10 



BULLETIN 300, U. S. DEPARTMENT OF AGRICULTURE. 



A very great saving can be effected by covering the boiler with, an 

 asbestos coat. Ordinarily, about 25 pounds of coal per horsepower- 

 hour are consumed on dredges. The cost of repairs depends largely 

 upon the operator; a careless operator will cause many unnecessary 

 breakdowns. It is not only the high cost of repairs for machinery 

 but also the time lost which aids in increasing the actual cost of the 

 output. It is a well-established fact that it is not the initial cost of a 

 dredge or of any machine, but the operating and overhead expenses, 

 that reduce the profits. 



COST OF OPERATION. 



The cost of dredge work depends upon a number of factors. The 

 locality of the work, the kind of soil, repairs, delays, labor, etc., 

 greatly influence the actual cost of any work. If the water level can 

 naturally be maintained within a foot or so of the surface of the 

 ground, the cost of excavation can be reduced very low with this type 

 of machine. The data given in the following pages were obtained 

 from the actual cost records of the various projects. Unfortunately, 

 the figures are not always strictly comparable, one project with 

 another, owing to variations in the items of cost included. Unless 

 otherwise stated, interest is taken at 6 per cent and depreciation at 

 35 per cent per annum on the cost of the dredging outfit. Interest 

 and depreciation are, however, charged only for the interval of time 

 upon which the unit cost is based. This is not strictly correct, as a 

 certain amount of time consumed in getting the machine on and off 

 the work should be charged to each project. In most cases it was 

 impossible to ascertain the time that should be charged to moving, 

 building, etc., and therefore the item has been ignored in all cases, for 

 the sake of uniformity. On some projects figures for operation over an 

 extended period were not obtainable. In such cases the unit cost is 

 based upon the daily cost of operation and the average amount of ditch 

 dug per day, no allowance being made for interest and depreciation. 



In the construction of a ditch in North Carolina a new l|-yard 

 dipper dredge was employed. This dredge had a 5 by 20 by 70 foot 

 hull and was equipped with 8f by 10 inch double-cylinder hoisting 

 engines; 7 by 7 inch double cylinder, reversible swinging engines; 

 a 50-horsepower Scotch marine return-flue boiler; a l|-yard dipper, 

 31-foot dipper handle, and 45-foot boom. The spuds were converti- 

 ble to bank or vertical and were operated by the hoisting engines. 

 The cost of this dredge, erected, was $10,342.19. The dredge was 

 operated continuously, each shift working 11 hours per day. The 

 men were paid at the following rates per month: Superintendent in 

 charge, $110; engineers, $100; cranemen, $60; firemen, $48; deck- 

 hands, $36. The men furnished their own subsistence. The ditch 



