ship Maneuvering in Deep and Confined Waten 



1.6 

 1.4 

 1.2 

 1.0 

 0-6 



0.6 

 0.4 



0.2 h 







Theory ( Tuck ) 



Exp. FnL=0.2 

 ( V Leeuwen ) 



0.10 



0.05 



Theory ( Tuck ) 



a 



□ D 



. Exp. FnL=0.2 D 

 ( V Leeuwen ) 



Fig. 8. Total added mass and added moment of Inertia for a 

 Series 60 Block . 70 form according to theory and 

 experiments . 



(Note that the strip theory is not valid for small "reduced frequencies" 

 co' = a)"/i^"> where it shall be replaced by a slender body theory, [31] ,) 

 The dotted curves in the diagrams indicate predictions for 

 FnL = u" = 0.20. 



The Series 60 Block .70 form was subjected to oscillator 

 experiments in lateral modes at several frequencies and forward 

 speeds by van Leeuwen, [32] . The results for the naked hull with 

 rudder at F„l = 0. 20 are compared with the predictions from strip 

 theory in Fig. 8. The experimental values fall well below these 

 predictions in the entire range of frequencies, especially in case 

 of the moments in yaw. Although it is inherent in the testing tech- 

 nique that very low frequencies could not be included van Leeuwens 

 results do cover the critical range around co" • u" = 1/4. 



Consider a surface body in steady motion along the centre- 

 line between two parallel walls width W apart; the diverging bow 

 wave displays an angle to the centreline. If the motion is steady 

 the reflected wave will pass aft of the body only if W/L > tgP, 

 regardless of the speed. For the simple travelling pressure point 

 the cusp line angle is equal to 19947 according to the Kelvin theory, 

 whereas slightly different values may be observed for real ship 

 forms. In case the body is oscillating (as in the simple example may 



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