Topic summary
Rudder post
Extracted from the Wikipedia article Rudder.
Boat rudders details
Rudder post and mast placement defines the difference between a ketch and a yawl, as these two-masted vessels are similar. Yawls are defined as having the mizzen mast abaft (i.e. "aft of") the rudder post; ketches are defined as having the mizzen mast forward of the rudder post.