226 Prof. F. Elgar. The Variation of 



which freeboard is measured. The horizontal ordinates of these 

 curves represent the moments BR x V, at the draughts to which they 

 correspond ; the scale of moments in foot-tons being shown upon the 

 base line. The displacement of the vessel when wholly immersed 



FIG. 13. 



is 11,800 tons, and when displacing half this amount or 5,900 tons 

 she draws 20 feet 6 inches of water ; and this depth of flotation, with 

 the corresponding values of BRx V, are shown by the ordinate drawn 

 at the point a. a 2 represents the draught of water at which the 

 vessel was launched, and a^ the draught at which there is an equal 

 volume out of water to that below water at the draught a s . The 

 draught of water at the point Oj is 11 feet, and the freeboard above 

 the point j is 7 feet. 



If the centre of gravity be taken at 19 feet above the top of keel 

 for all draughts of water it always varies, and in some cases con- 

 siderably, with the draught, as has been stated, but 19 feet is found 

 to be a fair mean height for the ship in question and the moment 

 V x BGsin 6 be deducted from the ordinates of the curves in fig. 13, 

 we obtain new ordinates, which represent the curves of righting 

 moments, V x GZ ; and these are shown in fig. 14. It will be seen 

 that the righting moments which correspond with the ordinates of 

 the usual curves of stability are much larger at deep draughts 

 than at light draughts. For instance, the ordinates of the usual 



