Question 4190 Deck General

The correct answer is D) Balanced spade. At high angles of attack (10 degrees or more), a balanced spade rudder may lose some of its effectiveness due to flow separation and stall on the rudder surface. This is because the balanced spade design has a larger surface area exposed to the flow, making it more susceptible to stall compared to other rudder types like the flat plate or unbalanced rudder. The other options are incorrect because: A) Flat plate rudders are generally less prone to stall at high angles, B) Unbalanced rudders have a smaller exposed surface area, and C) Contra-guide rudders have a different design that maintains effectiveness at higher angles.