122 REPORT—1868. 
Forebody. Afterbody. Middlebody. 
Log 653 =2-°8149132 Log 653=2°8149132 Log 6538 =2-8149132 
Log 157:476=2:1972144 Log 104:984=2:0211066 Log 74:04=1-8694664 
Log ‘5 =9-6989700 Log ‘5 =9-6989700 ————— 
— —. 4-6843796 
4-7110976 45349898 Log 35 =1:5440680 
Log 35 =1-5440680 Log 35 =1-5440680 ———— ae 
—_____—_ 3:1403116 
3:1670296 2-9909218 Nat! nt =1381 
Nat! n™ = 1469tons Nat'n" = 979-3 tons : 
Log 19635 =9-2930309 
Tog 40:92 =1°6119356 
Log 653 =2°8149132 
3°7198797 
Log 35 =1-5440680 
2:1758117 
Nat! n" =149-9 
1469 +.979-34 149-94 1381 =3979-2 tons, or just two-tenths of a ton more 
than the actual displacement. Now there is no length of forebody, after- 
body, and middlebody possible that will fulfil the conditions required ; and it 
would therefore be wrong to compute the length of forebody in any other 
way than through means of the coefficient of fineness of ends. The ‘ Atrato’ 
has no actual middlebody; but we see that she really could have had a 
parallel middlebody of 74 feet without in the least injuring her qualities. 
The length of forebody, afterbody, and middlebody, through means of the 
mentioned formule, have been calculated for several ships, and the result has 
been appended in a Table which follows the Table of Analysis according to 
Mr. Scott Russell’s method. 
It will easily be seen that this length of middlebody varies with the draft 
of water; the lighter the vessel is, the shorter the middlebody, and the 
deeper the vessel the longer the middlebody, the different coefficients of fine- 
ness necessarily becoming smaller when light, and larger when laden. 
The coefficient of diminished resistance is therefore (40-92+157:476) 
=0-0675. 
Resistance due to ship’s way, equal to area of midship section multiplied 
by the square of the speed of the ship in feet per second ; and this product 
multiplied by the coefficient of diminished resistance gives 15850 pounds’ re- 
sistance due to ship’s way. 
Girth at midship section in feet.........00e ee ee eee 62°80 
This item, when the lines are in hand, is not immediately necessary, al- 
though, when such is the case, that girth must be measured, in order to lay 
down the surface of the skin; but in the absence of the lines of the vessel 
the girth at the midship section becomes a great function of the surface of 
the skin. The 66 feet, as above, has been actually measured from the 
body-plan ; but where a certain proportion exists between the beam and 
the draft of water, the girth may be found to a close approximation by 
multiplying the beam plus twice the draft with a certain coefficient, which 
coefficient may be found from a Table at the end of this Report, in which the 
girths at the midship section have all been found from the lines of the ship. 
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