Mary B. "Ma" Greene was one of the co-founders of the Delta Queen Steamboat Company, and a big supporter of the temperance movement. She was one of the first licensed riverboat pilots, and she forbade the sale of liquor aboard the steamboat.
After she died in 1949, the crew installed a saloon aboard the Delta Queen. Just after the first drink was sold, a barge crashed into the riverboat and smashed the saloon's bar. The barge was named the "Mary B." after Ma Greene. She apparently wasn't too happy about the new addition and decided to make her feelings crystal clear.