BOLLARDS AND WHARF MOORINGS. 



407 



a 2^ inch studded chain is 135 tons ; it will therefore be 

 sufficient to provide a resistance of say 400 tons to cover con- 

 tingencies. 



A cast-iron bollard or mooring-post of 

 2-inch metal, as shown by Fig. 354, with a 

 top diameter of 2 feet 3 inches, tapering to 

 1 foot 11 inches at the ground level, and 

 about 21 inches at the bottom flange, with 

 an overall length of 7 feet, fixed 5 feet into 

 a concrete base, leaving 2 feet above the 

 ground level, will occupy but a small space, 

 and give the required strength. 



Fio. 359. 



Different types of bollards are shown by Figs. 355 to 359. 



