Why rudders are optimized for working speed

Which matters most for a fast ship: hull size, hull shape, or rudder placement?

Hull proportions and form drive speed, while rudder design provides control and is usually optimized around the ship's normal operating speed.

Length-to-beam ratio and hull form shape a ship's speed and ability to move through the water, while the rudder redirects water flow to maneuver. Because a rudder becomes more effective as flow increases, designers tend to optimize it around the speeds a ship uses most often. Larger rudders can provide more authority, but they also demand more powerful steering machinery to overcome the greater hydrodynamic force.