Knuckleboom cranes for nacelles

Palfinger Marine’s nacelle knuckleboom Palfinger Marine’s nacelle knuckleboom

Inside a recent, large wind crane contract for the Borkum II windfarm was an interesting element: while half Palfinger’s order was for stiffboom cranes, the other half was for folding knuckleboom units to be installed on the nacelles.

The Trianel farm is located in the North Sea approximately 40km north of the island Borkum and consists of 32 Senvion 6.2M152 turbines. These will generate about 200MW hours of electricity, but of course, downtime in such an energetic environment is always an issue, therefore ease of maintenance is high on any operator’s list.

However, unlike the 32 electro-hydraulic stiff boom cranes (PSM400) that Palfinger is also supplying for the towers’ service platforms, these nacelle cranes probably won’t be used on a regular basis. However, they do make a useful addition for safe and fast lifting of the turbine’s slightly smaller elements – such as spare jaw gears for the slewing drive, coolers or lubricants for maintenance, explained Rupert Reischl of Palfinger’s wind cranes department.

These components usually have to be brought up into the nacelle from the service platform or from the support vessel’s own helideck. Compared with the rope winch or chain tackle alternatives, these cranes are a lot more flexible in terms of operating area and manoeuvrability. Further, they can also provide man-riding capabilities for inspections outside the wind turbine.

But nacelle cranes require a particularly compact design as space is limited. So, these PK40002 knucklebooms design fold down into a space around 2.7m in height, 3m in length, and around 1.4m wide.

While they might not be able to handle an entire gearbox, these ‘continuous slewing’ cranes are still pretty capable: the maximum lift is 129.1kN or 13,160kg, or at 4.5m outreach, that’s 80.6kN or 8,220kg; given the maximum hydraulic extension of 20.4m its 9.4kN or 960kg.

The PK40002 design comes with a hydraulic power-pack generating the necessary 300bar pressure, but like the other Palfinger wind cranes, they can be integrated into the turbine’s own power system.

Of course, as little used, remote equipment, these power packs themselves need to be robust: and come equipped with fluid level indicator, thermometer and filler-breather filter. More, the PK series also has a regenerative hydraulic circuit which yields for almost a third faster boom extension speed.

Finally, they have Palfinger’s Power Link system which yields a constant lifting moment, resulting in maximum power at the hook, even given unfavourable boom angles

Considering the 25 year-plus lifespan of these wind turbines, nacelle cranes could be considered a worthwhile investment.

By Stevie Knight

Latest Press Releases

Damen begins work on Marine Aggregate Dredger dredging system

Innovative vessel for CEMEX UK is first of next generation of marine aggregate dredgers Read more

MIT deliver Bespoke Exhaust Suspension System by Rubber Design for Sir David Attenborough Research Vessel

MIT has successfully delivered a bespoke exhaust suspension system to Cammell-Laird Shipbuilders in ... Read more

Damen delivers two of four ASD 3212 tugs to Smit Lamnalco

Damen has delivered two of four ASD 3212 tugs to towage and related marine services’ company Smit La... Read more

Oceanscan invests in Sonardyne acoustics

International equipment supplier Oceanscan has added underwater acoustic positioning technology from... Read more

Damen Shipyards Galati welders scoop awards at International Welding Competition

Welders from Damen Shipyards Galati in Romania recently took part in the 2018 Arc Cup International ... Read more

Damen Shiprepair Brest completes maintenance programme on cruise ship Norwegian Breakaway

The 326-metre, 146,000 DWT, cruise ship Norwegian Breakaway arrived in Brest on 28 April for 11 days... Read more

View all