Prediction of Steering and Manoeuvring of Ships 



Figure 19 shows an example of nonlinear forces obtained in this manner by 

 means of the HyA planar-motion mechanism. The integrated forces have been 

 obtained as a result of pure yawing motion forced on a 20-ft model of the Mariner 

 hull-form. The model, the condition tested, and the nomenclature are identical 

 to that described in Ref. 5, except that the tests were made at a ship speed of 10 

 knots instead of 15 knots in order to facilitate the generation of large yaw veloc- 

 ities. The measured forces have been faired with linear and cubic terms, the 

 coefficients of the fairing polynomials being included in the figure. Steady-state 



0-30 o^s 



Oimensionlcss Yaw Velocity, r: 



Fig. 19 - Pure yaw results measured with the HyA planar-motion 

 mechanism: transverse (Y) gauge forces as functions of yaw 

 velocity 



345 



