THE COST OF OPERATING DREDGES 259 



of the plant at the end of each working season. All the various 

 machines should be looked over carefully and the parts that have 

 been worn should be replaced. Gears, chains, ropes showing indi- 

 cation of weakness should be replaced with new ones. All the timber 

 should be kept in first class order, well caulked and painted, and if 

 the hulls of the dredge and boats are made of steel they should be 

 cleaned, scraped and painted before being put in commission again. 

 It is difficult to estimate accurately this item of expense, but when 

 all the most important repairs have been made during the season 

 and the plant has been kept in good working order, 10 per cent of the 

 total cost of the plant should be sufficient to cover all the expenses 

 required for the general overhauling. 



The dredging plant should be insured against fire and maritime 

 accidents. The annual premiums for carrying these two insurances 

 are not heavy. Without more definite data, an amount equal to 

 2 or 3 per cent of the total value of the plant should be set aside 

 for covering both the premiums of the fire and maritime insurance. 



General expenses, as office rent, the renting of piers for mooring 

 the dredges and tugboats during repairs and while not at work, 

 the salaries of the engineers, superintendents, office clerks, all the 

 taxes, office and traveling expenses should be deducted from the 

 gross profits of the enterprise. In estimating without other data 

 at hand, an amount varying between 5 and 15 per cent of the total 

 amount of work done should cover general expenses. Five per 

 cent of the total cost should be sufficient in case of large and extensive 

 jobs, while for smaller ones, the general expenses should be estimated 

 at 15 per cent of the total cost. 



Another important item is the contractor's profit. He is entitled 

 to a profit, not only for the time and knowledge given to the work, 

 but also for the many risks that he runs. Ample compensation 

 should be allowed him. It is difficult to state the percentage to 

 allow for this item, but it is generally safe not to put it down for 

 less than 10 or 15 per cent. This should be sufficient for large 

 undertakings, but for smaller jobs a larger percentage must be 

 allowed, and also for working in dangerous and exposed places. 



