🔍 Key Concepts

• Hydrodynamic interaction between a ship’s hull and a nearby bank in a narrow channel • Difference between bank cushion (at the bow) and bank suction (often at the stern) • How water flow and pressure change on the bank side versus the open-water side of the vessel

💭 Think About

• Think about what happens to water flow and pressure between the vessel’s hull and a nearby bank when the space narrows. Does pressure there increase or decrease? • Consider where the water is being pushed and where it must ‘speed up’ to get around the hull. How does higher pressure act on the hull versus lower pressure? • Ask yourself: which part of the vessel (bow, stern, or whole vessel) is most directly affected by the pressure ‘cushion’ forming between the hull and the bank?

✅ Before You Answer

• Distinguish clearly between bank cushion (pressure on the bow near the bank) and bank suction (tendency of the stern to be drawn toward the bank) • Visualize the vessel going ahead near the bank: which end first encounters the ‘cushion’ of higher pressure water? • Verify whether the effect is localized (bow or stern) or acts equally on the entire vessel’s length before picking your option.