Question 4197 Deck General

The correct answer is C) sidewise force. When a single-screw vessel is going ahead, the rotation of the propeller creates a sidewise force that pushes the stern of the vessel to the right, causing the vessel to turn more rapidly to port. This is due to the asymmetric flow of water around the propeller, which generates an unbalanced force that pushes the stern of the vessel in the opposite direction of the propeller's rotation. The other answer choices are incorrect because they do not directly explain the turning tendency of a single-screw vessel going ahead. Propeller discharge current (A) and suction current (D) are related to the flow of water around the propeller, but do not directly cause the turning tendency. Thrust (B) is the forward force generated by the propeller, but does not explain the unbalanced lateral force that leads to the turning behavior.