174 A TREATISE ON DREDGES AND DREDGING 



increased the size of grab bucket dredges. Thus in the grab dredge 

 used at Buffalo Breakwater and described in the following chapter 

 the bucket was constructed with a capacity of 12 cu.yds. English 

 manufacturers usually build buckets of four sizes, varying from 

 to 1 cu.yds. capacity. The small efficiency of the English machines 

 compared with the American is due to the different manner in 

 which the dredging machines are mounted. Handling great 

 weights the small English vessel would easily capsize, hence the 

 buckets are made of small capacity. 



The other form of bucket used in connection with the grab 

 dredge is the orange peel bucket. This derives its name from the 

 fact that when the bucket is closed it is of hemispherical form and 



FIG. 52. Orange Peel Bucket, Open. FIG. 53. Orange Peel Bucket, Closed, 



closely resembles the peel of half an orange. The bucket consists 

 of three or four triangular blades and when closed forms a tight 

 hemispherical receptacle for the excavated materials. When open 

 the blades, provided with steel points, resemble sharp spades which 

 are well adapted for penetrating hard materials. The blades are 

 so adjusted that the maximum digging effect is produced with 

 but a slight tendency to lift the bucket when closing. Horizontal 

 arms are riveted to the blades, and their inner ends are attached 

 to a central block, while the outer ones are hinged to vertical connect- 

 ing-rods, pivoted at their upper ends to the upper center block. 

 The power wheel for closing the bucket is fastened to the lower 

 central block, and is somewhat eccentric in shape, so that it gives 

 its maximum power just as the bucket begins to close. The bucket 

 is well braced, and the shaft is extended on either side to receive 



