260 



L ship 



TOWED CONDITION 

 CHANGE OF TOTAL HEAD 



T ship 



FIGURE 6. Total head 

 distribution far from 

 a ship. 



U=l. 27m/sec 



583 . 3mm 



g(Ho-Hs)/|u2 



MEASUREMENT SECTION 

 O.SLpp behind A. P. 



self-propulstion test and the towing test, and 

 viscous resistances obtained from the wake survey. 



Discussion 



By analyzing the wake at a distant position behind 

 a ship, an estimate of the recovery of the wake 

 energy by the propeller is made, and the optimum 

 condition (92) is given. Table 3 shows that hull 



efficiency is better for the T ship than for the L 

 ship. Results of the self -propulsion test, therefore,^ 

 indicate that the energy recovery by the propeller 

 is better for the T ship. On the other hand, results 

 of wake survey measurement far from a ship indicate 

 that for the T ship, the peak of the head change 

 distribution agrees well with the peak of the head 

 distribution in the towed condition. Hence, it can 

 be considered that the propeller of the T ship makes 

 the wake flatter in order to adapt the conditon (92) . 



