Every sailboat I've owned, or know of, that was not a tiller boat had one. There are also some pretty cool stories about off shore sailors losing their rudder and rigging a bridle of the stern with a small drogue on it led to two winches in the cockpit. By changing the center of the bridle laterally behind the boat they had steerage underway and went thousands of miles.
When I got my last sailboat, a 42' Catalina, there were numerous stories on the forums of the stainless rudder posts corroding right where they went into the FRP rudder. Stainless needs air to be stainless..... There were a few cases where the rudder had broken off. Since I was planning, and did, some well off shore sailing I put on a new rudder. The thing was massive and had to drop down several feet for the post to clear the boat. Rather than spend money hanging in a travel lift waaay above the ground being rushed I had it blocked and dug a rather large hole to drop it in. Fun and games.
Of course with two props and a bow thruster this should never be an issue.
