Equipment: M80 USV, Coda Octopus real time 3D imaging sonar
Survey Mission: The purpose is to survey wind farm turbine pile foundation and inspect underwater cable scouring.
1. 15Km 100KV main cable inspection
2. 80Km 35KV loop cable inspection
3. 38 units of turbine
4. Booster station area
The survey and inspection were conducted continuously every day, M80 USV able to inspect 20 Km cable and 20 turbine piles each day. Realtime 3D imaging sonar data received in mother vessel and surveyor is able to adjust survey route and 3D sonar angle base on real time data. Extend the inspection area when abnormal scouring found.
Pic.1 M80 USV in mother vessel
M80 USV could follow the cable line and pile position within±1m for precise survey, each survey mission can be saved and use to compare with historical data.
After few days’ inspection, scouring problems were found:
12 places of piles foundation have cable suspendedover 4m,
29 places of cable were scoured and exposed
4places 100KV cables were deviated from original coordinates over 5m
1 place cable were overbendingdue to external force
Pic 3. M80 USV in Survey
Pic 4. Pile foundation damaged, nearly 7m cable suspended
Pic 5. Booster station scoured area, 4m suspended and nearly 10m exposed
Pic 6. Pile foundation have 100m exposed cable
Pic 7. Overbending cable
With smaller and flexible survey platform, M80 USV is able to get close to turbine and provide more completed data coverage. The trimaran hull design brings more stabilities and quality data. Autonomous survey checking cable line save great time on filed. The launch and recovery of USV can be operated efficiently on mother vessel.
M80 USV work with mother vessel at offshore is great solution for hydrographic survey cost reduction, less operation labor force and much lower fuel consumption comparing with big survey ships.
Unmanned operation minimizes surveyors’ safety risk at sea operation, especially in restricted area like contaminated area, polluted or toxic water etc.