A Swedish "copper wreck"

YouTube link. 

This to me is absolutely fascinating.  First, the YouTube notes:

Documentation made 2009-09-18 of the Copper wreck by Jan Öijeberg, Malmö Museer and divers from Malmö Sportdykarklubb MSDK. The wreck is situated at a depth of 42 m, south of Trelleborg southern Sweden. It is very damaged and only some wooden ship details can be seen. The cargo of copper ingots (discs up to 1 m in diameter) and long narrow iron billets is impressive. The ship is under supervision of the Swedish Coastguard and is protected by law, since it is more than 100 years old. Wood from the wreck is for the moment being dated by dendrochronological method by Hans Lindersson, Lund University.

Divers: Jan Öijeberg, Arne Sjöström, Joakim Sjöberg and Magnus Persson (camera).

I couldn't track down the dendrochronology results, but a link at the source to a "Gdansk Copper Wreck" indicates that that one was dated to the 14th century.

The ingots depicted on the seafloor in this video as discoid in shape, and thus a bit different from the classic oxhides, but the latter were shaped with protrusions to allow strapping onto pack animals (or humans), while these ingots were apparently intended for sea transport.

I have a longstanding (and totally amateur) interest in prehistoric copper culture.  There are some who suggest that "Old World" European sources of copper would not have been sufficient to supply the material used for art and weaponry in the Bronze Age, and that ancient mariners might have found their way to North America to mine the copper deposits of the Upper Peninsula of Michigan.  That's purely speculative, as far as I know.

p.s. - While researching this, I found a link that might be useful to those with an interest in maritime archaeology: Wrecks and shipfinds of Western and inland Europe.