Data for Ships of Minimum Resistance 



Fig. 8 - Residuary and Michell resistances for symmetric model. 

 Residuary resistance for equivalent models. 



the other hand, observation of the water surface during test runs near design 

 speed shows remarkably little surface disturbance. This leads one to suspect 

 that the residuary-resistance coefficient in this region may contain a significant 

 amount of form resistance, a suspicion partly confirmed by the observed sepa- 

 ration behind the stern bullD. 



Figure 9 shows Rt/pgV for the optimum- for ebody model, and for the equiv- 

 alent Taylor 's-Series ship, both extrapolated to a 400' ship. Over the range 

 from Fr = 0.25 to 0.35 the two are practically indistinguishable. 



Figure 10 shows the residuary resistance R^/pgV for this model together 

 with the Michell wave resistance %/pgV . It is evident that the agreement is 

 much better here than it was for the symmetric ship. 



SOME CONCLUSIONS 



As is evident from the foregoing, the "optimum" computer -de signed ships 

 have not shown any dramatic improvements in resistance properties over the 

 equivalent ones in Taylor's Standard Series. In fact, they are hardly distin- 

 guishable. For the ship with prescribed afterbody this should cause no sur- 

 prise, for the predicted improvement was a fairly modest part of the whole. The 

 situation is somewhat different with the symmetric ship. Here the predicted 



221-249 O - 66 - 68 



1057 



