CHAPTER VII 

 HINTS ON SELECTING DREDGES FOR VARIOUS WORK 



NOTHING is more important than the selection of the style and 

 size of a dredge to be used on a job. Thousands of dollars have 

 been wasted by errors in judgment made in this regard, or from 

 ignorance on the subject. Only a few years ago the writer saw a 

 mistake made of this kind that proved expensive to all concerned. It 

 is almost impossible for a novice to decide knowingly in such a matter. 

 Not only must one be conversant with the various styles or type 

 of dredges made and used, but the work they will do and their 

 general adaptability must be known. Even then it is not always 

 possible to select a dredge suitable from those already in use, but 

 it is frequently necessary to design a special machine, to do the 

 proposed work in an economical manner. 



At times, though, only some detail of the dredge has to be changed 

 to adapt it to the work. In America, both engineers and contractor 

 make the serious blunder of attempting to use a dredge already at 

 hand, instead of rebuilding it, or getting another machine, believing 

 that either by their determination or by their ingenuity they can 

 make the machine in question do the dredging economically. 



Although it is true that many dredges of special design are copied 

 in part from older types, yet no one but those of experience in d red ire 

 building and operation should attempt to design machines. Then- 

 are some monumental piles of junk in existence due to poor design inn. 

 and in some cases profits are quickly eaten up in repairs due to the 

 same reason. Dredges must not only be designed well, but must also 

 be well constructed. 



There are three important considerations that should be given 

 the selection of a dredge: First, the character of the soil or material 

 to be excavated. Second, the method to be used in the disposal 

 of the material and the distance from the point of dredging to the 

 place of deposit. Third, the local conditions that may surround the 

 work, such as whether harbor or river improvement, the traffic 



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