German crane and excavator manufacturer Liebherr has supplied Moray Council, the only authority in Scotland to own a dredger, with an excavator for direct mounting on its new £2.5 million dredger, ‘MV Selkie’.
The 936 excavator, supplied with marine specification and two excavation buckets, was selected for its ability to fulfil the requirement to dredge up to 8 m under water.
The 250 tonne MV Selkie has been custom built at Macduff Shipyard in Buckie and is a replacement for the Council’s previous dredger, The Shearwater, which was sold for scrap in 2012. Pupils from the local Cluny Primary School, who named the new dredger, were at the Buckie harbour quayside to see Lord Lieutenant of Banffshire, Clare Russell, smash a bottle of Scotch whisky over the bow of the MV Selkie during the official naming ceremony. Designed to access smaller harbours, the MV Selkie will be available to carry out dredging operations for other councils around Scotland’s coast in addition to dredging Moray harbours.
Liebherr was involved with the project from the ship design stage and worked with Macduff Shipyard’s design team using Liebherr drawings. The brief was for an excavator to be directly mounted on the front of the ship with a support turret that matched the Liebherr swing ring gear, also supplied by Liebherr, and the ability to dredge up to 8 m under water. The machine of choice was the 30 tonne class 936 excavator with a 10.2 m mono boom and a 7.7 m dipper arm.
The 936 has been supplied with a marine specification, which includes water resistant paint and both a foam-filled dipper arm and seals on all pins and bushes to prevent water ingress and internal rusting. It has also been supplied with two excavation buckets plus additional hydraulic circuits and pipework, including a boom and dipper arm, to allow the use of various attachments, such as a clamshell bucket if required. And for efficient underwater excavations, the 936 is fitted with the Prolec pcX-pro 3D positioning product that allows the operator to view what is going on under the water. Visibility is also aided by LED 2100 lights that illuminate both the work area and the area around the machine.
For optimal operator comfort, the 936 has a spacious, ergonomically-designed cab including a pneumatic seat with horizontal and vertical damping, optimal visibility from the operator’s platform thanks to the very large glazed surface area and minimal area of uprights, ergonomic proportional manipulators for sensitive, accurate and fluid operation of hydraulic tools and minimised acoustic power inside the cab to diminish fatigue at work and increase productivity. An automatic central lubrication system can also be adjusted by the operator from the cab, depending on application.
The MV Selkie made its inaugural journey from shipyard to sea last month and in its first dredging trip out earlier this month unloaded 260 tonnes from its hull within half an hour. The 936 benefits from two excavation buckets, a 0.55 m3 digging bucket with ESCO teeth and a 1.45 m3 straight edge bucket for dumping, and is able to switch between them for dredging work making it highly efficient in this type of operation. By Jake Frith