Computer and experimental simulations on the fin effect on ship resistance

Abstract

Container ships move at a higher speed compared to other merchant ship types. A fin attached to the ship hull proves to be more efficient in controlling the moving ship. However, such attachments on the naked hull attract additional problems such as slamming, requirement of continuous maintenance, etc. The main objective of this study is to find the influence of fin action at various angles of attack with the incoming flow and recommend the best possible fin position for the least resistance. While experiments were performed for different angles of attacks of the fin with respect to the flow, a reduction in resistance was observed for an Fn range of 0.13–0.26. The fin was fitted at the lowest possible location of the hull surface at the bow part of the ship. Experimental investigation was done using model tests in a towing tank to determine the resistance of a scaled down model and it was compared with computer simulation. The interaction of a bow fin fitted to a container ship with its own generated and encountering waves are discussed in this paper. It was observed that at certain angles of attack of the fins favourable resistance characteristics were observed. Modifications from the expected resistance due to fin effect are paid attention in this study. Various resistance values for different angles of attack of the fin were compared and an angle of attack of 5° is found to be the best.

Keywords:

• ship resistance
• fin system
• pitch reduction
• computer simulation
• towing tank

Acknowledgements

The first two authors would like to thank the Central Workshop of IIT Madras for fabricating and machining the mechanical hardware for fin housing on the FRP hull. They are also thankful to the scientists and technicians of the high-speed towing tank at NSTL, Visakhapatnam, India for conducting the tests. The authors record their gratitude to Professor S.K. Bhattacharyya for suggestions at critical stages of the study.

Additional information

Funding

The second and third authors are thankful for the support of the Ministry of Science, ICT and Future Planning (MSIP) for the part of the paper completed in PNU, Korea.