🔍 Key Concepts

• Hydrodynamic interaction between a vessel and a nearby bank in a narrow channel • Difference between bank cushion (pressure at the bow) and bank suction (effect on the stern) • How water flow changes around the bow vs stern when close to a river bank or canal side

💭 Think About

• Picture a single-screw vessel moving ahead close to one bank. What happens to the water being pushed aside at the bow when there is a solid bank right next to it? • Think separately about the bow and the stern: which end feels a higher-pressure ‘cushion’ from water piling up against the bank, and which end is more affected by lower pressure/suction? • When a vessel gets too close to a bank, which end tends to be pushed off the bank, and which end tends to swing in toward the bank, creating a sheer?

✅ Before You Answer

• Make sure you distinguish clearly between cushion (higher pressure pushing away) and suction (lower pressure drawing toward). • Focus on the bow’s behavior near the bank, not just the motion of the whole vessel. • Eliminate any answer that confuses the effect of bank cushion with the separate effect commonly called bank suction on the stern.