Oskarshamn Cog, after c. 1270
Country: Sweden
Place: Bossholmen, near Oskarshamn, Småland
Coordinates (approximate): 57.2500, 16.4600 (regional locality only)
Type: Cog (Bremen type), cargo vessel
Identified: Archaeological type; historical name unknown
Dated: Timber felled around AD 1270 (dendrochronology)
Beam: Surviving bottom width up to 3.55 m
Keel Length: 12.5 m (preserved)
Length Overall: Unknown.
Number of Masts: Unknown.
History of the wreck
Local residents found the wreck in 1964 and reported it to the Swedish National Maritime Museum. Surveys continued in the 1960s and 1970s, followed by dendrochronological sampling in 1984 and underwater excavation in 1985-1988.
A purpose-built cradle allowed the hull to be raised in one piece in October 1987 and placed in a tank for waterlogged storage. It was recorded out of the water in 1988-1990 (Adams 1990).
Description of the site
The find is associated with Bossholmen, near Oskarshamn; the coordinates are intentionally broad. Bilge sediments were sampled for microscopic cargo residues, although no main cargo survived.
Cargo
No main cargo survived; bilge sediments were sampled for residues.
Ballast
Not reported.
Anchors
Not reported.
Guns
Not applicable.
Iron concretions
Not reported.
Hull Remains
The flush-laid bottom and moss caulking place the vessel in the Bremen-type tradition. Unlike many cogs, built on a broad keel plank, the Oskarshamn wreck had a true keel, which makes it valuable for studying variation within cog construction.
Keel, keelson and mast step
A true keel, preserved for 12.5 m.
Frames
Not reported.
Planking
Flush-laid bottom planking.
Ceiling, thick stuff, and wales
Not reported.
Caulking
Moss.
Size and scantlings
Preserved keel 12.5 m; surviving bottom width up to 3.55 m.
Wood
Timber from south-western Scandinavia.
Bibliography
Adams, J. 1990. “The Oskarshamn cog. Part II.” [Full reference to be completed.]
MaSS. “Oskarshamn.” [Full reference to be completed.]