374 NOTES ON DOCKS AND DOCK CONSTRUCTION. 



for dredging TS5 pence, and for conveyance 1'54? pence, or 

 together 3'39 pence per ton, including every expense except 

 plant charges. 



As regards the cost of dredging, the rate is distributed as 

 follows : 



Pence. Per cent. 



Coals (H48 = 8 



Repairs 1'091 = 59 



"Wages, stores 0*610 = 33 



1819 100 



Aberdeen. The average cost of dredging with bucket-ladder 

 dredgers, taken over a period of eight years, viz. from 1879 to 

 1886, amounted to 2737 pence per ton, including all charges 

 except interest and depreciation, the distribution being as 

 follows : 



Pence. Per cent. 



Wages , 0-896 = 32'76 



Coals 0-237 = 8'6S 



Stores 0-116 = 4*25 



Repairs 1-487 = 54'34 



2-736 100-03 



The average cost of dredging and removal by hopper-barges, 

 taken over a period of twenty years, viz. from 1866 to 1886, 

 amounted to 5*589 pence per ton, exclusive of charges on plant. 

 With the addition of these charges, the cost was 8*35 pence 

 per ton, or an increase of 50 per cent, on the working expenses. 1 



Mr. W. Dyce Cay, M.I.C.E., estimated the cost of dredging 

 and removing stiff clay boulders, gravel, sand, and mud at 7Jc?. 

 per ton, including interest and depreciation of plant ; and 

 assuming one ton of dredging equivalent to 18 cubic feet of 

 solid ground or excavation, the cost per cubic yard was HJcZ., 

 or, with general superintendence, Is. per cubic yard. 2 



Clyde. In the lower estuary of the Clyde below Port 

 Glasgow, under the control of the Clyde Lighthouse Trust, 

 dredging with a single-ladder dredger, and conveying the 

 dredged material a distance of seven miles by hopper-barges, 

 cost, including all working charges, repairs, interest and depre- 

 ciation on plant, for lifting and loading into barges, 2*54 pence 

 per cubic yard, transporting 2'47 pence per cubic yard ; together 

 5*01 pence per cubic yard. 



Dredging in hard material packed with boulders, presenting 



1 M.P.LC.R, pp. 107, 103. ' Ibid., p. 72. 



