NO. 15.] 



EMPIRICAL LAWS OF RESISTANCE. 



129 



in this respect are, however, not very reliable and definite, and a few experi- 

 ments were therefore made to determine with certainty whether vessels of 

 different shapes are influenced in markedly different degrees. The boat- 

 models used in these experiments, had about the same size as the larger 

 Fram-mode\ ; their length at the water-line was the same, namely 36 or 

 36'5 cm. Other principal dimensions etc. are given in the table below. 



Boat-models. 



Model 1 was the before mentioned model of the Fram; its lines are 

 given in Fig. 8 PL I, and its athwart-section in Fig. 1 PI. X. Model 2 is 

 the same as No. 1, only that the loading weight was moved from midships 

 to the stern so as to make the trim greater. Models 3 and 4 have diffe- 

 rent midship-sections, as may be seen in PI. X. In other respects, the 

 models 1, 3, and 4, are made as nearly as possible similar to one another, 

 so far as is consistent with the different midship-sections; Model 3 had a 

 stem somewhat more bluff below the water-line, than had the others. 

 Model 5 was only a (bin rectangular board, 36 cm. long and 14 - 7 cm. wide 

 and dipping 4 or 5 mm. into the water; at its ends it was thinned out to 

 nothing 1 . 



Experiments with Model 2 were made only in a surface-layer of 5 cm. 

 thickness (Experiments 185 — 194 p. 83). If the resistance-curve is drawn ac- 

 cording to the results obtained, it will be found almost identical with the 

 corresponding curve for Model 1. The resistance in homogeneous water, may 

 be assumed to be nearly the same for both models. As the trim of Model 



1 It should have been mentioned on p. 59, that all boat-models except the one used in 

 the small tank, were made at " Liljeholmen s boat-building yard". 



17 



