German Maritime Museum, Germany August 2017
On 8 October 1962 was in Bremen the wreck of a cog dating from 1380 discovered and between 1962-1965 salvaged. The one-masted square-rigged carvel or clinker-built cog had a tonnage of 90 tons, displacement of 55 tons and as dimensions 23,27 x 7,62 x 4 (hold) metres although the figures are estimated using exhibition notes. There were later three almost dental replicas constructed named Ubena von Bremen, Hansekogge and Roland von Bremen.
Cogs or cog-built vessels are known of existing since the 10th century although becoming popular since the 12th century and built of oak. In first instance it were open ships which also could be rowed but since the 13th century the vessels were decked. In 948 was for the first time a cog mentioned in the Dutch town Muiden probably using the Norwegian trade vessel of the Knarr type developing into a sea going ship even with fore and aft castles for defence or war purposes. Around the 14th century reached the design the limits of further improving and increasing and needed to be replaced by a new designed ship.
