Based on positive results in trials on DEME's CSD Amazone , VOSTA LMG has won an order to supply 11 cutterheads for the new dredger, which has a maximum cutting power of 8,150hp for operations in rocky soils. These include T6 type cutterheads in sand/clay, multi-purpose, and rock derivatives while T8 heads have also been ordered for rock cutting. The T6 cutterheads have been designed for a maximum cutter power of 6,000hp while the T8 system can take power of up to 8,000hp.

VOSTA LMG claims the T8 cutterheads in six and seven blade configurations are the strongest cutting systems ever built for dredgers, almost double the strength of state of the art systems from the early 1990s.

DEME's technical manager Etienne Clymans said, 'These developments mean a big step forward in the dredgeability of hard rock. The T8 cutterhead is a good match for the extreme load that our new jumbo cutter suction dredger can generate on the cutter head.'

Despite the extreme strength of the cutting system, the weight of the teeth does not exceed 20kg, meaning they can still be readily handled by the crew. The unique locking system allows worn teeth to be replaced much faster for increased dredging efficiency, especially when tooth consumption is high whilst cutting through hard rock.

The 11 cutterheads are currently in production, as are some 50 specially designed, high pressure ball joints of type VOSTA H15-1000 HP for D'Artagnan 's floating pipeline.

In contrast to conventional high pressure ball joints, these do not use a troublesome plastic liner in the gland to cope with the extreme pressure. With a bore of 1,050mm and an outer dimension of 2,000mm, the ball joints can handle a test pressure of at least 40 bar, whilst the weight of each is kept below 7,000kg.

VOSTA LMG has also engineered the giant dredger's spud carrier and specially developed two modular anchor platforms weighing 250 tons each which will enable the cutter ladder to work in hard rock.

MJ Information No: 20910