I guess this is a kind of forerunner of the boats in Bruno's post - great mood, Bruno
The large Viking ship (quote Wikipedia:) "Havhingsten fra Glendalough ("The Sea Stallion from Glendalough" or just "Sea Stallion")" from the Viking Ship Museum in Roskilde.
Yes, impressive technology and seamanship. As far as we know, these boats were the fastest of their time.
They posed a real threat to all their neighbours, as they could cover the distance to the nearest coastal settlement almost as quickly as the alarm chains.
Thus reducing the time window for defensive measures to almost zero.