This trajectory was reconstructed in a simulation analysis fully utilizing the following:

　

 Due to grounding on the rocky shore, the port side of the ship was damaged to a great extent. The portside propeller lost one of its blades as shown in Figure 8.

　

 This cruise ship line owns a range of cruise ship design including that with twin flap-rudders located behind twin-propellers.

　

 Accordingly, simulation analysis was made assuming that this 700 ft cruise ship had twin flap-rudders behind twin propellers. Ship trajectory obtained with this assumption is included in Figure 9. It is seen in the figure that the ship could have avoided grounding, clearly indicating the effectiveness of twin flap-rudders behind twin propeller.

　

 Pod propellers have been drawing attentions to large cruise ship design. For example, the 345-m long QUEEN MARY 2, scheduled for operation in April 2004, will have four pod propellers powered by 157,000 HP. Two pod propellers are fixed, whereas the other two are rotatable. This power can generate large control forces at the stern end, thus providing superior turning performance like that of flap-rudders.

　

 On the basis of the flap-rudder analysis mentioned above, it can be stated that if twin rotatable pod-propellers were on the TITANIC, the collision with the iceberg could have been avoided.

　

 Case studies were made in this paper for two cases of similar critical-maneuver, i.e., the collision of the TITANIC with iceberg and the grounding of a 700 ft long cruise ship. From these analyses we can learn the following important lessons:

　

 Flap-rudders located behind propellers or rotative pod-propellers are very effective in critical maneuvers such as collision-avoidance. Recent cruise ship design actively employs these types of rudder and propeller arrangements. Examples of simulation analysis were shown in this paper for cases of iceberg-collision-avoidance-maneuver on the TITANIC in 1912 and grounding-avoidance-maneuver of a cruise ship in 1994. When flap-rudders-behind-propellers were utilized in simulation runs, these collisions and groundings we re successfully avoided.

　

[1] Eda, H. et al, Principles of Naval Architecture, Vol. III, Controllability, Soc. of Nav. Arc. M. Eng., 1989

[2] Eda, H. et al, Ship Maneuvering Safety Studies, Trans. SNAME, Vol.87, 1979

[3] Ballard, R.D., The Discovery of the TITANIC, A Warner/Madison Press, 1987

[4] Garzke, W.H. et al, The TITANIC and LUSITANIA, Marine Technology, Oct. 1996

[5] Trans. SNAME, Vol.31, 1923

(6] SHIPBUILDER Vol.1, 19

　

 Haruzo Eda has been teaching at the US Merchant Marine Academy, Kings Point, New York since 1989. During 1961 to 1989, he was a research scientist and a professor at Stevens Institute of Technology in New Jersey. In 1952 to 1961, he was a research engine er at Ship Research Institute (presently National Maritime Research Institute), in Tokyo. For these years, he has been engaged in the area of ship-motions. Four books and more than one hundred of papers and reports have been published by him in this field, including:"Controllability" , PRINCIPLES OF NAVAL ARCHITECTURE Vol. III, SNAME, 1989. He holds Bachelor and Doctoral Degrees from Osaka University, and a Master Degree from Stevens Institute of Technology in the area of Engineering.

　

 Masayoshi Numano gained a Master of Engineering degree at the graduate school of Kyoto University majored in aeronautical engineering. He has been engaged in researches on energy saving, prevention of pollution, maritime safety, automation, human interface and related simulation technology at National Maritime Research Institute since 1978.