for moving the carriage to tense or relax the anchoring element,   control the or each fourth actuator ( 43 ) of the locking means of the anchoring element in the active abutting position to lock the anchoring element,   control the or each third actuator ( 33 ,  34 ) of the grasping means in the retracted released position of the anchoring element,   control the first actuators ( 17  to  20 ) of the locking means in the retracted released position of the distinct part to allow it to be detached from the rest of the fairlead.   
     
     
         8 . The offshore structure according to  claim 2 , wherein the actuators comprise jacks. 
     
     
         9 . The offshore structure according to  claim 1 , wherein the distinct part ( 13 ,  14 ) includes means ( 60 ,  61 ,  62 ,  63 ) for attaching to handling means thereof. 
     
     
         10 . The offshore structure according to  claim 9 , further comprising a plurality of guide fairleads arranged around it, and wherein the handling and movement means of the distinct part are suitable for moving said part between at least some of said fairleads. 
     
     
         11 . The offshore structure according to  claim 2 , wherein the means for movement in translation of the anchoring element comprise a carriage for movement and tensioning of the anchoring element, movable in a to-and-fro movement, on guideways of the distinct part, by at least one second actuator. 
     
     
         12 . The offshore structure according to  claim 3 , wherein the means for movement in translation of the anchoring element comprise a carriage for movement and tensioning of the anchoring element, movable in a to-and-fro movement, on guideways of the distinct part, by at least one second actuator. 
     
     
         13 . The offshore structure according to  claim 1 , wherein the locking means able to lock the translation of the anchoring element in the guide means comprise stop means for the latter, movable under the control of at least one fourth actuator, between an active stop position to lock the anchoring element and a retracted position to release said element. 
     
     
         14 . The offshore structure according to  claim 2 , wherein the locking means able to lock the translation of the anchoring element in the guide means comprise stop means for the latter, movable under the control of at least one fourth actuator, between an active stop position to lock the anchoring element and a retracted position to release said element. 
     
     
         15 . The offshore structure according to  claim 3 , wherein the locking means able to lock the translation of the anchoring element in the guide means comprise stop means for the latter, movable under the control of at least one fourth actuator, between an active stop position to lock the anchoring element and a retracted position to release said element. 
     
     
         16 . The offshore structure according to  claim 4 , wherein the locking means able to lock the translation of the anchoring element in the guide means comprise stop means for the latter, movable under the control of at least one fourth actuator, between an active stop position to lock the anchoring element and a retracted position to release said element. 
     
     
         17 . The offshore structure according to  claim 3 , wherein the actuators comprise jacks. 
     
     
         18 . The offshore structure according to  claim 4 , wherein the actuators comprise jacks. 
     
     
         19 . The offshore structure according to  claim 5 , wherein the actuators comprise jacks. 
     
     
         20 . The offshore structure according to  claim 6 , wherein the actuators comprise jacks.