"Is the RBC a real River Boat Captain or is that just a costume?"
Mavis18, thanks for your question. I met Dennis Dickerson when he was competing in Berlin, and let me tell you something: he's the real deal. And by real deal I mean I think he mentioned something about it. Anyway, he's got the hat.
UPDATE: Heard back from the RBC regarding his chops. He says:
"I have a 100 ton inland masters license from the US Merchant Marines, and am also a Retired Coast Guard Reserve Officer as well."
Then he signed his email like this:
"Rollin on the River,
Click here to see the RBC in action. He invites you to take a trip with him on the Potomac this summer.