Parameter Study of Position Keeping for Semi-submersible Offshore Structure by Tugs

Tug에 의한 반잠수식 해양 구조물 위치 유지를 위한 제반 파라메터 검토

  • Received : 2014.04.02
  • Accepted : 2014.08.19
  • Published : 2014.08.30


This paper investigates the line dynamic forces connecting tugs and a floater, where the planar motion of the floater is due to the weather criteria during the position keeping of the offshore structure by tugs. The analysis situation consists of the position keeping states for the seabed mooring line connection work of the offshore structure at the offshore site. Specifically, the decision about the tug power capacity for the position keeping is essential and depends on the weather criteria, line characteristics, length of line, etc. The planar motion of the structure is constrained by the interference of the installation vessel's operational range, behavior of the underwater fairlead, and other surrounding structures. In this paper, the tug line forces and planar motion of an offshore structure are summarized dependent on the tug line length and line material characteristics in the states fora given floater draft and weather criteria. The tug line dynamic forces and planar motion evaluated here will be used to determine the proper tug power and clearance of an offshore structure.


Semi-submersible Offshore Structure;Position Keeping;Environmental Loads;Tug Line Dynamic Force;Planar Motion


  1. Hancox, M., 2011. Towing, Positioning and Hook-up for Offhore Production - Oilfield Seamanship Series Volume 8. Clarkson Research Services Ltd.
  2. Lee, J.H., 2011. Analytical Research of Topside Installation in Mating Phase with Crane Vessel. Journal of Ocean Engineering and Technology, 25(4), 1-6.
  3. Lee, J.H., Jung, H.S., Kim, B.W., 2013. Evaluation of Mating Dynamic Forces of Semi-submersible Offshore Structure Topside Module. Journal of Ocean Engineering and Technology, 27(1), 9-15.
  4. Nachlinger, R. 2013. Reference Manual for MOSES. Ultramarine, Inc.
  5. Chakrabarti, S.K., 2005. Handbook Of Offshore Engineering - Volumn 2. Elsevier.
  6. Gerwick, B.C., 2007. Construction of Marine and Offshore Structures. Third Edition, CRC Press.
  7. Hancox, M., 1997. Towng - Oilfield Seamanship Series Volume 4. Oilfield Publications.