Friday, July 26, 2013

Marta Perlińska, Antoni Nowak, students of our courses in Digital Archaeology (ARKN10-ARKN09), Lund University

Marta Perlińska
Antoni Nowak


Every archaeologist in Scandinavia knows the iconic Bronze Age carvings from Swedish site Tanumshede.
There are many interpretations of these images. As we experienced on our own, the carvings are truly astonishing. They are just simple graffiti, representation of people mythology etc. Most of authors agree on fact that those carvings are representation of ship/boats. Their special form, two-stems, made other interpretation problems for researchers. Before the World War II in Hjortspring, Denmark, the answer for all questions was discovered – the ship, maybe not from the same time as Tanumshede, but closest to it. The reconstructed boat is quite overwhelming, especially when you are standing in front of it. It was made in 90s, and looks quite good – maybe a bit strange, but convincible. The sea test went worse – boat turned out to be very stiff – which made characteristic of waves’ attack very aggressive. That resulted in very uncomfortable boating and wet crew on board. All those problems, alongside with idea of two-stems in one-hull boat, quite difficult to motivate, made us think about proposition of other reconstruction of Tanumshade boats. The need to trade on longer distances during Bronze Age is obvious. The idea of rigging to British Islands on Hjortspring-like boat is ridiculous and two-stems is not motivated neither by practical nor technological needs. We decided that those boats should look like outrigger proas. As we will try to show, the hypothesis is not truly nonsense and the capabilities of two-hull boats were tested by many during the last few thousand years – such type of boat was used to populate islands on the Pacific Ocean, over the area of thousands square kilometers. 

During our research we found out that we are not the only one with this idea. In 1924 Ossian Elgrstrom had make an experiment. He created a small proa model, and ordered a group of children to draw it. The results were almost the same as the rock carvings. Also, in 1925 Gustaf Hallstrom published similar article, presenting the same ideas. Finally, in 1997, Sven Osterholm had made a small dugout two-hull boat. But, as we found out, all of them thought that these boats were a dugouts.

Our primary aim was to design a boat model in 3DS Max, using Bronze Age rock carvings from Tanumshede as a reference. We wanted to do it as persuasive as we could with our poor skills. We thought that those boats were made with similar techniques as Hjortspring and Ferriby boats – from wide and long planks, literally sewed together in shape of boat and straighten by frames, so we tried to show it on the model. Our model has real dimensions, which corresponds with the model made in Delftship. Our model grown from 1 to more than 500 thousands polygons in total. 

Due to irregular shape, we were forced to think more during texturing – we divided our model by adding ID to every part with different direction of normals. Finally we ended up with 2 multi/sub objects, 6 different textures and materials. We are especially proud of the final effect of our water struggle. We made it by trials and errors method, based only on knowledge from the course, without any further tutorials.

We added some bipeds to make it more convincing and to add a bit of life to the model. The boat of that type is stable enough for a man to stand in it and the characteristics of relation between width and length allow to build boats with big displacement, which are easy to move using only oars. Although such a way of moving seems to be more strongly motivated by rock carvings, we found some clues to risk a hypothesis of use mast and sails.The outrigger design allow to use relatively big sails in such small boats easily and safely. Two pictures presented below were taken from Copenhagen Museum catalog (read carefully the description :))

DelftShip is a CAD software, used for designing ships and making simple hydrostatic calculations. It is free, and we have decided to use it to check our boat’s proprieties. Using the Internet, it was possible to learn the basics in just one day, as well as to become a fully-educated specialist in hydrostatic ;-). We thought that there will be a possibility to import a DXF file from 3DS Max, but that turned out impossible, so we have designed a new model from scratch. Nevertheless we exported DXF file and, after cleaning in AutoCAD, we received a good blueprint.

Aka (the linking between the hull and outrigger) is not the same as in the 3DS Max model, but that does not affect the calculations. To keep things simple, we have made explanations directly on the report (we highly recommend you to open those in new tab - it will be bigger).

                The last thing we have done was a small analysis, which took us surprisingly long time. We created a plain white background with boat carving, and we aligned it, the model, camera and lights to create a little “shadow theatre”. We set a VRay sun, hence the yellowish color of the plain – it is a sunrise. But it looks like a glittering torch light, and that looks fine. As it turned out, the shadow looks very similar to the original carving – quod erat demonstrandum.

                Our primary goal was to make a model in 3DS Max, and we fulfilled that in 100%. Creating it was not so difficult, which cannot be said about the texturing part. As it can be seen on the stems, we gave up fighting with proper unwrap and the software created texture perpendicular to the natural one. The best fun was with placing bipeds (Pompeii team, regret that you did not use them ;).
                Our latter goal was to create a model in DelftShip and to try this software, as we have never used it before. The calculations coming from DelftShip has proved that the boat’s properties were quite good, especially the displacement value. Displacement is very interesting – even if this is a small boat, with 8 men on-board, it could still be used for trade. That only strengthens our hypothesis about the multi-hull ships in the Bronze Age.
                The result of our “torch” analysis seems to be very similar to the carvings. Perhaps we can imagine peoples, waiting for their relatives to come home from distant journeys, and sailors, waving to them (like on some carvings)?

Elgström, O. 1924. De bohuslänska hällristningarnas skeppbilder. Fornvännen 19.
Flemming, K. 1998. Ships on Bronzes: A study in Bronze Age Religion. Copenhagen.
Hallström, G. 1925. Utriggade kanoter i Sverige? Fornvännen 20.
Wright, E.V. The Ferriby boats: seacraft of the Bronze Age. London, New York.

Österholm, S. 1997. Forntidens båtar – ett försök med experimentell arkeologi. In  Burenhult, G (red.) Ajvide och den moderna arkeologin. Stockholm.

1 comment:

  1. The digitally generated model is quite interesting. Congratulations for the new ideas you have put in it! Your calculation sheets attached herewith are however not legible enough to find out what are the hull proportions (length, breadth and draught) at a given displacement of the reconstructed model.

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