There is a Dampier newsletter called the BUCCANEER, started by Jim Dampier of TN. Many of who are Dampier descendants believe that he is our common ancestor. In his book, VOYAGES AND DISCOVERIES, he says he spent several months on the VA coast. He also writes that he will not bore his readers with "the troubles that befell me in Virginia." We don't know if he means an irate father, or a wife(I know he had a wife in England)who died, or just what his troubles were. The first Dampier we find in the US is Daniel who was old enough in 1720 to witness a legal document (21).
Jim Dampier has a record of an old bible where it is written by his great uncle that the uncle's great grandfather was "a seafaring man who went to sea and never returned."
By assuming that William the Explorer is of my line, I have connected many Dampiers in the US with his family line. I will be glad to share any or all of the Dampier information that I have with you. I probably need your mailing address, because the information I have is quite lengthly.