434 
ME. E. J. SEED ON THE UNEQUAL DISTRIBUTION OF 
of the weights would cause a hogging-moment of 600 foot-tons, which, combined with 
the sagging-moment previously existing of 170 foot-tons, would leave as a final result 
a hogging-moment of 430 foot-tons at the station where sagging-strains previously 
existed. 
These examples will serve to show the error of supposing that an excess of weight amid- 
ships, or at any other part of a ship, necessarily causes sagging, as well as the necessity 
for taking into account the effect of all the forces on one side of the section for which 
the bending-moment is being calculated. Unless this is done it is almost impossible to 
determine whether sagging will take place or not : for in some cases the hogging- 
moment due to unsupported weights at the extremities will more than counterbalance 
the sagging-moment due to the excess of weight amidships, as is the case in the 
‘ Bellerophon’ and the ‘Audacious;’ or the reverse maybe true, as in the ‘ Victoria and 
Albert.’ 
The effect which alterations in the weights carried by a ship have upon the bending- 
strains is well illustrated by the comparison of the curves M M in Plate XVII. figs. 
10 & 11. By removing all the weights except the engines and boilers, and altering the 
curve of loads in the manner previously described, the curve of moments in fig. 11 is made 
to assume a very different form from that in fig. 10. Hereafter I shall have occasion to 
refer to the principal points of difference; for the present it will suffice to say that in the 
latter the greatest bending-moment falls nearly amidships, instead of in the after body as 
before, notwithstanding the fact that at some parts of the middle body there is an excess of 
weight. The amount of the greatest bending-moment when the ship is light is also 
somewhat greater than that when she is fully laden ; and the curve M M in fig. 11 approx- 
imates more nearly in form to that of the similarly marked curve for the ‘Minotaur’ 
(fig. 8) than it does in fig. 10, although striking points of difference still exist. Another 
illustration of the variation in bending-moments which variation in the amount of the 
weights on board a ship may produce is afforded by comparing figs. 10 & 12 (Plate XVII.) ; 
and here we see also how, by reducing the excess of weight between the stations B 4 R 4 and 
IP R 5 , we have rendered the curve M M in fig. 12 more nearly continuous in its concavity 
towards the axis than is the similar curve in fig. 11. The differences between these last 
two curves have a special interest, on account of the fact that they are entirely due to 
alterations in the stowage of the weights on board, the total amount of weight carried 
being the same in both cases. The greatest bending-moment, in fig. 12 is found at the 
station c c', and amounts to 13,800 foot-tons, or about one-eighth more than it is at the 
corresponding station in fig. 11, this increase being due to the transposition of weights 
to the extremities. 
It may be well here to revert briefly to the fact that no ship having an excess of weight 
over buoyancy at the extremities (as all, or nearly all, ships have) can sag throughout 
her length when afloat in still water, although she may hog and not sag. The cases of 
the ‘ Minotaur,’ ‘ Bellerophon,’ and ‘ Audacious ’ prove the possibility of the latter con- 
dition, and no more need be said respecting it. That sagging alone cannot take place 
