126 NOTES ON DOCKS AND DOCK CONSTRUCTION. 



16 to 28 inches, and reaching a maximum length of 90 feet. 

 Practically, the hard bottom was, as a rule, too deep to be 

 reached by the piles, their sustaining power therefore depended 

 almost entirely on the friction of the mud on their sides or skin 

 resistance. The piles were shod only where loose stones had 

 to be penetrated. 



All the vertical piles arranged as shown by Figs. 92 to 95 

 were driven first. The three front rows (Fig. 94) were then cut 



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4" Planking \ > 



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FIG. 94. 



off at 15 feet 3 inches below low water by a circular saw, which 

 was attached to a large timber, lowered to the required depth, 

 and worked from a floating pile-driver. 



The rear rows of piles terminate 2 inches above mean low- 

 water, and are notched at the top to receive the transverse caps 

 or sleepers and planking forming a rear platform just above 

 mean low water (Figs. 92, 93, 94). 



