Living Danube Limes Valorising cultural heritage and fostering sustainable tourism by LIVING the common heritage on the DANUBE LIMES as basis for a Cultural Route

Logbook of Shipbuilding

Reconstruction of a late Roman Danube ship

Based on the remains of Roman ship wrecks discovered in Mainz, our partner Friedrich-Alexander University reconstructs a late Roman Danube ship from the 4th century CE. Follow the progress in detail!



1 The felling of the oaks


The hull of the Danuvina Alacris requires 18 oak trunks, some of which are 20 metres long. The oaks were felled in the week from 9 to 14 November 2020, with the participation of local television stations.

Only in the autumn, preferably in winter, when the trunks are maximally sapped, the oak may be felled. This is of crucial importance for subsequent drying. Due to continuous planks, some of the oaks had to be over 20 metres long. In addition, we have selected about 60 pieces of krummholz (oak), which are used, for example, for the stern frame. Roman methods were also used for the sawing and moving of the wood. The next step is to transport the solid oak trunks to the building site. Considering the length and weight (approx. 1t/m³) this is a great challenge.

Photo: Mathias Orgeldinger


2 Week from 15 to 20 November


After felling with a press date on 9.11., further (initially up to 12 trunks) oaks were felled. On several dates since then, on 14.11. in a Roman way, we have been out in the forest and sawed logs.

First we sawed the logs ourselves, later together with the boat builder, who picked out the most important big branches and trunks. In the end we came up with about 70 knee timbers.

At the same time, we continued to plane oars and made progress in terms of line planing.

Photo:  Alexander Hilverda


3 The templates (malls) are ready!


Many things happen at the same time. The malls for the boat building are ready, so are the felled oaks for the transport to the Altmühlsee, study seminars are in progress.

All 15 oaks have been felled and are waiting for their transport. They are at least 50 cm wide and almost all 20 m long. In addition, there are various types of krummholz. The logs are to be processed into planks at Altmühlsee, where the boat building will also take place, which is a challenge due to the length of 19.3 m. The 18 malls (templates) are built. Also the lofting is ready: Clean work of the boat builder. Meanwhile the oars for the Danuvina Alacris and the F.A.N., an imperial patrol boat, are being built: 49 x 4.10 m oars and 42 x 4.70 or 4.40 m oars are pre-cut or even already finished and painted. We still have beams for three more 4.40/4.70 oars.

In the meantime the student seminars have started where shields are being reconstructed and built. So far 4 oval shields have been produced. Our reconstruction model is based on a combination of two different shield types, in line with our aim to cover a timeframe between 250 and 400 AD. We decided to use an oval shape based on the Dura Europos finds in Syria, mixed with a construction of little boards which is passed down through three shields which are now part of a private art collection dating from the late 4rd until early 5th cen. Of course we also had the technical skills of our students in mind, but we think that such a construction is also possible based on the few finds we have. We are very enthusiastic about the result, as it is the first time that our students have produced such not easy to build shields. Furthermore were able to test birch against poplar – both documented in Dura Europos and on the 3 fragmented shields from the private art collection – and decided to use poplar (easier to bend).

Photo: Margit Schedel


4 The transport of the oaks


At the beginning of December, another important hurdle was taken: the transport of the 15 felled oaks from the Sebald Reichswald to the building site at the Altmühlsee, 80 km away.

It was no easy undertaking when the oak trunks, each about 21 m long, had to be hoisted onto the transporter in adverse weather conditions and then transported to the Altmühlsee. Also because of the enormous weight: one cubic metre of oak weighs about 1.3 tonnes.

But in the end we were successful. But there are still about 50 krummholz to be transported.

Photo: Mathias Orgeldinger


5 Workshop: From archaeological finds to reconstruction


The first workshop on traditional craftsmanship was held on 14 December 2020 – progress with the double hall at the construction side

On 14 December the University of Erlangen-Nuremberg, hosted the first workshop connected to the reconstruction of the 4th century lusoria. Due to COVID-19, it had to take place online via Zoom, but was still a success. Around 50 people took part, including project partners, experts and the general public. Simultaneous translation into German was provided. Speakers were Prof Dr Boris Dreyer (Erlangen), Dr Ronald Bockius (Mainz) and Dr Timm Weski (Munich). They talked about the reconstruction according to the inventory in Mainz and with the help of parallel finds as well as about the status of the reconstruction of the Danuvina Alacris and the classification in the overall project.The evaluations after the workshop show that the audience was very satisfied.

For the Danuvina Alacris, further oars were planed and cut in Arberg.

The building permit for the double hall in Schlungenhof came through successfully. Tenders to companies have already started, offers have been received.

Photo: Alexander Hilverda


6 Latticing of the oak trunks


In Schlungenhof, the oak logs and oak krummholtz transported there before Christmas were latticed. A team of students, boat builders, professional sawyers and - as far as allowed by Covid 19 conditions - volunteers sawed the oak logs according to the specifications. Exemplary Roman frame saws were also used. However, most of it was sawn after initial difficulties with the modern mobile frame saw, which came specially from Bremen and can saw excess lengths (up to about 19.30 m). These sawn laths were well layered and secured so that they can dry well.

Photo: Boris Dreyer


7 The construction of the boat hall has begun!


The authentic replica of the late antique patrol boat is not to be done behind closed doors. Rather, the concept is to make the construction as transparent as possible. That is why the Danuvina Alacris is built in a hall with two sides glazed. A large swing door will be installed at the front and at the back. This allows interested parties to experience the boat building process live. An important step has now been taken: Here, at the Altmühlsee (Gunzenhausen), where the boat will also be stationed later, the construction of the hall has now begun.

Photo: Andreas Gronau


8 The oars of the Danuvina Alacris


For the Danuvina Alacris we assume 20 rowers. The shape and texture (spruce) of the necessary oars can be determined with some certainty, but the length is unclear and thus the subject of experiments. For this reason we produce them with two different lengths: 4.1 m and 4.7 m. We aim at a total of 40 oars. We have finished about half of them and have already started with the rest. They are planed with a Roman plane, which has been faithfully reproduced according to finds. The planing is a real hard work, because you have to make sure that the oars are uniform. It is also possible that knots will become visible after the squared timber has been planed. These then represent a predetermined breaking point.

Photo: Boris Dreyer




On Saturday and Sunday, the participants were introduced to the EU Interreg DTP project „Living Danube Limes“, accompanied by the media and in compliance with hygiene regulations. The context of boat building, the history of inland navigation, the special features of current boat building, but also the Roman past of the Limes and of Gunzenhausen were discussed by Boris Dreyer, the boat building basics also in the special case were reported by master boat builder Andreas Gronau, boat builder Frank Jäcklein, journeyman Alexander Blümel and apprentice Lena-Marie Kulke. This included the treatment of wood, the drying of wood, the making of working templates, the handling of tools, the explanation of the lines and body plans as construction plans of the boat builders in general and in the specific case, the essentials about the Gallo-Roman boat building method.

Practical work was also done: On Saturday, the keel was towed from the lumber yard to the boat building site, cut to size and protected. On Sunday, building on this, the stem of the boat was first made as a template from the plan, then sawn out at the timber yard and then transported to the building site, where it was further cut to size.

Photo: Miriam Sapio - The spoon auger driven by a rope bow represents an ancient and very effective way of woodworking.




On 29 April the keel laying of the Danuvina Alacris took place at the Altmühlsee, Gunzenhausen (Germany), an important stage at the beginning of the boat-building process. The boat builders under the direction of master Andreas Gronau have done the preliminary work by making sure that the keel is firmly anchored in the ground and then comes to rest on a crossed pawl, a framework of squared timbers. The laying of the keel is also of strong symbolic power. That is why "real" Romans also placed a coin under the keel in the first section. This is supposed to bring good luck. Furthermore, the "Romans" symbolically fixed the keel to the pawl and also offered a "libation". The keel was then properly fixed and aligned by the "modern" boat builders, and then also protected against wind and weather. Let's wish the boat always a hand's breadth of water under the keel!

The construction of the hall is still a challenge due to delivery bottlenecks caused by Covid-19. The glue trusses cannot be delivered until July. If no replacement can be found quickly, construction of the hall will have to be put on hold until then.

Photo: Mathias Orgeldinger


11 Working on the keel and installing the malls


Malls are frame templates that are used to shape the later plank courses. We had finished them before, but had to wait with using them until the roof over our building site was constructed, because the malls have to be braced with the roof so that they are fixed. The malls are now braced with a so-called donkey.

We also built a temporary corrugated iron roof to protect the wood and the helpers building the boat from the rain. In addition, we were able to receive more crooked timbers (krummholtz) that were delivered from northern Germany. Their natural curvature is of great importance for certain wooden parts of the boat (e.g. the frames). The oak trunk selected for the keel (length 18 m) is already planed. We discovered some rotten spots (brown rot) in the wood, which we chiselled out. These spots were replaced by bungs (i.e. replacement wood). Such rot is completely normal in an oak trunk of such length and does not pose any further problem.

Photo: Constantin Gläser


12 Stems are connected to the keel of the boat


The stems are components of the "framework" of the hull. They are the forward and aft (sternpost), upward extension of the keel.

First, the 3 mm thick templates of the 1:10 model were transferred to the original size. Then, with the help of these original-size templates, we sawed oak blocks to size with a band saw. For the sternpost we needed a larger block. The sternpost consists of two parts that are lashed together. Then the stems were planed until they were sufficiently thin and pointed. In the end, the sterns were attached to the keel.

The templates (malls) have also been finally adjusted, but they still have to be connected to the keel and to the so-called donkey.

Photo: Boris Dreyer

13 First plank is in place


The latest work initially covered the preparation of the construction site. The so-called donkey was fixed. The keel was prepared and treated with linseed oil. Then the templates (malls) were fixed in their previously determined positions, and these fixed templates were connected with the aligned donkey. Next, the fore and aft sterns were cut from the solid wood and fixed to the keel. Then strips were produced, which, when attached to the template, should make it easier to fair the edges of the template.

At the height marked on the templates for the sheer strake, two battens were attached at the top and bottom to mark the first plank. The model for the first plank was placed in their centre. Small battens were attached to this model batten so that they touched the edge battens for the first plank. Once these were fixed and dry, they were removed and could be placed on the oak planks that had been pre-sawn in January. After that, the oak was sawn out, planed and then fixed. On Monday 21 June, an 18 m continuous oak plank was, as the first plank, fixed.

Photo: Boris Dreyer


14 Activities Around Shipbuilding


For the crew of the Danuvina Alacris we produce shields, for which colours, ornaments and figures are tested. The shield bosses are worked at a Roman forge, demonstrated by an artisan blacksmith. The many volunteers involved in shipbuilding also meet again and again at the shipbuilding site for acticities in a Roman context. Not only do they talk about the latest progress in shipbuilding and what's next, but they also discuss authentic Roman clothing. Roman nails or shield bosses are forged then with a Roman forge. As far as food is concerned, we experience with Roman recipes. For example, we bake Roman flatbread, which we eat with moretum. To go with it, we drink mead in Roman dishes, for example.


Photo: FAU


15 The second milestone


The second milestone has been reached with the adjustment of the top plank courses to starboard and portside, and the schedule has been made up despite the delay caused by Corona at the start (until the end of April).

At the end of June, an Austrian film crew accompanying the project, filmed Roman craft methods on and near the boat. Forging processes were also filmed, for which the forge was fired up. Shield bosses were forged, planks were sawn with a Roman box saw, and holes were drilled in planks with a drill bit/spoon bit.

Further, the motifs for the sign were tested. Colour nuances and shades were tested with the different colours in antique composition. The Victoria motif, especially her face, was also practiced.


Photo: Margit Schedel


16 Workshop: Roman craftsmanship and Roman shipbuilding


Date: 22-23 July, 2021 (each 10:00 am - 05:00 pm)

Venue: Seestraße 17, 91710 Gunzenhausen


At the workshop on Roman craftsmanship and Roman shipbuilding, the workshops proceeded separately according to major craft categories, but always maintained a connection to each other and in particular to shipbuilding.

The programmes and the schedule were partly simultaneous, but in such a way that the introduction and the introduction to a new craft activity were nested one after the other. In this way, everyone could participate in each introduction, but could also choose to stay with the active participation in the craft. Then each participant was given the opportunity to carry out the craft activities themselves, while respecting hygienic regulations.

Among other things, participants could forge iron nails and shield bosses at the blacksmithing stand whereas the boatbuilding stand offered explanations regarding different planking techniques: clinker and carvel.

Additionally to boatbuilding and blacksmithing topics the construction of the shield was explained in the individual phases on the second day.


Photo: Mathias Orgeldinger



17 Floor plates and ribs


The floor plates are the side braces and side stiffeners that cross the keel beam in the boat. We are close to the historical model, but in such a way that the floor plates are cut from the solid wood along the grain as far as possible. This makes the side stiffening more stable.

There will be well over 30 floor plates in total. In addition, there will be twice as many ribs: Transverse stiffeners that stiffen the starboard and portside of the boat up to the rubber rail. They do not go over the keel. The floor plates and ribs have a thickness of about 5 cm and are thus relatively narrow, true to the findings, but the quantity guarantees safety, just like in the original, even if it is more unsystematic here. This painstaking work will keep us busy for some time. First of all, each floor plate has to be removed with a chain, using the ribbands, and this has to be done anew at each position, because each time it is fitted it gives a new shape. The shape is drawn on the solid wood (oak) using the shape chain and then the floor plate is sawn out. These processes must be repeated several times until the optimum fit is achieved.


Photo: FAU


18 Floor Plates and Ribs (Part 2)


The diligence work continues. Up to 35 floor plates are made. These are fitted from the hull with a flexible chain. To do this, three modelling strips are placed on portside, as far as the floor plate will later reach, on the outside of the chine at the faired mall edges. At least three points must be able to be transferred to the chain through the strips. This means that three strips must be attached over 18 metres.

These three points are then transferred from the chain to the template (poplar, 3 mm). The points are connected with a small  faired batten, the poplar is sawn out as a template and transferred to a floor plate of a suitable oak trunk. Using this template, the oak is then sawn out and planed. This has to be repeated over thirty times, each floor plate has an individual shape.

The same must then be done for the ribs (futtocks): from the chaine to the sheerstrake.


Photo: Boris Dreyer


19 Floor Plates and Ribs (Part 3)


The floor plates are now cut out in sufficient quantity. They are now planed and smoothed for their position. These are followed by the ribs (futtocks). Their number corresponds to twice the quantity of the floor plates. For driving safety, the diameters and lengths always deviate a little from the historical model, so that accidents are avoided and the boat can also withstand being lifted by a crane and transported over land: something the Roman model did not have to endure. A solid piece of oak is made into the mast frame. This work is now underway.


Photo: FAU


20 Our Boatbuilder


Master boat and ship builder Andreas Gronau (born 1984) is in charge of building the Danuvina Alacris. Andreas Gronau completed his training as a boat and ship builder at the Rathje Yacht and boat building yard in Kiel (1999-2003). This was followed by longer stays for further professional training in England, Ireland and Scandinavia during which he worked at various wooden boat and shipyards (2003-2007). In 2004, he founded a boatyard for classic racing dinghies, followed in 2012 by the establishment of a shipyard for the restoration, repair, new construction and reproduction of wooden boats. Since 2004, he has built a total of 26 new wooden boats. He has already gained experience in the field of rebuilding historic boats, for example, he worked on the historic rebuilding of the Dunbrody Famine Ship. From 2004 to 2012, Andreas Gronau was also responsible for the restoration and conservation of numerous originals (type: racing dinghy) from the 1920s and 1930s. He is regularly involved in the conception of exhibitions on shipping in the Altona Museum. So far, Andreas Gronau has trained 12 apprentices as boat and ship builders.


Photo: Miriam Sapio


21 OUR Blacksmith


The authentic reconstruction we strive for the Danuvina Alacris also means that the tools used to build the boat are made in an authentic way. This requires a skilled as well as dedicated blacksmith.


Thomas Hürner was trained as an artisan blacksmith from 1979 to 1983. After successfully passing the journeyman's examination in metal construction, he completed further training in old forging techniques (stylistics, shaping and working techniques). In 1989 he passed the master craftsman's examination in metal construction. In 1996 he took over the family business. In 2005-2007 he studied to become a restorer in the smithery, which he successfully completed. Since 2010 he has been a member of the examination board of the Chamber of Crafts for Middle Franconia. In addition to metal design and the restoration of metal objects, his areas of work also include the reconstruction of objects using classical forging techniques. In addition, he also distinguishes himself as a committed lecturer. 


Photos: Mathias Orgeldinger

Programme co-funded by European Union funds (ERDF, IPA, ENI)