The mooring and maneuvering of floating offshore structures involves large forces, on which there is little published information. The aim of this paper is to provide model test data on how the drag of a floating body is affected by its basic geometry when subjected to a combination of uniform flow and regular waves of a given height and period. The results enable the following conclusions to be drawn: The total drag force is simply the sum of the still water drag and the wave drift force. The still water drag coefficients are quite sensitive to geometric shape and are presented in Table 2. The blockage effect is very important. In full scale this is normally determined by the draft to water depth ratio only, but in model tests the beam to tank width is also important. A simple empirical method is presented to correct for any blockage effect. The wave drift force is usually greatest for a given wave height when the wave length is of the order of one to two diameters of the body. Although most previous literature assumes that the drift force is proportional to wave height squared this was not found to be generally true.

  • Corporate Authors:

    North East Coast Inst of Engineers & Shipbuilders

    Bolbec Hall, Westgate Road
    Newcastle upon Tyne,   England 
  • Authors:
    • Ractliffe, A T
    • Mitchell, GHG
  • Publication Date: 1976-11

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Filing Info

  • Accession Number: 00157630
  • Record Type: Publication
  • Source Agency: Engineering Index
  • Files: TRIS
  • Created Date: Aug 4 1977 12:00AM