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XVI. On the Unequal Distribution of Weight and Support in Ships, and its Effects in Still 
Water, in Waves, and in Exceptional Positions on Shore. By E. J. Reed, C.B., 
Vice-President of the Institution of Naval Architects. Communicated by Professor 
G. G. Stokes, Sec. B.S. 
Received December 31, 1870, — Read February 9, 1871. 
The object of the present paper is to bring within the grasp of calculation a much 
neglected division of ship building scienceand art. Many writers of great ability (French, 
Spanish, Dutch, Swedish, and English) have studied and explained the forces brought 
into action upon a ship by her own weight and stability, and by the action of the wind 
upon her sails and of the waves upon her hull ; and the result of their investigations 
has been to encourage the construction of ships of such forms and such dispositions of 
weights as conduce to moderate and easy motions in the waves of the sea. The relative 
positions of the centre of gravity and the metacentre, the excursions of the centres of 
gravity and buoyancy, the inclinations of the axis of rotation, and many other like 
questions have been very fully and thoroughly discussed, especially by modern English 
naval architects ; in some cases, I venture to say, with even more elaboration and minute- 
ness of inquiry than their intrinsic importance demands. But while the means of 
securing ease and moderation of movement of the ship at sea have been thus elaborately 
studied, in order, mainly, as we have been told, to save the fabric of the ship and its 
fastenings from excessive strains, comparatively few writers upon naval architecture have 
pursued the subject to its legitimate and necessary development, by seeking to investigate 
the actual longitudinal bending- and shearing-strains to which the fabric is in fact exposed 
in ships of various forms under the various circumstances to which every ship is liable. 
But more than this : not only has the question of internal strain and strength in the 
ship been left undeveloped, but a serious fallacy has underlain many of the writings 
even of men of the greatest eminence upon this subject, viz. the fallacy of considering 
ease of motion identical with moderation of strain. No doubt ease of motion is very 
desirable in all ships, and violence of motion tends to distress any given fabric ; but at 
the same time it is quite practicable, as will clearly appear hereafter, to so design and 
build two ships, that in a sea-way the easier of the two shall be the more distressed even 
with precisely the same structural arrangements, and therefore it is obviously very desi- 
rable to examine the actual strains, both static and dynamic, with which we have to deal. 
The weakness exhibited by many ships, notwithstanding the greatest care on the part of 
the designers, has long pointed to the necessity of further investigation in this direction ; 
but two modern events — the introduction of armoured ships, and the use of iron and 
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