160 



EXPERIMENTS ON SIMPLIFIED SHIP FORMS. 



The fuller models, marked lo per cent and 20 per cent, were obtained from 

 the finer forms by adding 10 per cent and 20 per cent middle body and contracting 

 the form of the ends to keep the length constant. 



The curves of sectional areas and load waterline are shown in Figs. 4 and 5, 

 Plates 87 and 88, and in connection with the latter it will be noticed that, in order 

 to use the same form in all cases, this necessitated a somewhat fuller' line forward 

 than was compatible with ease of propulsion. For purely comparative purposes it 

 was deemed advisable to keep the same waterline throughout. 



The general results are summarized in the curves (Figs. 6, 7 and 8, Plates 89, 

 90 and 91). A comparison of each set of curves for each type shows that the ship- 

 shape is the best, and that, of the other two forms with the corner off, the one with 

 the steeper slope to the bilge diagonal gives better results than where this is at a 

 smaller angle. 



At the lower speed-length ratios there is little, if any, difference, and such as 

 there is is of the order of i to 2 per cent. 



The effect of retaining the sharp corner appears in all cases to increase the re- 

 sistance somewhat as shown in Figs. 9 and 10, Plates 92 and 93, i. e., the resistance 

 increases at a somewhat more rapid ratio than the added wetted surface. 



The remaining form with the lower knuckle line dropped (Fig. la, Plate 86) 

 shows slightly more resistance than the best of the other forms, but the amount is 

 small ; in fact it seems to lie between the first two forms. 



SERIES 2. 



A similar set of tests was carried out upon a model of fuller form. In this case 

 the curve of sectional areas was changed to one suitable for this type. The body 

 plans are shown in Figs. 11 and 12, Plate 94. The particulars of the models are 

 given in the following table : — 



