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A TREATISE ON DREDGES AND DREDGING 



four spuds. These are heavy square beams which are sunk into 

 the ground so as to firmly support the float in the same manner 

 as the legs of a table. Spuds have been used for many years, as 

 evidenced by the machine described by Mr. Hachette, employed 

 at Venice, which is really the prototype of the dipper dredge. 



Spuds may be either vertical or inclined; in the latter case they 

 rest on the banks of the canal to be excavated by the dredge, and 

 are called bank spuds. They are used only on dredges of small 

 capacity when employed in the excavation of small and shallow 

 canals. (Fig. 44.) Vertical spuds are very important on dredges 



/ 



Elevation. 



FIG. 43. Plan and Elevation of Steel Trusses Reinforcing the Hull of the Dm lire 



"Chicago." 



of large capacity and then they are operated by special engines. 

 As a rule dredges are provided with three spuds two of them 

 located at the bow either side of the frame supporting the boom, 

 and these are of larger dimensions than the spuds at the stern. 

 Thus for instance the dredge " Chicago " was provided with three 

 spuds, each of the two forward ones being composed of a single 

 stick of Oregon fir 40X40 in., 55 ft. long. The stern spud was 

 of white oak 24X22 in., 55 ft. long. To facilitate the penetration 

 of the spuds into the ground their lower end is provided with heavy 

 castings. The raising and lowering of the spuds is done by means 

 of steel wire ropes passing over sheaves and controlled by special 



