20 



STRUCTUUE OF VESSELS. 

 Cross-section of a Vessel at midships— knees not inserted. 



Beam 



A first foot-hook alternates mth each floor, and 

 second foot-hook, alongside, extending from o to ^ ; 

 and a top-timber, or third foot-hook, alternates 

 alongside of each second foot-hook, and chock ex- 

 tending from q to a. These timbers are bolted to- 

 gether, and constitute a frame or double rib ; and 

 the skeleton is composed of a series of double ribs 

 (several inches separate, of coui'se wider above than 

 lower down, as the timbers decrease in thickness), 

 to within a little of the bow and stern, where the 

 timbers are usually placed singly, \^ithout framing. 



