WEIGHT AND SUPPORT IN SHIPS. 
439 
strain, no matter what number of sections there maybe at which that strain has a maxi- 
mum value. For example, in the ‘Victoria and Albert’ there are two sections of maxi- 
mum hogging-moment (c c' and a a' in Plate XVI. fig. 7), but the absolute maximum is 
found in the fore body ; while in the ‘ Bellerophon’ and ‘ Audacious’ (see Plate XVII. 
figs. 9 & 10) the absolute maximum is found in the after body. In cases such as the 
‘ Minotaur’s,’ where there is only one section of water-borne division, that is, of course 
the section of maximum bending. Attention has previously been drawn to the fact that 
in such cases the sections of maximum bending (such as a a! in Plate XVII. fig. 8) usually 
lie very near the middle of the length; and many writers on the subject, considering 
the distribution of weight and buoyancy too exclusively, refer to the midship section 
as being most severely strained. For Stillwater, however, I have shown above that this 
is by no means true in many ships ; and it is only proper to add that some authors of 
standing have recently put forward views on this point which are not borne out by my 
calculations. For example, even Professor Rankine, speaking of a ship that tends to 
hog in Stillwater, says*: — “Let M be a transverse section which divides the ship into 
two parts, each separately water-borne (and which is seldom far from the midship sec- 
tion); then at the section M the bending-moment is a maximum;” and further 
on he adds, “ in the case of a ship that tends to sag amidships the greatest bending- 
moment is still at M , being a sagging-moment instead of a hogging-moment.” 
Having proved above that the “greatest bending-moment” in ships which “tend to sag 
amidships ” falls not at M but in the fore or after bodies, I need not dwell at length on 
the too hasty inference here made. It will suffice to say that the section of greatest 
sagging does in such cases sometimes come near the middle of the ship ; but in Plate 
XVI. fig. 7 we have an illustration of the fact that it may come considerably abaft the 
middle ; and there are doubtless cases in which it comes before the middle, its actual 
position being determined, as Professor Rankine himself states, by the position of the 
central section of water-borne division. This sagging-moment, however, is by no means 
“ the greatest bending-moment ” experienced by the ship, the distribution of weight and 
buoyancy determining whether the true maximum bending-moment is experienced by 
some section in the fore or after body. I may add, that without accurate calculation 
it is generally possible to tell which body has to bear the greatest strain, by simply ob- 
serving at which end the excess of weight is greater. For example, in the ‘ Victoria and 
Albert ’ the excess of weight over buoyancy is greater at the bow than at the stern, and 
the section of absolute maximum bending-strain falls in the fore body ; had the reverse 
been true, the section would have fallen in the after body, as it does in the cases of the 
4 Bellerophon ’ and 4 Audacious.’ Professor Rankine, while recognizing the existence of 
these sections of maximum hogging-moment, does not seem to have noticed the fact that 
the strains at them would generally be more severe than those at the section of maximum 
sagging-moment. 
With respect to the actual amounts of the bending-moments experienced by the typical 
* ‘ Shipbuilding, Theoretical and Practical,’ p. 151. 
3 p 2 
