Exam Question

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

(b) A propeller 6m 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 propeller efficiency is 0.65, calculate: (10)

(i) Blade area

(ii) Ship speed

(iii) Thrust power

(iv) Shaft power

(v) Torque.