296 



OF STEAM NAVIGATION. 



[SECT. x. 



Putting y = N/ 2 r x, and b = 2 x ; j- = a = , and correcting by comparison 

 with particular cases, we have, 



j-(-^2 ' + 0-0833) + -0032 (/ + -29 4 jl + 2 * ) j = the resistance in Ibs. 



V- C 



622. Now, by taking a radius that will describe an arc nearly agreeing with 

 the form, the resistance will be found with tolerable accuracy, even in the most 

 complicated forms ; and in cases where the curve is a circle, it will be very near 

 the truth. To render it more easy to make such calculations, the following table 

 is added, with examples to explain its application. 



In this table b is the breadth of the vessel at the surface of the water, / the 

 length of the part which is parallel, c the girt from water edge to water edge, 

 of the lower part of the midship section, v the velocity in feet per second, and the 

 result is the resistance in Ibs. To find the power, multiply the resistance again 

 by the velocity ; or use the cube instead of the square of the velocity in the above 

 table, the result is the Ibs. raised one foot per second. 



623. Required the resistance of a vessel of which the breadth is 22 feet, the 

 length of the parallel part 80 feet, and the girt of the midship section 31 feet, 

 when the velocity is 10 feet per second, and the radius of curvature equal 4 half 

 breadths. 



In this case, by the table we have, 



* c (-041 6 + -0032 (/ + -87 4)) = 10" x 31 (-041 x 22 + -0032 (80 + -87 x 22)) = 



