Two millennia ago, the land beyond the Alps was difficult to access: endless forests, swamps and no trace of paved roads. Anyone wanting to move troops, goods or news at that time did not do so over land, but via the rivers, which therefore took on a very special significance. The situation was similar at this time with the northern border of the empire - the Danube. Here the Romans patrolled with boats, bringing supplies and soldiers to the outposts. Their boats therefore played an extremely important role in securing the Roman Empire.
Today, Prof Dr Boris Dreyer from Friedrich-Alexander-Universität Erlangen-Nürnberg is investigating how the ancient ships actually functioned. He is investigating what speed they reached, how resilient their hulls were and how effectively their sails worked. However, he is not looking for the answers to his questions in ancient texts, but on the water.
The Roman fleet of scientists
Professor Dreyer now has three ships at his disposal that look as if they have just returned from ancient Rome: "Fridericiana Alexandrina Navis" (F.A.N.), "Danuvina Alacris" and "Alchmona Rediviva".
The oldest boat in the University of Erlangen's fleet is the "F.A.N.". It is 16 metres long, 2.7 metres wide and has a draught of 70 centimetres. She was built between 2016 and 2018 to mark the university's 275th anniversary - as a gift from students and researchers to their alma mater. The replica is based on the wreck found at Oberstimm near Ingolstadt, an ancient patrol boat from around 100 AD that was in excellent condition.
But now we wanted to know how such a boat actually behaves, not in the museum, but on the water," says Dreyer.
Expedition with the Roman boat to the Black Sea
When the "F.A.N." is launched in 2018, an unusual journey begins for Boris Dreyer and his team. Over 2,000 kilometres lie ahead of them, from Bavaria via Romania to the Black Sea. Along a route that marked the northern border of the Roman Empire two millennia ago.
The start is in Kehlheim. From there, the "F.A.N." follows the Danube through locks, canals and ever-widening river courses. The boat is fully crewed. A total of 18 crew members in Roman uniforms sit in rows 89 centimetres apart and row to the beat. Their workload is considerable: they row for up to ten hours a day, covering around 40 to 50 kilometres a day.
After just a few days, they are already familiar with the boat. The crew has got a good feel for the "F.A.N." and the oars are moving more and more evenly through the water.
The Roman soldiers were their own rowers," explains Dreyer. "They only progressed with discipline and perseverance. That was part of their service."
The Danube shows just how diverse it is. In Austria, it is sluggish and orderly, the banks well maintained and the locks modern. In Hungary, it is warmer, more yellowish and livelier.
In the heat of over 35 degrees, the rowers lose strength more quickly. But there are hardly any breaks. "This is not an adventure holiday," says Dreyer. "This is really scientific work." It is only after Budapest that what the professor later calls "the real Danube" begins. A river that knows how to defend itself against all predictability.
Downstream into the past
The further the "F.A.N." travels eastwards, the more the borders become blurred - geographically and temporally. Military boats pass by in Serbia, people wave from the shore in Romania. Sometimes the team moors in small harbours, sometimes they simply pull the "F.A.N." into the reeds in the evening. They spend the night in a tent or on the boat.
During the summer of 2018, when the water level is exceptionally low, every day becomes a logistical challenge. The current is of little help, the river is shallow and unpredictable. In some places, the rowers have to make it easier by getting out.
In the Romanian Danube Delta, the river finally loses all form. The sky is low, the water is still and the sun is beating down on the crew. "We had to deploy the sail here," says Dreyer. "The lateen sail was the best solution in this situation. It equalises the wind pressure well and can take the strain off the crew." Although the sail reacts more slowly than modern sails, it reliably pushes the "F.A.N." when the wind is astern. When the wind shifts, however, you have to react quickly. Every wrong angle costs valuable metres.
After a while, to the relief of the exhausted crew, they are joined by Romanian rowers, a couple of experienced men from the Danube delta who have grown up with the river. They know every current, every smell, every change of colour in the water. "They showed us how to handle the Danube," says Dreyer.
After weeks on the water, through rain, heat and low water, the team finally reaches the mouth of the Danube. The Black Sea lies before them, grey and still. The boat, like the crew, is marked by the strenuous journey: Algae on the hull, abraded oars and cracks in the wood. But it floats. The construction works and the oars perform as the sources suggest. The attempt was a success.
Hands-on research
The shipyard on Lake Altmühl is a hive of activity. All the boats that are built under Dreyer's supervision at the University of Erlangen are made by hand. The same techniques are used that were used 2,000 years ago.
The "F.A.N.", for example, was built using the Mediterranean "tongue and groove" construction method, in which each plank is connected with oak pins and nails. Modern adhesives are taboo. Instead, the joints are filled with hemp and tarred. For the "Danuvina", on the other hand, the team used the Gallo-Roman frame construction, in which planks are attached to frames with wooden nails.
Knowledge of the belts was also developed experimentally. The Romans left no exact measurements. So the team builds belts in three lengths: 3.70 metres, 4.10 metres and 4.70 metres. Each variant is tested, measured and recorded. "The antique oars are twice as heavy as modern sculls," says Dreyer. "But they work."
The tests follow scientific standards: flow analyses, wind tunnel models, material tests. The historians work together with engineers, fluid physicists and digital technicians. Sophisticated 3D printed models of the boats serve as the basis for simulations in water and wind tunnels. New tests are scheduled for spring 2026. Hydrodynamic comparisons between boats, carriages and catapults are to be carried out together with Hungarian flow researchers.
Between antiquity, education and adventure
What began as a scientific project is now an interdisciplinary network. Archaeologists work in the shipyard alongside mechanical engineers, boat builders, sports scientists and educationalists. School groups hammer in nails and student teachers develop teaching concepts. In summer 2025, young people from the "Rummelsberger Wohngruppen" will row the "F.A.N" across the Altmühlsee under the guidance of the professor. Dreyer calls this "experiential learning". For the professor from Erlangen, history only comes alive when you feel it. Including sore muscles and wet hands.
The association "Erlebnis Geschichte und experimentelle Archäologie e. V." coordinates citizen participation. The projects are open to the public and anyone can help build, row and think along. "You just have to lend a hand," says Dreyer. "That's part of it if you want to explore antiquity in this way."
New start for the Roman boat in winter storage
In autumn 2025, the "Danuvina Alacris", the second ship in the university fleet, returned to Gunzenhausen after three years on the Danube. In the shipyard, she will be caulked, re-tarred and painted with encaustic wax paint over the winter. She is due to set sail again in April 2026: from Osijek via Serbia to Bulgaria. At the same time, the new Alchmona is also being overhauled, while the latest project team is working on new oars, oar suspensions and sail variants.
All results are incorporated into specialist publications and courses. The aim is to familiarise students with antiquity in a practical way. Dreyer summarises his work as follows: "We don't reconstruct the past, we test hypotheses. Every blow with the belt, every gust of wind provides us with new insights."
