Ploughing vs. Trenching

General Plough vs. Trencher Pros and Cons: (relative to OWF Inter-Array Cable)

Plough Pros: Plough Cons:
  • Can be completed in one process
  • Generally faster rates than trenching
  • Generally good burial
  • Can penetrate harder sea beds
  • More economical over longer distances
  • Instant cable burial and protection

 

  • Must be completed properly in one pass
  • Difficult to monitor product cable tension
  • Can cause cable damaging tension spikes
  • Difficult to maneuver and position near foundations
  • More difficult to steer as it is towed
  • Requires tow cable catenary management
  • Requires umbilical management
  • Risk of mechanical impact/abrasion/stress on product cable
  • Higher risk in the vicinity of adjacent cables
  • Plough “grade-in” and “grade-out” at each end of span or a recovery leaves exposed cable requiring BLIB
  • Can’t “cut & grip” damaged cable
  • Requires bigger ship and more crew

 

Trencher Pros: Trencher Cons:
  • Self-propelled control
  • Maneuverable to optimal cable position
  • Can work adjacent to vessel and foundation
  • Multiple pass option to improve burial
  • More deploy/recover operation flexibility
  • Mobilization layout flexibility – stern or side launch
  • Generally single man launch capable
  • Wider operating weather window
  • Can remain working for long periods
  • Can perform cable/foundation inspections
  • Can “cut and grip” damaged cable
  • Can conduct cable and scour surveys
  • Can assist with messenger lines in the cable “pull-in” process
  • Scheduling flexibility – lay then bury

 

  • Generally slower than a plough
  • Less effective in harder sea beds
  • Post-lay burial – two-part process
  • Generally requires returning after the lay to then trench
  • Requires more power from the ship for cutting or jetting

 

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