🔍 Key Concepts

• bank suction and squat effects in narrow or shallow channels • how water flow changes around the hull when under way in restricted vs. deep water • visual signs of a vessel operating in shallow / restricted water (e.g., boiling, turbulence, sluggish handling)

💭 Think About

• Think about which condition causes the greatest disturbance to the water flow right under and behind the vessel, especially near the stern. • Ask yourself: in which of these situations does the ship tend to "squat" (sit lower in the water) and create strong suction and turbulence? • Consider which of the four choices would most directly change the under-keel clearance and water pressure beneath the vessel.

✅ Before You Answer

• Identify which option is most clearly related to under-keel clearance rather than current direction. • Eliminate any choices that mainly describe horizontal water movement (current direction) instead of vertical or pressure effects under the hull. • Recall that visible "boiling" water at the stern in a channel is often a sign of restricted / shallow water effects on the propeller wash and return flow.