Colin Sharman is a priest, and he uses his ship as a chruch. He has visitors and seromonies there.
He just did what he thought was right, but that doesn't mean it was always right. As his left arm suggests, he wasn't an ordinary priest. He was able to posess and summon sea creatures. He used the powers to raid bigger ships and he caused a lot of disasters during his lifetime.

Personailty wise he was generally a nice man, despite his violent behavior.