Jack-up offshore platform and its use for assembling and servicing a structure at sea

Abstract

A jack-up offshore platform includes a work deck and a lifting device for manipulating a load from the work deck. The lifting device includes a main boom for manipulating the load, which main boom is pivotally connected to a support structure at a pivot. The support structure is provided to support the pivot in an elevated position with respect to the work deck, which allows manipulation of heavier loads and moreover saves space on the work deck. In a preferred embodiment, the platform further includes a counterbalancing structure that is connectable to the platform and/or the support structure. Also included is the use of the platform for assembling and servicing a structure at sea.

1 . A jack-up offshore platform, comprising a work deck and a lifting device for lifting a load from the work deck, the lifting device comprising a main boom for manipulating the load, which main boom is pivotally connected to support means at a pivot, the support means being provided to support the pivot in an elevated position with respect to the work deck. 
     
     
         2 . A jack-up offshore platform according to  claim 1 , wherein the elevated position is at least 10 m above the work deck of the platform. 
     
     
         3 . A jack-up offshore platform according to  claim 2 , wherein the elevated position is at least 40 m above the work deck of the platform. 
     
     
         4 . A jack-up offshore platform according to  claim 1 , wherein the support means comprise a pre-defined fixed-height support means. 
     
     
         5 . A jack-up offshore platform according to  claim 1 , wherein the height of the elevated position above the work deck of the platform ranges from 20 to 80% of the total height of the lifting device in its highest position. 
     
     
         6 . A jack-up offshore platform according to  claim 1 , wherein the height of the elevated position above the work deck of the platform ranges from 40 to 60% of the total height of the lifting device in its highest position. 
     
     
         7 . A jack-up offshore platform according to  claim 1 , wherein the support means comprise a static support structure, preferably provided on the work deck of the platform. 
     
     
         8 . A jack-up offshore platform according to  claim 7 , wherein the support structure comprises a truss framework. 
     
     
         9 . A jack-up offshore platform according to  claim 1 , wherein the lifting device comprises counterbalancing means that are connectable to the platform and/or the support means. 
     
     
         10 . A jack-up offshore platform according to  claim 9 , wherein the counterbalancing means are connectable to the platform nearby edges of the jack-up offshore platform. 
     
     
         11 . A jack-up offshore platform according to  claim 1 , wherein the lifting device comprises at least one sensor for detecting forces and control means for counterbalancing the load such that the lifting device remains in equilibrium, on the basis of the outcome of the detected forces. 
     
     
         13 . A jack-up offshore platform according to  claim 1 , wherein the lifting device is adapted for lifting loads to a height between 50 and 150 meters, preferably between 60 and 130 meters and most preferably between 70 and 110 meters above the work deck of the jack-up offshore platform. 
     
     
         14 . Use of a jack-up offshore platform according to  claim 1  for assembling and servicing a structure at sea.