A whole wooden ship was not found.
Debated. Nails and bits of wood are read as a ship from before the Viking Age.
The mound is Herlaugshaugen, on the island of Leka, in Norway. The burial is dated to around AD 700. That is nearly a century before the usual start of the Viking Age. The mound is over 60 metres across and about 12.5 metres high. The dig found 29 iron rivets, and pieces of wood that may be elm or oak. From the nails, the ship is thought to be more than 20 metres long.
The old story of King Herlaug does not match this date. The page cannot name who was buried.
https://www.ancient-origins.net/news-history-archaeology/herlaugshaugen-ship-burial-00102707