Engineering news
The Goliath crane ordered by Babcock for the final assembly of the aircraft carriers at Rosyth has arrived at the dockyard from Shanghai Zhenhua Port Machinery (ZPMC) yard in China, where it has been manufactured.
The transport vessel (with a beam of 39 metres and overall length of 244 metres) bringing the crane entered the non-tidal basin via the newly widened direct entrance, completed in December 2010.
The partially-erected crane, with the girder and upper sections of the legs assembled, has been shipped to the UK mounted on the deck of a specialist transport vessel from the Chinese crane manufacturer’s fleet, along with all components including temporary erection towers, which will be used in Rosyth to complete the crane assembly.
The crane will now be erected to its full height on the ship deck over a six-week period, before being transferred from ship to shore directly onto the crane rails. These were installed last year, involving a total of 380 piles through varying ground conditions into the underlying bedrock, followed by reinforced concrete foundation beams, and the rail track. It will take four months to erect, test and commission the crane, for final handover in the summer, ensuring that the crane will be ready for its operational availability target of 1 September 2011.
The Goliath crane will be the largest in the UK, at a height of 68 metres to the underside of the main beams, with a span of 120 metres to cover the construction area of the new carriers at Rosyth. The crane will lift and place the carrier sub-blocks, and components including the upper blocks and sponsons, bow block, islands, and aircraft lifts, without disrupting the dockside area adjacent to the ship.
The crane’s 1,000 tonne lifting capacity is provided by three hooks. The individual capacity of each provides a degree of flexibility in lifting some awkward loads with difficult centres of gravity, and allows units or blocks to be turned over, up to a unit load of 500 tonnes.
Two of the hooks are suspended from an upper trolley (each hook having a 300 tonne capacity) and one from a central, lower, trolley with a 500 tonne capacity. While the three hooks have a greater cumulative lifting capacity than 1,000 tonnes, the total capacity is defined by the crane structure.
The arrival of the crane also marks the first use of the newly widened direct entrance. Rosyth has the largest non-tidal basin for ship repair in the UK, separated from the Firth of Forth by a sliding gate entrance to hold the water back. This has been widened by four metres to over 42 metres to allow entry of the blocks from the various dockyards where they are being built, departure of the completed vessel, and return for maintenance, in a grand civil engineering project.
Babcock project director Sean Donaldson said: “The arrival of the Goliath crane is a significant visible milestone in the aircraft carrier programme, and an exciting step forward.
“The civil works, crane, electrical package and general shipyard upgrade forms a £80m programme designed to make the Babcock Rosyth facility capable of assembling the Queen Elizabeth class aircraft carriers. All projects within the programme are performing to budget and schedule, to high safety standards, and when complete the facility will be unique in the UK.”