The main working area for the machine is the approximately 11.3km long Hindenburgdamm embankment, which connects the island of Sylt with the German mainland, close to the Danish border. Around 8.1km of the Hindenburg embankment runs through the Wadden Sea.
The machine is owned and operated by the company Sven Jacobs Tief-, Garten- und Landschaftsbau, based in Tating in Schleswig-Holstein. The conversion was carried out by Olko-Maschinentechnik in Olfen (about 20 miles north of Dortmund) and the excavator was supplied by local Doosan dealer Atlas Hamburg.
Jacobs has been using Doosan excavators since 2014 and the new machine is its fifth Doosan crawler excavator.
To prevent the standard crawler excavator from sinking into the water, a particularly low ground pressure is required. For this purpose, the superstructure of the Doosan DX225LC-5 is mounted on an all-terrain undercarriage, not a standard pontoon, to ensure the full manoeuvrability of the excavator has been maintained.
The Olko undercarriage is designed for difficult applications in adverse conditions and on challenging surfaces, such as those found in wetlands, for example. It also makes it possible to carry out work on lakes, rivers and coastal areas. The type U/1800 undercarriage used on the Doosan DX225LC-5 has a length of 10.80 metres, a width of 6.20 metres and a height of 2.35 metres. The undercarriage alone weighs around 27 tonnes and produces a buoyancy of 580 kN. It achieves a load capacity of 18 tonne and a maximum speed of 4 km/h.
In addition to the conversion of the chassis, a number of other modifications were made by Olko. This included fitting the crawler excavator with a nine-metre boom and a six-metre dipper stick. The extended reach makes it possible to dig below the water. In addition, a supplementary fuel tank and a shelf for an anchor were installed.
To comply with environmental regulations, the machine was also converted to biodegradable Panolin hydraulic oil.
Olko-Maschinentechnik was founded in 1989, specialising in shaft construction and conveying technology for the mining industry. But with mining in the region declining sharply in recent years, the company has had to diversify. It exhibited at the Las Vegas Conexpo construction machinery exhibition in 2017 and has subsequently found itself a niche market in these special all-terrain carriers. The conversion of this Doosan DX225LC-5 is the first such project that the company has completed in Germany.