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Schiedam-based salvager uses robots to work at great depths

High demand for newcomer

Tags: Excerpts from the Windmill

SCHIEDAM — Dutch specialist firms Wijsmuller and Smit have established a long and solid tradition in the business of rescuing ships in distress and taking them to safe ports. Newcomer Mammoet Salvage has added a new dimension to such operations, unloading sunken ships at depths in excess of fifty metres.

Earlier this year, Mammoet Salvage in one such job retrieved 4100 tons of aluminum ingots from a shipwreck 85 to 95 meters beneath the surface of the Gulf of Finland. Originally specializing in heavy lifting and transport, Mammoet developed a taste for salvage work as a result of its involvement in bringing the Russian submarine Kursk to the surface. That was how Mammoet Salvage was born.

Over a period of only seventeen months, Mammoet Salvage successfully completed fourteen salvage assignments. One of the larger assignments involved salvaging the wreck of a freighter, the Safmarine Agulhas, which had smashed into a harbour pier in South Africa.

When it comes to salvaging ships, no two jobs are alike, as each situation demands a unique approach. Salvaging the aluminum from the bottom of the Gulf of Finland last spring where the Russian vessel (formerly the Dutch Leliegracht feeder vessel) had gone down, is a case in point.

The ship, which was carrying 5300 tons of aluminum, had been en route from St. Petersburg to Rotterdam. At its depth, the wreck posed no hazard to shipping or to the environment, especially, once most of the oil had been removed. However, given the enormous demand for raw materials, the cargo was valuable enough to justify bringing it to the surface.

Mammoet Salvage has developed two special underwater excavators to add to the wide range of cranes possessed by its parent company Mammoet. Using this equipment, Mammoet Salvage started its work, operating from a large floating pontoon. The underwater excavators are fitted with excavator arms attached with special suction pads, which were used to salvage the aluminum ingots. According to company officials, this approach to salvage at great depths has enormous potential. They anticipate that this Mammoet innovation will generate considerable interest within its sector.

To gain access to the cargo, salvagers first remove any deck cranes and hatch covers from the wreck. Working inside the hold, the excavators which had also been equipped with shears, then removed a lower deck as well. Had the weather cooperated, the crew may have been able to salvage all the ingots.

Mammoet Salvage also has a job on its schedule in the Straits of Malacca, where it must remove a 240 meter bulk carrier from this important shipping lane. The carrier is laden with 93,000 tons of iron ore.