(a) Sketch and describe a positive displacement pump where the fluid is displaced by the movement of piston. Why are such pump chosen for bilge pumping duties? (6)

(b) Explain the working principle of a double acting reciprocating pump. (4)

(c) State,

(i) why these pumps should not be started with the discharge valve closed and,

(ii) the purpose of accumulators fitted at the discharge in these pumps. (6)