TRANSPORTATION OF THE DEBRIS 



201 



the same ladder. Fig. 69 represents a floating elevator with single 

 bucket as built by H. Satre & Co. while Fig. 70 represents a floating 

 elevator with double buckets used in the North Baltic Sea Canal 

 and built by A. F. Smulders of Rotterdam. It is obvious that 

 in connection with the bucket elevators only two types of barges 

 can be used, and these are the open-hold barges and the deck barges 

 with cargo boxes. 



Other machines for elevating the debris from the barges are 

 derricks or cranes. These are so extensively used on public works 



FIG. 70. Floating Elevator with Double Ladder. 



and so well known that a description is not necessary. They can 

 be mounted, either on a fixed scaffold erected along the shores 

 of the river or canal, or on a float. The scow with the dredged 

 materials is placed alongside or under the derrick; the skips deposited 

 on deck are attached to the hoisting chain of the derrick, lifted and 

 swung to the land. The skips are dumped either directly into the 

 cars, or into bins from which the material is loaded into cars when 

 required. As previously stated, this method of transporting and 

 lifting the materials is very seldom used. 



