Quite a few passers-by stop on the banks of the Danube and pull out their mobile phones for a quick photo of two supposedly floating excavators. What appears surreal at first glance turns out to be two Liebherr R 938 crawler excavators tirelessly transporting gravel to the surface of the river. The spectacular deployment of the Liebherr machines is necessary to ensure the flow of the Danube along this section, thus contributing to flood prevention in the nearby city centre of Ulm. It seems to be a duel of opposites that is taking place in the Danube. Two Liebherr R 938 crawler excavators defy the strong current to remove gravel washed into the Danube from the river Iller. The goal is to remove around 80,000 tonnes of gravel from the Danube thus making a fundamental contribution to flood prevention and playing an important part of the circular economy. The excavated material is sent to a nearby gravel works for processing and is then reused for various purposes. The Nagel Baumaschinen Ulm GmbH quickly modified two powerful crawler excavators to meet the requirements of the executing construction company HEIM Holding GmbH & Co. KG and made them available. Working in the Danube is a demanding challenge for the Liebherr machines and especially for the two machine operators. The R 938 crawler excavator: Powerful generation 8 machine Liebherr crawler excavators are made of robust material, which was also proven in this application, however due to the flowing water, more performance is required because of the associated increased resistance. At the same time, this means that the working movements on the dipper arm result in a significantly higher temperature than the cool Danube water. The two excavators master this contrast in an excellent way, thus emphasising the high Liebherr quality. The R 938 has a weight range of 22 to 45 tonnes and is part of the 8th generation of crawler excavators launched in 2019 and developed at Liebherr-France SAS in Colmar. The range is characterised by its modern design, high performance and versatility as well as optimised ergonomics, comfort and safety. The low fuel consumption of the R 938, afforded by a Liebherr stage V 4-cylinder in-line engine, also ensures maximum efficiency and profitability of the machine in operation. Fishing in the dark: Liebherr crawler excavators keep a clear view Liebherr crawler excavators are used to performing to their full potential in rough terrain, however, working in the river poses a special challenge for the two operators of the R 938s. The material to be removed is not always visible, so man and machine have to approach their operating area carefully, particularly as the depth of the Danube increases in the middle of the river The two excavators have had to build a foundation below the water surface to enable gravel to be removed at these points. At times, only the striking Liebherr-yellow uppercarriages of the R 938s can be seen. For outsiders, this creates the impression of two floating excavators fishing in the murky waters - against the spectacular backdrop of the famous Ulm Minster.