The Bremen-Cog: reconstructed one more time

Within the three-year project “Between the North Sea to the Norwegian Sea: interdisciplinary research on the Hanse” (2015-2018), established by the Leibniz Association at the German Maritime Museum, questions were raised on the seaworthiness of ships of the Bremen-type1. The main object of the resulting research was the late medieval Bremen-Cog, from 1378-1379, which was found in 1962 in the River Weser close to Bremen and is today on display at the museum in Bremerhaven.The project did not begin with the intention of reconstructing an already reconstructed ship find, but rather to examine the overall hydrodynamic and seakeeping abilities of the ship, in order to see whether ships of this building method were the oceangoing trading vessels of their era, and could sail the North Atlantic all the way to Iceland.In order to evaluate the complex concepts of seakeeping and oceangoing, a reliable hull form as well as accurate construction details are required. Establishing the vessel’s overall hydrostatic characteristics, static and dynamic stability, and overall sailing abilities, requires detailed calculations using the centres of buoyancy, flotation and gravity.