Re: The x bow and its whereabouts.

[iosif gross]

I have to admit that I was not aware of the Kogge boat design so I made a google search.
What I find out is that the Kogge design (starts at 950AD) used by the Baltic HANSE tread association from around 1200AD was later than the Viking boats (starts at around 600AD), much bigger and much less seaworthy.
The Vikings were the first using a deep keel filled with stones for stability. 848AD they reach Island, two years later Greenland and two years Canada (researchers suggest).
All the mono-hull yachts are based on the Viking design.

Have a nice day 🙂
Iosif