LUCIA FOR THE UNITED STATES SHIPPING BOARD. S3 



Professor Hovgaard's method gives us: — 



Section modulus of reduced water plane equals ( i ) or 



B X 



2 t n/i 1 M 



— '— X — = M or 



96 BV t 



Method employed by me in this paper gives us : — 



Section modulus of original water plane equals ® + © + (3) or 



— - — X — = 7^+ — X — Xi9x — + — x^x — X — X 

 62 24 42 32 



or-l = ,^. + ^H--l or ^ ^ 



12 BL'^t ' 32 ' 24 "' 96 BV t 



Hence same results are arrived at by the two methods. 



( I ) denotes moment of water to original water line. 



® + (D + ® denotes moment of water to bilged water line. 



Draught. — The increase of mean draught is also arrived at in slightly different 

 manner. 



Professor Hovgaard figures first out to what extent the reduced water plane 

 would be immersed by the water up to the original water line. To this he adds the 

 change of trim taken at the qj axis. The sum is the increase in mean draught. 



In our method we figure out to what extent the original water plane would be 

 immersed by the total water inside the ship. This amount is the increase in mean 

 draught. 



Naturally both answers are the same as the change of trim at the 'P axis is 

 just the amount the original water plane would be sunk by the water denoted as (2) 

 and @ as shown above. 



DISCUSSION. 



The President : — This paper No. 3, entitled, "Application of Buoyancy Boxes to the 

 S. S. Lucia for the United States Shipping Board," is open for discussion. 



Mr. Donnelly: — Now, it happens, you may think quite oddly or coincidentally, 

 but still as a matter of war, that since the writing of this paper the Lucia has been tor- 

 pedoed at sea, and because of that fact I desire to add in the discussion just a brief state- 

 ment of these results. As is usual in human affairs, they are predicted on a theory, and 

 therefore the results are not altogether conclusive one way or the other. They have been 

 obtained from such sources as are available, and we will record them and leave them for 

 the study and review of individuals, and, we hope, of modification if necessary, and the ad- 

 vance of our ideas. 



