The aim of this paper is to investigate cavitation and pressure pulse on the stern due to the operating propellers of a container ship. Three optimally designed propellers are tested in this paper. Two propellers are conventional type. The third one is unconventional, and formed by a tip-end plate. These three propellers are design optimally at the same design point, and compared according to the experimental results. The tests are carried out in the large cavitation tunnel of National Taiwan Ocean University (NTOU), and evidence is offered regarding the remarkable improvements in the cavitation extension and the exciting force on the stern achieved by the unconventional propeller.