4 RELATIVE RESISTANCES OF SOME MODELS WITH BLOCK 



It is obvious that the full-ended models run materially better in this shallow- 

 water than the fine-ended models. We know that for very high speed in deep 

 water the same thing occurs, namely, that full-ended models are superior to fine- 

 ended models. This is the case, for instance, at speed-length ratios of 1.5 and over. 

 It may be that in the shallow water the same type of form drives easiest at low 

 speeds. 



Another possible explanation is that in shallow water the shape of the mid- 

 ship section has the most material influence upon the resistance and that the low 

 resistances associated with the fine midship sections are due mainly to these fine sec- 

 tions and not to t;he accompanying full ends. If this is the case the coefficient of 

 midship section has a different effect upon resistance in shallow water from that 

 which it has in deep water. My 1908 paper showed clearly that for the speeds we 

 are now considering in deep water the full midship section coefficients were favor- 

 able to speed. 



If I must venture one conclusion, which seems warranted by the shallow water 

 experiments, it would be that, unless for excessively shallow water, there is probably 

 no gain as regards resistance by adopting a midship section coefficient materially 

 below .90. 



It will be observed that even for the very shallow water in which these models 

 were tested there was very little gain in dropping from midship section coefficient 

 of .92 to one of .86. I would anticipate that as the water deepens the larger mid- 

 ship section coefficients would show a steady gain, and that for any depth of water 

 greater than, say, I ^ times the draught there would be no advantage from the 

 point of view of resistance in adopting midship section coefficients below .90. 



Pending systematic investigation of the features of form associated with mini- 

 mum resistance in various depths of water it would seem that there are possibili- 

 ties of great gain by careful model basin investigations of vessels of importance 

 intended for shallow water work. 



DISCUSSION. 



The Chairman : — Gentlemen, this paper is before you for discussion. Mr. Taylor's 

 work is invaluable, and has an international reputation, and the least tribute we can pay to 

 it is to give it a thorough discussion. Professor Peabody, are you prepared to say any- 

 thing ? 



Prof. C. H. Peabody, Member of Council: — The statement in the introduction made 

 by our chairman is, after all, the most important thing we can say in regard to the papers 

 presented by our honored member. The several papers which he has presented to this So- 

 ciety and other publications which he has offered present a body of information which is 



