Stability with Draught of Water in Ships. 



227 



curve of stability for the launching draught of 11 feet at a 2 give very 

 much smaller moments than the curve for the deep draught at a x , 

 where there is an equal volume above water to what there is below 

 in the other case, and the freeboard is only 7 feet. 



Fio. 14. 



The centre of gravity taken in fig. 14 is 1*1 feet below where it 

 would be if the external surface of the ship inclosed a homogeneous 

 volume. Its position with reference to that of the centre of gravity 

 of a homogeneous body of the same form largely determines the 

 stability at all except small angles of inclination, and also the 

 relation between the stability at light and deep draughts. Figs. If* 

 and 16 show what fig. 14 becomes changed into, if the centre of 

 gravity is first raised I'l feet, so as to be in the same position as if 

 the ship were a homogeneous body, and, second, if it is raised a further 

 I'l feet, so as to be as much above this point in fig. 16 as it is below 

 it in fig. 14. A comparison of these figures will show that, except in 

 the case of a very high centre of gravity, the stability at light, 

 draughts with various positions of centre of gravity is less than at 

 deep draughts. 



It appears, therefore, that in the case of this ship, and she is a 

 type of many mercantile passenger steamers, the proposition respect- 

 ing the equality of the stability at light and deep draughts which 

 has been shown to apply to homogeneous symmetrical bodies, requires 



Q2 



