🔍 Key Concepts

• Bank suction and bank cushion when a vessel is close to one side of a narrow channel • How the stern and bow of a single-screw vessel are each affected by nearby shallow or sloping banks • Effect of propeller side (single-screw, usually right-handed) and pivot point when moving ahead in a channel

💭 Think About

• Picture your vessel moving ahead close along the right-hand bank of a narrow channel: which end (bow or stern) will feel the stronger suction toward the bank? • How does the pressure and water flow differ on the side of the hull close to the bank versus the open-water side? What does that do to the vessel’s heading? • For a single-screw vessel going ahead, where is the pivot point located, and how does that make the swing of the bow look compared with the movement of the stern?

✅ Before You Answer

• Be clear on the difference between bank cushion (pressure on the bow pushing it off the bank) and bank suction (low pressure drawing the stern toward the bank) • Verify in your mental picture which way the bow swings and which way the stern moves when the vessel is too close to one bank, with engines ahead • Check that your final choice matches a situation where the vessel tends to sheer away with the bow while the stern is sucked in toward the bank