Strake systems and methods

Abstract

There is disclosed a system comprising a structural element; at least one strake holder connected to the structural element; and at least one flexible helical strake connected to the at least one strake holder.

1 . A system comprising:
 a structural element;   at least one strake holder connected to the structural element; and   at least one flexible helical strake connected to the at least one strake holder.   
   
   
       2 . The system of  claim 1 , wherein the structural element is selected from the group consisting of a shell, a collar, an oil flowline, a pipeline, a drilling riser, a production riser, a steel tubular, import and export risers, subsea pipelines, tendons for tension leg platforms, legs for traditional fixed and for compliant platforms, space-frame members for platforms, cables, umbilicals, mooring elements for deepwater platforms, hull structures for tension leg platforms and for spar type structures, and column structures for tension leg platforms and for spar type structures. 
   
   
       3 . The system of  claim 1 , wherein the structural element comprises a plurality of sections welded or threaded to each other. 
   
   
       4 . The system of  claim 1 , wherein the at least one flexible helical strake comprises a flexible material having a Young's Modulus E from 0.01 to 0.5 GPa. 
   
   
       5 . The system of  claim 1 , wherein the at least one flexible helical strake comprises at least three flexible helical strakes. 
   
   
       6 . The system of  claim 1 , wherein the at least one strake holder comprises a high strength material having a Young's Modulus E from 0.5 to 500 GPa. 
   
   
       7 . The system of  claim 1 , wherein the at least one flexible helical strake comprises a rubber strake having a t-shaped cross section, at least a portion of the strake extending out of the strake holder. 
   
   
       8 . The system of  claim 1 , wherein a first end of the at least one strake holder is attached to a first collar, and a second end of the at least one strake holder is attached to a second collar, the first collar and the second collar attached about the structural element. 
   
   
       9 . A method of installing a structural element in a body of water comprising: attaching at least one flexible helical strake about the structural element; and moving the structural element and the flexible strake over a roller, so that the flexible strake is temporarily deformed when the flexible strake interfaces with the roller. 
   
   
       10 . The method of  claim 9 , wherein the structural element is selected from the group consisting of a shell, a collar, an oil flowline, a pipeline, a drilling riser, a production riser, a steel tubular, import and export risers, subsea pipelines, tendons for tension leg platforms, legs for traditional fixed and for compliant platforms, space-frame members for platforms, cables, umbilicals, mooring elements for deepwater platforms, hull structures for tension leg platforms and for spar type structures, and column structures for tension leg platforms and for spar type structures. 
   
   
       11 . The method of  claim 9 , wherein the structural element comprises a plurality of sections welded to each other. 
   
   
       12 . The method of  claim 9 , wherein the structural element comprises a plurality of sections threaded to each other. 
   
   
       13 . The method of  claim 9 , wherein attaching at least one helical strake about the structural element comprises attaching at least three helical strakes about the structural element. 
   
   
       14 . The method of  claim 9 , wherein attaching at least one helical strake about the structural element comprises attaching a plurality of flexible sheets to each other. 
   
   
       15 . The method of  claim 9 , wherein attaching at least one helical strake about the structural element comprises attaching a plurality of flexible sheets to each other with an adhesive. 
   
   
       16 . The method of  claim 9 , wherein the first roller is azimuthally spaced apart from the second roller by 90 to 150 degrees measured as an arc angle of the structural element. 
   
   
       17 . A system comprising:
 a structural element;   at least one strake sheet connected to at least one other strake sheet about the structural element to form at least two strakes.   
   
   
       18 . The system of  claim 17 , wherein the at least one strake sheet comprises a flexible material having a Young's Modulus E from 0.00001 to 0.5 GPa. 
   
   
       19 . The system of  claim 17 , wherein the at least one strake sheet comprises a rubber strake sheet. 
   
   
       20 . The system of  claim 17 , comprising at least three strakes.