Effect of Waterjet Propulsion on Sway and Yaw Static Maneuvering Coefficients

Results are presented from captive model tests on the effect of waterjet propulsion flows on the static maneuvering coefficients for sway force and yaw moment for a model of a large waterjet-propelled sealift ship configuration. Towing basin tests were conducted for the measurement of hull surge force and side forces at static (fixed) hull yaw angles of 0, 1, and 3 degrees at four ship speeds, ranging from 20 to 36 knots. Side force and yaw moment data were analyzed in terms of the standard linear sway force and yaw moment derivative coefficients Y'v and N'v. These play a role in ship controls-fixed maneuvering factors. It is shown that the maneuvering factors for the waterjet-propelled case differ by as much as 20% and 25% from the bare hull values for the sway- and yaw- derivative coefficients, respectively.