Walkingfeather, I've authored or coauthored three history books, with a fourth coming out. You ask for my credentials as an expert on Scandinavian history. Might I suggest you instead start wondering about the credentials in Scandinavian history, or any other kind of history, of "geologist" Scott Wolter and "engineer" Dick Nielson?
I am a student of all these claims, my favorite (being a Scots-American) that of "Prince Henry of Orkney" (Henry Sinclair, Earl of Caithness in Scotland), who was supposed to have voyaged to America circa 1400 (with an Italian-Polish crew!) and carved the Sinclair coat of arms on a rock in New England. The latest book I've seen was about an asserted Chinese voyage to America. These claims are all amusing. I suggest anyone interested read Naval historian and Columbus expert Samuel Eliot Morrison and his debunking of them.