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
|