That requires pirates>ninja. Which simply isn't true. Ninja are awesome, deadly, have had years of training in the use of many weapons and tools, as well as skill in several unique forms of communication; secret codes and the like. Pirates are... drunk idiots that know nothing about anything.
I should explain now why pirates were always drunk. See, the only beverage that didn't spoil on ships was alchoholic stuff, which was, naturally, already spoiled.
Ninja were probably never drunk, as their jobs required constant mental focus.