Research Ship LUDWIG PRANDTL
Forty Years at Sea
It sways back and forth on the gentle waves of the Elbe in its home port of Oortkaten, waiting for the next exciting adventure: it is the HZG’s LUDWIG PRANDTL research ship.
Photo: HZG/ Christian Schmid
The vessel is named after the physicist Ludwig Prandtl, who in 1904 succeeded for the first time in visualising flow processes with a water channel. The ship launched in 1983 in Hamburg. Today scientists use the LUDWIG PRANDTL for collecting assorted samples from the water or the seabed and examine them, studying various aspects. Due to its shallow draught (only 1.7m!), it is especially used in areas of shallow water—an important factor for research conducted in rivers and at the coasts. For taking samples, the Ferrybox is often utilised. This is a measurement device that continuously collects data pertaining to the water, including, temperature, salinity, chlorophyll content, turbidity and oxygen content. The researchers use the laboratories on deck the LUDWIG PRANDTL as well as additional measurement devices to do so.
Our research vessel will soon turn forty years old. It’s now time to revisit the ship’s loveliest moments.
Experiments and Measurement Campaigns
Dr Jochen Horstmann releases a drifter. Photo: HZG/ Christian Schmid
A Wealth of Data
Every year, numerous journeys are taken to collect data and gain new insights. The PRANDTL has been used for many years to study the Elbe, the Baltic Sea and the North Sea. An important research area is the nutrient transport and budgets in the Elbe and its estuary. The first studies on nutrient budgets using the most modern isotope technology began in 2005 and are still carried out today. New studies indicate that the nutrient input is increasing again - mainly due to more intensive agricultural use and fertilisation. The concentrations of compounds such as ammonia and toxic nitrite in the port area are also increasing as a result. This means additional stress for the fish and other living creatures. The scientists have access to a wealth of data for the Elbe, including nutrients, pH values, salinity, temperature and stable nitrogen isotopes that allow the researchers to study and determine the biochemical turnover processes in detail. The studies serve as the basis for many publications. The research ship is also made available to external research groups.
The Measurement Pole in the Oderhaff (Baltic Sea) was anchored at a depth of four meters to determine the amount of energy flowing through a wave using wave dynamics. Photo: HZG/ Christian Schmid
Oderhaff Measurement Pole
The LUDWIG PRANDTL also helps in deploying permanently installed measurement devices: a measurement pole in the Oderhaff (Baltic Sea) was anchored in 2018 at four metres deep. It uses wave dynamics to determine the quantity of energy flowing through a wave. The correct description of this complex energy flow is used, for example, to optimise mathematical climate models. A laser apparatus called the “AirSeaPix” is therefore affixed to the eleven-metre-tall measurement pole. This way the scientists can gather knowledge on the formation of hurricanes. The measurement pole in the Baltic Sea continuously records waves and the flow of mist droplets, but oxygen and carbon dioxide content in the sea can also be determined using the devices.
The LUDWIG PRANDTL in the Media
Captain Helmut Bornhöft has been steering the ship for decades. Photo: HZG/Patrick Kalb-Rottmann
Many measurement campaigns in which the PRANDTL has participated are not publicised at all or only to a very limited extent. One media appearance, however, made the research vessel famous: “Clockwork Ocean” In June of 2016. During this expedition, a Zeppelin was used for the first time in the history of sea and coastal research to study ocean eddies. The aim was to determine what role these eddies play in energy transport and in the sea’s food chain. The scientists measured the temperature differences at the ocean’s surface and determined the water’s colour spectrum. Measurement equipment, such as the drifter, the Acoustic Doppler Current Profiler (ADCP), and the towed instrument chain supported the research ships LUDWIG PRANDTL, EDDY and the ELISABETH MANN-BORGESE while studying the eddies. A great deal of data was collected, and an eddy could be measured for the first time, from its emergence to its collapse.
Photo: HZG/ Gesa Seidel
Coastal Research on Tour
LUDWIG PRANDTL has greeted numerous visitors during its “Coastal Research on Tour” events. Since 2009, coastal research work has been presented annually on the ship in ports along the German North Sea and Baltic Sea coasts. Everyone—whether young or old—can take a free tour during the “Open Ship”, get a glimpse of the research and ask the scientists questions. But there’s also something hands-on to do: the guests can carry out measurements themselves and get acquainted with coastal research in an entirely different way. This always provides a great sense of enthusiasm and participation.
Now in charge of the ship: Captains Heiko Gerbatsch and Marco Schacht. Photo: HZG/ Emma Lefebvre
Searching for Gottfried
It’s hard to believe, but there’s a treasure in the Elbe estuary near Cuxhaven. In March 1822, a ship named the GOTTFRIED sank with a cargo that included hundreds of ancient Egyptian treasures. The treasure has never been found - neither has the ship. In the summer of 2010, the HZG made the LUDWIG PRANDTL available to Schleswig-Holstein’s state archaeological office to locate the GOTTFRIED’s cargo using a novel hydroacoustic method. One type of equipment used for the treasure hunt was a side-scan sonar. It transmits sound signals that are reflected back from the seabed to locate conspicuous objects. Using the sediment echo sounder, a complete image of the seafloor can be produced on the computer. Under optimal conditions—no wind, no waves and with bright weather - the researchers can even look into the seafloor. The search did not result in the discovery for which they had hoped. The experts, however, are not giving up and are continuing to search for the ghost ship and its valuable cargo.
Youtube - Searching for Gottfried
Good News for the German Research Fleet: The Federal Government Supports Construction of a New Research Vessel, the LUDWIG PRANDTL II
This is how the LUDWIG PRANDTL II could look like. Graphic: HZG
Due to the age of the current ship, its replacement is necessary with a new vessel. The LUDWIG PRANDTL II is to cover a broad, interdisciplinary spectrum of coastal research, materials research, polymer science and digitisation. It is therefore to be used in a variety of ways by the HZG and its partners for research and teaching. Construction of the new vessel will cost approximately 13.5 million Euros. A wet laboratory, electrical laboratory and external laboratory as well as a a lab for hydrogen technology is planned for the LUDWIG PRANDTL II. There will also be observation technologies with autonomous measurement devices, instruments for flow measurements and various other systems that can be used flexibly. The ship’s propulsion design will use a metal hydride storage tank developed in the materials research division at the HZG in Geesthacht. Membranes developed by the polymer research division are to be used to minimise pollutant emissions from engines based on heavy oil and diesel combustion by treating the charge air. In addition, the research vessel is to be equipped with a completely new information system and data management. The keel-laying ceremony is planned for 2022.
Press Release from 26.11.2020
Author: Charleen Schwabe (HZG)
Published in in2science #10 (December 2020)