Question 4189 Deck General

The correct answer is A) torque from the velocity and angle at which the surrounding water impinges upon the propeller blades. The sidewise force, or yaw, of the propeller is caused by the asymmetry in the water flow over the propeller blades. As the propeller rotates, the blades on one side are moving against the direction of the vessel's travel, creating higher water velocities and lower pressures on that side. This asymmetric pressure distribution generates a net lateral force that causes the stern to turn in the direction of the lower pressure side. The other options are incorrect because: B) lower pressure on one side is the effect, not the cause; C) the rudder's back current is a separate phenomenon; and D) greater pressure on one side is the opposite of the actual mechanism.