WATER PERFORMANCE 



181 



Now actually our getting-off speed is 48-5 miles per hour, so 

 we are quite near enough for practical purposes. 



Now 10, 15, 20, 23, 26, and 29 knots are equivalent to ii'S, 

 17-3, 23-0, 26-5, 29-9, and 33-4 miles per hour. Therefore we 

 have, observing that 

 'L\ 3 W 

 ^> 



Now with Vj = 49*2 miles per hour (using this figure so as 

 to correspond correctly to the model tests) we obtain P 1 = 107 ; 

 then : 



w , P, and P T are plotted on V on page 1 80, from which we 

 see that the machine will get off the water in a calm. 



