The X-STERN is the X-BOW® effect implemented in the aft ship. While the traditional transom plate causes slamming and vibrations when the vessel is backing, the pointed X-STERN has no such effect. The softer motions are energy saving and increase comfort and safety.
Market insight from the offshore wind industry shows that 70 % of the vessels operate backwards in-field, despite the slamming experienced with the flat transom plate. The X-STERN hull solution was welcomed and taken in use on service vessels for the offshore wind industry shortly after its introduction in 2015.
The SOV crews give various reasons for astern operations:
- All the work is being performed at the aft. Keeping the aft first leads to a better overview of the vessel’s positioning, as the gangway, the turbine and the ship’s side can all be observed from the bridge
- Most power is installed in the aft part of the ship, enabling it to keep positioned more easily
- The vessel doesn’t have to turn around before leaving for the next turbine, saving manoeuvering time between turbines
Crews on X-STERN vessels have additional reasons for operating astern:
- The X-STERN is kept towards the weather while on standby during night. The service crews get complete rest in between their maintenance shift due to no slamming or vibrations
- There will also be no slamming due to the X-STERN while on DP or even when transferring between the turbines
- If the weather is not too adverse, the ship stays on the spot with two thrusters running, which leads to substantial reduction in fuel consumption
Example vessels of the SX175 design -
'Windea La Cour' and 'Windea Leibniz':
"The X-STERN met all our expectations. It is amazing to see a vessel going backwards in bad weather without slamming or having spray on deck." BS Offshore feedback on the 'Windea La Cour'
Why is backing preferred in SOVs?
Operational feedback shows that SOV crews choose to operate the vessels in astern mode while in-field. The 'aft first' experience is improved with the X-STERN, which has been introduced to several offshore wind service ships.Backing made natural
Hard rocker at work, enjoying the silence
Checking out that ocean view! If the weather is good, this is Matthias Giebichenstein's everyday sight. He works six weeks as a senior DP operator on the Windea La Cour, on one of the world's largest wind farms. Then he goes ashore and takes on his alter ego, 'Chief Mad', as the singer of the hard rock band Magic Hum.Meet Matthias
Example vessels of the SX195 design -
Acta Auriga and Acta Centaurus:
"We are quite convinced that the Acta SX195 vessels will create higher efficiency in offshore logistics operations and thus reduce the overall cost of constructing windfarms and, also, contribute towards a higher uptime of the installed base of offshore wind.” Rob Boer, managing director at Acta Marine
This is why Acta Auriga was chosen for BARD Offshore 1
Acta Auriga was contracted to work at the offshore wind farm BARD Offshore 1: “Ocean Breeze Energy decided on this vessel due to a favourable combination of capability, capacity, design and fuel consumption. The delivery precision from Ulstein was also important.”The X-STERN an added advantage