Spade rudder
A rudder supported only by its stock, with no skeg or keel ahead of it.
A spade rudder hangs from its own shaft with nothing in front of it. Balanced spade rudders give light, responsive steering and are standard on modern designs and on fin-keel boats from the Catalina 27 onward. The trade-off is vulnerability: the stock carries the whole load, so a grounding or a collision with debris can bend it or damage the bearings, and the blade is easy to foul with lines or weed. Rudder-stock play and water intrusion into the blade are routine survey checks.