Offshore Platform with Movable Cantilever Extending Beyond the Deck

Abstract

This invention relates to an offshore system comprising a rig having a deck ( 2 ) and further comprising a cantilever ( 4 ), which is mounted on the deck and which is at least moveable in a longitudinal direction of the cantilever between a retracted position and an extended position. Said cantilever has an operational end ( 4 a ) which extends beyond the deck in an extended position of the cantilever, and an inner end ( 4 b ) opposite the operational end. Furthermore said cantilever has one or more cantilever support rails ( 10 ) in the longitudinal direction of the cantilever. The system further comprises support means ( 7 ) comprising rail engagement members ( 7 a ) which allow longitudinal movement of the cantilever. The system further comprises a support rail extension part ( 6 b ′) for each cantilever support rail, that allows to extend the cantilever support rail at the inner end of the cantilever by being positioned in line with the cantilever support rail, for the purpose of increasing the length of the cantilever support rail and thereby the longitudinal reach of the cantilever.

1 . Offshore system comprising:
 a rig having a deck,   a cantilever, which is mounted on the deck and which is at least moveable in a longitudinal direction of the cantilever between a retracted position and an extended position,   said cantilever having an operational end which extends beyond the deck in an extended position of the cantilever,   said cantilever having an inner end opposite the operational end,   said cantilever having one or more cantilever support rails in the longitudinal direction of the cantilever,   the system further comprising support means comprising rail engagement members which allow longitudinal movement of the cantilever,   
     characterized in that 
     the system further comprises a support rail extension part for each cantilever support rail, that allows to extend the cantilever support rail at the inner end of the cantilever by being positioned in line with the cantilever support rail, for the purpose of increasing the length of the cantilever support rail and thereby the longitudinal reach of the cantilever. 
   
   
       2 . Offshore system according to  claim 1 , wherein the support rail extension part is mountable on the cantilever. 
   
   
       3 . Offshore system according to  claim 1 , wherein the support rail extension part is hingedly mounted on the cantilever. 
   
   
       4 . Offshore system according to  claim 1 , wherein the support rail extension part is a flap. 
   
   
       5 . Offshore system according to  claim 4 , wherein the flap comprises one or more hinges extending substantially perpendicular to the longitudinal direction of the cantilever, which hinges are connected or connectable to the inner end of the cantilever. 
   
   
       6 . Offshore system according to  claim 1 , wherein bearing means are provided between the rail engagement members on the support means and the cantilever support rails on the cantilever. 
   
   
       7 . Offshore system according to  claim 1 , wherein the cantilever support rails comprise a longitudinal bearing surface. 
   
   
       8 . Offshore system according to  claim 1 , wherein the support means are mounted moveable on the deck, so that the cantilever is also moveable in a second direction. 
   
   
       9 . Offshore system according to  claim 8 , wherein the cantilever is also moveable in a translational direction perpendicular to the first longitudinal movement. 
   
   
       10 . Offshore system according to  claim 8 , wherein the support means is connectable or connected to the rig so that the cantilever is rotatable about a rotating axis. 
   
   
       11 . Offshore system according to  claim 10 , wherein said rotating axis is positionable at multiple positions with respect to the rig. 
   
   
       12 . Offshore system according to  claim 1 , wherein rails are mounted on the deck which allow for a movement of the support means. 
   
   
       13 . Offshore system according to  claim 12 , wherein an circular shaped rail is mounted on the deck, which allows for a rotational movement of the support means. 
   
   
       14 . Offshore system according to  claim 12 , wherein friction reducing bearing means are provided between the rails mounted on the deck and the support means. 
   
   
       15 . Offshore system according to  claim 14 , wherein said support means comprise a frame arranged between the deck and the cantilever. 
   
   
       16 . Offshore system according to  claim 14 , wherein said bearing means include one or more hydrostatic bearings. 
   
   
       17 . Offshore system according to  claim 1 , wherein at the operational end of the cantilever borehole equipment is provided. 
   
   
       18 . Offshore system according to  claim 1 , wherein at the operational end of the cantilever a tower, a derrick and/or a crane is provided. 
   
   
       19 . Offshore system according to  claim 1 , wherein said rig is a drilling rig. 
   
   
       20 . Offshore system according to  claim 1 , wherein said rig is a member of the group: a Compliant Tower, a Deep Draft Caisson vessel, a SPAR, a Tension Leg Platform, Temporary Tension Leg Platform, a Semi Submersible rig, Jack-Up platform and Mono Hull Ship.