The cog was a common cargo vessel in medieval Europe, especially in the Baltic and North Sea regions between the 10th and 15th centuries. It had a flat-bottomed, clinker-built design with a single mast and square sail. Cogs were found in shipwrecks across the Baltic and North Sea, and dendrochronological analysis was used to date the wooden ships. Several cogs have been reconstructed based on the best preserved wreck, the Bremen Cog from 1380, including the Ubena von Bremen and Roland von Bremen.

2. Mediewal cog
A cog (German- kogge) it was most popular cargo vessel on area of Baltic Sea and North Sea
from 10th
century.
These vessels were widely used for seagoing trade in medieval Europe, especially by the Hanseatic League.
She was flat bottom, clinker- built ships with stern-mounted rudder and single mast with single square sail
equipped with 2-3 bonnets.
The bonnets it was separate parts of sails with possibility of remove out in case when was required reduction
of sail area ( during strong wind).
In several places of Baltic and North Sea was found shipwreck of such ships.
Thanks of dendrochronological analysis of the oak timber from which the cog was built was possible to date
ships.
Danish findings:
Kollerup ca. 1150; Kolding ca. 1190; Skagen ca. 1200; Vejby ca. 1372; Lille Kregme ca. 1358; Skanør ca. 1390.
German findings:
Bremer Kogge ca.1380 ;
Dutch findings:
Kampen ca.1335.
The best preserved and most complete is Bremer Kogge displayed at the German Shipping Museum in
Bremerhaven.
She was basis for the reconstruction, three ships were built: Roland von Bremen, Ubena von Bremen
and Hanse-Kogge.

3. Ship
( Home port)
Length
over all
Length
of hull
Length
of keel
Breadth
Moulded
depth
Draught
Displace-
ment
Mast
Height/dia.
Sail
area
m m m m m m ton m/m m2
Bremer Kogge 23,27 - - 7,62 - - - - -
Ubena von Bremen
( Bremen, Germany)
23,23 22,66 15,60 6,46 3,14
1,25
empty
2,25
loaded
-
23,0 form KWL
21,0 from deck
200
Roland von Bremen
( Bremen, Germany)
- 23,98 - 7,18 - 1,80 120 - 180
Hanse-Kogge
( Kiel, Germany)
23,27 - - 7,62 - 1,90 - - 200
Tvekamp av Elbogen
(Malmo, Sweden)
28,0 21,00 18,4 8,00 3,40 2,40 100 - 225
Wissemara
(Wissmar, Germany)
31,46 25,00 - 8,50 3,65 2,00 - 32,0 275
Arka
( Lithuania)
17,50 - - 4,70 - 0,90 - - -
Kamper Hanze Kogge
(Kampen , Holland)
- 19,60 - 17,30 - 1,90 - - 140
Specifications reconstructed vessels

13. © Tadeusz Probulski
June 2013