Exam Question

(a) Describe the fundamental principle of a propeller. (6)

(b) A propeller 6m in diameter has a pitch ratio of 0.9, BAR 0.48, and, when turning at 110 rev/min, has a real slip of 25% and wake fraction 0.30. If the propeller delivers a thrust of 300 kN and the propeller efficiency is 0.65, calculate: (10)

(a) Blade area

(b) Ship speed

(c) Thrust power

(d) Shaft power

(e) Torque