Recently I ran into an old book about Viking ships dug up from burial mounds.  It was a small book from the Viking Ship Museum. I don’t know how I got it.  It may have come from one of my grandparents or from a book sale. Anyway I scanned a few pages.

These were remarkable finds back in the early 20th Century and greatly increased the knowledge of how the dragon ships went together.

https://en.wikipedia.org/wiki/Viking_Ship_Museum_(Oslo)

http://www.khm.uio.no/english/visit-us/viking-ship-museum/

https://en.wikipedia.org/wiki/Oseberg_Ship

https://en.wikipedia.org/wiki/Gokstad_ship

Of course, since then, replica ships have been built using the old techniques and sailed.  Sailing a vessel is the only way to understand how it functions and how well it does.  You can’t sail an ancient artifact and having a real ship to replicate makes the whole thing possible.  Here’s a stack of videos to watch.