A Doosan DX225LC-5 has learnt to swim in Germany

To allow the company, Sven Jacobs Tief-, Garten- und Landschaftsbau, based in Tating (Schleswig-Holstein) in Germany, to carry out a series of projects in the Wadden Sea, including work on the Hindenburgdamm, a dedicated 22 tonne Doosan DX225LC-5 crawler excavator has had to learn how to swim. This was achieved by converting the excavator purchased from the Doosan dealer, Atlas Hamburg, into an amphibious vehicle, a process carried out by the company, OLKO-Maschinentechnik GmbH from Olfen (NRW).

The main application area for the new excavator is the approximately 11.3 km long Hindenburgdamm, which connects the island of Sylt with the mainland in Germany. Around 8.1 km of the Hindenburg embankment runs through the Wadden Sea. In order to prevent the standard 22-tonne crawler excavator from sinking into the water, a particularly low ground pressure is required. For this purpose, Jens Mewes, from Sales at Atlas Hamburg, who has been working with the Jacobs company for four years, established contact with the company, OLKO. The latter mounted the superstructure of the Doosan DX225LC-5 on an amphibious undercarriage, not a standard pontoon so that the full manoeuvrability of the excavator could be maintained.

Individually adapted to customer requirements

Jacobs has been using Doosan excavators since 2014 and the new machine is the fifth Doosan crawler excavator they have purchased. The DX225LC-5 features the same new distinctive engine design that characterizes all the excavators in the latest Doosan LC-5 generation and is powered by the proven water-cooled Doosan 6-cylinder DL06P turbo diesel that delivers 124 kW (168 hp) 1800 rpm. This provides more than sufficient power with high torque at a lower speeds.

The OLKO undercarriage is designed for difficult applications in adverse conditions and on challenging surfaces, such as those found in, for example, wetlands, as well as performing environmentally friendly work in sensitive environments. 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 m, a width of 6.20 m and a height of 2.35 m. The undercarriage alone weighs around 27 tonne 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 9 m boom and a dipper stick 6 m in length. The extended reach makes it possible to work underwater without any problems. In addition, a supplementary fuel tank and a shelf for an anchor were installed. In order to comply with environmental regulations, the machine was converted to biodegradable Panolin hydraulic oil. OLKO ensured that the finished machine is certified with the CE mark and accompanied by the documentation required by the EU Machinery Directive.

Atlas Hamburg / von Wehl Gruppe

ATLAS Hamburg GmbH, founded in 1982, is part of the Wehl Group and, since 2012, the company has been a Doosan dealer for the areas of Hamburg, Northern Lower Saxony and Schleswig-Holstein. The group today employs 232 people. In addition to the sale of new and used equipment, the company also offers its customers a comprehensive rental fleet and a wide range of other services. The dealer also offers vehicle construction and painting for its customers.


Since the founding of the company in 1989, OLKO-Maschinentechnik GmbH from Olfen has been one of the driving forces in the field of shaft construction and conveying technology. With mining in the region declining sharply in recent years, the company has been looking for new business opportunities that promise long-term growth. As part of this process, OLKO first concentrated on amphibious machines as a niche segment of the construction machinery market. Introduced for the first time at the Conexpo 2017 exhibition in the US, the conversion of the Doosan DX225LC-5 is the first project the company has completed in Germany.