133 NOTES ON DOCKS AND DOCK CONSTRUCTION. 



The bottom ring differs from the others, and is called the 

 corbled ring, because it is made less in thickness at the bottom 

 to fit into the shoe, and tapers upwards to the full thickness 

 of 1 foot 11 inches (Figs. 100, 101). 



The shoe is made of cast iron 2 feet deep, 1 inch metal, and 

 of the same external size and shape as the rings. The under 

 side of the bottom ring rests on a shelf in the shoe, placed 6 



SECTION OF WALL ON LINE C D 

 Fio. 101. 



inches below the top edge, and about 12 inches wide. This 

 shelf is formed by an inner ring of cast iron 1 inch thick, which, 

 being connected with the bottom of the outer plate, forms a 

 bevelled cutting edge to the shoe. The total weight of the shoe 

 is about 4 tons 10 cwt., and for convenience of handling is made 

 in six sections. 



