The increasing pressure drop under a hull and the corresponding increase in velocity is described by which principle?

• A. Bernoulli's Principle
• B. Pascal's Law
• C. Archimedes' Principle
• D. Venturi Effect

Answer: (A)

When a fluid speeds up, its static pressure tends to drop. Under a hull, the flow is guided and often constricted, so water accelerates as it moves past the hull surfaces. Bernoulli's principle describes this balance along a streamline in steady, incompressible flow: the sum of pressure energy and kinetic energy per unit volume stays roughly constant, so an increase in velocity comes with a decrease in pressure. That’s why you see a pressure drop as velocity rises beneath the hull. The Venturi effect is a specific case of Bernoulli’s principle in a constricted tube, but the general relationship here is captured by Bernoulli’s principle. Pascal's law and Archimedes’ principle describe other fluid behaviors that don’t explain this velocity–pressure trade-off.