134 A TREATISE ON DREDGES AND DREDGING 



pump for the hydraulic dredging. These two different systems of 

 dredging are entirely independent of one another. The ladder 

 dredge is used in the excavation of soils of great resistance, u -hi li- 

 the hydraulic dredge is used for sands or other finely divided soils. 

 The independence of the two sets of machinery is such that without 

 dismounting any part, a change can be made instantly from one 

 to the other and vice versa. 



The dimensions of the dredge are as follows : 



Length 131 . 20 ft. 



Width 31.5 " 



Depth 10.5 " 



The hull is built entirely of steel according to the specifications 

 of Bureau Veritas. The hull is open in front to allow the dredge 

 to cut its own way with the ladder clear out of water. It is 

 divided into six compartments by means of watertight bulkheads. 

 The first and second compartments are located forward and are 

 used for chains and storage. The third at the starboard contains 

 the quarters for the crew, the tower and a store; the fourth at the 

 port side contains the messroom for the officers, and their sleeping 

 quarters, while on deck a large room provided with all the possible 

 conveniences is reserved for the engineers. In the fifth compartment 

 there are located all the boilers and engines and the centrifugal 

 pump for the hydraulic dredging. 



The engine is a compound surface-condensing and reversible 

 of the Gliick system; it is provided with a friction clutch to regulate 

 the speed of the bucket chain according to the resistance of the 

 soils encountered in dredging. 



When hard rocks or other obstacles are encountered, the breaking 

 of any part of the dredging machinery is avoided by means of a 

 brake acting automatically, thus arresting the travel of the bucket 

 chain. 



A starting gear driven by a special motor permits the engines to be 

 turned at slow speed so as to facilitate the mounting or dismounting 

 of the bucket chain. In the same compartment with the engines 

 there is a well-equipped repairing shop. 



There are two marine boilers of an improved type. The fire- 

 boxes are both extensible and movable. The heating surface of the 

 two boilers together is 1721.6 sq.ft. The grates are of a special 

 system which permit the use of any fuel under the most favorable 



