Temporary floatation stabilization device and method

Abstract

A temporary stability module and method for marine structures during construction, transportation and installation is taught. The device and method permit the structure, including platforms, deck and equipment to be constructed in an upright position, towed to an ocean installation site, and installed by ballasting the structure or temporary stability module and subsequent removal of the module.

We claim:  
     
         1 . An apparatus comprising an offshore structure and a temporary stabilization module detachable connected to the structure, where at least a portion of the module extends above a waterline and increases stability of the structure.  
     
     
         2 . The apparatus of  claim 1 , wherein the module is sufficient to maintain the structure in a substantially upright orientation.  
     
     
         3 . The apparatus of  claim 1 , further comprising a plurality of temporary stabilization modules attached to the structure.  
     
     
         4 . The apparatus of  claim 1 , wherein the modules are sufficient to maintain the apparatus in a substantially upright orientation.  
     
     
         5 . The apparatus of  claim 3 , wherein the modules are symmetrically positioned about a central axis of the structure.  
     
     
         6 . The apparatus of  claim 1 , wherein the structure comprises an offshore platform.  
     
     
         7 . The apparatus of  claim 6 , wherein the platform includes a deck, equipment, machinery and ancillary facilities.  
     
     
         8 . The apparatus of  claim 6 , wherein the platform is a tension leg platform or a single column floater.  
     
     
         9 . The apparatus of  claim 8 , wherein the platform is an extended base tension leg platform.  
     
     
         10 . The apparatus of  claim 1 , further comprising a securing apparatus adapted to detachably connect each module to the structure.  
     
     
         11 . The apparatus of  claim 10 , wherein the securing apparatus comprises a plurality of lateral and/or longitudinal shear blocks affixed to the structure and at least one movable locking block affixed to the module and at least one shear locking block affixed to the structure, where the locking blocks can be moved from a locked to an unlocked state.  
     
     
         12 . The apparatus of  claim 10 , wherein the securing apparatus comprises at least one hook affixed to the module structure and at least one peg affixed to the structure, where the hook is adapted to receive the peg in its lock state.  
     
     
         13 . The apparatus of  claim 1 , wherein each modules is floodable.  
     
     
         14 . The apparatus of  claim 1 , wherein each module includes valves and pumps to controllably to change the ballast of each module.  
     
     
         15 . The apparatus of claim of  1 , wherein the modules increase a water plane area of the structure and an area moment of inertia of the structure and increases its righting moment.  
     
     
         16 . The apparatus of  claim 1 , wherein each module comprises a substantially hollow, watertight structure made of metal or metal alloys.  
     
     
         17 . The apparatus of  claim 16 , wherein the metal is steel, aluminum or alloys thereof.  
     
     
         18 . An apparatus comprising an offshore structure and a plurality of temporary stabilization modules detachable connected to the structure, where at least a portion of each module extends above a waterline and increases stability of the structure.  
     
     
         19 . The apparatus of  claim 18 , wherein the modules are sufficient to maintain the structure in a substantially upright orientation.  
     
     
         20 . The apparatus of  claim 18 , wherein the modules are symmetrically positioned about a central axis of the structure.  
     
     
         21 . The apparatus of  claim 18 , wherein the structure comprises an offshore platform.  
     
     
         22 . The apparatus of  claim 21 , wherein the platform includes a deck, equipment, machinery and ancillary facilities.  
     
     
         23 . The apparatus of  claim 21 , wherein the platform is a tension leg platform or a single column floater.  
     
     
         24 . The apparatus of  claim 23 , wherein the platform is an extended base tension leg platform.  
     
     
         25 . The apparatus of  claim 18 , further comprising a securing apparatus adapted to detachably connect each module to the structure.  
     
     
         26 . The apparatus of  claim 25 , wherein the securing apparatus comprises a plurality of lateral and/or longitudinal shear blocks affixed to the structure and at least one movable locking block affixed to the module and at least one shear locking block affixed to the structure, where the locking blocks can be moved from a locked to an unlocked state.  
     
     
         27 . The apparatus of  claim 25 , wherein the securing apparatus comprises at least one hook affixed to the module structure and at least one peg affixed to the structure, where the hook is adapted to receive the peg in its lock state.  
     
     
         28 . The apparatus of  claim 18 , wherein each modules is floodable.  
     
     
         29 . The apparatus of  claim 18 , wherein each module includes valves and pumps to controllably to change the ballast of each module.  
     
     
         30 . The apparatus of claim of  18 , wherein the modules increase a water plane area of the structure and an area moment of inertia of the structure and increases its righting moment.  
     
     
         31 . The apparatus of  claim 18 , wherein each module comprises a substantially hollow, watertight structure made of metal or metal alloys.  
     
     
         32 . The apparatus of  claim 31 , wherein the metal is steel, aluminum or alloys thereof.  
     
     
         33 . A method for transporting an offshore structure comprising the steps of: 
 attaching one or a plurality of temporary stabilization modules to a structure in a body of water at a first draft to form a stabilized structure; and    transporting the stabilized structure from a first site to a second site,    where at least a portion of each module extends above a waterline and the modules increase a stability of the structure sufficient to maintain the structure in a substantially upright orientation during transporting.    
     
     
         34 . A method for installing an offshore structure comprising the steps of: 
 attaching one or a plurality of temporary stabilization modules to a structure in a body of water at a first draft to form a stabilized structure; and    transporting the stabilized structure from a first site to a second site, where at least a portion of each module extends above a waterline and the modules increase a stability of the structure sufficient to maintain the structure in a substantially upright orientation during transporting;    ballasting the modules and/or the structure to change the first draft to a lower, installation draft, where a portion of each module is still above the waterline;    attaching a plurality of tendons to the structure;    deballasting the structure and/or the modules to tension the structure so that the structure can assume its installed draft; and    removing the modules from the structure.    
     
     
         35 . A method for transporting a stabilized offshore structure comprising the steps of: 
 attaching one or a plurality of temporary stabilization modules to a structure in a body of water at an tensioned draft moored to a bottom of the body of water by a plurality of tendons, where at least a portion of each module extends above a waterline and the modules increase a stability of the structure sufficient to maintain the structure in a substantially upright orientation;    ballasting the modules and/or the structure to change the draft of the structure from its tensioned draft to a lower, tendon detachment draft, where a portion of each module is still above the waterline;    deattaching the tendons from the structure;    deballasting the structure and/or the modules to a transportation draft;    transporting the structure with the modules, which maintain the structure in its substantially upright orientation to a new site; and    removing the modules from the structure.