Modeling of flat otter boards motion in three dimensional space

평판형 전개판의 3차원 운동 모델링

  • Choe, Moo-Youl (Department of Fisheries Physics, Graduate school, Pukyong National University) ;
  • Lee, Chun-Woo (Division of Marine Production System Management, Pukyong National University) ;
  • Lee, Gun-Ho (Department of Fisheries Physics, Graduate school, Pukyong National University)
  • 최무열 (부경대학교 수산물리학과) ;
  • 이춘우 (부경대학교 해양생산시스템관리학부) ;
  • 이건호 (부경대학교 수산물리학과)
  • Published : 2007.02.28


Otter boards in the trawl are the one of essential equipments for the net mouth to be spread to the horizontal direction. Its performance should be considered in the light of the spreading force to the drag and the stability of towing in the water. Up to the present, studies of the otter boards have focused mainly on the drag and lift force, but not on the stability of otter boards movement in 3 dimensional space. In this study, the otter board is regarded as a rigid body, which has six degrees of freedom motion in three dimensional coordinate system. The forces acting on the otter boards are the underwater weight, the resistance of drag and spread forces and the tension on the warps and otter pendants. The equations of forces were derived and substituted into the governing equations of 6 degrees of freedom motion, then the second order of differential equations to the otter boards were established. For the stable numerical integration of this system, Backward Euler one of implicit methods was used. From the results of the numerical calculation, graphic simulation was carried out. The simulations were conducted for 3 types of otter boards having same area with different aspect ratio(${\lambda}=0.5,\;1.0,\;1.5$). The tested gear was mid-water trawl and the towing speed was 4k't. The length of warp was 350m and all conditions were same to each otter board. The results of this study are like this; First, the otter boards of ${\lambda}=1.0$ showed the longest spread distance, and the ${\lambda}=0.5$ showed the shorted spread distance. Second, the otter boards of ${\lambda}=1.0$ and 1.5 showed the upright at the towing speed of 4k't, but the one of ${\lambda}=0.5$ heeled outside. Third, the yawing angles of three otter boards were similar after 100 seconds with the small oscillation. Fourth, it was revealed that the net height and width are affected by the characteristics of otter boards such as the lift coefficient.


  1. Crewe, P.R., 1964. Some of the general engineering principles of trawl gear design. Modem fishing gear of the world II, Fishing New Ltd, pp. 165 - 180
  2. Deng, Z., M.C. Richmond, C.S. Simmons and T.J. Carlson, 2004. Six-degree-of-freedom sensor fish design: governing equations and motion modeling. Pacific Northwest National Laboratory, Richland, Washington, pp. 40
  3. Jiaming, W. and Allen T.C., 2000. A hydrodynamic model of a two - part underwater towed system. Ocean Engineering 27, 455-472
  4. Kim, B.S., Y.D. Kim, H.C. Bang, M.J. Tak and S.K. Hong, 2004. Flight dynamics and control. Kyugn-Moon press, Korea, pp. 319
  5. Ko, K.S., B.G. Kwon and K.D. Ro, 1990. Computational fluid analysis for the otter boards - 1. Pattern of fluid flow besides otter board - . Bull. Korean Fish. Tech. Soc., 26(4), 333 - 340
  6. Ko, K.S., B.G. Kwon and K.D. Ro, 1991. Computational fluid analysis for the otter boards - 2. Efficiency analysis for the otter boards of various types -. Bull. Korean Fish. Tech. Soc., 27(3), 163 - 169
  7. Kwon, B.G. 1993. A study on the hydrodynamic characteristics of otter board. Ph.D. thesis, National Fisheries university of Pusan, Korea. pp. 105
  8. Lee, B.G., 1989. Fishing methods of modern Trawl. TaeHwa Press, pp. 116 - 145
  9. Lee, C.W., S. Igarashi, T. Mikami, and N. Yamashita, 1990. A mechanical analysis of hook separation. Nippon Suisan Gakkaishi, 56(11), 1797-1802
  10. Lee, C.W., J.H. Lee, B.J. Cha, H.Y. Kim and J.H. Lee, 2005. Physical modeling for underwater flexible systems dynamic simulation. Ocean Engineering 32, 331-347
  11. Morton, G., and G.R. Hagen, 1967. Standard equations of motion for submarine simulation. Technical report DTMB 2510, David Talylor Research Center, pp. 27
  12. Park, C.D., 1994. A study on the fluid characteristics of otter boards. Ph.D. thesis, Graduate school of Tokyo university of marine science and technology, Japan. pp.154
  13. Park, K.H., J.H. Lee, B.S. Hyun and J.H. Bae, 2001. The study on the hydrodynamic characteristics of the single slot cambered otter board. Bull. Korean Soc. Fish. Tech., 37(1), 1-8
  14. Park, K.H., J.H. Lee, B.S. Hyun, Y.H. Ro and J.H. Bae, 2002. Study on the measurements of flow field around cambered otter board using particle image velocimetry. Bull. Korean Soc. Fish. Tech., 38(1), 43 - 57
  15. Timothy, P., 2001. Verification of a six - degree of freedom simulation model for the REMUS autonomous underwater vehicle. Master's thesis, Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, pp. 128