Abandon ship: does this symbol of slavery shame Manchester and its football clubs?

A three-masted vessel adorns the city's buildings and both teams' crests. But is it an emblem of a crime against humanity? I got my first Manchester City football badge when I was a little boy. It was gorgeous - a golden ship in full sail on the top half of the crest, the red rose of Lancashire on the bottom half, all framed in sky blue. The ship made a huge impression. It reminded me of the Blue Peter badge and pirates. Pirates were exciting. They did as they wanted, plundered what they fancied...