O.Y SHIP WAVES. 497 



beam and 3626 tons displacement a broader and 

 larger ship with no parallel middle body, but with 

 fine lines swelling out gradually the wave resist- 

 ance is much more favourable. At 13 knots the 

 skin resistance is rather more than in the case of 

 the other ship, being 6'95 tons as against 5 '8 tons ; 

 while the wave resistance is only 2*45 tons as 

 against 3*2 tons. At 14 knots there is a very re- 

 markable result in this broader ship with its fine 

 lines, all entrance and run and no parallel middle 

 body: at 14 knots the skin resistance is 8 tons 

 as against 6'6 tons in ship A, while the wave resist- 

 ance is only 3*15 tons as compared with 6*15 tons. 

 Another case which I can give you is that of a 

 torpedo boat 125 feet long, weighing 51 tons. At 

 a speed of 20 knots an hour the skin resistance 

 is i'2 ton, and the wave resistance ri ton ; total 

 resistance 2*3 tons. To calculate the horse-power 

 you multiply the speed in knots per hour by 6f , 

 and then multiply the resistance in tons by the 

 product so obtained ; and the result for the 

 torpedo boat going at 20 knots an hour is 307 

 horse-power to overcome a resistance of 2*3 tons 

 VOL. ill. K K 



