Very possibly and yes the attempted Phoenician circumnavigation of Africa to a point at least south of the equator is pretty certain (they recorded the change in position of the sun). They may well have got up into Scandinavia, but possibly is not the same as probably and not at all the same as proven. Amber and other trade goods can move via very long trade routes over a period of extended time simply by trading from place to place in a chain. The presence of amber in Egypt or walrus ivory in Tyre or Carthage doesn't prove a direct trade link between points A and B - stuff also gets passed on as high status gifts etc

I am a bit resistant to explanations that put forward ideas of superior foreign technology. You know what I mean - the Phoenicians built Zimbabwe because native Africans couldn't build in stone. Same thing currently with the stone structures in NE America and all the tosh we have been brought up on regarding waves of incoming middle-eastern farmers, beaker folk and celts.

Why cannot we accept the simple solution - That is that the early Neolithic and Bronze Age Scandinavians, in their watery world, built excellent ships and boats. They then engraved them on rock surfaces as "comic strips" to illustrate stories, histories, myths and legends. Everything evolves and the skills of the Bronze Age shipwrights eventually flowered into the most beautiful ships ever built - the Viking longship.