An innovative method of documenting shipwrecks

Photogrammetric image of 200 year-old ship called Głazik. Image: National Maritime Museum in Gdańsk

Photogrammetric image of 200 year-old ship called Głazik. Image: National Maritime Museum in Gdańsk

Three shipwrecks lying in the Gulf of Gdańsk have been documented in 3D. This innovative method allows underwater archaeologists to work effectively even with minimal visibility.

The work, carried out by the National Maritime Museum (NMM) in Gdańsk, involves divers who take a large number of pictures of all the elements of the wrecks and their surroundings, at various angles. Then, with the help of specialised software, they are combined to create a photogrammetric, accurate, three-dimensional image of the vessel.

Non-invasive documentation

The method allows for non-invasive, documentation of ships in their place of discovery, and is an alternative to traditional underwater drawing, which is much more time-consuming and usually less accurate.

Spatial, 3D model of the wreck built on the basis of photograms gives you an opportunity to present its state of preservation and the spatial arrangement of its individual elements” – said Tomasz Bednarz, underwater archaeologist and lead 3D developer of the Undersea Research Department at NMM.

The method was first used in 2013 to document the 19th century wreck called “Porcelanowiec” (porcelain ship) because of the ceramic cargo, mainly porcelain and English earthenware from Staffordshire. Photogrammetry of this ship was the first attempt in Poland and one of the first in the world to prepare a 3D documentation of an underwater archaeological site.

Photogrammetric image of 200 year-old ship called Głazik. Image: National Maritime Museum in Gdańsk

Photogrammetric image of 200 year-old ship called Głazik. Image: National Maritime Museum in Gdańsk

Improved method

This year, the underwater archaeologists used the new method to document “Głazik” (little rock), which is more than 200 years old and carried a cargo of stone. Tomasz Bednarz explained that the documentation method had been improved after last year’s experience with “Porcelanowiec”.

The 3D model of the wreck was based on more than 6 000 photograms. It is much better quality than last year’s 3D model of Porcelanowiec“- said Tomasz Bednarz. – “We are pleased that we can create these models even at low water clarity, without loss of quality. Just few feet of visibility is enough to create such a model“.

Bednarz believes that the models are an excellent form of documenting sites and can be used to monitor the state of preservation of underwater objects and changes therein. An important aspect of the technology is the ability to create animations and virtual shots of underwater sites and their components, also for exhibition and educational purposes.

Since 2013, the method has been simultaneously used and developed by two research centres: the National Maritime Museum in Gdańsk and Texas A&M University (Gnalic Project – Croatia).

Photogrammetric model of the Gnalic Shipwreck:

Research carried out in Poland is possible thanks to funding from the Ministry of Culture and National Heritage, both for the last year’s “Porcelanowiec” project and the “Głazik” project implemented this year. Currently, the documentation work is underway for another vessel resting in the Gulf of Gdańsk.

Science and Scholarship in Poland