Current-Induced Vessel Forces and Yaw Moments from Full-Scale Measurements

Abstract

Abstract : Full-scale measurements of the current-induced forces and yaw moments on a T-2 tanker and Spruance class destroyer are presented. The T-2 data set is made up of 23 tests, including water depth-to-draft ratios between 2.5 and 6, incident current angles between 0 and 95 degrees, current speeds up to 4 ft/sec, and horizontal and vertical current shears. Results are presented from 14 tests of head-on and beam-on loads on a Spruance class destroyer. The deep water lateral force coefficient is shown to be independent of hull shape but with a magnitude that varies 50% depending on the vertical current shear. Analysis of the deep water longitudinal force, the shallow water lateral force, and the yaw moments shows that these coefficients do not follow 'accepted' patterns. These data provide a unique and reliable data set for validating current load methodologies and for validating similitude relationships for small-scale mooring and maneuvering studies. Keywords: Water flow; Mooring; Current; Ships; Drag forces; Maneuvering; Berthing; and Tanker Ships.