WEIGHT AND SUPPORT IN SHIPS. 
451 
‘ Victoria and Albert’ type. Strains under various conditions. 
Still Water. 
On Wave-crest. 
In Wave-hollow. 
Maximum shearing-force 1 
~ displacement. j 
Maximum bending-momentl 
-f- displacement x length.) 
l 
X 6 
rig (hogging) 
l 
X 1 
Ts (hogging) 
l 
6 
Ts (sagging) 
The variation in the amount and character of the bending-moments is the most inter- 
esting feature in this summary. On the wave-crest the maximum hogging-moment is 
somewhat, more than three times as great as the maximum hogging-moment, for still 
water ; and in this respect there is a clear resemblance to the similar proportions for the 
4 Minotaur,’ although, in proportion to the products of the lengths and disjjlacements, the 
‘ Victoria and Albert’ is much less severely strained than the ‘ Minotaur.’ For the wave- 
hollow, however, the case is widely different. In the 4 Minotaur’ the bending- (sagging-) 
moment there has a maximum value less than twice as great as the still-water hogging- 
moment ; but in the ‘ Victoria and Albert’ the sagging-moment is about six times as 
great as the still-water hogging-moment. The ‘ Minotaur,’ therefore, experiences her 
absolute maximum bending-moment when suspended on a wave-crest, while that for 
the 4 Victoria and Albert’ is incidental to flotation in a wave-hollow. This result 
would naturally be anticipated, when the conditions of strain previously shown to exist 
when the ships are floating in still water are taken in connexion with the distribution 
of the buoyancy in the extreme positions of support among waves. Hence follows the 
practical deduction that ships of the ‘ Minotaur’ type are likely to be subjected to hogging- 
strains severer in their character than any sagging-strains that will be brought upon 
them ; while vessels of the ‘ Victoria and Albert’ type are likely to be most strained by 
sagging. Although, as I have said previously, the latter type only includes, at present, 
ships intended for special services, such as yachts, blockade-runners, &c., its investiga- 
tion leads to a valuable extension of the ordinary theory respecting bending-strains, and 
appears to have been overlooked even by the most recent writers. For instance, Pro- 
fessor Rankine (at page 153 of 4 Shipbuilding, Theoretical and Practical’) says of the 
sagging-moment incidental to support in a wave-hollow, that 44 in all cases of ordinary 
occurrence in practice, the sagging-moment thus produced is less severe than the hogging- 
moment produced when the ship is balanced on the crest of a wave.” This statement 
is undoubtedly true of many ships ; but it would apparently lead to very erroneous 
results if it were'supposed to hold universally, and I have therefore drawn attention to it. 
The method which in my opinion ought to be followed in approximating to the probable 
strains that a ship will experience, is first to determine, from her form and stowage, to 
what type she is likely to belong, and then to consider whether or not it is necessary 
to take the sagging- as well as the hogging-strains into account in calculating the strength 
required in her structure. 
