WEIGHT OE MATEEIAL IN THE CONSTRUCTION OF IRON-CLAD SHIPS. 483 
And supposing the engines (including boilers, &c.) to weigh 1 ton per nom. H.P., 
and the coal to weigh as much as the engines and boilers, we have 
TT7 - w r . J •, 2-4b{2d+b)s 3 
Weight of engines and coal = 1Q0Q() 
Equating the two expressions for the displacement, we shall have 
{145° +28-U(d+id')}w + 28-i .b.d ' . Vx 2 + 2 - 4i 1 ( o y sS +3W. . (I) 
In the new ship let s=14 knots, d = 25 ft., ^'=24 ft., W=450 tons; and while w 
remains the same as in ‘ Bellerophon,’ say, one- tenth of a ton, let w' be doubled, say, 
- 2 % ton ; the equation (I) then becomes 
10y=(14y + 28-4ix43)x-l + 28-4Sx24x^ + 2 , 4 - j 5 1 o ^ 2744 + 1360, 
or 7-94^=3015=1350, 
whence 6= 41*95 ; 
consequently 
Length = 14&= 587*3 feet. 
Breadth = 2 b— 83*9 ,, 
I.H.P = 8890 H.P. 
Weight of hull . = 7586*7 tons. 
Weight of armour and backing . = 6124*7 „ 
Weight of engines and coals . . = 2541*3 „ 
Weight of equipment . . . . = 1350 ,, 
Displacement = 17602 7 tons. 
The area of the immersed surface of this ship = 146 2 +28 , 4£xd. 
=54422 sq. ft. 
and area of immersed mid. sec =83*9x25 
=2097*5 sq. ft. 
Next, let us take the case of a curve-of-sines ship having a proportion of length to 
breadth of 5 to 1. It will be found by construction that the length along the curve will 
be to breadth as 5*12 to 1. All the previous notation and values will be retained, ex- 
cept that V will be substituted for b, and 2W for 3W, the latter change conditioning 
that this vessel shall carry two-thirds the dead weight of the former vessel. 
Surface for weight of hull .... =20•48£'(^Z+i^ , )^ _ lM ,2 • 
Surface for armour and backing . . = 20 * 48 ^'^'. 
Taking Professor Ranxine’s rule as before, 
Angle of maximum obliquity of water-line curve . — — 2 °° Xx=18 0 . 
Therefore coefficient of augmentation = 1 + 4 x *0669 + *0049 
=1*273, 
and augmented surface = 10b'(2d+b')x 1*273, 
