🔍 Key Concepts

• Transverse thrust (sideways force) created when using only one stern-working propeller • Effect of twin-screw backing with rudders amidships versus angled rudders • Which way the vessel’s stern will tend to swing when only the port engine is backing and the starboard is stopped

💭 Think About

• When both engines are backing with rudders amidships, what keeps you on a straight course? What changes when one engine stops? • With only the port engine backing, which direction will the stern tend to move, and how can rudder angle counter that swing? • Is increasing speed alone enough to correct sideways swing, or do you need directional control from the rudder?

✅ Before You Answer

• Determine which propeller (port or starboard) is still providing thrust and in which direction it turns when backing on your type of vessel • Visualize the natural swing of the stern with just the port engine backing and no rudder input • Ask yourself which rudder angle would create water flow over the rudder that opposes the unwanted swing, helping you continue backing on your original course