>>1912201Two words, flame thrower.
>>1912236Your question interested me so I did some light research on the topic. At the end, it all kind of boils down to every other country in Europe were copying the vikings ship building techniques after a few dozen raids too many. Which all in all made raids more difficult to achieve/worth it. It came to an end during sometime around the 13th century where ships wen't from light and maneuverable long ships, to stronger and heavier "cogs". "Cogs" being the new type of ship the Scandinavians were using afterwards. Do note that some isolated regions like the Hebrides and the northern coast of Ireland still used long ships well into the 17th century. If you needed anymore proof of how stubborn Celts can be lol. There's a little bit more in the article I read down below if you want to give it a try.
https://www.danishnet.com/vikings/when-did-viking-ships-disappear-use/ 
