Ships and Shipping. i6i 



Another simple rule for approximately estimating the 

 difference in draught of a vessel according to whethershe be 

 in fresh, brackish, or salt water is by the rule of proportion. 



Suppose a vessel draws i8 feet when lying in water 

 where the hydrometer shows a cubic foot of water 

 weighs 1008 ounces, on getting to sea she would rise 

 2t2 inches, or draw 1 7 feet 8^\ inches. 



7894 



3i^ inches. 7175 



719 

 12 



1025) 8628( 

 8200 



428 

 The tons per inch may be ascertained by multiplying 



the length on the Water line by the beam, and dividing 



the produdl by a Constant M. 



M. is supposed to have the following values :— 



For fine-lined ships ... ... ... ... m, = 600 



For a moderate fine-lined ship ... ... w. = 560 



For Cargo ships ... ... ... ... m. = 540 



For ship of very full form *w.= 500 



X 



