at least one of a spacing between the windings and an angle of slope between the windings and a pipeline longitudinal axis varies along the pipeline longitudinal axis to change the winding density along the pipeline longitudinal axis as {HEAD ~ a function} of {TAIL ~ local mechanical load requirements} of the pipeline 
at least one of a spacing between the windings and an angle of slope between the windings and a pipeline longitudinal axis varies along the pipeline longitudinal axis to change the winding density along the pipeline longitudinal axis as { HEAD ~ a function } of { TAIL ~ local mechanical load requirements } of the pipeline
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH