COST DATA 265 



for every day on which it has worked at all. At 9 cts. per yd., the 

 price paid for contract work in the same channel, this amounts to 

 $801 per day, and at this per diem valuation the value of time lost 

 by reason of repairs in eleven months as above is $110,538, while 

 the money actually paid for these repairs was $43,721. 



ESTIMATES OF EXPENSES 



"In September, 1905, a preliminary estimate was made of the 

 total expenses which each dredge would have to meet and pay for 

 out of the results of the work, if operated by a contractor. This 

 estimate, $12,500 per month, has proved so nearly accurate that no 

 general revision of it has yet been made. It is as follows : 



MONTHLY OPERATING EXPENSES 



Payroll $2,660 



Coal 2,480 



Water 60 



Subsistence 700 



Engine-room supplies 150 



Other supplies 250 



Casual repairs 500 



Total per month $6,800 



ANNUAL CARE OF PLANT 



Docking and painting, twice a year $1,250 



Renewals of equipment 12,150 



Miscellaneous 1,000 



Total per year 14,400 



Average per month 1,200 



ANNUAL FIXED CHARGES UPON ORIGINAL COST, 

 ESTIMATED AT $341,800 



Sinking fund, toward original cost, 10% $34,180 



Interest, at 4% 13,672 



Insurance risk, 2% 6,836 



Fixed charges per year $54,688 



Average of fixed charges, per month 4,500 



Total, per month $12,500 



" The sinking fund is meant to cover depreciation. The insurance 

 covers risk only, not what would be actual cost. For steel boats not 

 going more than five miles from harbor, it probably more than covers 

 any risk incurred. To meet these charges out of excavations which 

 would otherwise be made under contract at 9 cts. per yd. requires an 

 average output for each dredge of 138,900 cu.yds. per month 277,800 



