A Jumbo job of monopile delivery

The monopiles’ final destination was DONG Energy’s Walney Offshore Wind Farm 2, which is being built some 15 km off Walney Island, Cumbria, in the Irish Sea.

Walney 1 and Walney 2 will each comprise 51 turbines with a total capacity of 367.2 MW. The development includes foundations, turbines, export- and array cables, offshore substations and onshore connection to grid.

When the project is completed, approximately 320,000 homes, or one and a half times the number of households in Cumbria, could be provided with clean electricity in the years to come. Walney 1 began generating power in January of this year, with construction of Walney 2 commencing in March.

Crane barges, jack-up vessels and tugs are working out of ports in the East Irish Sea area, primarily Barrow and Mostyn harbours.

When Jumbo’s contract was awarded, the first shipment was only seven weeks away, during which time Jumbo engineered all shipments and designed and manufactured saddles for the monopiles. Within this short period of time all was ready and approved by the Marine Warranty Surveyor.

Jumbo’s HLV Fairpartner, a 13,278 dwt J1800 Class vessel fitted with two 900 ton cranes, made six consecutive voyages carrying eight monopiles at a time, two in the hold and six on deck. The largest monopile weighed 806 metric tons and measured 68 meters in length and 6.5 meters in diameter. The 144m LOA vessel can sail at 17 knots.

In order to improve the delivery schedule, DONG Energy asked Jumbo to employ HLV Jumbo Vision to transport the last three monopiles. This 7,051 dwt H 800 Class vessel measures 110.5m LOA, has two 400 ton cranes, and can sail at 14.5 knots. The transport engineering plus design and fabrication of the stoppers for the sea fasting of these monopiles was done within only two weeks’ time.

At Barrow in Furness, the discharging of the monopiles was done round the clock in order to make the port stay as short as possible. Jumbo’s shallow draft vessel entered the port during high water, after which the dock gate had to be closed and no marine traffic was possible. Each discharge operation of eight monopiles was completed within 36 hours.

By transporting as many as eight monopiles per voyage, Jumbo was able to complete the project in a substantially small number of voyages and thus reduced the project’s environmental impact.