User blog comment:Brandon Rhea/Changing the World, One Wiki at a Time/@comment-5247965-20130117172230/@comment-5247965-20130118183110

There actually were tri-cannons actually, but very rarely for they were expensive, if I recall correctly the Queen Anne's Revenge (Blackbaerd) had some. (Researchers are still not sure if they even called Blackbeard Blackbeard back then, but just Edward Teach (or Thatch))